Utility of NT-proBNP as an objective marker of postoperative heart failure after coronary artery bypass surgery: a prospective observational study

Background Postoperative heart failure (PHF) is the main cause for mortality after cardiac surgery but unbiased evaluation of PHF is difficult. We investigated the utility of postoperative NT-proBNP as an objective marker of PHF after coronary artery bypass surgery (CABG). Methods Prospective study on 382 patients undergoing isolated CABG for acute coronary syndrome. NT-proBNP was measured preoperatively, the first (POD1) and third postoperative morning (POD3). A blinded Endpoints Committee used prespecified criteria for PHF. Use of circulatory support was scrutinized. Results After adjusting for confounders PHF was associated with 1.46 times higher NT-proBNP on POD1 ( p = 0.002), 1.54 times higher on POD3 ( p < 0.0001). In severe PHF, NT-proBNP was 2.18 times higher on POD1 ( p = 0.001) and 1.81 times higher on POD3 ( p = 0.019). Postoperative change of NT-proBNP was independently associated with PHF (OR 5.12, 95% CI 1.86–14.10, p = 0.002). The use of inotropes and ICU resources increased with incremental quartiles of postoperative NT-proBNP. Conclusions Postoperative NT-proBNP can serve as an objective marker of the severity of postoperative myocardial dysfunction. Due to overlap in individuals, NT-proBNP is useful mainly for comparisons at cohort level. As such, it provides a tool for study purposes when an unbiased assessment of prevention or treatment of PHF is desirable. Trial registration ClinicalTrials.gov Identifier: NCT00489827 https://clinicaltrials.gov/ct2/show/NCT00489827?term=glutamics&draw=2&rank=1 .