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Posts Tagged ‘cardiopulmonary bypass’


Call for the abandonment of the Off-pump CABG surgery (OPCAB) in the On-pump / Off-pump Debate, +100 Research Studies

Curator: Aviva Lev-Ari, PhD, RN

The curator shadowed Dr. J. Walker @MGH performing On-pump CABG in 1/2005 and On-pump CABG performed @Texas Heart Institute in 2/2005, and attended demos of ECMO at Vanderbilt Medical Center, Department of Surgery, Perfusion Program, 8/2005.

 

Public release date: 22-Jul-2013

Contact: Gina Orlando
gina.orlando@bmc.org
617-638-8490
Boston University Medical Center

BMC surgeon recommends off-pump coronary artery bypass grafting be abandoned

(Boston) – In a Special Report in the current issue of Circulation, Boston Medical Center cardiothoracic surgeon Harold Lazar, MD, has found that off-pump coronary artery bypass graft (OPCAB) surgery has failed to show any significant improvement in short-term morbidity or mortality as compared to the traditional on-pump coronary artery bypass graft (CABG) surgery. He recommends that the technique be abandoned, unless surgeons who perform off-pump surgery can show that their own results are as good as results reported with the traditional on-pump surgery.

During off-pump coronary artery bypass graft surgery, the heart is still beating while the graft attachments are made to bypass a blockage. While performing on-pump CABG surgery, the heart is stopped and a heart-lung machine takes over the work for the heart and lungs. This method has been an effective, safe and time-proven technique and is considered the gold standard with which all other surgical revascularization methods have been compared. However, performing coronary revascularization this way can result in myocardial ischemic injury, neurocognitive deficits, and strokes and activate inflammatory pathways that contribute to pulmonary, renal and hematologic complications.

In order to accurately compare the advantages and disadvantages of OPCAB and to determine what, if any, role it should have in the practice of surgical coronary artery revascularization, Lazar examined clinical data from numerous studies worldwide and found the OPCAB technique had failed to show any significant improvement in short-term morbidity or mortality.

According to Lazar a major impetus for performing OPCAB was to avoid the possible detrimental effects of cardiopulmonary bypass, which include activation of inflammatory pathways, changes in neurological and cognitive function and alterations in quality of life. “However, patients undergoing OPCAB have not shown any benefits in these areas,” said Lazar, a professor of surgery at Boston University School Medicine. “Even in those studies in which OPCAB has resulted in a small improvement in early postoperative outcomes, these improvements are no longer apparent on long-term follow-up,” he added.

In fact, several studies suggest that long-term survival may be significantly reduced in OPCAB patients compared with patients in whom on-pump techniques were used. Lazar explains that this may be attributable to the significant increase in incomplete revascularization seen in OPCAB patients and may be responsible for the increase in recurrent angina and need for revascularization procedures seen in OPCAB patients.

“Unless individual surgeons can demonstrate that they can achieve short- and long-term outcomes with OPCABG that are comparable to on-pump CABG results, they should abandon this technique,” said Lazar.

 

The debate over abandoning off-pump CABG surgery

JULY 29, 2013 

Boston, MA Off-pump coronary artery bypass graft (OPCAB) surgery is not as durable or as effective as coronary surgery performed with cardiopulmonary bypass (CPB) and should be abandoned in favor of conventional CABG surgery, according to one expert.

In the July 23, 2013 issue of CirculationDr Harold Lazar (Boston Medical Center, MA) argues that the primary focus of surgical coronary revascularization is complete revascularization and a technically perfect anastomosis that uses the best conduits with a minimal amount of hemodynamic instability. He adds that the procedure should be able to be performed “under all circumstances, on all patients, at all institutions, regardless of their cardiac volume.

“We must not forget that patients are sent for surgical revascularization because medical management has failed, their cardiologists believe that stents will not result in complete revascularization, and the goal is for optimal long-term survival and enhanced freedom from recurrent angina and the need for [repeat] revascularization,” writes Lazar. “These goals can be best achieved with on-pump CABG surgery.”

Dr Robbin Cohen (University of Southern California, LA), on the other hand, said that many physicians are routine off-pump CABG surgeons and the data suggest that results achieved by experienced operators are excellent. It is also a cheaper operation in experienced hands. He does not believe that OPCAB should be abandoned but acknowledged there is a need to better identify the ideal patient who would benefit from the procedure.

While there is yet no consensus and no studies have identified subgroups with better results, the ideal OPCAB candidate is one with a severely diseased descending aorta and those with single-vessel or two-vessel disease—in other words, a patient with favorable anatomy that doesn’t require moving the heart around too much, he said.

“I don’t doubt that I have treated some patients with off-pump surgery where if I had put them on the pump I would have killed them,” Cohen told heartwire.

Looking at the big picture

In his perspective, Lazar analyzes previously published retrospective studies and prospective, randomized controlled clinical trials, including the Randomized On/Off Bypass (ROOBY), Smart Management of Arterial Revascularization Therapy (SMART), and Coronary Artery Bypass Surgery Off- or On-Pump Revascularization (CORONARY) studies.

In ROOBY, the primary short-term end point of death and major cardiovascular events at 30 days was similar in the on-pump and off-pump treatment arms, while cardiac-related mortality and major adverse events were higher in the OPCAB arm at one year. The SMART trial also failed to show a mortality benefit with OPCAB. The CORONARY investigators reported no difference in the composite of death, nonfatal cerebrovascular accidents, nonfatal MIs, or new renal failure requiring dialysis between OPCAB and on-pump CABG surgery. In CORONARY, there was also no difference in quality-of-life scores and neurocognitive function at one year.

Importantly, Lazar says the data from published meta-analyses show that OPCAB patients tend to receive fewer grafts and have a higher incidence of incomplete revascularization. “Despite advances in stabilizers and other equipment, it may be difficult to graft inferior and posterolateral vessels because of right and left ventricular distension and hemodynamic changes,” he writes.

Abandoned? Not so fast, says another expert

So, will OPCAB be abandoned? Not likely, says Cohen. OPCAB is performed often in other countries, mainly because the procedure is quicker and has lower costs than conventional CABG surgery. Cohen had high praise for the systematic review by Lazar, however, noting that the OPCAB vs on-pump CABG debate is a complicated topic and nearly each month brings a new review, journal article, or other analysis in the medical journals.

“Early on, most of us assumed that the morbidity associated with cardiac surgery, that being stroke, renal failure, and so on, was the result of cardiopulmonary bypass,” said Cohen. “And when we started doing off-pump procedures, we assumed that the morbidity would be eliminated. That wasn’t the case. Some of the early studies showed an advantage with blood use and sometimes with the utilization of resources, but morbidity and mortality with the two surgeries were the same.”

Cohen addressed the criticism that OPCAB provides incomplete revascularization compared with on-pump CABG and that the anastomoses are not as good, saying these are all valid criticisms of the procedure. He agreed with Lazar’s point that if surgeons must cross over from OPCAB to conventional bypass, the outcomes are poor. To date, however, OPCAB “has been a moving target,” he added, noting that there has been a move toward addressing these shortcomings.

At one point, Cohen said his group was performing up to 90% of cardiac surgeries with OPCAB but now do just 10% of procedures off-pump. The reasons for decline in use include all of the previously cited reasons:

  • incomplete revascularization,
  • poorer anastomoses, and
  • no reduction in morbidity and mortality to show it is better than conventional CABG, as well the fact that
  • it is difficult to teach to residents.

For OPCAB to move forward, he said that research needs to provide evidence that the procedure is as least as effective and as durable as on-pump CABG. There is also a need to identify specific patient subgroups that would benefit from OPCAB, such as

  • older patients, those with
  • existing renal failure, or
  • patients who have previously had a stroke.
Source

  1. Lazar HL. Should off-pump coronary artery bypass grafting be abandoned? Circulation 2013; 128:406-413. 

 

Related links

Lazar and Cohen report no conflicts of interest. 

http://www.theheart.org/article/1564393.do?utm_medium=email&utm_source=20130731_heartwire&utm_campaign=newsletter

REVIEWS in

http://www.ncbi.nlm.nih.gov/pubmed?linkname=pubmed_pubmed_reviews&from_uid=23877063

Should off-pump coronary artery bypass grafting be abandoned?

Lazar HL.

Circulation. 2013 Jul 23;128(4):406-13. doi: 10.1161/CIRCULATIONAHA.113.003388. No abstract available.

PMID: 23877063 [PubMed – in process]

Related citations

 

Off-pump coronary artery bypass grafting: simple concept but potentially sublime scientific value.

Ngaage DL.

Med Sci Monit. 2004 Mar;10(3):RA47-54. Epub 2004 Mar 1. Review.

PMID: 14976442 [PubMed – indexed for MEDLINE]

Related citations

 

Coronary artery surgery: conventional coronary artery bypass grafting versus off-pump coronary artery bypass grafting.

Salzberg SP, Adams DH, Filsoufi F.

Curr Opin Cardiol. 2005 Nov;20(6):509-16. Review.

PMID: 16234622 [PubMed – indexed for MEDLINE]

Related citations

 

Outcomes of off-pump coronary artery bypass surgery: current best available evidence.

Raja SG, Berg GA.

Indian Heart J. 2007 Jan-Feb;59(1):15-27. Review.

PMID: 19098331 [PubMed – indexed for MEDLINE]

Related citations

 

Off-pump coronary artery bypass grafting through sternotomy: for whom?

Noora J, Puskas JD.

Curr Opin Cardiol. 2006 Nov;21(6):573-7. Review.

PMID: 17053406 [PubMed – indexed for MEDLINE]

Related citations

 

Reoperative off-pump coronary artery bypass grafting: current outcomes, concerns and controversies.

Raja SG, Amrani M.

Expert Rev Cardiovasc Ther. 2010 May;8(5):685-94. doi: 10.1586/erc.10.14. Review.

PMID: 20450302 [PubMed – indexed for MEDLINE]

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Off-pump versus on-pump coronary artery bypass grafting.

Halkos ME, Puskas JD.

Surg Clin North Am. 2009 Aug;89(4):913-22, ix. doi: 10.1016/j.suc.2009.06.015. Review.

PMID: 19782844 [PubMed – indexed for MEDLINE]

 

Select item 228458138.

Myocardial revascularization for the elderly: current options, role of off-pump coronary artery bypass grafting and outcomes.

Raja SG.

Curr Cardiol Rev. 2012 Feb;8(1):26-36. Review.

PMID: 22845813 [PubMed – indexed for MEDLINE]  Free PMC Article

Related citations

 

Current status of off-pump coronary artery bypass surgery.

Raja SG, Dreyfus GD.

Asian Cardiovasc Thorac Ann. 2008 Apr;16(2):164-78. Review.

PMID: 18381881 [PubMed – indexed for MEDLINE]

Related citations

 

Off-pump versus on-pump coronary artery bypass grafting for ischaemic heart disease.

Møller CH, Penninga L, Wetterslev J, Steinbrüchel DA, Gluud C.

Cochrane Database Syst Rev. 2012 Mar 14;3:CD007224. doi: 10.1002/14651858.CD007224.pub2. Review.

PMID: 22419321 [PubMed – indexed for MEDLINE]

Related citations

REFERENCES in 

http://www.ncbi.nlm.nih.gov/pubmed

1.

Should off-pump coronary artery bypass grafting be abandoned?

Lazar HL.

Circulation. 2013 Jul 23;128(4):406-13. doi: 10.1161/CIRCULATIONAHA.113.003388. No abstract available.

PMID: 23877063 [PubMed – in process]

Related citations

Select item 14762348

 

2.

