Coronary Circulation Combined Assessment: Optical Coherence Tomography (OCT), Near-Infrared Spectroscopy (NIRS) and Intravascular Ultrasound (IVUS) – Detection of Lipid-Rich Plaque and Prevention of Acute Coronary Syndrome (ACS)

Author, and Content Consultant to e-SERIES A: Cardiovascular Diseases: Justin Pearlman, MD, PhD, FACC

and

Article Curator: Aviva Lev-Ari, PhD, RN

The clinical motivations for coronary artery imaging include identifying and characterizing obstructive lesions, analyzing suitability for various feasible interventions, and assessing comparative risk with and without interventions. With improvements in non-invasive detection of fixed obstructions in the coronary arteries, it should not be surprising that half of the lesions that cause heart attacks (myocardial infarction) among those who had recent imaging consisted of unstable plaques that were less than 50% obstructive. Therefore there is growing interest not only in more reliable detection of lesions that exceed 50% obstruction, but also improved characterization of lesions that are not obstructive but may be unstable.

By way of analogy, think of impaired blood supply to the heart as a traffic jam in a roadway. The best time to check for a traffic jam is during rush hour. The corresponding clinical scenario is stress testing. There are three major roadways in the heart: left anterior, left circumflex, and right, each with branches (forks). The two left major vessels stem from a short but treacherous left main (“widow maker”). A temporary traffic jam results in symptoms of impaired delivery (angina, from hunger due to late delivery of food). Alternatively, a prolonged traffic disruption can result in suicidal tissue destruction (starvation). A fixed obstruction consists of potholes and landslides resulting in a persisting shutdown of half or more of the lanes in the highway. An unstable plaque consists of a less severe abnormality that can cause accidents (plaque rupture, local hemorrhage, sudden occlusion). A road may shutdown not only from progressive road damage, but also a truck can flip over and shutdown a relatively clean roadway.

Among patients who had recent coronary imaging prior to the onset of a heart attack, half do not have occlusive lesions. Instead of slow progressive reduction in vessel diameter leading to a critically severe flow reduction, the mechanism in the cases of no severe narrowing is attributed to unstable plaque, meaning plaque with thin fibrous caps that rupture, causing sudden thrombosis. Stress tests focus on detection of fixed obstructions and do not warn who has unstable plaque. Thus the next great frontier for coronary imaging is not just to identify flow reducing lesions, but also to identify unstable plaque even if it is not currently flow limiting. This article presents candidate imaging methods and their current capabilities.

Coronary imaging methods include:

• intra-coronary ultrasound (IVUS)
• optical coherence imaging (fiberoptic)
• computed tomographic xray angiography (CTA)
• magnetic resonance angiography (MRA)
• near infra-red spectroscopic imaging (NIRS)
  

  NIRS-IVUS Imaging To Characterize the Composition and Structure of Coronary Plaques 

  David Rizik, MD1 and James, A. Goldstein, MD2

  1. Scottsdale Healthcare Hospital, Scottsdale, AZ

  2. Department Cardiovascular Medicine, William Beaumont Hospital, Royal Oak, MI

  This supplement,

  http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

  authored by highly experienced interventional cardiologists expert in the field of coronary plaque characterization, contains a detailed description of the new NIRS-IVUS combination catheter, and the clinical information obtained during its use in over 90 hospitals in over 10 countries. Case vignettes, cohort outcomes, reviews, and plans for future studies are also presented. It is our hope that this information will be useful in the near term to those seeking to improve PCI. For the longer term, we believe that the NIRS-IVUS system is an excellent candidate for evaluation as a detector of vulnerable plaque. Success in the prospective studies that are planned will make it possible to detect vulnerable plaques and thereby enhance efforts to prevent coronary events.

  Imaging Methods for Detection of Intravascular Plaque – Direct, Robust and/or Validated

  Cap Thickness – OCT

  Expansive Remodeling – IVUS & NIRS-IVUS [Combination TVC System & TVC Insight Catheter]

  Plaque Volume – IVUS & NIRS-IVUS

  Calcification – Angiography, IVUS & NIRS-IVUS

  Thrombus – Angioscopy & OCT

  Inflammation Macrophages – Indirect by OCT

  Lipid Core – IVUS & NIRS-IVUS

  Requires Blood-Free FOV – Angioscopy & OCT

  based on Table 1 p.5

  http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

  Comparative Intravascular Imaging for Lipid Core Plaque: VH-IVUS vs OCT vs NIRS

  Eric Fuh, MD and Emmanouil S. Brilakis, MD, PhD

  VA North Texas Healthcare System, Dallas, TX and Division of Cardiology, Dept of Medicine, UT Southwestern Medical Center, Dallas, TX

  Conclusions

  VH-IVUS, OCT, and NIRS can assist in the detection and evaluation of lipid core plaque. Comparative studies have shown important differences between modalities, but are all limited from lack of comparison with the gold standard of histology. Given the different strengths and weaknesses of each modality, combination imaging will likely provide the best results.41 Further refinement of the clinical implications of LCP detection and its impact on optimizing treatment strategy selection will stimulate advances in LCP detection imaging.

  OCT and NIRS can image through calcified lesions, whereas IVUS cannot. LCPs are often accompanied by neovascularization, which can only be visualized by OCT. VH-IVUS may classify stents, which usually appear white (misclassified as “calcium”) surrounded by red (misclassified as “necrotic core”), although this does not appear to be a limitation for NIRS and OCT.54

  Reference 41:

  Bourantas CV, Gracia-Gracia HM, Naka KK, et al. Hybrid intravascular imaging: current applications and prospective potential in the study of coronary atherosclerosis, JACC 2013;61:1369-1378

  Abstract

  The miniaturization of medical devices and the progress in image processing have allowed the development of a multitude of intravascular imaging modalities that permit more meticulous examination of coronary pathology. However, these techniques have significant inherent limitations that do not allow a complete and thorough assessment of coronary anatomy. To overcome these drawbacks, fusion of different invasive and noninvasive imaging modalities has been proposed. This integration has provided models that give a more detailed understanding of coronary artery pathology and have proved useful in the study of the atherosclerotic process. In this review, the authors describe the currently available hybrid imaging approaches, discuss the technological innovations and efficient algorithms that have been developed to integrate information provided by different invasive techniques, and stress the advantages of the obtained models and their potential in the study of coronary atherosclerosis.

  http://content.onlinejacc.org/article.aspx?articleid=1671094

  Reference 54

  Kim SW, Mintz GS, Hong YJ, et al. The virtual histology intravascular ultrasound appearance of newly placed drug-eluting stents. Am J Cardiol. 2008;102:1182-1186.

