Exploring the Utility of Brain Natriuretic Peptide Measurement in Vascular Surgery

Abstract

The Canadian Cardiovascular Society 2016 guidelines recommend pre-operative measurement of brain natriuretic peptide (BNP) to risk-stratify patients for a 30-day composite outcome of death, myocardial infarction, or asymptomatic myocardial injury after noncardiac surgery (MINS). Whether this practice affects outcomes is unclear. The aim of this study was to examine the clinical utility of brain natriuretic peptide and myocardial injury after noncardiac surgery. Analysis of a prospectively maintained database identified all elective open vascular surgery cases at an academic teaching hospital from January 2015 to December 2018. Pre-operative BNP values were available from June 2018 onward after becoming institutionally mandated. Co-morbidities were also collected to stratify patients using the Revised Cardiac Risk Index. The composite outcome of 30-day mortality, myocardial infarction, or MINS was determined. Prior to BNP becoming an institutionally required test, data was available from 1176 open cases. The 30-day mortality was 1.3% (15/1176) and post-operative myocardial infarction rate was 2.3% (27/1176). BNP measurements were collected in 91 consecutive patients. Ten patients (11%) experienced the composite outcome of mortality, myocardial infarction, or MINS. Elevated BNP was associated with increased odds of the composite outcome (P=0.04), but not with mortality or myocardial infarction. Revised Cardiac Risk Index score was not predictive of outcomes. The majority of patients who qualified for the composite outcome experienced only an asymptomatic troponin rise (80%). Two patients met the universal definition of myocardial infarction, one of whom died. No other deaths occurred within 30 days. Detection of MINS did not result in any significant changes to patient management. Elevated BNP correlates with increased MINS. An asymptomatic troponin rise is the most commonly observed event, with unclear clinical implications. BNP may over-estimate surgical risk. Further studies on the long-term outcomes of patients with elevated BNP and MINS are required before widely adopting this strategy in vascular surgery patients.