Propensity case-matched analysis of off-pump coronary artery bypass grafting in patients with atheromatous aortic disease.

Sharony R, Grossi EA, Saunders PC, Galloway AC, Applebaum R, Ribakove GH, Culliford AT, Kanchuger M, Kronzon I, Colvin SB.

J Thorac Cardiovasc Surg. 2004 Feb;127(2):406-13.

PMID: 14762348 [PubMed – indexed for MEDLINE]

Related citations

Select item 14752427

 

3.

Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease.

Mack MJ, Pfister A, Bachand D, Emery R, Magee MJ, Connolly M, Subramanian V.

J Thorac Cardiovasc Surg. 2004 Jan;127(1):167-73.

PMID: 14752427 [PubMed – indexed for MEDLINE]

Related citations

Select item 12324731

 

4.

Intrapulmonary shunt after cardiopulmonary bypass: the use of vital capacity maneuvers versus off-pump coronary artery bypass grafting.

Tschernko EM, Bambazek A, Wisser W, Partik B, Jantsch U, Kubin K, Ehrlich M, Klimscha W, Grimm M, Keznickl FP.

J Thorac Cardiovasc Surg. 2002 Oct;124(4):732-8.

PMID: 12324731 [PubMed – indexed for MEDLINE]

Related citations

Select item 14976442

 

5.

Off-pump coronary artery bypass grafting: simple concept but potentially sublime scientific value.

Ngaage DL.

Med Sci Monit. 2004 Mar;10(3):RA47-54. Epub 2004 Mar 1. Review.

PMID: 14976442 [PubMed – indexed for MEDLINE]

Related citations

Select item 18455592

 

6.

Myocardial injury in coronary artery bypass grafting: on-pump versus off-pump comparison by measuring high-sensitivity C-reactive protein, cardiac troponin I, heart-type fatty acid-binding protein, creatine kinase-MB, and myoglobin release.

Chowdhury UK, Malik V, Yadav R, Seth S, Ramakrishnan L, Kalaivani M, Reddy SM, Subramaniam GK, Govindappa R, Kakani M.

J Thorac Cardiovasc Surg. 2008 May;135(5):1110-9, 1119.e1-10. doi: 10.1016/j.jtcvs.2007.12.029.

PMID: 18455592 [PubMed – indexed for MEDLINE]

Related citations

Select item 19185140

 

7.

Effects of on- and off-pump coronary artery surgery on graft patency, survival, and health-related quality of life: long-term follow-up of 2 randomized controlled trials.

Angelini GD, Culliford L, Smith DK, Hamilton MC, Murphy GJ, Ascione R, Baumbach A, Reeves BC.

J Thorac Cardiovasc Surg. 2009 Feb;137(2):295-303. doi: 10.1016/j.jtcvs.2008.09.046.

PMID: 19185140 [PubMed – indexed for MEDLINE] Free PMC Article

Related citations

Select item 12086378

 

8.

Beating heart versus conventional reoperative coronary artery bypass surgery.

Mishra Y, Wasir H, Kohli V, Meharwal ZS, Bapna R, Mehta Y, Trehan N.

Indian Heart J. 2002 Mar-Apr;54(2):159-63.

PMID: 12086378 [PubMed – indexed for MEDLINE]

Related citations

Select item 22436550

 

9.

Evolution of Off-Pump Coronary Artery Bypass Grafting over 15 Years: A Single-Institution Experience of 14,030 Cases.

Mishra YK, Mishra M, Malhotra R, Meharwal ZS, Kohli V, Trehan N.

Innovations (Phila). 2005 Winter;1(2):88-91. doi: 10.1097/01.imi.0000189937.33748.19.

PMID: 22436550 [PubMed]

Related citations

Select item 16863772

 

10.

Propensity case-matched analysis of off-pump versus on-pump coronary artery bypass grafting in patients with atheromatous aorta.

Mishra M, Malhotra R, Karlekar A, Mishra Y, Trehan N.

Ann Thorac Surg. 2006 Aug;82(2):608-14.

PMID: 16863772 [PubMed – indexed for MEDLINE]

Related citations

Select item 18249555

 

11.

Late dialysis rate for coronary artery bypass grafting patients with moderate-to-severe renal impairment: comparison between off-pump and conventional method.

Yu HY, Li JY, Sun S, Hung KY, Wang JL, Chen YS, Wang SS, Lin FY.

Eur J Cardiothorac Surg. 2008 Mar;33(3):364-9. doi: 10.1016/j.ejcts.2007.12.027. Epub 2008 Feb 4.

PMID: 18249555 [PubMed – indexed for MEDLINE]

Related citations

Select item 11565659

 

12.

Off-pump bypass grafting is safe in patients with left main coronary disease.

Dewey TM, Magee MJ, Edgerton JR, Mathison M, Tennison D, Mack MJ.

Ann Thorac Surg. 2001 Sep;72(3):788-91; discussion 792.

PMID: 11565659 [PubMed – indexed for MEDLINE]

Related citations

Select item 15276508

 

13.

A prospective randomized study to evaluate stress response during beating-heart and conventional coronary revascularization.

Velissaris T, Tang AT, Murray M, Mehta RL, Wood PJ, Hett DA, Ohri SK.

Ann Thorac Surg. 2004 Aug;78(2):506-12; discussion 506-12.

PMID: 15276508 [PubMed – indexed for MEDLINE]

Related citations

Select item 12698142

 

14.

Off-pump coronary artery bypass grafting provides complete revascularization with reduced myocardial injury, transfusion requirements, and length of stay: a prospective randomized comparison of two hundred unselected patients undergoing off-pump versus conventional coronary artery bypass grafting.

Puskas JD, Williams WH, Duke PG, Staples JR, Glas KE, Marshall JJ, Leimbach M, Huber P, Garas S, Sammons BH, McCall SA, Petersen RJ, Bailey DE, Chu H, Mahoney EM, Weintraub WS, Guyton RA.

J Thorac Cardiovasc Surg. 2003 Apr;125(4):797-808.

PMID: 12698142 [PubMed – indexed for MEDLINE]

Related citations

Select item 16733171

 

15.

Relationship between atrial histopathology and atrial fibrillation after coronary bypass surgery.

Mariscalco G, Engström KG, Ferrarese S, Cozzi G, Bruno VD, Sessa F, Sala A.

J Thorac Cardiovasc Surg. 2006 Jun;131(6):1364-72.

PMID: 16733171 [PubMed – indexed for MEDLINE]

Related citations

Select item 14666033

 

16.

Combined use of off-pump techniques and a sutureless proximal aortic anastomotic device reduces cerebral microemboli generation during coronary artery bypass grafting.

Scarborough JE, White W, Derilus FE, Mathew JP, Newman MF, Landolfo KP; Neurological Outcome Research Group.

J Thorac Cardiovasc Surg. 2003 Nov;126(5):1561-7.

PMID: 14666033 [PubMed – indexed for MEDLINE]

Related citations

Select item 16305860

 

17.

Renal dysfunction in high-risk patients after on-pump and off-pump coronary artery bypass surgery: a propensity score analysis.

Chukwuemeka A, Weisel A, Maganti M, Nette AF, Wijeysundera DN, Beattie WS, Borger MA.

Ann Thorac Surg. 2005 Dec;80(6):2148-53.

PMID: 16305860 [PubMed – indexed for MEDLINE]

Related citations

Select item 21051050

 

18.

Is off-pump coronary artery bypass grafting superior to conventional bypass in octogenarians?

LaPar DJ, Bhamidipati CM, Reece TB, Cleveland JC, Kron IL, Ailawadi G.

J Thorac Cardiovasc Surg. 2011 Jan;141(1):81-90. doi: 10.1016/j.jtcvs.2010.09.012. Epub 2010 Nov 4.

PMID: 21051050 [PubMed – indexed for MEDLINE] Free PMC Article

Related citations

Select item 17258568

 

19.

Coronary artery bypass grafting with or without cardiopulmonary bypass in patients with preoperative non-dialysis dependent renal insufficiency: a randomized study.

Sajja LR, Mannam G, Chakravarthi RM, Sompalli S, Naidu SK, Somaraju B, Penumatsa RR.

J Thorac Cardiovasc Surg. 2007 Feb;133(2):378-88. Epub 2007 Jan 16.

PMID: 17258568 [PubMed – indexed for MEDLINE]

Related citations

Select item 14752428

 

20.

Coronary artery bypass grafting: are risk models developed from on-pump surgery valid for off-pump surgery?

Wu Y, Grunkemeier GL, Handy JR Jr.

J Thorac Cardiovasc Surg. 2004 Jan;127(1):174-8.

PMID: 14752428 [PubMed – indexed for MEDLINE]

Related citations

Select item 21529848

 

21.

On-pump versus off-pump surgical revascularization in patients with acute coronary syndromes: analysis from the Acute Catheterization and Urgent Intervention Triage Strategy trial.

Ben-Gal Y, Stone GW, Smith CR, Williams MR, Weisz G, Stewart AS, Takayama H, Genereux P, Argenziano M.

J Thorac Cardiovasc Surg. 2011 Aug;142(2):e33-9. doi: 10.1016/j.jtcvs.2011.03.022. Epub 2011 Apr 29.

PMID: 21529848 [PubMed – indexed for MEDLINE]

Related citations

Select item 16482929

 

22.

Physiological comparison of off-pump and on-pump coronary artery bypass grafting in patients on chronic hemodialysis.

Manabe S, Arai H, Tanaka H, Tabuchi N, Sunamori M.

Jpn J Thorac Cardiovasc Surg. 2006 Jan;54(1):3-10.

PMID: 16482929 [PubMed – indexed for MEDLINE]

Related citations

Select item 16234622

 

23.

Coronary artery surgery: conventional coronary artery bypass grafting versus off-pump coronary artery bypass grafting.

Salzberg SP, Adams DH, Filsoufi F.

Curr Opin Cardiol. 2005 Nov;20(6):509-16. Review.

PMID: 16234622 [PubMed – indexed for MEDLINE]

Related citations

Select item 15063246

 

24.

On-pump versus off-pump coronary artery bypass grafting: impact on postoperative renal failure requiring renal replacement therapy.

Bucerius J, Gummert JF, Walther T, Schmitt DV, Doll N, Falk V, Mohr FW.

Ann Thorac Surg. 2004 Apr;77(4):1250-6.

PMID: 15063246 [PubMed – indexed for MEDLINE]

Related citations

Select item 19098331

 

25.

Outcomes of off-pump coronary artery bypass surgery: current best available evidence.

Raja SG, Berg GA.

Indian Heart J. 2007 Jan-Feb;59(1):15-27. Review.

PMID: 19098331 [PubMed – indexed for MEDLINE]

Related citations

Select item 23084105

 

26.

Off-pump coronary artery bypass grafting attenuates morbidity and mortality for patients with low and high body mass index.

Keeling WB, Kilgo PD, Puskas JD, Halkos ME, Lattouf OM, Guyton RA, Thourani VH.

J Thorac Cardiovasc Surg. 2012 Oct 16. doi:pii: S0022-5223(12)01147-6. 10.1016/j.jtcvs.2012.09.035. [Epub ahead of print]

PMID: 23084105 [PubMed – as supplied by publisher]

Related citations

Select item 16305858

 

27.

Perioperative patency of coronary artery bypass grafting is not influenced by off-pump technique.

Onorati F, Olivito S, Mastroroberto P, di Virgilio A, Esposito A, Perrotti A, Renzulli A.

Ann Thorac Surg. 2005 Dec;80(6):2132-40.