  American Journal of Cardiology
  Volume 102, Issue 9 , Pages 1182-1186, 1 November 2008

  The Virtual Histology Intravascular Ultrasound Appearance of Newly Placed Drug-Eluting Stents

  • Sang-Wook Kim, MD
  • Gary S. Mintz, MD
  • Young-Joon Hong, MD
  • Rajbabu Pakala, PhD
  • Kyung-Sook Park, MPH
  • Augusto D. Pichard, MD
  • Lowell F. Satler, MD
  • Kenneth M. Kent, MD
  • William O. Suddath, MD
  • Ron Waksman, MD
  • Neil J. Weissman, MD

  Received 17 January 2008; received in revised form 17 March 2008; accepted 17 March 2008. published online 13 June 2008.

  • Abstract
  • Full Text
  • PDF
  • Images
  • References
  Intravascular ultrasound (IVUS) is used before and after intervention and at follow-up to assess the quality of the acute result as well as the long-term effects of stent implantation. Virtual histology (VH) IVUS classifies tissue into fibrous and fibrofatty plaque, dense calcium, and necrotic core. Although most interventional procedures include stent implantation, VH IVUS classification of stent metal has not been validated. In this study, the VH IVUS appearance of acutely implanted stents was assessed in 27 patients (30 lesions). Most stent struts (80%) appeared white (misclassified as “calcium”) surrounded by red (misclassified as “necrotic core”); 2% appeared just white, and 17% were not detectable (compared with grayscale IVUS because of the software-imposed gray medial stripe). The rate of “white surrounded by red” was similar over the lengths of the stents; however, undetectable struts were mostly at the distal edges (31%). Quantitatively, including the struts within the regions of interest increased the amount of “calcium” from 0.23 ± 0.35 to 1.07 ± 0.66 mm² (p <0.0001) and the amount of “necrotic core” from 0.59 ± 0.65 to 1.31 ± 0.87 mm² (p <0.0001). Most important, because this appearance occurs acutely, it is an artifact, and the red appearance should not be interpreted as peristrut inflammation or necrotic core when it is seen at follow-up. In conclusion, acutely implanted stents have an appearance that can be misclassified by VH IVUS as “calcium with or without necrotic core.” It is important not to overinterpret VH IVUS studies of chronically implanted stents when this appearance is observed at follow-up. A separate classification for stent struts is necessary to avoid these misconceptions and misclassifications.

   http://www.ajconline.org/article/S0002-9149(08)00567-5/abstract?refissn=1936-8798&refuid=S1936-8798%2812%2900367-6

  Table 2. Comparison of three intravascular imaging modalities for the detection of coronary lipid core plaque.

  Intravascular Imaging Modalities for Detecting LCP

  Vol. 25, Supplement A, 2013

  13A

   VH-IVUS (20 MHz)                        OCT                          NIRS-IVUS (40 MHz)

  Hybrid intravascular imaging  No No Yes

  Axial resolution, μm 200 10 100

  Imaging through blood ++ – ++

  Need for blood column clearance during image acquisition No Yes No

  Imaging through stents No Yes Yes

  Imaging through calcium No Yes Yes for NIRS – No for IVUS

  Imaging neovascularization No Yes No

  Detection of non-superficial LCPs Yes No No

  Evaluation of LCP cap thickness + ++ *

  Detection of thrombus – + *

  Expansive remodeling ++ – ++

  Need for manual image processing for LCP detection Yes Yes No

  ++ = excellent; + = good; ± = possible; – = impossible; * = potential under investigation

  VH-IVUS = virtual histology intravascular ultrasound; OCT = optical coherence tomogra-phy; NIRS = near-infrared spectroscopy; LCP = lipid core plaque 

  The Search for Vulnerable Plaque — The Pace Quickens

   

  Ryan D. Madder, MD1, Gregg W. Stone, MD2, David Erlinge, MD3, James E. Muller, MD4

  Affiliations

  1Frederik Meijer Heart & Vascular Institute, Spectrum Health, Grand Rapids, Michigan;

  2New York Presbyterian Hospital, Columbia University and Car-diovascular Research Foundation, New York, New York;

  3Department of Cardiology, Lund University, Lund, Sweden;

  4Infraredx, Inc., Burlington, Massachusetts

  Disclosure: Drs. Madder and Erlinge report no financial relationships or conflicts of interest regarding the content herein.

  Dr. Stone is a consultant for Infraredx, Inc., Volcano Corp., Medtronic, and Boston Scientific, and is a member of the scientific advisory boards for Boston Scientific and Abbott Vascular.

  Dr. Muller is a full-time employee of Infraredx, Inc from which he receives salary and equity.

  Address for Correspondence: Email: ryan.madder@spectrumhealth.org

  The search for the vulnerable plaque has been a lengthy endeavor requiring the work of multiple individuals and institutions over many years. It is disappointing that in more than 2 decades since the “vulnerable plaque” concept was formulated, over 40 million coronary events have occurred. However, it is encouraging that positive answers are now available for most of the questions related to a vulnerable plaque detection and treatment strategy. As shown in Table 1, most of the essential preconditions of a successful vulnerable plaque strategy are present. This positive information has accelerated the pace of work in this area. The pathophysiology of coronary events is well-understood; powerful imaging methods are available; and therapies, both existing and novel, may well be effective (although appropriately powered randomized trials are required to demonstrate their safety and effectiveness). The time is approaching for the conduct of prospective outcome trials to determine the value of a vulnerable plaque strategy for more effective prevention of coronary events.

