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

Abstract

Objective: 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.

Methods: 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.

Results: 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.

Conclusions: 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.