PMID: 16305858 [PubMed – indexed for MEDLINE]

Related citations

Select item 22002967

 

28.

Comparison of the effects of pulsatile cardiopulmonary bypass, non-pulsatile cardiopulmonary bypass and off-pump coronary artery bypass grafting on the inflammatory response and S-100beta protein.

Bayram H, Erer D, Iriz E, Zor MH, Gulbahar O, Ozdogan ME.

Perfusion. 2012 Jan;27(1):56-64. doi: 10.1177/0267659111424639. Epub 2011 Oct 14.

PMID: 22002967 [PubMed – indexed for MEDLINE]

Related citations

Select item 20447041

 

29.

Beating-heart coronary artery bypass grafting with miniaturized cardiopulmonary bypass results in a more complete revascularization when compared to off-pump grafting.

Reber D, Brouwer R, Buchwald D, Fritz M, Germing A, Lindstaedt M, Klak K, Laczkovics A.

Artif Organs. 2010 Mar;34(3):179-84. doi: 10.1111/j.1525-1594.2009.00836.x.

PMID: 20447041 [PubMed – indexed for MEDLINE]

Related citations

Select item 16740529

 

30.

Effect of off-pump coronary artery bypass surgery on clinical, angiographic, neurocognitive, and quality of life outcomes: randomised controlled trial.

Al-Ruzzeh S, George S, Bustami M, Wray J, Ilsley C, Athanasiou T, Amrani M.

BMJ. 2006 Jun 10;332(7554):1365. Epub 2006 Jun 1.

PMID: 16740529 [PubMed – indexed for MEDLINE] Free PMC Article

Related citations

Select item 12902131

 

31.

Off-pump long onlay bypass grafting using left internal mammary artery for diffusely diseased coronary artery.

Takanashi S, Fukui T, Hosoda Y, Shimizu Y.

Ann Thorac Surg. 2003 Aug;76(2):635-7.

PMID: 12902131 [PubMed – indexed for MEDLINE]

Related citations

Select item 12698147

 

32.

Endotoxemia in coronary artery bypass surgery: a comparison of the off-pump technique and conventional cardiopulmonary bypass.

Aydin NB, Gercekoglu H, Aksu B, Ozkul V, Sener T, Kiygil I, Turkoglu T, Cimen S, Babacan F, Demirtas M.

J Thorac Cardiovasc Surg. 2003 Apr;125(4):843-8.

PMID: 12698147 [PubMed – indexed for MEDLINE]

Related citations

Select item 11544625

 

33.

Progression to 100% off-pump coronary artery bypass with the Octopus 1 dual holder.

Roy A, Stanbridge RL, O’Regan D, Salerno G, Saldanha C, Griselli M, Cherian A.

Heart Surg Forum. 2001;4(2):174-8.

PMID: 11544625 [PubMed – indexed for MEDLINE]

Related citations

Select item 20083683

 

34.

No major differences in 30-day outcomes in high-risk patients randomized to off-pump versus on-pump coronary bypass surgery: the best bypass surgery trial.

Møller CH, Perko MJ, Lund JT, Andersen LW, Kelbaek H, Madsen JK, Winkel P, Gluud C, Steinbrüchel DA.

Circulation. 2010 Feb 2;121(4):498-504. doi: 10.1161/CIRCULATIONAHA.109.880443. Epub 2010 Jan 18.

PMID: 20083683 [PubMed – indexed for MEDLINE] Free Article

Related citations

Select item 22036259

 

35.

Off-pump coronary artery bypass grafting does not preserve renal function better than on-pump coronary artery bypass grafting: results of a case-matched study.

Elmistekawy E, Chan V, Bourke ME, Dupuis JY, Rubens FD, Mesana TG, Ruel M.

J Thorac Cardiovasc Surg. 2012 Jan;143(1):85-92. doi: 10.1016/j.jtcvs.2011.09.035. Epub 2011 Oct 27.

PMID: 22036259 [PubMed – indexed for MEDLINE]

Related citations

Select item 15173734

 

36.

Solid and gaseous cerebral microembolization during off-pump, on-pump, and open cardiac surgery procedures.

Abu-Omar Y, Balacumaraswami L, Pigott DW, Matthews PM, Taggart DP.

J Thorac Cardiovasc Surg. 2004 Jun;127(6):1759-65.

PMID: 15173734 [PubMed – indexed for MEDLINE]

Related citations

Select item 15172262

 

37.

Skeletonization of gastroepiploic artery graft in off-pump coronary artery bypass grafting: early clinical and angiographic assessment.

Kamiya H, Watanabe G, Takemura H, Tomita S, Nagamine H, Kanamori T.

Ann Thorac Surg. 2004 Jun;77(6):2046-50.

PMID: 15172262 [PubMed – indexed for MEDLINE]

Related citations

Select item 15561032

 

38.

Off-pump coronary artery bypass grafting in patients with renal dysfunction.

Tabata M, Takanashi S, Fukui T, Horai T, Uchimuro T, Kitabayashi K, Hosoda Y.

Ann Thorac Surg. 2004 Dec;78(6):2044-9.

PMID: 15561032 [PubMed – indexed for MEDLINE]

Related citations

Select item 16142517

 

39.

Diabetes in patients undergoing coronary artery bypass grafting. Impact on perioperative outcome.

Bucerius J, Gummert JF, Walther T, Doll N, Barten MJ, Falk V, Mohr FW.

Z Kardiol. 2005 Sep;94(9):575-82.

PMID: 16142517 [PubMed – indexed for MEDLINE]

Related citations

Select item 17053406

 

40.

Off-pump coronary artery bypass grafting through sternotomy: for whom?

Noora J, Puskas JD.

Curr Opin Cardiol. 2006 Nov;21(6):573-7. Review.

PMID: 17053406 [PubMed – indexed for MEDLINE]

Related citations

Select item 17384571

 

41.

A propensity score analysis on the effect of eliminating cardiopulmonary bypass for coronary artery bypass grafting.

Crescenzi G, Landoni G, Romano A, Boroli F, Giardina G, Bignami E, Fochi O, Aletti G, Rosica C, Zangrillo A.

Minerva Anestesiol. 2007 Mar;73(3):135-41.

PMID: 17384571 [PubMed – indexed for MEDLINE] Free Article

Related citations

Select item 17014446

 

42.

A single-blinded case controlled study on effects of cardiopulmonary circulation on hearing during coronary artery bypass grafting.

Donne AJ, Waterman P, Crawford L, Balaji HP, Nigam A.

Clin Otolaryngol. 2006 Oct;31(5):381-5.

PMID: 17014446 [PubMed – indexed for MEDLINE]

Related citations

Select item 20450302

 

43.

Reoperative off-pump coronary artery bypass grafting: current outcomes, concerns and controversies.

Raja SG, Amrani M.

Expert Rev Cardiovasc Ther. 2010 May;8(5):685-94. doi: 10.1586/erc.10.14. Review.

PMID: 20450302 [PubMed – indexed for MEDLINE]

Related citations

Select item 16399291

 

44.

Clinical outcomes of nonelective coronary revascularization with and without cardiopulmonary bypass.

Stamou SC, Hill PC, Haile E, Prince S, Mack MJ, Corso PJ.

J Thorac Cardiovasc Surg. 2006 Jan;131(1):28-33.

PMID: 16399291 [PubMed – indexed for MEDLINE]

Related citations

Select item 21281950

 

45.

Neurologic complications after off-pump coronary artery bypass grafting with and without aortic manipulation: meta-analysis of 11,398 cases from 8 studies.

Misfeld M, Brereton RJ, Sweetman EA, Doig GS.

J Thorac Cardiovasc Surg. 2011 Aug;142(2):e11-7. doi: 10.1016/j.jtcvs.2010.11.034. Epub 2011 Feb 1.

PMID: 21281950 [PubMed – indexed for MEDLINE]

Related citations

Select item 18805269

 

46.

Early and long-term outcomes in the elderly: comparison between off-pump and on-pump techniques in 1191 patients undergoing coronary artery bypass grafting.

Li Y, Zheng Z, Hu S.

J Thorac Cardiovasc Surg. 2008 Sep;136(3):657-64. doi: 10.1016/j.jtcvs.2007.12.069. Epub 2008 Jul 26.

PMID: 18805269 [PubMed – indexed for MEDLINE]

Related citations

Select item 16307999

 

47.

The role of tissue factor and P-selectin in the procoagulant response that occurs in the first month after on-pump and off-pump coronary artery bypass grafting.

Parolari A, Mussoni L, Frigerio M, Naliato M, Alamanni F, Polvani GL, Agrifoglio M, Veglia F, Tremoli E, Biglioli P, Camera M.

J Thorac Cardiovasc Surg. 2005 Dec;130(6):1561-6.

PMID: 16307999 [PubMed – indexed for MEDLINE]

Related citations

Select item 16153906

 

48.

Effects of off-pump versus on-pump coronary artery bypass grafting on function and viability of circulating endothelial progenitor cells.

Ruel M, Suuronen EJ, Song J, Kapila V, Gunning D, Waghray G, Rubens FD, Mesana TG.

J Thorac Cardiovasc Surg. 2005 Sep;130(3):633-9.

PMID: 16153906 [PubMed – indexed for MEDLINE]

Related citations

Select item 22523305

 

49.

On-pump versus off-pump coronary artery bypass surgery in elderly patients: results from the Danish on-pump versus off-pump randomization study.

Houlind K, Kjeldsen BJ, Madsen SN, Rasmussen BS, Holme SJ, Nielsen PH, Mortensen PE; DOORS Study Group.

Circulation. 2012 May 22;125(20):2431-9. doi: 10.1161/CIRCULATIONAHA.111.052571. Epub 2012 Apr 20.

PMID: 22523305 [PubMed – indexed for MEDLINE] Free Article

Related citations

Select item 17588377

 

50.

Off-pump coronary artery bypass grafting with skeletonized bilateral internal thoracic arteries in insulin-dependent diabetics.

Kai M, Hanyu M, Soga Y, Nomoto T, Nakano J, Matsuo T, Umehara E, Kawato M, Okabayashi H.

Ann Thorac Surg. 2007 Jul;84(1):32-6.

PMID: 17588377 [PubMed – indexed for MEDLINE]

Related citations

Select item 17703615

 

51.

[Coronary artery bypass grafting in patients with dialysis-dependent renal failure].

Mizumoto T, Adachi K, Hatanaka K, Sakamoto R, Seko H, Nakanishi R, Kinoshita T, Fujii H.

Kyobu Geka. 2007 Aug;60(9):785-9; discussion 790-3. Japanese.

PMID: 17703615 [PubMed – indexed for MEDLINE]

Related citations

Select item 19379976

 

52.

Surgical volume and outcomes of off-pump coronary artery bypass graft surgery: Does it matter?

Konety SH, Rosenthal GE, Vaughan-Sarrazin MS.

J Thorac Cardiovasc Surg. 2009 May;137(5):1116-23.e1. doi: 10.1016/j.jtcvs.2008.12.038. Epub 2009 Mar 25.

PMID: 19379976 [PubMed – indexed for MEDLINE]

Related citations

Select item 19782844

 

53.

Off-pump versus on-pump coronary artery bypass grafting.

Halkos ME, Puskas JD.

Surg Clin North Am. 2009 Aug;89(4):913-22, ix. doi: 10.1016/j.suc.2009.06.015. Review.

PMID: 19782844 [PubMed – indexed for MEDLINE]

Related citations

Select item 15224025

 

54.

Effects of tranexamic acid on postoperative bleeding and related hematochemical variables in coronary surgery: Comparison between on-pump and off-pump techniques.

