Troponin I in Patients without Chest Pain

Abstract

Background: Testing for troponin has important clinical value for patients who present with typical symptoms of acute coronary syndromes (ACS) such as chest pain (CP). Much less is known about the value of troponin testing for patients who present with other symptoms of ACS (anginal equivalent symptoms). Methods: The utilization and prognostic value of cardiac troponin I (cTnI) were evaluated at a Veterans Affairs Acute Care Facility. Clinical charts of 1184 predominantly male patients, who submitted specimens for initial cTnI testing by AxSYM, were evaluated for demographic data, cardiovascular risk factors, major diseases, and complaints at the time of testing. The endpoint was defined as all-cause death during a 200-day period after initial testing. Results: Sixty-one percent of cTnI tests were ordered for patients who did not present with CP. Patients presenting with symptoms other than CP did not have significantly lower plasma cTnI than patients with CP. However, patients with symptoms other than CP were rarely diagnosed with ACS unless cTnI was >2 g/L. The mortality during the follow-up period was severalfold higher among patients presenting with symptoms other than CP (CP, 6%; without CP, 22%; P <0.0001, 2 test). cTnI >0.2 g/L provided significant additional predictive information for patients who presented with anginal equivalent symptoms such as shortness of breath or general weakness. Conclusion: Patients with anginal equivalent symptoms of ACS and low-positive cTnI are less often diagnosed with ACS and have a higher mortality than patients with CP.

Enhancing the Diagnostic Performance of Troponins in the Acute Care Setting

“…The decision that has to be made is whether to discharge the patient home from the ED, reschedule for outpatient evaluation, or to admit the patient as having high-risk ACS. This can be especially true for the subset of patients (elderly, diabetics) who have atypical presentations, what have been described by some as angina-equivalent symptoms such as shortness of breath or weakness (29).…”

Elevated Serum Cardiac Markers Predict Coronary Artery Disease in Patients With a History of Heart Failure Who Present With Chest Pain: Insights From the i*trACS Registry

“…A recent analysis of the Acute Decompensated Heart Failure National Registry (ADHERE) database, 24 examining nearly 68,000 patients hospitalized for acute decompensated HF, found that although the rate of positive troponin (6.2%) was lower, their outcomes were much worse than that of patients without troponin elevation. In that analysis, patients hospitalized for acute decompensated HF with a positive troponin marker had an increased rate of procedures (intra‐aortic balloon counter pulsation in 3.0% vs 1.0%, and mechanical ventilation in 11.0% vs 4.0%), longer hospitalizations (5.1 vs 4.1 days), longer intensive care unit admissions (2.9 vs 2.3 days), and a higher mortality rate (8.0% vs 2.7%), compared with patients without troponin elevation 5,19 . Troponin elevations in patients with HF not complicated by an ACS have significantly increased rates of adverse outcomes.…”

“…Troponin I has also been detected in patients with HF, correlating with lower left ventricular ejection fractions and higher systolic pulmonary artery pressure. Detectable troponin I correlates with a high‐risk group of symptomatic HF patients, independent of the presence of ischemia 2,19 . It has been proposed that an increased troponin I level in the HF patient may not be the result of CAD and may be explained by subclinical myocardial pathology rather than acute coronary ischemia 20 .…”

“…It is hypothesized that loss of cell membrane integrity during reversible myocardial injury may lead to leakage of cytosolic pool troponin and account for positive markers associated with a chronically injured myocardium 21 . Therefore, troponin elevations could indicate the presence but not the mechanism of myocardial injury, 16,19 leading researchers to coin the term minor myocardial damage . This includes an ill‐defined condition in which markers such as troponins are detected in serum, while traditional cardiac enzymes such as CK‐MB mass may not be elevated 22 .…”

The new definition of myocardial infarction and the impact of troponin determination on clinical practice

“…More importantly, it seems that some physicians still have not adopted the concept that any amount of myocardial necrosis caused by ischemia constitutes MI, but rather they demand a substantial amount of ischemic necrosis to define MI [33]. In other words, physicians may find it difficult to adopt the new MI definition that gives sensitive biomarkers greater importance than classical, less sensitive cardiac elements such as the assessment of the patient's symptoms and scrutiny of ECG [39][40][41].…”