Diagnostic and prognostic role of cardiac troponins

Dear Sir, We applaud the work of Lucreziotti et al. [1] in investigating the role of cardiac troponins (cTns) and their usefulness in an expanding population of patients at risk for ischaemic complications. Proper risk stratification of a population in which cardiovascular disease is prevalent is a priority of any primary-care physician. And, considering the anticipated increase in patients at risk for perioperative cardiovascular complications after noncardiac surgery, examining the usefulness of cardiac troponins is well founded. We agree that the presence of troponin I and T at any concentration is highly specific for myocardial necrosis and its early detection is of paramount importance. Our concern is regarding the proposed prognostic power of cardiac troponins. It is known that persons suffering from myocardial infarction are at increased risk for postinfarction arrhythmias, reinfarction and other events. However, we feel the assertion that the detection of cTns may predict the risk of death and other cardiac events is misleading. The diagnosis of infarction itself is the chief predictor of some adverse outcome, not the detection of cTns. Rather, the presence of cTns as a diagnostic tool (much as ST segment elevation, Q-waves or creatine kinase elevation) simply allows for the detection of injury earlier and with more sensitivity. Then, perhaps actions could be taken or discovered that will reduce the incidence of postinfarction. At this point, we could agree on cTn detection as important in prognosis. Further, the additional comments regarding patients with elevated cTnT having more frequent coronary stenosis and diffuse coronary artery disease is more of a restating what is intuitively known. This being that patients who have demonstrated injury are more likely to have more severe disease than those without evidence of injury. We feel that the article does state quite clearly, the usefulness of cTns in the detection of myocardial infarction. Their discovery has improved our success in earlier diagnosis of myocardial injury. Further study into maximizing myocardial oxygenation and other possible preventive strategies in the perioperative period is needed to reduce the occurrence of myocardial infarction. Received 5 August 2002; accepted 10 September 2002. Peter J. Riga, Naval Medical Center, 314 Washington St., Apt. B, Portsmouth, VA 23704, USA (e-mail: PJRiga@aol.com).