Casati V, Della Valle P, Benussi S, Franco A, Gerli C, Baili P, Alfieri O, D’Angelo A.

J Thorac Cardiovasc Surg. 2004 Jul;128(1):83-91.

PMID: 15224025 [PubMed – indexed for MEDLINE]

Related citations

Select item 10881825

 

55.

Stroke in octogenarians undergoing coronary artery surgery with and without cardiopulmonary bypass.

Ricci M, Karamanoukian HL, Abraham R, Von Fricken K, D’Ancona G, Choi S, Bergsland J, Salerno TA.

Ann Thorac Surg. 2000 May;69(5):1471-5.

PMID: 10881825 [PubMed – indexed for MEDLINE]

Related citations

Select item 23335652

 

56.

Haemostasis alterations in coronary artery bypass grafting: comparison between the off-pump technique and a closed coated cardiopulmonary bypass system.

Scrascia G, Rotunno C, Guida P, Conte M, Amorese L, Margari V, Schinosa Lde L, Paparella D.

Interact Cardiovasc Thorac Surg. 2013 May;16(5):636-42. doi: 10.1093/icvts/ivs525. Epub 2013 Jan 18.

PMID: 23335652 [PubMed – in process] Free Article

Related citations

Select item 22845813

 

57.

Myocardial revascularization for the elderly: current options, role of off-pump coronary artery bypass grafting and outcomes.

Raja SG.

Curr Cardiol Rev. 2012 Feb;8(1):26-36. Review.

PMID: 22845813 [PubMed – indexed for MEDLINE] Free PMC Article

Related citations

Select item 16286278

 

58.

Sternal wound complications in bilateral internal thoracic artery grafting: a comparison of the off-pump technique and conventional cardiopulmonary bypass.

Aydin NB, Sener T, Kehlibar IK, Turkoglu T, Karpuzoglu OE, Ozkul V, Gercekoglu H.

Heart Surg Forum. 2005;8(6):E456-61; discussion E461.

PMID: 16286278 [PubMed – indexed for MEDLINE]

Related citations

Select item 9768998

 

59.

Minimally invasive coronary artery bypass grafting: port-access approach versus off-pump techniques.

Reichenspurner H, Boehm DH, Welz A, Schmitz C, Wildhirt S, Schulze C, Meiser B, Schütz A, Reichart B.

Ann Thorac Surg. 1998 Sep;66(3):1036-40.

PMID: 9768998 [PubMed – indexed for MEDLINE]

Related citations

Select item 17888966

 

60.

Coronary artery bypass grafting with single cross-clamp results in fewer persistent neuropsychological deficits than multiple clamp or off-pump coronary artery bypass grafting.

Hammon JW, Stump DA, Butterworth JF, Moody DM, Rorie K, Deal DD, Kincaid EH, Oaks TE, Kon ND.

Ann Thorac Surg. 2007 Oct;84(4):1174-8; discussion 1178-9.

PMID: 17888966 [PubMed – indexed for MEDLINE]

Related citations

Select item 15236490

 

61.

Off-pump coronary artery bypass grafting versus on-pump coronary artery bypass grafting: which is better in patients with chronic obstructive pulmonary disease?

Zhu YB, Xu JP, Liu ZY, Yang DN, Li XD, Li HY.

J Zhejiang Univ Sci. 2004 Aug;5(8):1005-8.

PMID: 15236490 [PubMed – indexed for MEDLINE]

Related citations

Select item 9769005

 

62.

Off-pump multivessel coronary bypass via sternotomy is safe and effective.

Puskas JD, Wright CE, Ronson RS, Brown WM 3rd, Gott JP, Guyton RA.

Ann Thorac Surg. 1998 Sep;66(3):1068-72.

PMID: 9769005 [PubMed – indexed for MEDLINE]

Related citations

Select item 18329466

 

63.

Risk factors for wound infection after off-pump coronary artery bypass grafting: should bilateral internal thoracic arteries be harvested in patients with diabetes?

Nakano J, Okabayashi H, Hanyu M, Soga Y, Nomoto T, Arai Y, Matsuo T, Kai M, Kawatou M.

J Thorac Cardiovasc Surg. 2008 Mar;135(3):540-5. doi: 10.1016/j.jtcvs.2007.11.008.

PMID: 18329466 [PubMed – indexed for MEDLINE]

Related citations

Select item 18329463

 

64.

On-pump beating-heart coronary artery bypass grafting after acute myocardial infarction has lower mortality and morbidity.

Miyahara K, Matsuura A, Takemura H, Saito S, Sawaki S, Yoshioka T, Ito H.

J Thorac Cardiovasc Surg. 2008 Mar;135(3):521-6. doi: 10.1016/j.jtcvs.2007.10.006.

PMID: 18329463 [PubMed – indexed for MEDLINE]

Related citations

Select item 18329465

 

65.

The effects of on-pump and off-pump coronary artery bypass grafting on intraoperative graft flow in arterial and venous conduits defined by a flow/pressure ratio.

Balacumaraswami L, Abu-Omar Y, Selvanayagam J, Pigott D, Taggart DP.

J Thorac Cardiovasc Surg. 2008 Mar;135(3):533-9. doi: 10.1016/j.jtcvs.2007.10.027.

PMID: 18329465 [PubMed – indexed for MEDLINE]

Related citations

Select item 18381881

 

66.

Current status of off-pump coronary artery bypass surgery.

Raja SG, Dreyfus GD.

Asian Cardiovasc Thorac Ann. 2008 Apr;16(2):164-78. Review.

PMID: 18381881 [PubMed – indexed for MEDLINE]

Related citations

Select item 21421501

 

67.

[Circulating endothelial cell injury in on-pump and off-pump coronary-artery bypass grafting].

SONG TN, GAO BR, ZHAO QM.

Nan Fang Yi Ke Da Xue Xue Bao. 2011 Mar;31(3):535-8. Chinese.

PMID: 21421501 [PubMed – indexed for MEDLINE] Free Article

Related citations

Select item 17599498

 

68.

Comparison of early platelet activation in patients undergoing on-pump versus off-pump coronary artery bypass surgery.

Ballotta A, Saleh HZ, El Baghdady HW, Gomaa M, Belloli F, Kandil H, Balbaa Y, Bettini F, Bossone E, Menicanti L, Frigiola A, Bellucci C, Mehta RH.

J Thorac Cardiovasc Surg. 2007 Jul;134(1):132-8.

PMID: 17599498 [PubMed – indexed for MEDLINE]

Related citations

Select item 14752424

 

69.

Equivalent midterm outcomes after off-pump and on-pump coronary surgery.

Sabik JF, Blackstone EH, Lytle BW, Houghtaling PL, Gillinov AM, Cosgrove DM.

J Thorac Cardiovasc Surg. 2004 Jan;127(1):142-8.

PMID: 14752424 [PubMed – indexed for MEDLINE]

Related citations

Select item 23597624

 

70.

Outcomes of off-pump versus on-pump coronary artery bypass grafting: Impact of preoperative risk.

Polomsky M, He X, O’Brien SM, Puskas JD.

J Thorac Cardiovasc Surg. 2013 May;145(5):1193-8. doi: 10.1016/j.jtcvs.2013.02.002.

PMID: 23597624 [PubMed – indexed for MEDLINE]

Related citations

Select item 17670644

 

71.

Emergency conversion in off-pump coronary artery bypass grafting.

Tabata M, Takanashi S, Horai T, Fukui T, Hosoda Y.

Interact Cardiovasc Thorac Surg. 2006 Oct;5(5):555-9. Epub 2006 Jun 15.

PMID: 17670644 [PubMed] Free Article

Related citations

Select item 19379995

 

72.

A differential release of matrix metalloproteinases 9 and 2 during coronary artery bypass grafting and off-pump coronary artery bypass surgery.

Sokal A, Zembala M, Radomski A, Kocher A, Pacholewicz J, Los J, Jedrzejczyk E, Zembala M, Radomski M.

J Thorac Cardiovasc Surg. 2009 May;137(5):1218-24. doi: 10.1016/j.jtcvs.2008.11.004. Epub 2009 Feb 23.

PMID: 19379995 [PubMed – indexed for MEDLINE]

Related citations

Select item 18815649

 

73.

Autologous bone marrow cell transplantation combined with off-pump coronary artery bypass grafting in patients with ischemic cardiomyopathy.

Yoo KJ, Kim HO, Kwak YL, Kang SM, Jang YS, Lim SH, Hwang KC, Cho SW, Yang YS, Li RK, Kim BS.

Can J Surg. 2008 Aug;51(4):269-75.

PMID: 18815649 [PubMed – indexed for MEDLINE] Free PMC Article

Related citations

Select item 20971248

 

74.

Left main coronary artery disease does not affect the outcome of off-pump coronary artery bypass grafting.

Suzuki T, Asai T, Matsubayashi K, Kambara A, Hiramatsu N, Kinoshita T, Nishimura O.

Ann Thorac Surg. 2010 Nov;90(5):1501-6. doi: 10.1016/j.athoracsur.2010.06.023.

PMID: 20971248 [PubMed – indexed for MEDLINE]

Related citations

Select item 11565657

 

75.

Influence of diabetes on mortality and morbidity: off-pump coronary artery bypass grafting versus coronary artery bypass grafting with cardiopulmonary bypass.

Magee MJ, Dewey TM, Acuff T, Edgerton JR, Hebeler JF, Prince SL, Mack MJ.

Ann Thorac Surg. 2001 Sep;72(3):776-80; discussion 780-1.

PMID: 11565657 [PubMed – indexed for MEDLINE]

Related citations

Select item 11279409

 

76.

Reduced postoperative blood loss and transfusion requirement after beating-heart coronary operations: a prospective randomized study.

Ascione R, Williams S, Lloyd CT, Sundaramoorthi T, Pitsis AA, Angelini GD.

J Thorac Cardiovasc Surg. 2001 Apr;121(4):689-96.

PMID: 11279409 [PubMed – indexed for MEDLINE]

Related citations

Select item 12078783

 

77.

Evaluation of the effectiveness of off-pump coronary artery bypass grafting in high-risk patients: an observational study.

Chamberlain MH, Ascione R, Reeves BC, Angelini GD.

Ann Thorac Surg. 2002 Jun;73(6):1866-73.

PMID: 12078783 [PubMed – indexed for MEDLINE]

Related citations

Select item 11603449

 

78.

Off-pump coronary artery bypass grafting decreases risk-adjusted mortality and morbidity.

Cleveland JC Jr, Shroyer AL, Chen AY, Peterson E, Grover FL.

Ann Thorac Surg. 2001 Oct;72(4):1282-8; discussion 1288-9.

PMID: 11603449 [PubMed – indexed for MEDLINE]

Related citations

Select item 22419321

 

79.

Off-pump versus on-pump coronary artery bypass grafting for ischaemic heart disease.

Møller CH, Penninga L, Wetterslev J, Steinbrüchel DA, Gluud C.

Cochrane Database Syst Rev. 2012 Mar 14;3:CD007224. doi: 10.1002/14651858.CD007224.pub2. Review.

PMID: 22419321 [PubMed – indexed for MEDLINE]

Related citations

Select item 19559187

 

80.

In-hospital outcomes of off-pump multivessel total arterial and conventional coronary artery bypass grafting: single surgeon, single center experience.

Raja SG, Siddiqui H, Ilsley CD, Amrani M.

Ann Thorac Surg. 2009 Jul;88(1):47-52. doi: 10.1016/j.athoracsur.2009.04.013.

