Diagnostic Value of Cardiac Biomarkers

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Diagnostic Value of Cardiac Biomarkers

January 4, 2014 by larryhbern

Diagnostic Value of Cardiac Biomarkers

Author and Curator: Larry H Bernstein, MD, FCAP

These presentations covered several views of the utilization of cardiac markers that have evolved for over 60 years. The first stage was the introduction of enzymatic assays and isoenzyme measurements to distinguish acute hepatitis and acute myocardial infarction, which included lactate dehydrogenase (LD isoenzymes 1, 2) at a time that late presentation of the patient in the emergency rooms were not uncommon, with the creatine kinase isoenzyme MB declining or disappeared from the circulation. The world health organization (WHO) standard definition then was the presence of two of three:

1. Typical or atypical precordial pressure in the chest, usually with radiation to the left arm

2. Electrocardiographic changes of Q-wave, not previously seen, definitive; ST- elevation of acute myocardial injury with repolarization;
T-wave inversion.

3. The release into the circulation of myocardial derived enzymes –
creatine kinase – MB (which was adapted to measure infarct size), LD-1,
both of which were replaced with troponins T and I, which are part of the actomyosin contractile apparatus.

The research on infarct size elicited a major research goal for early diagnosis and reduction of infarct size, first with fibrinolysis of a ruptured plaque, and this proceeded into the full development of a rapidly evolving interventional cardiology as well as cardiothoracic surgery, in both cases, aimed at removal of plaque or replacement of vessel. Surgery became more imperative for multivessel disease, even if only one vessel was severely affected.

So we have clinical history, physical examination, and emerging biomarkers playing a large role for more than half a century. However, the role of biomarkers broadened. Patients were treated with antiplatelet agents, and a hypercoagulable state coexisted with myocardial ischemic injury. This made the management of the patient reliant on long term followup for Warfarin with the international normalized ratio (INR) for a standardized prothrombin time (PT), and reversal of the PT required transfusion with thawed fresh frozen plasma (FFP). The partial thromboplastin test (PPT) was necessary in hospitalization to monitor the heparin effect.

Thus, we have identified the use of traditional cardiac biomarkers for:

1. Diagnosis
2. Therapeutic monitoring

The story is only the beginning. Many patients who were atypical in presentation, or had cardiovascular ischemia without plaque rupture were problematic. This led to a concerted effort to redesign the troponin assays for high sensitivity with the concern that the circulation should normally be free of a leaked structural marker of myocardial damage. But of course, there can be a slow leak or a decreased rate of removal of such protein from the circulation, and the best example of this would be the patient with significant renal insufficiency, as TnT is clear only through the kidney, and TNI is clear both by the kidney and by vascular endothelium. The introduction of the high sensitivity assay has been met with considerable confusion, and highlights the complexity of diagnosis in heart disease. Another test that is used for the diagnosis of heart failure is in the class of natriuretic peptides (BNP, pro NT-BNP, and ANP), the last of which has been under development.

While there is an exponential increase in the improvement of cardiac devices and discovery of pharmaceutical targets, the laboratory support for clinical management is not mature. There are miRNAs that may prove valuable, matrix metalloprotein(s), and potential endothelial and blood cell surface markers, they require

1. codevelopment with new medications
2. standardization across the IVD industry
3. proficiency testing applied to all laboratories that provide testing
4. the measurement on multitest automated analyzers with high capability in proteomic measurement (MS, time of flight, MS-MS)

Posted in Atherogenic Processes & Pathology, Best evidence, Ca2+ triggered activation, Calmodulin Kinase and Contraction, Cardiac & Vascular Repair Tools Subsegment, Cardiac and Cardiovascular Surgical Procedures, Cardiomyopathy, Cardiovascular Pharmacogenomics, Cardiovascular Research, Coagulation Therapy and Internal Bleeding, Curation, Diabetes Mellitus, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Drug Delivery Platform Technology, Evidence-based decision-making, Evolutionary cognition, Frontiers in Cardiology and Cardiovascular Disorders, Genomic Testing: Methodology for Diagnosis, Immunodiagnostics, Inferential analysis, Medical and Population Genetics, Medical Devices R&D and Inventions, Medical Imaging Technology, Image Processing/Computing, MRI, CT, Nuclear Medicine, Ultra Sound, Molecular Genetics & Pharmaceutical, Nephrology, Nutritional Supplements: Atherogenesis, lipid metabolism, Personalized and Precision Medicine & Genomic Research, Pharmacogenomics, Pharmacologic toxicities, Population Health Management, Genetics & Pharmaceutical, Proteomics, Quality Assurance, Systemic Inflammatory Response Related Disorders, Technology Advance Assessment of, Technology Transfer: Biotech and Pharmaceutical, Translational Effectiveness, Translational Science | Tagged 2, Acute coronary syndrome, acute myocardial infarction, American College of Cardiology ACC, Antiplatelet drug, aspartate aminotransferse (AST), Atrial fibrillation, cardiac biomarkers, cardiomyocyte, Cardiomyopathy, CK isoenzyme MB, confounders, coronary artery plaque, Coumadin, Creatine kinase, endothelial cell, hs-troponins, hypercoagulable state, INR, Lactate dehydrogenase, LD isoenzyme(s)-1, miRNAs, myocardial contraction, plaque rupture, platelet activation, practice guidelines, PT, PTT, troponin I, Troponin T, World Health Organization | 2 Comments