  Table 1. Essential Components of a Strategy to Prevent Coronary Events by the Detection and Treatment of Vulnerable Plaques

  Essential Components	Evidencefrom  Published Research
  Pathophysiology of Coronary Events
  • Are the causes of coronary events known?	Yes	Constantinides and others have shown that most coronary events are caused by rupture of a thin-capped LRP with subsequent formation of an occlusive thrombus.1-5
  • Are LRPs focal?	Yes	Cheruvu et al demonstrated that ruptures and TCFA occupy less than 4% of the length of arteries studied at autopsy.8
  • Are LRPs stable over time?	Yes	Kubo et al demonstrated that most fibroatheromas by radiofrequency IVUS remain fibroatheromas over time.39
  Detection of Suspected Vulnerable Plaque by Invasive Imaging (For Secondary Prevention)
  • Can invasive imaging safely detect LRP?	Yes	Waxman et al, Ino et al, and many others have demonstrated the safety of detecting LRP in patients.40
  • Do cross-sectional studies show increased LRP concentrated at culprit sites?	Yes	Madder et al, Erlinge et al, Ino et al have shown LRP concentrated at the culprit site across the spectrum of ACS.14,16,41
  • Do prospective studies show that suspected vulnerable plaque can be detected in advance?	Yes	PROSPECT, VIVA, PREDICTION established the principle by proving that increased plaque burden predicted events but prediction lacked specificity.23-25
  • Is more specific detection of vulnerable plaque possible?	?	NIRS-IVUS and OCT may provide more specific detection of VP, but have not yet been tested in a prospective study.
  Can Vulnerable Plaques be Treated?
  • Is systemic treatment of LRPs possible with current agents?	Yes	YELLOW study showed a reduction in LRP with rosuvastatin.33
  • Is focal treatment of LRPs possible with current methods?	Yes	Ruptured LRPs are routinely stented in ACS in clinical practice with good outcomes.
  • Can systemic treatment be enhanced with new agents?	?	PCSK9 inhibitors, Apo A1 Milano, other agents in development may be more effective than statins, but more costly.35,36
  • Can focal treatments be enhanced with new methods?	?	Bioresorbable vascular scaffolds and/or drug-coated balloons may be useful for VP.
  Primary Prevention
  • Can demographic and serum biomarkers be used as a first step in a screening strategy?	Yes	Framingham Risk Score, improved serum biomarkers, and genetic markers can identify individuals at increased risk.
  • Can non-invasive imaging with CTA detect LRP and increased risk?	Yes	Motoyama et al have identified CTA markers associated with future events.26
  Cost-Effectiveness
  • Will a strategy of detection and treatment of vulnerable plaque, if proven to be successful, be cost-effective for secondary prevention?	Probably	Bosch et al demonstrated that for patients already undergoing invasive imaging, the added costs of detection and treatment of VP are likely to be less than the cost of second events, leading to a cost-saving approach that also improves health.38
  • Will a strategy of detection and treatment of vulnerable plaque, if proven to be successful, be cost-effective for primary prevention?	?	Bosch et al: For primary prevention the cost of screening would be greater than for secondary prevention. Cost-effectiveness would depend upon cost, the accuracy of detection, and effectiveness of therapy.38
  ACS = acute coronary syndrome; CTA = coronary computed tomographic angiography; LRP = lipid-rich plaque; TCFA = thin-capped fibroatheroma;

  References

  1. Constantinides P. Plaque fissures in human coronary thrombosis. J Atheroscler Res. 1966;6:1-17.

  2. Friedman M, Van den Bovenkamp GJ. The pathogenesis of a coronary thrombus. Am J Pathol. 1966;48:19-44.

  3. Burke AP, Farb A, Malcom GT, et al. Coronary risk factors and plaque morphology in men with coronary disease who died suddenly. N Engl J Med. 1997;336:1276-1282.

  4. Farb A, Tang AL, Burke AP, et al. Sudden coronary death. Frequency of active coronary lesions, inactive coronary lesions, and myocardial infarction. Circulation. 1995;92:1701-1709.

  5. Virmani R, Kolodgie FD, Burke AP, Farb A, Schwartz SM. Lessons from sudden coronary death: a comprehensive morphological classification scheme for atherosclerotic lesions. Arterioscler Thromb Vasc Biol. 2000;20:1262-1275.

  6. Waksman R, Serruys PW. Handbook of the Vulnerable Plaque. Martin Dunitz: London, England, 2004.

  7. Libby P, Ridker PM, Hansson GK. Progress and challenges in translating the biology of atherosclerosis. Nature. 2011;473:317-325.

  8. Cheruvu P, Finn A, Gardner C, et al. Frequency and distribution of thin-cap fibroatheroma and ruptured plaques in human coronary arteries – a pathologic study. J Am Coll Cardiol. 2007;50:940-949.

  9. Hong M, Mintz GS, Lee CW, et al. Comparison of coronary plaque rupture between stable angina and acute myocardial infarction: a three-vessel intravascular ultrasound study in 235 patients. Circulation. 2004;110:928-933.

  10. Fujii K, Kobayashi Y, Mintz GS, et al. Intravascular ultrasound assessment of ulcerated ruptured plaques. A comparison of culprit and non-culprit lesions of patients with acute coronary syndromes and lesions in patients without acute coronary syndromes. Circulation. 2003;108:2473-2478.

  11. Ehara S, Kobayashi Y, Yoshiyama M, et al. Spotty calcification typifies the culprit plaque in patients with acute myocardial infarction. An intravascular ultrasound study. Circulation. 2004;110:3424-3429.

  12. Lee SY, Mintz GS, Kim SY, et al. Attenuated plaque detected by intravascular ultrasound: clinical, angiographic, and morphologic features and post-percutaneous coronary intervention complications in patients with acute coronary syndromes. J Am Coll Cardiol Intv. 2009;2:65-72.

  13. Asakura M, Ueda Y, Yamaguchi O, et al. Extensive development of vulnerable plaques as a pan-coronary process in patients with myocardial infarction: an angioscopic study. J Am Coll Cardiol. 2001;37:1284-1288.

  14. Ino Y, Kubo T, Tanaka A, et al. Difference of culprit lesion morphologies between ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndrome. J Am Coll Cardiol Intv. 2011;4:76-82.

  15. Madder RD, Smith JL, Dixon SR, Goldstein JA. Composition of target lesions by near-infrared spectroscopy in patients with acute coronary syndrome versus stable angina. Circ Cardiovasc Interv. 2012;5:55-61.

  16. Madder RD, Goldstein JA, Madden SP, et al. Detection by near-infrared spectroscopy of large lipid core plaques at culprit sites in patients with acute ST-segment elevation myocardial infarction. J Am Coll Cardiol Intv. In press, 2013.

  17. Hoffmann U, Moselewski F, Nieman K, et al. Noninvasive assessment of plaque morphology and composition in culprit and stable lesions in acute coronary syndrome and stable lesions in stable angina by mulitdetector computed tomography. J Am Coll Cardiol. 2006;47:1655-1662.

  18. Motoyama S, Kondo T, Sarai M, et al. Multislice computed tomographic characteristics of coronary lesions in acute coronary syndromes. J Am Coll Cardiol. 2007;50:319-326.

  19. Madder RD, Chinnaiyan KM, Marandici AM, Goldstein JA. Features of disrupted plaques by coronary computed tomographic angiography: correlates with invasively proven complex lesions. Circ Cardiovasc Imaging. 2011;4:105-113.