PMID: 19559187 [PubMed – indexed for MEDLINE]

Related citations

Select item 22197616

 

81.

Off-pump bilateral skeletonized internal thoracic artery grafting in elderly patients.

Kinoshita T, Asai T, Suzuki T, Kuroyanagi S, Hosoba S, Takashima N.

Ann Thorac Surg. 2012 Feb;93(2):531-6. doi: 10.1016/j.athoracsur.2011.09.077. Epub 2011 Dec 23.

PMID: 22197616 [PubMed – indexed for MEDLINE]

Related citations

Select item 12902081

 

82.

Is the use of cardiopulmonary bypass for multivessel coronary artery bypass surgery an independent predictor of operative mortality in patients with ischemic left ventricular dysfunction?

Al-Ruzzeh S, Athanasiou T, George S, Glenville BE, DeSouza AC, Pepper JR, Amrani M.

Ann Thorac Surg. 2003 Aug;76(2):444-51; discussion 451-2.

PMID: 12902081 [PubMed – indexed for MEDLINE]

Related citations

Select item 22154798

 

83.

On-pump versus off-pump coronary artery bypass surgery in high-risk patients: operative results of a prospective randomized trial (on-off study).

Lemma MG, Coscioni E, Tritto FP, Centofanti P, Fondacone C, Salica A, Rossi A, De Santo T, Di Benedetto G, Piazza L, Rinaldi M, Schinosa AL, De Paulis R, Contino M, Genoni M.

J Thorac Cardiovasc Surg. 2012 Mar;143(3):625-31. doi: 10.1016/j.jtcvs.2011.11.011. Epub 2011 Dec 10.

PMID: 22154798 [PubMed – indexed for MEDLINE]

Related citations

Select item 15854936

 

84.

Functional renal outcome in on-pump and off-pump coronary revascularization: a propensity-based analysis.

Weerasinghe A, Athanasiou T, Al-Ruzzeh S, Casula R, Tekkis PP, Amrani M, Punjabi P, Taylor K, Stanbridge R, Glenville B.

Ann Thorac Surg. 2005 May;79(5):1577-83.

PMID: 15854936 [PubMed – indexed for MEDLINE]

Related citations

Select item 16967324

 

85.

Does totally endoscopic access for off-pump cardiac surgery influence the incidence of postoperative atrial fibrillation in coronary artery bypass grafting? A preliminary report.

Scherer M, Sirat AS, Dogan S, Aybek T, Moritz A, Wimmer-Greinecker G.

Cardiovasc Eng. 2006 Sep;6(3):118-21.

PMID: 16967324 [PubMed – indexed for MEDLINE]

Related citations

Select item 18245699

 

86.

Off-pump coronary artery bypass grafting in left ventricular dysfunction.

Masoumi M, Saidi MR, Rostami F, Sepahi H, Roushani D.

Asian Cardiovasc Thorac Ann. 2008 Jan;16(1):16-20.

PMID: 18245699 [PubMed – indexed for MEDLINE]

Related citations

Select item 10536955

 

87.

Indication and patient selection in minimally invasive and òff-pump’ coronary artery bypass grafting.

Diegeler A, Matin M, Falk V, Binner C, Walther T, Autschbach R, Mohr FW.

Eur J Cardiothorac Surg. 1999 Sep;16 Suppl 1:S79-82.

PMID: 10536955 [PubMed – indexed for MEDLINE]

Related citations

Select item 15223396

 

88.

Trainees operating on high-risk patients without cardiopulmonary bypass: a high-risk strategy?

Ascione R, Reeves BC, Pano M, Angelini GD.

Ann Thorac Surg. 2004 Jul;78(1):26-33.

PMID: 15223396 [PubMed – indexed for MEDLINE]

Related citations

Select item 9262597

 

89.

Coronary artery bypass grafting “on pump”: role of three-day discharge.

Ott RA, Gutfinger DE, Miller MP, Selvan A, Codini MA, Alimadadian H, Tanner TM.

Ann Thorac Surg. 1997 Aug;64(2):478-81.

PMID: 9262597 [PubMed – indexed for MEDLINE]

Related citations

Select item 15784358

 

90.

Is cardiopulmonary bypass a reason for aspirin resistance after coronary artery bypass grafting?

Zimmermann N, Kurt M, Wenk A, Winter J, Gams E, Hohlfeld T.

Eur J Cardiothorac Surg. 2005 Apr;27(4):606-10. Epub 2005 Jan 19.

PMID: 15784358 [PubMed – indexed for MEDLINE]

Related citations

Select item 15063245

 

91.

Coronary surgery in patients with peripheral vascular disease: effect of avoiding cardiopulmonary bypass.

Karthik S, Musleh G, Grayson AD, Keenan DJ, Pullan DM, Dihmis WC, Hasan R, Fabri BM.

Ann Thorac Surg. 2004 Apr;77(4):1245-9.

PMID: 15063245 [PubMed – indexed for MEDLINE]

Related citations

Select item 12538138

 

92.

Off-pump coronary artery bypass surgery–initial experience in Gdansk: a brief review.

Keita L, Anisimowicz L.

Heart Surg Forum. 2002;5(3):240-2.

PMID: 12538138 [PubMed – indexed for MEDLINE]

Related citations

Select item 12202877

 

93.

Improved outcomes in coronary artery bypass grafting with beating-heart techniques.

Mack M, Bachand D, Acuff T, Edgerton J, Prince S, Dewey T, Magee M.

J Thorac Cardiovasc Surg. 2002 Sep;124(3):598-607.

PMID: 12202877 [PubMed – indexed for MEDLINE]

Related citations

Select item 16399302

 

94.

Single crossclamp improves 6-month cognitive outcome in high-risk coronary bypass patients: the effect of reduced aortic manipulation.

Hammon JW, Stump DA, Butterworth JF, Moody DM, Rorie K, Deal DD, Kincaid EH, Oaks TE, Kon ND.

J Thorac Cardiovasc Surg. 2006 Jan;131(1):114-21. Epub 2005 Dec 9.

PMID: 16399302 [PubMed – indexed for MEDLINE]

Related citations

Select item 14635411

 

95.

[Right heart support during coronary artery bypass grafting without cardiopulmonary bypass].

Fernández AL, Tamayo E, Echevarría JR, Hernando MJ, Cubero T, Agudado MJ, López G.

Rev Med Univ Navarra. 2003 Apr-Jun;47(2):14-7. Spanish.

PMID: 14635411 [PubMed – indexed for MEDLINE]

Related citations

Select item 22698600

 

96.

Ten-year outcome analysis of off-pump sequential grafting: single surgeon, single center experience.

Raja SG, Salhiyyah K, Navaratnarajah M, Rafiq MU, Felderhof J, Walker CP, Ilsley CD, Amrani M.

Heart Surg Forum. 2012 Jun;15(3):E136-42. doi: 10.1532/HSF98.20111087.

PMID: 22698600 [PubMed – indexed for MEDLINE]

Related citations

Select item 23430415

 

97.

Monitoring brain oxygen saturation during awake off-pump coronary artery bypass.

Toda A, Watanabe G, Matsumoto I, Tomita S, Yamaguchi S, Ohtake H.

Asian Cardiovasc Thorac Ann. 2013 Feb;21(1):14-21. doi: 10.1177/0218492312444908.

PMID: 23430415 [PubMed – in process]

Related citations

Select item 9671898

 

98.

Coronary artery bypass grafting without cardiopulmonary bypass using the octopus method: results in the first one hundred patients.

Jansen EW, Borst C, Lahpor JR, Gründeman PF, Eefting FD, Nierich A, Robles de Medina EO, Bredée JJ.

J Thorac Cardiovasc Surg. 1998 Jul;116(1):60-7.

PMID: 9671898 [PubMed – indexed for MEDLINE]

Related citations

Select item 15282460

 

99.

Does off-pump total arterial grafting increase the incidence of intraoperative graft failure?

Balacumaraswami L, Abu-Omar Y, Anastasiadis K, Choudhary B, Pigott D, Yeong SK, Taggart DP.

J Thorac Cardiovasc Surg. 2004 Aug;128(2):238-44.

PMID: 15282460 [PubMed – indexed for MEDLINE]

Related citations

Select item 22436497

 

100.

Routine off-pump coronary artery bypass: reasons for on-pump conversion.

Hirose H, Amano A.

Innovations (Phila). 2005 Fall;1(1):28-31.

PMID: 22436497 [PubMed]

Related citations

Select item 18637191

 

101.

Rationale, design and methodology for a Prospective Randomized Study of graft patency in Off-pump and On-pump MultI-vessel coronary artery bypasS Surgery (PROMISS) using multidetector computed tomography.

Uva MS, Matias F, Cavaco S, Magalhães MP.

Trials. 2008 Jul 17;9:44. doi: 10.1186/1745-6215-9-44.

PMID: 18637191 [PubMed] Free PMC Article

Related citations

 

 

Read Full Post »


aprotinin-sequence.Par.0001.Image.260

aprotinin-sequence.Par.0001.Image.260 (Photo credit: redondoself)

English: Protein folding: amino-acid sequence ...

Protein folding: amino-acid sequence of bovine BPTI (basic pancreatic trypsin inhibitor) in one-letter code, with its folded 3D structure represented by a stick model of the mainchain and sidechains (in gray), and the backbone and secondary structure by a ribbon colored blue to red from N- to C-terminus. 3D structure from PDB file 1BPI, visualized in Mage and rendered in Raster3D. (Photo credit: Wikipedia)

 

 

 

 

 

 

 

 

 

 

 

 

The Effects of Aprotinin on Endothelial Cell Coagulant Biology

Demet Sag, PhD*†, Kamran Baig, MBBS, MRCS; James Jaggers, MD, Jeffrey H. Lawson, MD, PhD

Departments of Surgery and Pathology (J.H.L.) Duke University Medical Center Durham, NC  27710

Correspondence and Reprints:

                             Jeffrey H. Lawson, M.D., Ph.D.

                              Departments of Surgery & Pathology

                              DUMC Box 2622

                              Durham, NC  27710

                              (919) 681-6432 – voice

                              (919) 681-1094 – fax

                              lawso006@mc.duke.edu

*Current Address: Demet SAG, PhD

                          3830 Valley Centre Drive Suite 705-223, San Diego, CA 92130

Support:

Word Count: 4101 Journal Subject Heads:  CV surgery, endothelial cell activationAprotinin, Protease activated receptors,

Potential Conflict of Interest:         None

Abstract

Introduction:  Cardiopulmonary bypass is associated with a systemic inflammatory response syndrome, which is responsible for excessive bleeding and multisystem dysfunction. Endothelial cell activation is a key pathophysiological process that underlies this response. Aprotinin, a serine protease inhibitor has been shown to be anti-inflammatory and also have significant hemostatic effects in patients undergoing CPB. We sought to investigate the effects of aprotinin at the endothelial cell level in terms of cytokine release (IL-6), tPA release, tissue factor expression, PAR1 + PAR2 expression and calcium mobilization. Methods:  Cultured Human Umbilical Vein Endothelial Cells (HUVECS) were stimulated with TNFa for 24 hours and treated with and without aprotinin (200KIU/ml + 1600KIU/ml). IL-6 and tPA production was measured using ELISA. Cellular expression of Tissue Factor, PAR1 and PAR2 was measured using flow cytometry. Intracellular calcium mobilization following stimulation with PAR specific peptides and agonists (trypsin, thrombin, Human Factor VIIa, factor Xa) was measured using fluorometry with Fluo-3AM. Results: Aprotinin at the high dose (1600kIU/mL), 183.95 ± 13.06mg/mL but not low dose (200kIU/mL) significantly reduced IL-6 production from TNFa stimulated HUVECS (p=0.043). Aprotinin treatment of TNFa activated endothelial cells significantly reduce the amount of tPA released in a dose dependent manner (A200 p=0.0018, A1600 p=0.033). Aprotinin resulted in a significant downregulation of TF expression to baseline levels. At 24 hours, we found that aprotinin treatment of TNFa stimulated cells resulted in a significant downregulation of PAR-1 expression. Aprotinin significantly inhibited the effects of the protease thrombin upon PAR1 mediated calcium release. The effects of PAR2 stimulatory proteases such as human factor Xa, human factor VIIa and trypsin on calcium release was also inhibited by aprotinin. Conclusion:  We have shown that aprotinin has direct anti-inflammatory effects on endothelial cell activation and these effects may be mediated through inhibition of proteolytic activation of PAR1 and PAR2. Abstract word count: 297

INTRODUCTION   Each year it is estimated that 350,000 patients in the United States, and 650,000 worldwide undergo cardiopulmonary bypass (CPB). Despite advances in surgical techniques and perioperative management the morbidity and mortality of cardiac surgery related to the systemic inflammatory response syndrome(SIRS), especially in neonates is devastatingly significant. Cardiopulmonary bypass exerts an extreme challenge upon the haemostatic system as part of the systemic inflammatory syndrome predisposing to excessive bleeding as well as other multisystem dysfunction (1). Over the past decade major strides have been made in the understanding of the pathophysiology of the inflammatory response following CPB and the role of the vascular endothelium has emerged as critical in maintaining cardiovascular homeostasis (2).

