The effect of postoperative myocardial ischemia on long-term survival after vascular surgery

Abstract

Introduction: The impact of a postoperative troponin elevation on long-term survival after vascular surgery is not well-defined. We hypothesize that a postoperative troponin elevation is associated with significantly reduced long-term survival.

Methods: The Vascular Study Group of New England registry identified all patients who underwent carotid revascularization, open abdominal aortic aneurysm repair (AAA), endovascular AAA repair, or infrainguinal lower extremity bypass (2003-2011). The association of postoperative troponin elevation and myocardial infarction (MI) with 5-year survival was evaluated. Multivariable models identified predictors of survival and of postoperative myocardial ischemia.

Results: In the entire cohort (n = 16,363), the incidence of postoperative troponin elevation was 1.3% (n = 211) and for MI was 1.6% (n = 264). Incidences differed across procedures (P < .0001) with the highest incidences after open AAA: troponin elevation, 3.9% (n = 74); MI, 5.1% (n = 96). On Kaplan-Meier analysis, any postoperative myocardial ischemia predicted reduced survival over 5 years postoperatively: no ischemia, 73% (standard error [SE], 0.5%); troponin elevation, 54% (SE, 4%); MI, 33% (SE, 4%) (P < .0001). This pattern was observed for each procedure subgroup analysis (P < .0001). Troponin elevation (hazard ratio, 1.45; 95% confidence interval, 1.1-2.0; P = .02) and MI (hazard ratio, 2.9; 95% confidence interval, 2.3-3.8; P < .0001) were independent predictors of reduced survival at 5 years.

Conclusions: Postoperative troponin elevation and MI predict a 26% or a 55% relatively lower survival in the 5 years following a vascular surgical procedure, respectively, compared with patients who do not experience myocardial ischemia. This highlights the need to better characterize factors leading to postoperative myocardial ischemia. Postoperative troponin elevation, either alone, or in combination with an MI, may be a useful marker for identifying high-risk patients who might benefit from more aggressive optimization in hopes of reducing adverse long-term outcomes.

Fig 1

Univariate Kaplan-Meier (K-M) analysis of 5-year survival among the total cohort, stratified by postoperative myocardial ischemia; log-rank, P < .0001.

Fig 2

Kaplan-Meier analysis of 5-year survival among the total cohort, stratified by postoperative myocardial ischemia and adjusted for the mean values of all nonexposure variables; log-rank, P < .0001. EKG, Electrocardiograph; MI, myocardial infarction.

Fig 3

Univariate Kaplan-Meier (K-M) curves of survival at 5 years, stratified according to postoperative myocardial ischemia, among (A) carotid revascularization; P < .0001, (B) open abdominal aortic aneurysm (AAA) repair; P < .0001, (C) endovascular AAA repair; P < .0001, and (D) lower extremity bypass; P < .0001.