N-terminal fragment of pro-B-type natriuretic peptide is a predictor of cardiac events in high-risk patients undergoing acute hip fracture surgery.

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.

Predictors of cardiac events in high-risk patients undergoing emergency surgery.

BACKGROUND: The aim of this study was to determine the incidence of myocardial damage and left ventricular myocardial dysfunction and their influence on outcome in high-risk patients undergoing non-elective surgery. METHODS: In this prospective observational study, 211 patients with American Society of Anesthesiologists classification III or IV undergoing emergent or urgent surgery were included. Troponin I (TnI) was measured pre-operatively, 12 and 48 h post-operatively. Pre-operative N-terminal fragment of B-type natriuretic peptide (NT-proBNP), as a marker for left ventricular systolic dysfunction, was analyzed. The diagnostic thresholds were set to TnI >0.06 microg/l and NT-proBNP >1800 pg/ml, respectively. Post-operative major adverse cardiac events (MACE), 30-day and 3-months mortality were recorded. RESULTS: Elevated TnI levels were detected in 33% of the patients post-operatively. A TnI elevation increased the risk of MACE (35% vs. 3% in patients with normal TnI levels, P<0.001) and 30-day mortality (23% vs. 7%, P=0.003). Increased concentrations of NT-proBNP were seen in 59% of the patients. Elevated NT-proBNP was an independent predictor of myocardial damage post-operatively, odds ratio, 6.2 [95% confidence interval (CI) 2.1-18.0] and resulted in an increased risk of MACE (21% vs. 2.5% in patients with NT-proBNP < or = 1800 pg/ml, P<0.001). CONCLUSION: Myocardial damage is common in a high-risk population undergoing unscheduled surgery. These results suggest a close correlation between myocardial damage in the post-operative period and increased concentration of NT-proBNP before surgery. The combinations of TnI and NT-proBNP are reliable markers for monitoring patients at risk in the peri-operative period as well as useful tools in our risk assessment pre-operatively in emergency surgery.