CPB results in endothelial cell activation and initiation of coagulation via the Tissue Factor dependent pathway and consumption of important clotting factors. The major stimulus for thrombin generation during CPB has been shown to be through the tissue factor dependent pathway. As well as its effects on the fibrin and platelets thrombin has been found to play a role in a host of inflammatory responses in the vascular endothelium. The recent discovery of the Protease-Activated Receptors (PAR), one of which through which thrombin acts (PAR-1) has stimulated interest that they may provide a vital link between inflammation and coagulation (3).

Aprotinin is a nonspecific serine protease inhibitor that has been used for its ability to reduce blood loss and preserve platelet function during cardiac surgery procedures requiring cardiopulmonary bypass and thus the need for subsequent blood and blood product transfusions. However there have been concerns that aprotinin may be pro-thrombotic, especially in the context of coronary artery bypass grafting, which has limited its clinical use. These reservations are underlined by the fact that the mechanism of action of aprotinin has not been fully understood. Recently aprotinin has been shown to exert anti-thrombotic effects mediated by blocking the PAR-1 (4). Much less is known about its effects on endothelial cell activation, especially in terms of Tissue Factor but it has been proposed that aprotinin may also exert protective effects at the endothelial level via protease-activated receptors (PAR1 and PAR2). In this study we simulated in vitro the effects of endothelial cell activation during CPB by stimulating Human Umbilical Vein Endothelial Cells (HUVECs) with a proinflammatory cytokine released during CPB, Tumor Necrosis Factor (TNF-a) and characterize the effects of aprotinin treatment on TF expression, PAR1 and PAR2 expression, cytokine release IL-6 and tPA secretion.  In order to investigate the mechanism of action of aprotinin we studied its effects on PAR activation by various agonists and ligands.

These experiments provide insight into the effects of aprotinin on endothelial related coagulation mechanisms in terms of Tissue Factor expression and indicate it effects are mediated through Protease-Activated Receptors (PAR), which are seven membrane spanning proteins called G-protein coupled receptors (GPCR), that link coagulant and inflammatory pathways. Therefore, in this study we examine the effects of aprotinin on the human endothelial cell coagulation biology by different-dose aprotinin, 200 and 1600units.  The data demonstrates that aprotinin appears to directly alter endothelial expression of inflammatory cytokines, tPA and PAR receptor expression following treatment with TNF.  The direct mechanism of action is unknown but may act via local protease inhibition directly on endothelial cells.  It is hoped that with improved understanding of the mechanisms of action of aprotinin, especially an antithrombotic effect at the endothelial level the fears of prothrombotic tendency may be lessened and its use will become more routine.  

METHODS Human Umbilical Vein Endothelial Cells (HUVECS) used as our model to study the effects of endothelial cell activation on coagulant biology. In order to simulate the effects of cardiopulmonary bypass at the endothelial cell interface we stimulated the cells with the proinflammatory cytokine TNFa. In the study group the HUVECs were pretreated with low (200kIU/mL) and high (1600kIU/mL) dosages of aprotinin prior to stimulation with TNFa and complement activation fragments. The effects of TNFa stimulation upon endothelial Tissue Factor expression, PAR1 and PAR2 expression, and tPA and IL6 secretion were determined and compared between control and aprotinin treated cells. In order to delineate whether aprotinin blocks PAR activation via its protease inhibition properties we directly activated PAR1 and PAR2 using specific agonist ligands such thrombin (PAR1), trypsin, Factor VIIa, Factor Xa (PAR2) in the absence and presence of aprotinin.

Endothelial Cell Culture HUVECs were supplied from Clonetics. The cells were grown in EBM-2 containing 2MV bullet kit, including 5% FBS, 100-IU/ml penicillin, 0.1mg/mL streptomycin, 2mmol/L L-glutamine, 10 U/ml heparin, 30µg/mL EC growth supplement (ECGS). Before the stimulation cells were starved in 0.1%BSA depleted with FBS and growth factors for 24 hours. Cells were sedimented at 210g for 10 minutes at 4C and then resuspended in culture media. The HUVECs to be used will be between 3 and 5 passages.

Assay of IL-6 and tPA production Levels of IL-6 were measured with an ELISA based kit (RDI, MN) according to the manufacturers instructions. tPA was measured using a similar kit (American Diagnostica).

  Flow Cytometry The expression of transmembrane proteins PAR1, PAR2 and tissue factor were measured by single color assay as FITC labeling agent. Prepared suspension of cells disassociated trypsin free cell disassociation solution (Gibco) to be labeled. First well washed, and resuspended into “labeling buffer”, phosphate buffered saline (PBS) containing 0.5% BSA plus 0.1% NaN3, and 5% fetal bovine serum to block Fc and non-specific Ig binding sites. Followed by addition of 5mcl of antibody to approx. 1 million cells in 100µl labeling buffer and incubate at 4C for 1 hour. After washing the cells with 200µl with wash buffer, PBS + 0.1% BSA + 0.1% NaN3, the cells were pelletted at 1000rpm for 2 mins. Since the PAR1 and PAR2 were directly labeled with FITC these cells were fixed for later analysis by flow cytometry in 500µl PBS containing 1%BSA + 0.1% NaN3, then add equal volume of 4% formalin in PBS. For tissue factor raised in mouse as monoclonal primary antibody, the pellet resuspended and washed twice more as before, and incubated at 4C for 1 hour addition of 5µl donkey anti-mouse conjugated with FITC secondary antibody directly to the cell pellets at appropriate dilution in labeling buffer. After the final wash three times, the cell pellets were resuspended thoroughly in fixing solution. These fixed and labeled cells were then stored in the dark at 4C until there were analyzed. On analysis, scatter gating was used to avoid collecting data from debris and any dead cells. Logarithmic amplifiers for the fluorescence signal were used as this minimizes the effects of different sensitivities between machines for this type of data collection.  

Intracellular Calcium Measurement

Measured the intracellular calcium mobilization by Fluo-3AM. HUVECs were grown in calcium and phenol free EBM basal media containing 2MV bullet kit. Then the cell cultures were starved with the same media by 0.1% BSA without FBS for 24 hour with or without TNFa stimulation presence or absence of aprotinin (200 and 1600KIU/ml). Next the cells were loaded with Fluo-3AM 5µg/ml containing agonists, PAR1 specific peptide SFLLRN-PAR1 inhibitor, PAR2 specific peptide SLIGKV-PAR2 inhibitor, human alpha thrombin, trypsin, factor VIIa, factor Xa for an hour at 37C in the incubation chamber. Finally the media was replaced by Flou-3AM free media and incubated for another 30 minutes in the incubation chamber. The readings were taken at fluoromatic bioplate reader. For comparison purposes readings were taken before and during Fluo-3AM loading as well.  

RESULTS Aprotinin reduces IL-6 production from activated/stimulated HUVECS The effects of aprotinin analyzed on HUVEC for the anti-inflammatory effects of aprotinin at cultured HUVECS with high and low doses.  Figure 1 shows that TNF-a stimulated a considerable increase in IL-6 production, 370.95 ± 109.9 mg/mL.   If the drug is used alone the decrease of IL-6 at the low dose is 50% that is 183.95 ng/ml and with the high dose of 20% that is 338.92 from 370.95ng/ml being compared value.  TNFa-aprotinin results in reduction of the IL-6 expression from 370.95ng/ml to 58.6 (6.4fold) fro A200 and 75.85 (4.9 fold) ng/ml, for A1600.  After the treatment the cells reach to the below baseline limit of IL-6 expression. Aprotinin at the high dose (1600kIU/mL), 183.95 ± 13.06mg/mL but not low dose (200kIU/mL) significantly reduced IL-6 production from TNF-a stimulated HUVECS (p=0.043).  Therefore, the aprotinin prevents inflammation as well as loss of blood.  

Aprotinin reduces tPA production from stimulated HUVECS Whether aprotinin exerted part of its fibrinolytic effects through inhibition of tPA mediated plasmin generation examined by the effects on TNFa stimulated HUVECS. Figure 2 also demonstrates that the amount of tPA released from HUVECS under resting, non-stimulated conditions incubated with aprotinin are significantly different. Figure 2 represents that the resting level of tPA released from non-stimulated cells significantly, by 100%, increase following TNF-a stimulation for 24 hours.  After application of aprotinin alone at two doses the tPA level goes down 25% of TNFa stimulated cells.  However, aprotinin treatment of TNF-a activated endothelial cells significantly lower the amount of tPA release in a dose dependent manner that is low dose decreased 25 but high dose causes 50% decrease of tPA expression (A200 p=0.0018, A1600 p=0.033) This finding suggests that aprotinin exerts a direct inhibitory effect on endothelial cell tPA production.

Aprotinin and receptor expression on activated HUVECS

TF is expressed when the cell in under stress such as TNFa treatments. The stimulated HUVECs with TNF-a tested for the expression of PAR1, PAR2, and tissue factor by single color flow cytometry through FITC labeled detection antibodies at 1, 3, and 24hs.

 

Tissue Factor expression is reduced:

Figure 3 demonstrates that there is a fluctuation of TF expression from 1 h to 24h that the TF decreases at first hour after aprotinin application 50% and 25%, A1600 and A200 respectively.  Then at 3 h the expression come back up 50% more than the baseline.  Finally, at 24h the expression of TF becomes almost as same as baseline.  Moreover, TNFa stimulated cells remains 45% higher than baseline after at 3h as well as at 24h.

PAR1 decreased:
Figure 4 demonstrates that aprotinin reduces the PAR1 expression 80% at 24h but there is no affect at 1 and 3 h intervals for both doses.

During the treatment with aprotinin only high dose at 1 hour time interval decreases the PAR1 expression on the cells. This data explains that ECCB is affected due to the expression of PAR1 is lowered by the high dose of aprotinin.

PAR2 is decreased by aprotinin:

  Figure 5 shows the high dose of aprotinin reduces the PAR2 expression close to 25% at 1h, 50% at 3h and none at 24h.  This pattern is exact opposite of PAR1 expression.  Figure 5 demonstrates the 50% decrease at 3h interval only.  Does that mean aprotinin affecting the inflammation first and then coagulation?

