Troponin elevations following vascular surgery in patients without preoperative myocardial ischemia.

OBJECTIVES

A normal preoperative myocardial perfusion-imaging (MPI) test in advance of vascular surgery predicts a low risk of postoperative clinical events at 30 days. Among patients undergoing vascular surgery with a normal preoperative MPI, cardiac troponin I (cTnI) elevations are common and predictive of a poor long-term outcome.

METHODS

The study cohort comprised 182 patients. Between January 2005 and December 2009, we studied these patients, who had no evidence of myocardial ischemia on preoperative MPI and were undergoing vascular surgery. Blood was obtained in all of the patients in the first 2 days following vascular surgery, and cTnI levels were measured. The values that exceeded the upper reference limit (URL) were categorized as either low (+) (greater than or equal to the URL but less than three times the URL) or high (+) (greater than or equal to three times the URL). Long-term survival was determined from the time of the vascular operation.

RESULTS

The mean age of the population was 69 ± 8 years, and the mean revised cardiac risk index was 1.80 ± 0.77. The most common indication for vascular intervention was an expanding abdominal aortic aneurysm (n = 96, 52.5%). Within 48 hours of surgery, 58 patients (32%) had a typical rise and fall in TnI, with at least one value exceeding the URL. Of these patients, 17 (9%) were classified as high (+) and 41 (22.5%) as low (+). At 1 year post-vascular surgery, mortality was 8% for the overall cohort. A high (+) Tn elevation was an identifier of decreased 1-year survival (29%) relative to normal (3%) and low (+) (14%; P < 0.001). Stratified cTn was an independent predictor of the long-term risk of death.

CONCLUSIONS

Among patients undergoing vascular procedures without evidence of myocardial ischemia on MPI, an elevation in TnI is common and predictive of long-term mortality risk.