Ischemic heart disease is one of the leading causes of death world-wide. The ability to risk stratify those at increased risk for cardiovascular events would be beneficial. A number of previous studies have shown that routine troponin elevation may serve as a marker of poor prognosis independent of the traditional cardiovascular risk factors (e.g., hypertension, smoking, hyperlipidemia, diabetes, etc.).
In this week’s issue of NEJM, Everett et al. asked the question whether individuals with diabetes and stable coronary artery disease can be risk stratified using troponin levels and whether those at high risk for cardiovascular events may benefit from prompt coronary revascularization.
In this retrospective cohort study design, 2285 individuals with stable coronary artery disease and type 2 diabetes who were candidates for coronary revascularization were randomized to receive either prompt revascularization plus intense medical therapy or to medical therapy alone. The primary outcome was the composite events of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke. The median follow-up time was 5 years. Abnormal troponin level was considered to be > 14 ng/dL, corresponding to the upper reference limit (99th percentile) in a healthy population.
At the end of 5 years, those with abnormal baseline troponin level had a higher rate of the primary outcome when compared to those with normal troponin levels (27.1% versus 12.9%). Even after adjusting for traditional cardiovascular risk factors, history of prior myocardial infarction and heart failure, severity of diabetes, the primary outcome remained significantly different in the two groups based on troponin level (1.85, 95% CI 1.48-2.32, P < 0.001). Prompt revascularization was not associated with a reduction in cardiovascular death/myocardial infarction/stroke when compared to medical therapy alone (HR 0.98, 95% CI 0.80-1.19, P=0.83). Prompt revascularization also did not reduce the composite events among those with either baseline normal or abnormal troponin levels.
What did we learn from this study? We learned that elevated baseline troponin levels may be used as prognostic factor in addition to the traditional risks. However, the accompanying editorial by Melloni and Roe from Duke University Medical Center noted the concern that patients with elevated troponin levels were older and had more frequent history of heart failure, myocardial infarction, and chronic kidney disease making such conclusion complicated. We also learned that prompt revascularization did not add additional benefit over medical therapy in the study population which is consistent with previous findings on individuals with stable ischemic heart disease (NEJM. 2009 Jun 11;360(24):2503-15).
How do you risk stratify and manage those with stable ischemic heart disease and coronary artery disease?
What is the utility of biomarkers in guiding your clinical management of such patients?