  20. Muller JE, Tofler GH, Stone PH. Circadian variation and triggers of onset of acute cardiovascular disease. Circulation. 1989;79;733-743.

  21. Kolodgie FD, Burke AP, Farb A, et al. The thin-cap fibroatheroma: a type of vulnerable plaque: the major precursor lesion to acute coronary syndromes. Curr Opin Cardiol. 2001;16:285-292.

  22. Yamagishi M, Terashima M, Awano K, et al. Morphology of vulnerable coronary plaque: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary syndrome. J Am Coll Cardiol. 2000;35:106-111.

  23. Stone GW, Maehara A, Lansky A, et al. A prospective natural-history study of coronary atherosclerosis. N Engl J Med. 2011;364:226-235.

  24. Calvert PA, Obaid DR, O’Sullivan M, et al. Association between IVUS findings and adverse outcomes in patients with coronary artery disease: the VIVA (VH-IVUS in Vulnerable Atherosclerosis) study. J Am Coll Cardiol Imaging. 2011;4:894-901.

  25. Stone PH, Saito S, Takahashi S, et al. Prediction of progression of coronary artery disease and clinical outcomes using vascular profiling of endothelial shear stress and arterial plaque characteristics: the PREDICTION study. Circulation. 2012;126:172-181.

  26. Motoyama S, Sarai M, Harigaya H, et al. Computed tomographic angiography characteristics of atherosclerotic plaques subsequently resulting in acute coronary syndrome. J Am Coll Cardiol. 2009;54:49-57.

  27. Stone GW, Maehara A, Mintz GS. The reality of vulnerable plaque detection. J Am Coll Cardiol Imaging. 2011;4:902-904.

  28. Madder RD, Steinberg DH, Anderson RD. Multimodality direct coronary imaging with combined near-infrared spectroscopy and intravascular ultrasound: Initial US experience. Catheter Cardiovasc Interv. 2013;81:551-7.

  29. Kume T, Akasaka T, Kawamoto T, et al. Measurement of the thickness of the fibrous cap by optical coherence tomography. Am Heart J. 2006;152:755.e1-4.

  30. Nissen SE, Tuzcu EM, Schoenhagen P, et al. Effect of intensive compared with moderate lipid-lowering therapy on progression of coronary atherosclerosis: a randomized controlled trial. JAMA. 2004;291:1071-1080.

  31. Nissen SE, Nicholls SJ, Sipahi I, et al. Effect of very high-intensity statin therapy on regression of coronary atherosclerosis: the ASTEROID trial. JAMA. 2006;295:1556-1565.

  32. Nicholls SJ, Ballantyne CM, Barter PJ, et al. Effect of two intensive statin regimens on progression of coronary disease. N Engl J Med. 2011;365:2078-2087.

  33. Kini AS, Baber U, Kovacic JC, et al. Changes in plaque lipid content after short-term, intensive versus standard statin therapy: the YELLOW trial. J Am Coll Cardiol. 2013 (In press).

  34. Takarada S, Imanishi T, Kubo T, et al. Effect of statin therapy on coronary fibrous-cap thickness in patients with acute coronary syndrome: assessment by optical coherence tomography study. Atherosclerosis. 2009;202:491-497.

  35. Stein EA, Gipe D, Bergeron J, et al. Effect of a monoclonal antibody to PCSK9, REGN727/SAR236553, to reduce low-density lipoprotein cholesterol in patients with heterozygous familial hypercholesterolaemia on stable statin dose with or without ezetimibe therapy: a phase 2 randomised controlled trial. Lancet. 2012;380:29-36.

  36. Nissen SE, Tsunoda T, Tuzcu EM, et al. Effect of recombinant ApoA-I Milano on coronary atherosclerosis in patients with acute coronary syndromes: a randomized controlled trial. JAMA. 2003;290:2292-2300.

  37. Braunwald, E. Epilogue: What do clinicians expect from imagers? J Am Coll Cardiol. 2006;47:C101-C103.

  38. Bosch JL, Beinfeld MT, Muller JE, Brady T, Gazelle GS. A cost-effectiveness analysis of a hypothetical catheter-based strategy for the detection and treatment of vulnerable coronary plaques with drug-eluting stents. J Interv Cardiol. 2005;18:339-349.

  39. Kubo T, Maehara A, Mintz GS, et al. The dynamic nature of coronary artery lesion morphology assessed by serial virtual histology intravascular ultrasound tissue characterization. J Am Coll Cardiol. 2010;55:1590-1597.

  40. Waxman S, Dixon SR, L’Allier P, et al. In vivo validation of a catheter-based near-infrared spectroscopy system for detection of lipid core coronary plaques: initial results and exploratory analysis of the SPECTroscopic Assessment of Coronary Lipid (SPECTACL) multicenter study. J Am Coll Cardiol Imaging. 2009;2:858-868.

  41. Erlinge D, Muller JE, Puri R, et al. Validation of a near-infrared spectroscopic signature of lipid located at culprit lesions in ST-segment elevation myocardial infarction. European Atherosclerosis Society. June 2013 (abstract).

  http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

  Proposed Algorithm for Vulnerable Plaque Screening and Treatment 

  

  SOURCE

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  Long-term Consequences of a Lipid Core Plaque

  Christos V. Bourantas, MD, PhD1, Hector M. Garcia, MD, PhD1, Roberto Diletti, MD1, Carlos A.M. Campos, MD1, Yaojun Zhang, MD, PhD1, Scot Garg, MRCP, PhD2, Patrick W. Serruys, MD, PhD1

  1Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, The Netherlands and 2Department of Cardiology, East Lancashire NHS Trust, Haslingden Road, Blackburn, Lancashire, United Kingdom.

  Disclosures: The authors report no financial relationships or conflicts of interest regarding the content herein.

  Address for correspondence:  Email: p.w.j.c.serruys@erasmusmc.nl

  The advent of intravascular imaging in the 1980s allowed us to study in vivo plaque morphology and its prognostic implications.

  • Angioscopy and intravascular ultrasound (IVUS) were the first imaging techniques that provided information about the composition of plaque and allowed detection of its lipid component.7,8

  However, the first applications of these modalities in the clinical setting not only underscored their potential value in the study of atherosclerosis but also highlighted their limitations in characterizing atheroma.9-11 Therefore an effort was made over the last few years to develop advanced techniques that would allow more reliable assessment of a plaque’s composition. Today several modalities are available for this purpose including:

  • the radiofrequency analysis of the IVUS backscatter signal (RF-IVUS),
  • near-infrared spectroscopy (NIRS),
  • optical coherence tomography (OCT),
  • magnetic resonance spectroscopy,
  • intravascular magnetic resonance imaging,
  • Raman spectroscopy,
  • photoacoustic imaging, and
  • time resolved spectroscopic imaging (Figure 1).

