Prognostic role of a preoperative troponin elevation in patients undergoing urgent or emergency noncardiac surgery: a pooled analysis

Background 300 million surgeries are performed worldwide each year. 10% are urgent or emergency surgeries, with a 3-fold higher mortality than elective procedures. Preoperative troponin elevation is a well-established marker of risk in elective surgery, but prognostic value in urgent/emergency surgeries remains poorly defined. Purpose We aimed to determine the relationship between baseline preoperative troponin (elevated or not) and a composite outcome of death, myocardial injury after non-cardiac surgery (MINS), heart failure, atrial fibrillation, or non-fatal cardiac arrest, as well as the single components at 30 days. Additionally, we aimed to understand the relationship between time from troponin measurement to surgery and the occurrence of all-cause death and cardiovascular complications, in patients with and without preoperative troponin elevation. Methods We performed a pooled individual participant data analysis of the VISION-1 study and POISE-3 trial, including patients ≥ 45 years-old who had urgent/emergency noncardiac surgery and had at least one preoperative troponin measurement. We used multivariable Cox proportional hazards models to determine if a preoperative troponin measurement was an independent predictor of the primary composite outcome. We assessed time from troponin measurement to surgery based on troponin status (positive vs. negative) only in POISE-3 as physicians were not always aware of preoperative troponin values in VISION-1 to guide clinical decisions. We performed a mediation analysis to assess the role of time from troponin measurement to surgery as mediator of the outcome. Results Among 5,275 patients, 1,080 had preoperative troponin measured, of whom 242 (22.4%, 95% CI 20.1–25%) were elevated. The primary outcome occurred in 47.5% (95% CI 41.3–53.8) of patients with preoperative troponin elevation versus 11.1% (95% CI 9.1–13.4) without (Figure 1). Increasing age (aHR 1.03, 95% CI 1.02-1.05), preoperative troponin elevation (aHR 3.67, 95% CI 2.65-5.09), and vascular surgery (aHR 1.77, 95% CI 1.05–2.97) independently predicted the primary outcome (Figure 2). Analysis restricted to POISE-3 indicated that preoperative troponin elevation was associated with a slightly prolonged time to surgery (median 22 vs. 18.6 hours, absolute difference 3.4, 95% CI 1–7.3 hours). Mediation analysis indicated that the association between preoperative troponin elevation and primary composite outcome was primarily driven by the direct effect, and the proportion mediated by time to surgery was negligible (3.3%, 95% CI 2.5–12.4, P=0.277). Conclusion Preoperative troponin elevation is independently associated with an increased risk of death or cardiovascular complications after urgent or emergency surgery. Although patients with a preoperative troponin elevation had a slightly delayed time to surgery, the delay did not mediate worse cardiovascular outcomes.