High-Sensitivity Cardiac Troponin T and Frailty Predict Short-Term Mortality in Patients ≥75 Years Undergoing Emergency Abdominal Surgery: A Prospective Observational Study.

ABSTRACT

BACKGROUND: An elevated cardiac troponin concentration is a prognostic factor for perioperative cardiac morbidity and mortality. In elderly patients undergoing emergency abdominal surgery, frailty is a recognized risk factor, but little is known about the prognostic value of cardiac troponin in these vulnerable patients. Therefore, we investigated the prognostic significance of elevated high-sensitivity cardiac troponin T (hs-cTnT) concentration and frailty in a cohort of elderly patients undergoing emergency abdominal surgery. METHODS: We included consecutive patients ≥75 years of age who presented for emergency abdominal surgery, defined as abdominal pathology requiring surgery within 72 hours, in a university hospital in Norway. Patients who underwent vascular procedures or palliative surgery for inoperable malignancies were excluded. Preoperatively, frailty was assessed using the Clinical Frailty Scale (CFS), and blood samples were measured for hs-cTnT. We evaluated the predictive power of CFS and hs-cTnT concentrations using receiver operating characteristic (ROC) curves and Cox proportional hazard regression with 30-day mortality as the primary outcome. Secondary outcomes included (1) a composite of 30-day all-cause mortality and major adverse cardiac event (MACE), defined as myocardial infarction, nonfatal cardiac arrest, or coronary revascularization; and (2) 90-day mortality. RESULTS: Of the 210 screened and 156 eligible patients, blood samples were available in 146, who were included. Troponin concentration exceeded the 99th percentile upper reference limit (URL) in 83% and 89% of the patients pre- and postoperatively. Of the participants, 53% were classified as vulnerable or frail (CFS ≥4). The 30-day mortality rate was 12% (18 of 146). Preoperatively, a threshold of hs-cTnT ≥34 ng/L independently predicted 30-day mortality (hazard ratio [HR] 3.14, 95% confidence interval [CI], 1.13-9.45), and the composite outcome of 30-day mortality and MACE (HR 2.58, 95% CI, 1.07-6.49). In this model, frailty (continuous CFS score) also independently predicted 30-day mortality (HR 1.42, 95% CI, 1.01-2.00) and 30-day mortality or MACE (HR 1.37, 95% CI, 1.02-1.84). The combination of troponin and frailty, 0.14 × hs-cTnT +4.0 × CFS, yielded apparent superior predictive power (area under the receiver operating characteristics curve [AUC] 0.79, 95% CI, 0.68-0.88), compared to troponin concentration (AUC 0.69, 95% CI, 0.55-0.83) or frailty (AUC 0.69, 95% CI, 0.57-0.82) alone. CONCLUSIONS: After emergency abdominal surgery in elderly patients, increased preoperative troponin concentration and frailty were independent predictors of 30-day mortality. The combination of increased troponin concentration and frailty seemed to provide better prognostic information than troponin or frailty alone. These results must be validated in an independent sample.