Troponin I and NT-proBNP (N-terminal pro-Brain Natriuretic Peptide) Do Not Predict 6-Month Mortality in Frail Older Patients Undergoing Orthopedic Surgery

Abstract

To determine if troponin I and NT-proBNP were predictors of 6-month mortality after emergency orthopedic-geriatric surgery in a frail population. Prospective observational study. Orthopedic-geriatric unit of a metropolitan hospital in Australia. A total of 383 patients were screened; 44 were eligible for this study of which 33 patients consented who were receiving high-level care or had severe dementia or an illness with a prognosis of less than 12 months. Troponin I and NT-proBNP were tested on one preoperative sample and at least one postoperative blood sample. Cardiac events were defined as acute myocardial infarction, congestive cardiac failure, new onset or rapid atrial fibrillation, major arrhythmia, or cardiac arrest. The mean age of the patients was 85.8 +/- 9.6 years and 93.9% had a fractured neck of femur. Premorbid cardiac conditions were common (24.2% had ischemic heart disease and 21.2% congestive cardiac failure). A third of patients had a preoperative troponin elevation and 60.6% had a postoperative elevation. The mortality within 30 days of surgery was 15.2% (5/33 patients), rising to 39.4% (13/33) at 6 months with 46.2% (6/13) dying of a cardiac cause. The Kaplan-Meier survival curve was not significantly different between patients with and without a troponin elevation. A third of patients sustained a cardiac event at 6 months. The median preoperative NT-proBNP was 1651.50 pg/L, range 25 to 31,227, and median postoperative NT-proBNP was 3038.50pg/L, range 44 to 27,348. Troponin I and NT pro-BNP did not predict 6-month mortality or cardiac complications. Predictors of 6-month mortality using univariate analysis were number of comorbidities OR 2.0 (95% CI 1.1-3.8, P = .033) and premorbid atrial fibrillation OR 7.7 (95% CI 1.2-47.8, P = .028). Troponin I and NT-proBNP were not predictors of 6-month mortality or cardiac events in an older frailer population of patients undergoing orthopedic surgery. These patients sustained substantial cardiac morbidity and mortality at 6 months after surgery. The control of symptoms, rather than prolongation of life with cardiological intervention, may be more appropriate for this patient group.