  Some of these modalities are still in their infancy, while others have already been used in the clinical setting providing robust evidence about the prognostic implications of the differing compositions of the plaque. The aim of this review article is to present the most recent evidence about the long-term consequences of the atheroma’s phenotype. 

  Current Evidence from NIRS-based Clinical Studies

  NIRS relies on the principle that different organic molecules absorb and scatter NIRS light to different degrees and wavelengths. Recent advances in device technology enabled the development of a catheter suitable for assessing the plaque in human coronaries that is able to emit NIR light and acquire the scattered signal. Spectral analysis of the obtained signal provides a color-coded display, called a chemogram (Figure 1C), which provides the probability that lipid core is present in the superficial plaque (studied depth approximately: 1 mm). Several studies have examined the reliability of this technique using histology as the gold standard and demonstrated a high overall accuracy in detecting lipid-rich plaques while others demonstrated its feasibility in the clinical setting.19-20

  The European Collaborative Project on Inflammation and Vascular Wall Remodeling in Atherosclerosis (NCT01789411) – NIRS sub-study was the first prospective trial designed to evaluate the prognostic implications of an increased lipid component, as detected by NIRS, in coronary plaques. Two hundred three patients that underwent X-ray angiography, and PCI if it was indicated, had NIRS in a non-culprit coronary segment and were followed-up for 1 year. Twenty-eight patients sustained a MACE during the follow-up period; 21 of these events were non-culprit lesion related. Lipid plaque burden index appeared to be an independent predictor of MACE (hazard ratio: 4.04, 95% confidence interval: 1.33-12.29; P=0.01). 

  Currently, the Chemometric Observation of Lipid Rich Plaque of Interest in Native Coronary Arteries (COLOR, NCT00831116) registry is recruiting patients. This study is planning to recruit 2000 patients that will be investigated with NIRS imaging, and aims to examine the association between the presence of a necrotic core in the atheroma and subsequent coronary events. Preliminary results indicate that the absence of lipid-rich plaques is related with better outcomes (www.infraredx.com/the-color-registry). 

  Current Evidence From OCT-based Clinical Studies

  OCT imaging with its high resolution appears able to provide detailed assessment of the superficial plaque and visualize structures that are unseen by other techniques such as the presence of micro calculations of thin-capped fibroatheroma (TCFA). However, a significant limitation of this technique is its poor penetration (1-2 mm), which does not permit through visualization of plaque burden, as well as its low capacity in differentiating lipid from calcific tissue when these are deeply embedded in the vessel wall.21

  In this analysis, 53 patients who underwent PCI had OCT imaging in non-obstructive lesion sat baseline and repeat angiography at 7 months follow-up. They found that plaques with a TCFA phenotype, exhibiting vessel walldiscontinuities, macrophages, neo-vessels, and thrombi were morelikely to progress and cause significant angiographic obstructions.²²

  Future Perspective in Plaque Imaging – Conclusions

  Cumulative data derived from intravascular imaging studies have provided robust evidence about the prognostic implications of plaque’s composition and burden, and demonstrated a strong association between the presence of lipid-rich plaques and future cardiovascular events. Plaque pathology and quantification of lipid components is done by hybrid catheters able to acquire different intravascular imaging data.23

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   http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

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  9.Hiro T, Leung CY, Russo RJ, et al. Variability in tissue characterization of atherosclerotic plaqueby intravascular ultrasound: a comparison of four intravascular ultrasound systems. Am J CardImaging. 1996;10:209-218.

  10.ﾭdial infarction: ability of optical coherence tomography compared with intravascular ultrasoundand coronary angioscopy. J Am Coll Cardiol. 2007;50:933-939.

  11.ﾭated with future risk of acute coronary syndrome: detection of vulnerable patients by angioscopy.J Am Coll Cardiol. 2006;47:2194-2200.

  12.ﾭnary syndrome using integrated backscatter intravascular ultrasound. J Am Coll Cardiol.2006;47:734-741.

  13.Amano T, Matsubara T, Uetani T, et al. Lipid-rich plaques predict non-target-lesion ischemicevents in patients undergoing percutaneous coronary intervention. Circ J. 2011;75:157-166.

  14.ﾭsclerosis. N Engl J Med. 2011;364:226-235.

  15.Calvert PA, Obaid DR, O’Sullivan M, et al. Association between IVUS findings and adverseﾭsclerosis) Study. JACC Cardiovasc Imaging. 2011;4:894-901.

  16.Granada JF, Wallace-Bradley D, Win HK, et al. In vivo plaque characterization using intravascularultrasound-virtual histology in a porcine model of complex coronary lesions. Arterioscler ThrombVasc Biol. 2007;27:387-393.

  17.Sales FJ, Falcao BA, Falcao JL, et al. Evaluation of plaque composition by intravascular ultrasound“virtual histology”: the impact of dense calcium on the measurement of necrotic tissue. ﾭvention. 2010;6:394-399.

  18.ﾭtual histology intravascular ultrasound in porcine coronary artery disease. Circ Cardiovasc Imaging. 2010;3:384-391.

  19.ﾭmens with a novel catheter-based near-infrared spectroscopy system. JACC Cardiovasc Imaging. 2008;1:638-648.

  20.Waxman S, Dixon SR, L’Allier P, et al. In vivo validation of a catheter-based near-infrared spectrosﾭcopy system for detection of lipid core coronary plaques: initial results of the SPECTACL study.JACC Cardiovasc Imaging. 2009;2:858-868.

  21.Manfrini O, Mont E, Leone O, et al. Sources of error and interpretation of plaque morphology byoptical coherence tomography. Am J Cardiol. 2006;98:156-159.

  22.Uemura S, Ishigami K, Soeda T, et al. Thin-cap fibroatheroma and microchannel findings inoptical coherence tomography correlate with subsequent progression of coronary atheromatousplaques. Eur Heart J. 2012;33:78-85.

  23.ﾭplications and prospective potential in the study of coronary atherosclerosis. J Am Coll Cardiol.2013;61:1369-378.

  24.ﾭtroscopy and intra-vascular ultrasound catheter to identify composition and structure of coronaryplaque. EuroIntervention. 2010;5:755-756.