This suggests that aprotinin may affect the PAR2 expression at early and switched to PAR1 reduction later time intervals.  This fluctuation can be normal because aprotinin is not a specific inhibitor for proteases.  This approach make the aprotinin work better the control bleeding and preventing the inflammation causing cytokine such as IL-6.

Aprotinin inhibits Calcium fluxes induced by PAR1/2 specific agonists

  The specificity of aprotinin’s actions upon PAR studied the effects of the agent on calcium release following proteolytic and non-proteolytic stimulation of PAR1 and PAR2. Figure 6A (Figure 6) shows the stimulation of the cells with the PAR1 specific peptide (SFLLRN) results in release of calcium from the cells. Pretreatment of the cells with aprotinin has no significant effect on PAR1 peptide stimulated calcium release. This suggests that aprotinin has no effect upon the non-proteolytic direct activation of the PAR 1 receptor. Yet, Figure 6B (Figure 6) demonstrates human alpha thrombin does interact with the drug as a result the calcium release drops below base line after high dose (A1600) aprotinin used to zero but low dose does not show significant effect on calcium influx. Figure 7 demonstrates the direct PAR2 and indirect PAR2 stimulation by hFVIIa, hFXa, and trypsin of cells.  Similarly, at Figure 7A aprotinin has no effect upon PAR2 peptide stimulated calcium release, however, at figures 7B, C, and D shows that PAR2 stimulatory proteases Human Factor Xa, Human Factor VIIa and Trypsin decreases calcium release. These findings indicate that aprotinin’s mechanism of action is directed towards inhibiting proteolytic cleavage and hence subsequent activation of the PAR1 and PAR2 receptor complexes.  The binding site of the aprotinin on thrombin possibly is not the peptide sequence interacting with receptors.

Measurement of calcium concentration is essential to understand the mechanism of aprotinin on endothelial cell coagulation and inflammation because these mechanisms are tightly controlled by presence of calcium.  For example, activation of PAR receptors cause activation of G protein q subunit that leads to phosphoinositol to secrete calcium from endoplasmic reticulum into cytoplasm or activation of DAG to affect Phospho Lipase C (PLC). In turn, certain calcium concentration will start the serial formation of chain reaction for coagulation.  Therefore, treatment of the cells with specific factors, thrombin receptor activating peptides (TRAPs), human alpha thrombin, trypsin, human factor VIIa, and human factor Xa, would shed light into the effect of aprotinin on the formation of complexes for pro-coagulant activity.    DISCUSSION   There are two fold of outcomes to be overcome during cardiopulmonary bypass (CPB):  mechanical stress and the contact of blood with artificial surfaces results in the activation of pro- and anticoagulant systems as well as the immune response leading to inflammation and systemic organ failure.  This phenomenon causes the “postperfusion-syndrome”, with leukocytosis, increased capillary permeability, accumulation of interstitial fluid, and organ dysfunction.  CPB is also associated with a significant inflammatory reaction, which has been related to complement activation, and release of various inflammatory mediators and proteolytic enzymes. CPB induces an inflammatory state characterized by tumor necrosis factor-alpha release. Aprotinin, a low molecular-weight peptide inhibitor of trypsin, kallikrein and plasmin has been proposed to influence whole body inflammatory response inhibiting kallikrein formation, complement activation and neutrophil activation (5, 6). But shown that aprotinin has no significant influence on the inflammatory reaction to CPB in men.  Understanding the endothelial cell responses to injury is therefore central to appreciating the role that dysfunction plays in the preoperative, operative, and postoperative course of nearly all cardiovascular surgery patients.  Whether aprotinin increases the risk of thrombotic complications remains controversial.   The anti-inflammatory properties of aprotinin in attenuating the clinical manifestations of the systemic inflammatory response following cardiopulmonary bypass are well known(15) 16)  However its mechanisms and targets of action are not fully understood. In this study we have investigated the actions of aprotinin at the endothelial cell level. Our experiments showed that aprotinin reduced TNF-a induced IL-6 release from cultured HUVECS. Thrombin mediates its effects through PAR-1 receptor and we found that aprotinin reduced the expression of PAR-1 on the surface of HUVECS after 24 hours incubation. We then demonstrated that aprotinin inhibited endothelial cell PAR proteolytic activation by thrombin (PAR-1), trypsin, factor VII and factor X (PAR-2) in terms of less release of Ca preventing the activation of coagulation.  So aprotinin made cells produce less receptor, PAR1, PAR2, and TF as a result there would be less Ca++ release.    Our findings provide evidence for anti-inflammatory as well as anti-coagulant properties of aprotinin at the endothelial cell level, which may be mediated through its inhibitory effects on proteolytic activation of PARs.   IL6   Elevated levels of IL-6 have been shown to correlate with adverse outcomes following cardiac surgery in terms of cardiac dysfunction and impaired lung function(Hennein et al 1992). Cardiopulmonary bypass is associated with the release of the pro-inflammatory cytokines IL-6, IL-8 and TNF-a.  IL-6 is produced by T-cells, endothelial cells as a result monocytes and plasma levels of this cytokine tend to increase during CPB (21, 22). In some studies aprotinin has been shown to reduce levels of IL-6 post CPB(23) Hill(5). Others have failed to demonstrate an inhibitory effect of aprotinin upon pro-inflammatory cytokines following CPB(24) (25).  Our experiments showed that aprotinin significantly reduced the release of IL-6 from TNF-a stimulated endothelial cells, which may represent an important target of its anti-inflammatory properties. Its has been shown recently that activation of HUVEC by PAR-1 and PAR-2 agonists stimulates the production of IL-6(26). Hence it is possible that the effects of aprotinin in reducing IL-6 may be through targeting activation of such receptors.   TPA   Tissue Plasminogen activator is stored, ready made, in endothelial cells and it is released at its highest levels just after commencing CPB and again after protamine administration. The increased fibrinolytic activity associated with the release of tPA can be correlated to the excessive bleeding postoperatively. Thrombin is thought to be the major stimulus for release of t-PA from endothelial cells. Aprotinin’s haemostatic properties are due to direct inhibition of plasmin, thereby reducing fibrinolytic activity as well as inhibiting fibrin degradation.  Aprotinin has not been shown to have any significant effect upon t-PA levels in patients post CPB(27), which would suggest that aprotinin reduced fibrinolytic effects are not the result of inhibition of t-PA mediated plasmin generation. Our study, however demonstrates that aprotinin inhibits the release of t-PA from activated endothelial cells, which may represent a further haemostatic mechanism at the endothelial cell level.   TF   Resting endothelial cells do not normally express tissue factor on their cell surface. Inflammatory mediators released during CPB such as complement (C5a), lipopolysaccharide, IL-6, IL-1, TNF-a, mitogens, adhesion molecules and hypoxia may induce the expression of tissue factor on endothelial cells and monocytes. The expression of TF on activated endothelial cells activates the extrinsic pathway of coagulation, ultimately resulting in the generation of thrombin and fibrin. Aprotinin has been shown to reduce the expression of TF on monocytes in a simulated cardiopulmonary bypass circuit (28).

We found that treatment of activated endothelial cells with aprotinin significantly reduced the expression of TF after 24 hours. This would be expected to result in reduced thrombin generation and represent an additional possible anticoagulant effect of aprotinin. In a previous study from our laboratory we demonstrated that there were two peaks of inducible TF activity on endothelial cells, one immediately post CPB and the second at 24 hours (29). The latter peak is thought to be responsible for a shift from the initial fibrinolytic state into a procoagulant state.  In addition to its established early haemostatic and coagulant effect, aprotinin may also have a delayed anti-coagulant effect through its inhibition of TF mediated coagulation pathway. Hence its effects may counterbalance the haemostatic derangements, i.e. first bleeding then thrombosis caused by CPB. The anti-inflammatory effects of aprotinin may also be related to inhibition of TF and thrombin generation. PARs  

It has been suggested that aprotinin may target PAR on other cells types, especially endothelial cells. We investigated the role of PARs in endothelial cell activation and whether they can be the targets for aprotinin.  In recent study by Day group(30) demonstrated that endothelial cell activation by thrombin and downstream inflammatory responses can be inhibited by aprotinin in vitro through blockade of protease-activated receptor 1. Our results provide a new molecular basis to help explain the anti-inflammatory properties of aprotinin reported clinically.    The finding that PAR-2 can also be activated by the coagulation enzymes factor VII and factor X indicates that PAR may represent the link between inflammation and coagulation.  PAR-2 is believed to play an important role in inflammatory response. PAR-2 are widely expressed in the gastrointestinal tract, pancreas, kidney, liver, airway, prostrate, ovary, eye of endothelial, epithelial, smooth muscle cells, T-cells and neutrophils. Activation of PAR-2 in vivo has been shown to be involved in early inflammatory processes of leucocyte recruitment, rolling, and adherence, possibly through a mechanism involving platelet-activating factor (PAF)   We investigated the effects of TNFa stimulation on PAR-1 and PAR-2 expression on endothelial cells. Through functional analysis of PAR-1 and PAR-2 by measuring intracellular calcium influx we have demonstrated that aprotinin blocks proteolytic cleavage of PAR-1 by thrombin and activation of PAR-2 by the proteases trypsin, factor VII and factor X.  This confirms the previous findings on platelets of an endothelial anti-thrombotic effect through inhibition of proteolysis of PAR-1. In addition, part of aprotinin’s anti-inflammatory effects may be mediated by the inhibition of serine proteases that activate PAR-2. There have been conflicting reports regarding the regulation of PAR-1 expression by inflammatory mediators in cultured human endothelial cells. Poullis et al first showed that thrombin induced platelet aggregation was mediated by via the PAR-1(4) and demonstrated that aprotinin inhibited the serine protease thrombin and trypsin induced platelet aggregation. Aprotinin did not block PAR-1 activation by the non-proteolytic agonist peptide, SFLLRN indicating that the mechanism of action was directed towards inhibiting proteolytic cleavage of the receptor. Nysted et al showed that TNF did not affect mRNA and cell surface protein expression of PAR-1 (35), whereas Yan et al showed downregulation of PAR-1 mRNA levels (36). Once activated PAR1 and PAR2 are rapidly internalized and then transferred to lysosomes for degradation.

Endothelial cells contain large intracellular pools of preformed receptors that can replace the cleaved receptors over a period of approximately 2 hours, thus restoring the capacity of the cells to respond to thrombin. In this study we found that after 1-hour stimulation with TNF there was a significant upregulation in PAR-1 expression. However after 3 hours and 24 hours there was no significant change in PAR-1 expression suggesting that cleaved receptors had been internalized and replenished. Aprotinin was interestingly shown to downregulate PAR-1 expression on endothelial cells at 1 hour and increasingly more so after 24 hours TNF stimulation. These findings may suggest an effect of aprotinin on inhibiting intracellular cycling and synthesis of PAR-1.    

Conclusions   Our study has identified the anti-inflammatory and coagulant effects of aprotinin at the endothelial cell level. All together aprotinin affects the ECCB by reducing the t-PA, IL-6, PAR1, PAR 2, TF expressions. Our data correlates with the previous foundlings in production of tPA (7, (8) 9) 10), and  decreased IL-6 levels (11) during coronary artery bypass graft surgery (12-14). We have importantly demonstrated that aprotinin may target proteolytic activation of endothelial cell associated PAR-1 to exert a possible anti-inflammatory effect. This evidence should lessen the concerns of a possible prothrombotic effect and increased incidence of graft occlusion in coronary artery bypass patients treated with aprotinin. Aprotinin may also inhibit PAR-2 proteolytic activation, which may represent a key mechanism for attenuating the inflammatory response at the critical endothelial cell level. Although aprotinin has always been known as a non-specific protease inhibitor we would suggest that there is growing evidence for a PAR-ticular mechanism of action.  