2 Responses

on January 22, 2014 at 5:02 PM | Reply On-Hours vs Off-Hours: Presentation to ER with Acute Myocardial Infarction – Lower Survival Rate if Off-Hours | Pharmaceutical Intelligence

This is very insightful. There is no doubt that there is the bias you refer to. 42 years ago, when I was postdocing in biochemistry/enzymology before completing my residency in pathology, I knew that there were very influential mambers of the faculty, who also had large programs, and attracted exceptional students. My mentor, it was said (although he was a great writer), could draft a project on toilet paper and call the NIH. It can’t be true, but it was a time in our history preceding a great explosion. It is bizarre for me to read now about eNOS and iNOS, and about CaMKII-á, â, ã, ä – isoenzymes. They were overlooked during the search for the genome, so intermediary metabolism took a back seat. But the work on protein conformation, and on the mechanism of action of enzymes and ligand and coenzyme was just out there, and became more important with the research on signaling pathways. The work on the mechanism of pyridine nucleotide isoenzymes preceded the work by Burton Sobel on the MB isoenzyme in heart. The Vietnam War cut into the funding, and it has actually declined linearly since.

A few years later, I was an Associate Professor at a new Medical School and I submitted a proposal that was reviewed by the Chairman of Pharmacology, who was a former Director of NSF. He thought it was good enough. I was a pathologist and it went to a Biochemistry Review Committee. It was approved, but not funded. The verdict was that I would not be able to carry out the studies needed, and they would have approached it differently. A thousand young investigators are out there now with similar letters. I was told that the Department Chairmen have to build up their faculty. It’s harder now than then. So I filed for and received 3 patents based on my work at the suggestion of my brother-in-law. When I took it to Boehringer-Mannheim, they were actually clueless.

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on January 22, 2014 at 5:46 PM | Reply Acute Myocardial Infarction: Curations of Cardiovascular Original Research – A Bibliography | Pharmaceutical Intelligence

This is very insightful. There is no doubt that there is the bias you refer to. 42 years ago, when I was postdocing in biochemistry/enzymology before completing my residency in pathology, I knew that there were very influential mambers of the faculty, who also had large programs, and attracted exceptional students. My mentor, it was said (although he was a great writer), could draft a project on toilet paper and call the NIH. It can’t be true, but it was a time in our history preceding a great explosion. It is bizarre for me to read now about eNOS and iNOS, and about CaMKII-á, â, ã, ä – isoenzymes. They were overlooked during the search for the genome, so intermediary metabolism took a back seat. But the work on protein conformation, and on the mechanism of action of enzymes and ligand and coenzyme was just out there, and became more important with the research on signaling pathways. The work on the mechanism of pyridine nucleotide isoenzymes preceded the work by Burton Sobel on the MB isoenzyme in heart. The Vietnam War cut into the funding, and it has actually declined linearly since.

A few years later, I was an Associate Professor at a new Medical School and I submitted a proposal that was reviewed by the Chairman of Pharmacology, who was a former Director of NSF. He thought it was good enough. I was a pathologist and it went to a Biochemistry Review Committee. It was approved, but not funded. The verdict was that I would not be able to carry out the studies needed, and they would have approached it differently. A thousand young investigators are out there now with similar letters. I was told that the Department Chairmen have to build up their faculty. It’s harder now than then. So I filed for and received 3 patents based on my work at the suggestion of my brother-in-law. When I took it to Boehringer-Mannheim, they were actually clueless.

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