  25.ﾭﾭgrated Biomarker and Imaging Study-3 (IBIS-3). EuroIntervention. 2012;8:235-241.

   http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

  NIRS-IVUS Imaging Identifies Lesions at High Risk of Peri-Procedural Myocardial Infarction

  James A. Goldstein, MD, Simon R. Dixon, MBChB*, Gregg W. Stone, MD

  From the Department of Cardiovascular Medicine, William Beaumont Hospital, Royal Oak, MI.

  Address for correspondence: James A. Goldstein, MD, FACC, Department of Cardiovascular Medicine, William Beaumont Hospital, 3601 West 13 Mile Road, Royal Oak, Michigan 48073. Email: jgoldstein@beaumont.edu

  Disclosures: Dr. Goldstein is a consultant for and owns equity in Infraredx, Inc. Dr. Stone is a consultant for Infraredx, Inc., Volcano Corp., Medtronic, and Boston Scientific, and is a member of the scientific advisory boards for Boston Scientific and Abbott Vascular. Dr. Dixon reports no financial relationships or conflicts

  Abstract:

  Percutaneous coronary intervention (PCI) is associated with distal embolization complications, including peri-procedural myocardial infarction (PPMI), including no-reflow, in 3%-15% of cases. These complications are predominantly related to distal embolization of lipid core plaque (LCP) components. Catheter-based near-infrared spectroscopy (NIRS) provides rapid, automated detection of LCPs, the magnitude of which appears associated with a high-risk of PPMI. Employing this technique may facilitate development of preventive measures such as embolic protection devices (EPDs).

  J INVASIVE CARDIOL 2013;25 (Suppl A):14A-16A

  Key words: Distal embolization, lipid core plaque, near-infrared spectroscopy, peri-procedural myocardial infarction

  

  Figures 1. A 62-year-old man with stable angina underwent coronary angiography, which demonstrated a complex hazy ulcerated culprit lesion in the mid-right coronary artery (Figure 1A, solid arrow). Neither the angiogram nor an intravascular ultrasound image indicated the presence of thrombus. NIRS demonstrated a large yellow signal spanning the circumference of the culprit site (Figure 1B, white rectangle), indicating the presence of a napkin-ring LCP; a smaller LCP was evident distally (Figure 1, open arrow).

  

  Figure 2. Balloon angioplasty was performed (Figure 2A, arrow), which led to prompt no-reflow (Figure 2B, arrow) associated with severe bradyarrhythmia and profound hypotension (Figure 2C). After brief cardiopulmonary resuscitation and pharmacological support with atropine and dopamine, physiologic rhythm and blood pressure were restored and stenting resulted in excellent angiographic outcome. However, the patient developed a peri-stenting non-transmural infarction (peak creatine kinase of 512 ng/mL) and required an additional day of hospital care in an intensive care unit. (Goldstein JA, et al. JACC Cardiovasc Imaging. 2009;2(12):1420-1424. Reproduced with permission.)

  On Page 14A in

  http://www.invasivecardiology.com/files/Infraredx_FINALPDF.pdf

  Pharmacological Therapy of Lipid Core Plaque

  Jason C. Kovacic, MD, PhD, Annpoorna Kini, MD, MRCP

  From The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York.

  Address for correspondence: Dr. Annapoorna Kini, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1030, New York, NY, 10029. Email: annapoorna.kini@mountsinai.org

  Disclosures: Dr. Kovacic is supported by National Institutes of Health Grant K08HL111330 and has received research support from AstraZeneca. Dr. Kini acknowledges honoraria from Medscape and has received research grant support from InfraReDx.

  A new group of terms is slowly creeping in to the atherosclerotic disease lexicon: “Lipid Arc,” “Lipid Core Plaque,” “Lipid-Rich Plaque,” “Lipid Core Burden Index” and other similar phrases. While clinicians and researchers have long been aware of the central importance of lipid in the biology of atherosclerosis, the growing use of these terms is driven by the recent widespread use of novel imaging modalities that provide accurate detection, and even quantification, of the extent of lipid that is contained within the core of an atherosclerotic plaque. Our ability to detect and quantify lipid in plaques is opening up new therapeutic opportunities for modifying the atherosclerotic disease process, which may ultimately be of benefit to patients.

  At the present time there are 3 methods that are commonly used to measure the extent of lipid in atherosclerotic plaques. Perhaps most familiar of these is coronary computer tomographic (CT) scanning. While more commonly used to quantitate calcification or luminal stenosis, CT scanning is readily able to quantitate the extent of lipid associated with an atherosclerotic lesion. However, while several studies have reported various Hounsfield Unit (HU)-based criteria to distinguish lipid-rich from fibrous plaques, the HU cut-off points have so far been inconsistent. The use of CT for detecting lipid-rich plaque is further limited by its relatively low spatial resolution and the fact that the HU values for distinguishing between fibrous and lipid-rich plaques are overlapping.1 In contrast, optical coherence tomography (OCT) offers perhaps the greatest spatial resolution of all clinically available coronary imaging devices. OCT can offer exquisite detail of abluminal coronary artery anatomy, including detection of lipid core plaque. However, while automated systems are being developed, at the present time the quantitation of lipid by OCT is a somewhat specialized process that typically involves detailed off-line analysis.

  A specific intra-coronary imaging catheter for the quantitation of coronary artery lipid content is now available and FDA approved: diffuse reflectance near-infrared spectroscopy (NIRS). The application of NIRS to identify lipid deposition within coronary arteries has been validated ex vivo2-5 and in vivo.6,7 Although NIRS itself is essentially only able to detect and quantitate lipid, design changes and technological advances to this catheter have now made it possible to combine intravascular ultrasound (IVUS) and NIRS technology on a single instrument. In one of the few clinical studies published to date using this device, NIRS has already shown that a high lipid burden in a target lesion undergoing percutaneous coronary intervention (PCI) is associated with an increased likelihood of peri-procedural myocardial infarction.7

  It is well known that the reduction of cholesterol levels by statin therapy is associated with significant decreases in plaque burden. REVERSAL,8 ASTEROID,9 and more recently the SATURN II10 trial showed that in patients with coronary artery disease (CAD), lipid lowering with high-dose statin therapy reduced progression of plaque atheroma burden, even causing plaque regression of some lesions. However, while reduction in atheroma burden and plaque size are important anatomical endpoints, a major unresolved question had been the mechanism of action of statins and the unanswered question of whether they reduce plaque lipid content. Indeed, a high burden of plaque lipid is one of the cardinal features of a rupture-prone vulnerable lesion.11 Therefore, the ability to reduce plaque lipid content may have important effects on lesion stability and therefore, might impact clinical endpoints.

