Prognostic value of 12-lead electrocardiogram and peak troponin I level after vascular surgery

Abstract

The aim of this investigation was to determine if the presence of ischemic electrocardiographic (ECG) changes in patients undergoing vascular surgery provides incremental prognostic information about the long-term risk of death compared with a single peak troponin level within 48 hours after surgery. This was a retrospective analysis of 337 patients undergoing moderate-risk to high-risk vascular surgery at our institution whose ECG and biomarker data were complete. Peak cardiac troponin (cTn) I values that exceeded the upper reference limit (URL) were categorized as low-positive (+), at or exceeding the URL but less than three times the URL, or high-positive (+), at or exceeding three times the URL. ECGs were classified as ischemic or nonischemic. The primary outcome was death at 1 year after the vascular operation. Independent predictors of long-term mortality were determined by Cox proportional hazards regression analysis. The most common vascular problem was an expanding abdominal aortic aneurysm (n=185 [55%]). With regard to cTnI, 53 patients (16%) were classified as high (+) and 82 (24%) as low (+). The ECG in 21 patients (6%) showed evidence of myocardial ischemia. An increase in 1-year mortality of 3% for normal, 11% for low (+), and 17% for high (+) (P<.01) was seen with incremental cTn values. Independent predictors of long-term mortality were age (odds ratio [OR], 1.05, 95% confidence interval [CI], 1.02-1.07; P<.01), stratified troponin (OR, 1.62; 95% CI, 1.25-2.10; P<.01), tissue loss (OR, 3.30; 95% CI, 1.72-6.33; P<.01), stratified Revised Cardiac Risk Index (OR, 1.32; 95% CI, 0.97-1.81; P<.07), and statin use (OR, 0.62; 95% CI, 0.40-0.98; P=.04). The presence of ischemia on ECG was not a predictor of long-term mortality. In the presence of an elevated cTn I, the ECG is not an independent predictor of long-term mortality after vascular surgery. These results support a strategy of routine surveillance of cTns after vascular surgery for the detection of cardiac events and postoperative risk stratification.