Measuring Troponin Levels Can Help Predict Risk of Death Following Cardiac Surgery

P.J. Devereaux, MD, PhD

Measuring high-sensitivity troponin I (hs-TnI) after cardiac surgery could help clinicians identify patients at increased risk of death in the first 30 days, according to results of a new study in the New England Journal of Medicine.

A prospective cohort study with more than 13,000 patients from a dozen countries, results of the VISION Cardiac Surgery study provide evidence suggesting elevated hs-TnI within 1 day of surgery could serve as a marker for increased risk of death in the first 30 days indicate among patients who underwent cardiac surgery.

“We found that the levels of troponin associated with an increased risk of death within 30 days were substantially higher – 200 to 500 times the normal value– than troponin levels that surgical teams are currently told defines the risk of a patient having one of the most common complications after heart surgery – myocardial injury, a heart muscle injury associated with increased deaths,” said lead investigator P.J. Devereaux, MD, PhD, a professor of medicine and health research methodology at McMaster University and a cardiologist at Hamilton Health Sciences (HHS), in a statement.

With data from the American Heart Association suggesting more than 1 million adult patients in the US and Europe undergo cardiac surgery annually, the current study was conducted with the intent of providing information to develop a more definitive recommendation for threshold levels of cardiac troponin elevations for identifying elevated risk of mortality and major vascular complications in patients undergoing cardiac surgery. Funded in part by the Canadian Institutes of Health Research and Abbott, the VISION Cardiac Surgery study was a prospective cohort study of patients recruited from a convenience sample of 24 hospitals in 12 countries from May 2013 through April 2019.

A total of 13,862 were enrolled in the study and included in the investigators’ analyses. Of these, 296 died within 30 days of surgery. The study cohort had a mean age of 63.3 (SD, 12.3) years, 70.9% were men, 70.2% were White, and 29.3% had a history of myocardial infarction. The most common procedure among patients included in the study was isolated CABG followed by AVR, with the remaining patients classified as having undergone “other cardiac surgery”.Investigators pointed out the median preoperative hs-TnI value was 9 (IQR, 4-20) ng/L.

Patients in the study had hs-TnI measurements obtained 3-12 hours after surgery and on days 1, 2, and 3 after surgery. Investigators used Cox analyses with a regression spline to assess the relationship between peak troponin values and 30-day mortality, with adjustment for scores on the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II.

Upon analysis, results demonstrated the threshold troponin level, measured within 1 day after surgery, associated with an adjusted hazard ratio of more than 1.00 for death within 30 days was 5670 (95% CI, 1045-8260) ng/L, a level 218 times the upper reference limit, among patients whounderwent isolated CABG or AVR. For patients who underwent other cardiac surgery, the corresponding threshold troponin level was 12,981 (95% CI, 2673-16,591) ng/L, a level 499 times the upper reference limit.

“This study is a landmark for the health teams taking care of patients after cardiac surgery. For the first time, we have a marker that is fast and reliable for the monitoring of these patients after cardiac surgery,” said study investigator André Lamy, MD, professor in the department of surgery at McMaster University and cardiac surgeon at HHS, in the aforementioned statement.

This study, “High-Sensitivity Troponin I after Cardiac Surgery and 30-Day Mortality,” was published in the New England Journal of Medicine.