Background: The aim of this investigation was to assess the incidence of elevated N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) and its relation to outcome defined as perioperative adverse cardiac events and all-cause mortality in high-risk patients undergoing non-elective surgery for hip fracture.
Methods: A cohort of patients with hip fractures were extracted from a prospective observational study of high-risk patients (ASA class III or IV) undergoing emergency surgery. NT-proBNP and troponin I were measured before operation. An NT-proBNP > or = 3984 ng litre(-1) was set as the cut-off level for significance. Perioperative adverse cardiac events and 30 day and 3 month mortality were recorded.
Results: Sixty-nine subjects were included. Thirty-four subjects (49%) had an NT-proBNP > or = 3984 ng litre(-1) before surgery. Thirty-four subjects (49%) had a perioperative adverse cardiac event. Of these, 22 subjects (65%) had NT-proBNP above the diagnostic threshold compared with 12 subjects (34%) who had an NT-proBNP below the diagnostic threshold (P=0.01). Preoperative NT-proBNP > or = 3984 ng litre(-1) [odds ratio (OR) 3.0; 95% confidence interval (CI) 1.0-8.9] and congestive heart failure (OR 3.0; 95% CI 1.0-9.0) were independent predictors of perioperative adverse cardiac events. A total of eight subjects (12%) died within 30 days after operation.
Conclusions: There is a high incidence of elevated NT-proBNP in subjects undergoing non-elective hip fracture surgery. Preoperative NT-proBNP is a valuable predictor of cardiac complications in the perioperative period.