REFERENCES

1.         Levy, J. H., and Tanaka, K. A. Inflammatory response to cardiopulmonary bypass. Ann Thorac Surg. 75: S715-720, 2003.

2.         Verrier, E. D., and Morgan, E. N. Endothelial response to cardiopulmonary bypass surgery. Ann Thorac Surg. 66: S17-19; discussion S25-18, 1998.

3.         Cirino, G., Napoli, C., Bucci, M., and Cicala, C. Inflammation-coagulation network: are serine protease receptors the knot? Trends Pharmacol Sci. 21: 170-172, 2000. 4.         Poullis, M., Manning, R., Laffan, M., Haskard, D. O., Taylor, K. M., and Landis, R. C. The antithrombotic effect of aprotinin: actions mediated via the proteaseactivated receptor 1. J Thorac Cardiovasc Surg. 120: 370-378, 2000.

5.         Hill, G. E., Alonso, A., Spurzem, J. R., Stammers, A. H., and Robbins, R. A. Aprotinin and methylprednisolone equally blunt cardiopulmonary bypass-induced inflammation in humans. J Thorac Cardiovasc Surg. 110: 1658-1662, 1995.

6.         Hill, G. E., Pohorecki, R., Alonso, A., Rennard, S. I., and Robbins, R. A. Aprotinin reduces interleukin-8 production and lung neutrophil accumulation after cardiopulmonary bypass. Anesth Analg. 83: 696-700, 1996. 7.         Lu, H., Du Buit, C., Soria, J., Touchot, B., Chollet, B., Commin, P. L., Conseiller, C., Echter, E., and Soria, C. Postoperative hemostasis and fibrinolysis in patients undergoing cardiopulmonary bypass with or without aprotinin therapy. Thromb Haemost. 72: 438-443, 1994.

8.         de Haan, J., and van Oeveren, W. Platelets and soluble fibrin promote plasminogen activation causing downregulation of platelet glycoprotein Ib/IX complexes: protection by aprotinin. Thromb Res. 92: 171-179, 1998.

9.         Erhardtsen, E., Bregengaard, C., Hedner, U., Diness, V., Halkjaer, E., and Petersen, L. C. The effect of recombinant aprotinin on t-PA-induced bleeding in rats. Blood Coagul Fibrinolysis. 5: 707-712, 1994.

10.       Orchard, M. A., Goodchild, C. S., Prentice, C. R., Davies, J. A., Benoit, S. E., Creighton-Kemsford, L. J., Gaffney, P. J., and Michelson, A. D. Aprotinin reduces cardiopulmonary bypass-induced blood loss and inhibits fibrinolysis without influencing platelets. Br J Haematol. 85: 533-541, 1993.

11.       Tassani, P., Augustin, N., Barankay, A., Braun, S. L., Zaccaria, F., and Richter, J. A. High-dose aprotinin modulates the balance between proinflammatory and anti-inflammatory responses during coronary artery bypass graft surgery. J Cardiothorac Vasc Anesth.14: 682-686, 2000.

12.       Asehnoune, K., Dehoux, M., Lecon-Malas, V., Toueg, M. L., Gonieaux, M. H., Omnes, L., Desmonts, J. M., Durand, G., and Philip, I. Differential effects of aprotinin and tranexamic acid on endotoxin desensitization of blood cells induced by circulation through an isolated extracorporeal circuit. J Cardiothorac Vasc Anesth. 16: 447-451, 2002.

13.       Dehoux, M. S., Hernot, S., Asehnoune, K., Boutten, A., Paquin, S., Lecon-Malas, V., Toueg, M. L., Desmonts, J. M., Durand, G., and Philip, I. Cardiopulmonary bypass decreases cytokine production in lipopolysaccharide-stimulated whole blood cells: roles of interleukin-10 and the extracorporeal circuit. Crit Care Med. 28: 1721-1727, 2000.

14.       Greilich, P. E., Brouse, C. F., Rinder, C. S., Smith, B. R., Sandoval, B. A., Rinder, H. M., Eberhart, R. C., and Jessen, M. E. Effects of epsilon-aminocaproic acid and aprotinin on leukocyte-platelet adhesion in patients undergoing cardiac surgery. Anesthesiology. 100: 225-233, 2004.

15.       Mojcik, C. F., and Levy, J. H. Aprotinin and the systemic inflammatory response after cardiopulmonary bypass. Ann Thorac Surg. 71: 745-754, 2001.

16.       Landis, R. C., Asimakopoulos, G., Poullis, M., Haskard, D. O., and Taylor, K. M. The antithrombotic and antiinflammatory mechanisms of action of aprotinin. Ann Thorac Surg. 72: 2169-2175, 2001.

17.       Asimakopoulos, G., Kohn, A., Stefanou, D. C., Haskard, D. O., Landis, R. C., and Taylor, K. M. Leukocyte integrin expression in patients undergoing cardiopulmonary bypass. Ann Thorac Surg. 69: 1192-1197, 2000.

18.       Landis, R. C., Asimakopoulos, G., Poullis, M., Thompson, R., Nourshargh, S., Haskard, D. O., and Taylor, K. M. Effect of aprotinin (trasylol) on the inflammatory and thrombotic complications of conventional cardiopulmonary bypass surgery. Heart Surg Forum. 4 Suppl 1: S35-39, 2001.

19.       Asimakopoulos, G., Thompson, R., Nourshargh, S., Lidington, E. A., Mason, J. C., Ratnatunga, C. P., Haskard, D. O., Taylor, K. M., and Landis, R. C. An anti-inflammatory property of aprotinin detected at the level of leukocyte extravasation. J Thorac Cardiovasc Surg. 120: 361-369, 2000.

20.       Asimakopoulos, G., Lidington, E. A., Mason, J., Haskard, D. O., Taylor, K. M., and Landis, R. C. Effect of aprotinin on endothelial cell activation. J Thorac Cardiovasc Surg. 122: 123-128, 2001.

21.       Butler, J., Chong, G. L., Baigrie, R. J., Pillai, R., Westaby, S., and Rocker, G. M. Cytokine responses to cardiopulmonary bypass with membrane and bubble oxygenation. Ann Thorac Surg. 53: 833-838, 1992.

22.       Hennein, H. A., Ebba, H., Rodriguez, J. L., Merrick, S. H., Keith, F. M., Bronstein, M. H., Leung, J. M., Mangano, D. T., Greenfield, L. J., and Rankin, J. S. Relationship of the proinflammatory cytokines to myocardial ischemia and dysfunction after uncomplicated coronary revascularization. J Thorac Cardiovasc Surg. 108: 626-635, 1994.

23.       Diego, R. P., Mihalakakos, P. J., Hexum, T. D., and Hill, G. E. Methylprednisolone and full-dose aprotinin reduce reperfusion injury after cardiopulmonary bypass. J Cardiothorac Vasc Anesth. 11: 29-31, 1997.

24.       Ashraf, S., Tian, Y., Cowan, D., Nair, U., Chatrath, R., Saunders, N. R., Watterson, K. G., and Martin, P. G. “Low-dose” aprotinin modifies hemostasis but not proinflammatory cytokine release. Ann Thorac Surg. 63: 68-73, 1997.

25.       Schmartz, D., Tabardel, Y., Preiser, J. C., Barvais, L., d’Hollander, A., Duchateau, J., and Vincent, J. L. Does aprotinin influence the inflammatory response to cardiopulmonary bypass in patients? J Thorac Cardiovasc Surg. 125: 184-190, 2003.

26.       Chi, L., Li, Y., Stehno-Bittel, L., Gao, J., Morrison, D. C., Stechschulte, D. J., and Dileepan, K. N. Interleukin-6 production by endothelial cells via stimulation of protease-activated receptors is amplified by endotoxin and tumor necrosis factor-alpha. J Interferon Cytokine Res. 21: 231-240, 2001.

27.       Ray, M. J., and Marsh, N. A. Aprotinin reduces blood loss after cardiopulmonary bypass by direct inhibition of plasmin. Thromb Haemost. 78: 1021-1026, 1997.

28.       Khan, M. M., Gikakis, N., Miyamoto, S., Rao, A. K., Cooper, S. L., Edmunds, L. H., Jr., and Colman, R. W. Aprotinin inhibits thrombin formation and monocyte tissue factor in simulated cardiopulmonary bypass. Ann Thorac Surg. 68: 473-478, 1999.

29.       Jaggers, J. J., Neal, M. C., Smith, P. K., Ungerleider, R. M., and Lawson, J. H. Infant cardiopulmonary bypass: a procoagulant state. Ann Thorac Surg. 68: 513-520, 1999.

30.       Day, J. R., Taylor, K. M., Lidington, E. A., Mason, J. C., Haskard, D. O., Randi, A. M., and Landis, R. C. Aprotinin inhibits proinflammatory activation of endothelial cells by thrombin through the protease-activated receptor 1. J Thorac Cardiovasc Surg. 131: 21-27, 2006.

31.       Vergnolle, N. Proteinase-activated receptor-2-activating peptides induce leukocyte rolling, adhesion, and extravasation in vivo. J Immunol. 163: 5064-5069, 1999.

32.       Vergnolle, N., Hollenberg, M. D., Sharkey, K. A., and Wallace, J. L. Characterization of the inflammatory response to proteinase-activated receptor-2 (PAR2)-activating peptides in the rat paw. Br J Pharmacol. 127: 1083-1090, 1999.

33.       McLean, P. G., Aston, D., Sarkar, D., and Ahluwalia, A. Protease-activated receptor-2 activation causes EDHF-like coronary vasodilation: selective preservation in ischemia/reperfusion injury: involvement of lipoxygenase products, VR1 receptors, and C-fibers. Circ Res. 90: 465-472, 2002.

34.       Maree, A., and Fitzgerald, D. PAR2 is partout and now in the heart. Circ Res. 90: 366-368, 2002.

35.       Nystedt, S., Ramakrishnan, V., and Sundelin, J. The proteinase-activated receptor 2 is induced by inflammatory mediators in human endothelial cells. Comparison with the thrombin receptor. J Biol Chem. 271: 14910-14915, 1996.

36.       Yan, W., Tiruppathi, C., Lum, H., Qiao, R., and Malik, A. B. Protein kinase C beta regulates heterologous desensitization of thrombin receptor (PAR-1) in endothelial cells. Am J Physiol. 274: C387-395, 1998.

37.       Shinohara, T., Suzuki, K., Takada, K., Okada, M., and Ohsuzu, F. Regulation of proteinase-activated receptor 1 by inflammatory mediators in human vascular endothelial cells. Cytokine. 19: 66-75, 2002.

FIGURES

Figure 1: IL-6 production following TNF-a stimulation Figure 1

Figure 2:  tPA production following TNF-a stimulation Figure 2

Figure 3:  Tissue Factor Expression on TNF-a stimulated HUVECS Figure 3

Figure 4:  PAR-1 Expression on TNF-a stimulated HUVECS Figure 4

Figure 5:  PAR-2 Expression on TNF-a stimulated HUVECS Figure 5

Figure 6:  Calcium Fluxes following PAR1 Activation Figure 6

Figure 7:  Calcium Fluxes following PAR2 Activation Figure 7

 

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