Elevated troponin T may help predict 30-day mortality

Troponin T levels accurately predict 30-day mortality after noncardiac surgery, a new study found.

The prospective, international cohort study involved more than 15,000 patients age 45 and older who had noncardiac surgery requiring at least overnight hospital admission. Fourth-generation troponin T (TnT) measurements were taken six to 12 hours after surgery and on postsurgery days 1, 2 and 3. The patients' peak troponin T measurements were collected and compared with 30-day mortality rates.

Overall, 30-day mortality among the patients was 1.9%. In multivariable analysis, the study authors found that troponin T levels of 0.02 ng/mL or higher predicted increased risk of 30-day mortality. Compared to patients whose TnT never went above 0.01 ng/mL, those with a peak of 0.02 ng/mL had a adjusted hazard ratio of death of 2.41. The risk was even higher for patients with peaks of 0.03 to 0.29 ng/mL (hazard ratio, 5.00) and 0.30 ng/mL or above (hazard ratio, 10.48). Within the 30 days after surgery, mortality rates were 1.0%, 4.0%, 9.3% and 16.9% for patients with TnT peaks of 0.01 or greater, 0.02, 0.03 to 0.29, and 0.30 or greater, respectively.

Based on these findings, elevated TnT levels may have predicted 41.8% of the deaths in the study population, researchers calculated. They noted that this multicenter study had consistent results across sites, indicating that the observed TnT thresholds could be relevant worldwide. They also observed that while many laboratories consider TnT values below 0.04 ng/mL to be normal, because of the nearly absolute specificity of troponins for myocardial tissue, levels below this threshold following noncardiac surgery may reflect cardiac injury and are strongly associated with 30-day mortality.

The next step in this research would be to determine whether interventions in the immediate post-surgical period (74.2% of patients with elevated TnT had it in the first 24 hours after surgery) could reduce the risk of mortality, the authors said. Aspirin and statin therapy show promise, but large, randomized clinical trials of interventions are needed, they concluded. The study was published in the June 6 Journal of the American Medical Association.