Impact of glomerular filtration rate on minor troponin T elevations for risk assessment in patients undergoing operation for abdominal aortic aneurysm or lower extremity arterial obstruction

Abstract

Debate surrounds the impact of renal function on the prognostic value of minor troponin T release in vascular surgery patients. The objective of this study was to assess the long-term prognostic value of minor degrees of troponin T release in patients who undergo major vascular surgery, especially those with concomitant renal dysfunction. Survivors of major noncardiac vascular surgery (n = 558) were preoperatively screened for cardiac risk factors and renal function. Serial troponin T was measured on days 1, 3, and 7 after surgery, using a threshold of 0.03 ng/ml. All-cause mortality and major adverse cardiac events (MACEs) were noted during follow-up (mean 3.5 +/- 2.0 years). Minor (0.03 to 0.09 ng/ml) and major (> or =0.1 ng/ml) release of troponin T was observed in 5% and 8%, respectively. During follow-up, 21% of the patients died and 15% experienced MACEs. After adjustment for the estimated glomerular filtration rate, patients with minor and major troponin T release were at comparable increased risk for late mortality (hazard ratio [HR] 3.43, 95% confidence interval [CI] 1.79 to 6.58, and HR 3.72, 95% CI 2.37 to 5.85, respectively), and MACEs (HR 5.47, 95% CI 2.60 to 11.48, and HR 6.32, 95% CI 3.82 to 10.48, respectively) compared with patients with troponin T release <0.03 ng/ml. Tests for heterogeneity revealed that minor and major troponin T release have prognostic value across the entire spectrum of renal function. In conclusion, marginal elevations of troponin T strongly predict late mortality and MACEs after major vascular surgery, irrespective of renal function. A currently underestimated high-risk subgroup of patients may be identified using a lower troponin T threshold.