  The advent of sensitive imaging tools for the evaluation of plaque lipid content has paved the way for the investigation of potential pharmacological therapies for lipid core plaque. In particular, the ability of NIRS to provide an automated quantitation of plaque lipid provides a ready-made platform for this task. We recently completed the YELLOW study of high-dose statin therapy for the potential reduction of coronary artery lipid content as assessed by NIRS. We randomized 87 patients with multivessel CAD undergoing elective PCI to rosuvastatin 40 mg daily vs conventional statin therapy. Following PCI of the culprit lesion, non-culprit lesions with a fractional flow reserve (FFR) <0.8 were interrogated using IVUS and NIRS. Changes in plaque composition were assessed after 6-12 weeks during follow-up angiography. The core finding of this study was that high-dose statin therapy was associated with significant reductions in the lipid content of coronary atherosclerotic plaques. Interestingly, despite reduced plaque lipid content, in this relatively short time period concordant changes in gross lesion characteristics such as total atheroma volume or % plaque burden were not observed.12 In short, the YELLOW study identified that even before gross atheroma regression occurs, lipid removal from plaques is an early event upon initiation of high-dose statin therapy. Furthermore, the results of the YELLOW study are concordant with the known acute benefits of statin therapy in patients presenting with acute coronary syndromes, where the early introduction of these agents is known to be of clinical benefit.13 While the YELLOW study was the first of this nature and the results remain to be replicated in a larger trial, these findings have revived interest in the concept of the “vulnerable plaque” because it appears possible that by causing lipid core reduction over a just few weeks, high-dose statin therapy may have rapid plaque stabilizing effects. We are now embarking on the YELLOW II study, where we will further explore the utility of high-dose rosuvastatin for the early reduction of plaque lipid content and potential mechanistic pathways.

  What other agents might have therapeutic efficacy for lipid core reduction? This question is perhaps more complex than it might first appear, because at the present time we do not know the specific mechanism whereby high-dose rosuvastatin causes lipid reduction in plaques. Theoretically it may be due to reduced LDL, increased HDL, other mechanisms or a combination of these effects. Potentially, other agents that are already available such as bile acid sequestrants, ezetimibe, and fibrates may have a weak lipid core reducing effect. However, we would underscore the fact that at the present time the utility of these agents is speculative, and no other agent (apart from high-dose rosuvastatin in the YELLOW study) has been shown to reduce lipid content in vivo in human plaques. Furthermore, given the fact that these other agents are far less potent in their overall effect than rosuvastatin 40 mg/day, it may be clinically challenging to determine if they have efficacy for lipid core reduction beyond that of statins.

  In addition to pharmacotherapy, it must be remembered that we have several non-pharmacological treatments in our armamentarium that may impact lipid core reduction. For example, exercise is known to be associated with reduced plaque lipid content,14 and proper adherence to current guidelines with respect to lifestyle and diet are of paramount importance in any patient in whom it is considered desirable to reduce plaque lipid content.

  Looking ahead, there are several emerging and investigational agents that may hold promise for lipid core reduction. Microsomal triglyceride transfer protein (MTP) is expressed in the liver, intestine, and the heart and is required for the proper assembly of VLDL and chylomicrons. In animals, treatment with an MTP inhibitor leads to a rapid reduction in plasma lipid levels, with a significant decrease in lipid content and monocyte-derived (CD68+) cells in atherosclerotic plaques.15 On December 21, 2012, the first of the MTP inhibitors was approved for clinical use. Lomitapide (marketed as Juxtapid) was approved by the FDA as an adjunct to a low fat diet and other lipid-lowering treatments for patients with homozygous familial hypercholesterolemia. However, concerns have been raised due to hepatic side effects and liver toxicity. As a result, lomitapide will carry a boxed warning and will only be available through a restricted program.16 Another new drug that was recently given restricted approval in the US for homozygous familial hypercholesterolemia is mipomersen. This agent is an antisense therapeutic that targets messenger RNA for apolipoprotein B, leading to reduced apoB protein and LDL levels. While showing efficacy for lowering LDL,17 safety concerns have thus far prohibited this agent from gaining approval for use in Europe. PCSK9 inhibitors are yet another novel class of agents that may hold promise for reducing lipid core plaque. PCSK9 is involved in the degradation of the LDL receptor (LDLR), and by inhibiting PCSK9 it is believed that this permits more LDL receptors to remain active and participate in LDL removal from the blood, thereby reducing plasma LDL and cholesterol levels. Denis et al18 recently demonstrated that gene inactivation of PCSK9 in mice reduced aortic cholesterol accumulation and atherosclerotic lesion development in atherosclerosis-prone mice. Based on their powerful LDL lowering effect, intense efforts are currently underway to develop clinically efficacious PCSK9 inhibitors with several agents already moving to phase II/III human studies.19 While all of these new and emerging therapies are cause for optimism, the recent experience with CETP-inhibitors and the overall failure of this class so far to stand up to rigorous testing as HDL raising agents in phase III studies20,21 serves to remind us that not all “promising future therapies” survive through the arduous clinical testing pipeline.

  In conclusion, there is renewed interest in the concept of “plaque regression” and pharmacological therapy for “lipid core reduction.” This has been driven by our increasing ability to image and quantify these phenomena, and more recently by the provocative findings that high-dose statin therapy may achieve both of these clinical endpoints. Further studies are now required to evaluate novel agents, define mechanisms of action and, most importantly, to confirm that atherosclerotic lipid core reduction is associated with plaque stabilization and fewer clinical endpoints.

  References, pp. 27A-28A in the Supplement

  1. Kristanto W, van Ooijen PM, Greuter MJ, et al. Non-calcified coronary atherosclerotic plaque visualization on CT: effects of contrast-enhancement and lipid-content fractions. Int J Cardiovasc Imaging. 2013; online ahead of print.

  2. Cassis LA, Lodder RA. Near-IR imaging of atheromas in living arterial tissue. Anal Chem. 1993;65:1247-1256.

  3. Jaross W, Neumeister V, Lattke P, et al. Determination of cholesterol in atherosclerotic plaques using near infrared diffuse reflection spectroscopy. Atherosclerosis. 1999;147:327-337.

  4. Moreno PR, Lodder RA, Purushothaman KR, et al. Detection of lipid pool, thin fibrous cap, and inflammatory cells in human aortic atherosclerotic plaques by near-infrared spectroscopy. Circulation. 2002;105:923-927.

