Preoperative Myocardial Injury as a Predictor of Mortality in Emergency General Surgery: An Analysis Using the American College of Surgeons NSQIP Database

BACKGROUND: Recent studies have linked postoperative serum troponin elevation to mortality in a range of different clinical scenarios. To date, there has been no investigation into the significance of preoperative troponin elevation in emergency general surgery (EGS) patients. We define this as preoperative myocardial injury (PMI). We hypothesize that PMI seen in EGS patients may predict postoperative morbidity and mortality. STUDY DESIGN: Using the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database, we performed a retrospective review of all EGS cases between 2008 and 2014. Patients with preoperative troponin I drawn were compared. RESULTS: There were 464 EGS patients who had troponin I measurements preoperatively. Eighty-two (18%) had preoperative troponin elevations. Patients with PMI were more likely to have the following preoperative physiologic derangements: acute renal failure (18% vs 4%; p = 0.002) and septic shock (40% vs 13%; p < 0.001). Patient comorbidities associated with PMI included congestive heart failure (13% vs 3%; p = 0.007), dialysis dependence (16% vs 3%; p = 0.002), and American Society of Anesthesiologists (ASA) class ≥ 4 (52% vs 29%; p < 0.001). Compared with controls, patients with PMI had higher rates of postoperative events (77% vs 52%; p < 0.001) and mortality (34% vs 13%; p = 0.009). Univariate analysis showed that patients with PMI had an increased risk of postoperative events (odds ratio [OR] 3.02; 95% CI 1.74 to 5.25) and mortality (OR 3.53; 95% CI 1.66 to 7.47). Multivariate analysis revealed preoperative troponin I elevation was an independent predictor of mortality (OR 3.03; 95% CI 1.19 to 7.72, p = 0.020). CONCLUSIONS: Emergency general surgery patients with PMI are at increased risk for postoperative events and death. Preoperative myocardial injury is an independent predictor of mortality and has prognostic utility that can prepare surgical teams for adverse events so that they can be recognized, evaluated, and treated earlier.