Asymptomatic myocardial injury identified on postoperative troponin testing after open or endovascular surgical procedures is a predictor of mortality

Abstract

Objective: Elevated troponin (TnT) levels after open or endovascular surgical procedures have been previously shown to correlate with significantly higher postoperative and short-term mortality. The incidence of asymptomatic myocardial injury after vascular surgical procedures has also been shown to be high. The aim of the present study was to evaluate the utility of routine postoperative TnT screening and long-term outcomes for patients with postoperative TnT elevation.

Methods: Data from consecutive patients who had undergone open or endovascular surgery on an emergent or elective basis with routine postoperative TnT testing from January 2010 to December 2012 were retrospectively analyzed. Elevated postoperative TnT was considered >0.01 ng/mL. Patients with no documented postoperative TnT levels, those who had denied research authorization, and those with elevated TnT levels secondary to renal insufficiency alone were excluded. Patients were also excluded if they had required a dialysis access procedure, varicose vein procedure, or any procedure performed on an outpatient basis, because these were considered nonmajor surgeries. The end points were all-cause mortality at 30 days and 1, 2, 4, and 8 years postoperatively. Mortality data were retrieved from the electronic medical records and the Social Security Death Index and Accurint Death database.

Results: During the 3-year study period, 1632 patients with postoperative TnT levels available had met the inclusion criteria (70% men; 30% women; mean age, 69.7 years). Postoperatively, 410 patients (25.1%) had had elevated TnT levels (TnT+) and 1222 (74.9%) had had nonelevated TnT levels (TnT-). Of the 410 TnT+ patients, 261 had undergone open, 143 had undergone endovascular, and 6 had undergone hybrid procedures. These included 180 aortic, 128 infrainguinal, 22 cerebrovascular, and 80 upper extremity or miscellaneous procedures. Of the 410 TnT+ patients, 168 had experienced asymptomatic myocardial injury. The 30-day mortality was significantly higher for the TnT+ patients than for the TnT- patients (3.9% vs 0.8%; P < .001). The cumulative probability of death for the TnT+ patients remained significantly higher than that for the TnT- patients at 1 (13% vs 3.2%), 2 (17.8% vs 4.8%), 4 (43% vs 18.5%), and 8 (81.4% vs 48.6%) years (P < .0001). The difference held true even for the 168 asymptomatic TnT+ patients compared with the TnT- patients at 30 days (2.4% vs 0.8%) and 1 (7.6% vs 3.2%), 2 (13.3% vs 4.8%), 4 (43.6 vs 18.5%) and 8 (80.8 vs 48.6%) years (P < .0001).

Conclusions: In the present study, patients with elevated TnT levels after vascular surgery had had significantly higher early and late all-cause mortality compared with those with normal postoperative TnT levels. This was true even for patients with asymptomatic TnT elevation, suggesting a role might exist for routine postoperative TnT screening to allow for long-term risk stratification and targeted medical management.

Keywords: Cardiac risk; Mortality; Troponin.