  5. Wang J, Geng YJ, Guo B, et al. Near-infrared spectroscopic characterization of human advanced atherosclerotic plaques. J Am Coll Cardiol. 2002;39:1305-1313.

  6. Waxman S, Dixon SR, L’Allier P, et al. In vivo validation of a catheter-based near-infrared spectroscopy system for detection of lipid core coronary plaques: initial results of the SPECTACL study. JACC Cardiovasc Imaging. 2009;2:858-868.

  7. Goldstein JA, Maini B, Dixon SR, et al. Detection of lipid-core plaques by intracoronary near-infrared spectroscopy identifies high risk of periprocedural myocardial infarction. Circ Cardiovasc Interv. 2011;4:429-437.

  8. Nissen SE, Tuzcu EM, Schoenhagen P, et al. Statin therapy, LDL cholesterol, C-reactive protein, and coronary artery disease. N Engl J Med. 2005;352:29-38.

  9. Nissen SE, Nicholls SJ, Sipahi I, et al. Effect of very high-intensity statin therapy on regression of coronary atherosclerosis: the ASTEROID trial. JAMA. 2006;295:1556-1565.

  10. Nicholls SJ, Ballantyne CM, Barter PJ, et al. Effect of two intensive statin regimens on progression of coronary disease. N Engl J Med. 2011;365:2078-2087.

  11. Varnava AM, Mills PG, Davies MJ. Relationship between coronary artery remodeling and plaque vulnerability. Circulation. 2002;105:939-943.

  12. Kini AS, Baber U, Kovacic JC, et al. Changes in plaque lipid content after short-term, intensive versus standard statin therapy: The YELLOW Trial. J Am Coll Cardiol. 2013;62:21-29.

  13. Hulten E, Jackson JL, Douglas K, et al. The effect of early, intensive statin therapy on acute coronary syndrome: a meta-analysis of randomized controlled trials. Arch Intern Med. 2006;166:1814-1821.

  14. Yoshikawa D, Ishii H, Kurebayashi N, et al. Association of cardiorespiratory fitness with characteristics of coronary plaque: assessment using integrated backscatter intravascular ultrasound and optical coherence tomography. Int J Cardiol. 2013;162:123-128.

  15. Hewing B, Parathath S, Mai CK, et al. Rapid regression of atherosclerosis with MTP inhibitor treatment. Atherosclerosis. 2013;227:125-129.

  16. Cuchel M, Bloedon LT, Szapary PO, et al. Inhibition of microsomal triglyceride transfer protein in familial hypercholesterolemia. N Engl J Med. 2007;356:148-156.

  17. Raal FJ, Santos RD, Blom DJ, et al. Mipomersen, an apolipoprotein B synthesis inhibitor, for lowering of LDL cholesterol concentrations in patients with homozygous familial hypercholesterolaemia: a randomised, double-blind, placebo-controlled trial. Lancet. 2010;375:998-1006.

  18. Denis M, Marcinkiewicz J, Zaid A, et al. Gene inactivation of proprotein convertase subtilisin/kexin type 9 reduces atherosclerosis in mice. Circulation. 2012;125:894-901.

  19. Roth EM, McKenney JM, Hanotin C, et al. Atorvastatin with or without an antibody to PCSK9 in primary hypercholesterolemia. N Engl J Med. 2012;367:1891-1900.

  20. Schwartz GG, Olsson AG, Abt M, et al. Effects of dalcetrapib in patients with a recent acute coronary syndrome. N Engl J Med. 2012;367:2089-2099.

  21. Kovacic JC, Fuster V. From Treating Complex Coronary Artery Disease to Promoting Cardiovascular Health: Therapeutic Transitions and Challenges, 2010-2020. Clin Pharmacol Ther. 2011;90:509-518.

  KOVACIC and KINI

  28A

  The Journal of Invasive Cardiology^®

  KEY SOURCE for this Article

  Journal of Invasive Cardiology, August 2013, Vol 25/Supplement A

  Print ISSN 1042-3931 / Electronic ISSN 1557-2501

  Introduction 

  NIRS-IVUS Imaging To Characterize the Composition and Structure of Coronary Plaques

  D. RIZIK AND J.A. GOLDSTEIN……………………………………..2A

  Background 

  Imaging of Plaque Composition and Structure with the TVC Imaging System™ and TVC Insight™ Catheter

  B. SHYDO, ET AL…………………………………………………………5A

  Comparative Intravascular Imaging for Lipid Core Plaque: NIRS vs VH-IVUS vs OCT

  E. FUH AND E.S. BRILAKIS……………………………………………9A

  Plaque Characterization and PCI Procedural Outcomes

  NIRS-IVUS Imaging Identifies Lesions at High Risk of

  Peri-Procedural Myocardial Infarction

  J.A. GOLDSTEIN, ET AL……………………………………………..14A

  Case Vignettes:

  Multiple Plaque Ruptures in a Patient with ST-Segment Elevation Myocardial Infarction: Does Infrared Spectroscopy Evidence Explain a Significant Change in the Angiogram?

  M.J. LIM AND J.M. STOLKER……………………………………….16A

  Missing the Culprit Yellow Plaque

  D. ERLINGE…………………………………………………………….18A

  The Use of Near-Infrared Spectroscopy to Optimize Stent Length

  G.A. STOUFFER ………………………………………………………19A

  Employing NIRS-IVUS to Guide Optimal Lesion Coverage—Avoidance of Geographic Miss

  I. HANSON, ET AL……………………………………………………..20A

  Peri-Procedural Myocardial Injury Unraveled: Combined

  Assessment by Optical Coherence Tomography, Near-Infrared

  Spectroscopy, and IVUS

  A. KARANASOS, ET AL………………………………………………..22A

  Plaque Characterization and Long-Term 

  Clinical Outcomes

  Long-term Consequences of a Lipid Core Plaque

  C.V. BOURANTAS, ET AL…………………………………………….24A

  Pharmacological Therapy of Lipid Core Plaque

  J.C. KOVACIC AND A. KINI………………………………………….27A

  The Search for Vulnerable Plaque — The Pace Quickens

  R.D. MADDER, ET AL…………………………………………………29A

  Case Vignettes:

  Observations from Intracoronary Near-Infrared Spectroscopy in Patients with ST-Segment Elevation Myocardial Infarction

  R.D. MADDER…………………………………………………………34A

  NIRS Imaging of Cardiac Allograft Vasculopathy

  G. WEISZ ……………………………………………………………….35A

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