Aims: The predictors and outcomes of patients with a peri-operative elevation in cardiac troponin I above the 99th percentile of normal following an elective vascular operation have not been studied in a homogeneous cohort with documented coronary artery disease.
Methods and results: The Coronary Artery Revascularization Prophylaxis (CARP) trial was a randomized trial that tested the benefit of coronary artery revascularization prior to vascular surgery. Among 377 randomized patients, core lab samples for peak cardiac troponin I concentrations were monitored following the vascular operation and the blinded results were correlated with outcomes. A peri-operative myocardial infarction (MI), defined by an increase in cardiac troponin I greater than the 99th percentile reference (> or =0.1 microg/L), occurred in 100 patients (26.5%) and the incidence was not dissimilar in patients with and without pre-operative coronary revascularization (24.2 vs. 28.6%; P = 0.32). By logistic regression analysis, predictors of MI (odds risk; 95%CI; P-value) were age >70 (1.84; 1.14-2.98; P = 0.01), abdominal aortic surgery (1.82; 1.09-3.03; P = 0.02), diabetes (1.86; 1.11-3.11; P = 0.02), angina (1.67; 1.03-2.64; P = 0.04), and baseline STT abnormalities (1.62; 1.00-2.6; P = 0.05). At 2.5 years post-surgery, the probability of survival in patients with and without the MI was 0.73 and 0.84, respectively (P = 0.03, log-rank test). Using a Cox proportional hazards regression analysis, a peri-operative MI in diabetic patients was a strong predictor of long-term mortality (hazards ratio: 2.43; 95% CI: 1.31-4.48; P < 0.01).
Conclusion: Among patients with coronary artery disease who undergo vascular surgery, a peri-operative elevation in cardiac troponin levels is common and in combination with diabetes, is a strong predictor of long-term mortality. These data support the utility of cardiac troponins as a means of stratifying high-risk patients following vascular operations.