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Preoperative brain natriuretic peptide predicts late mortality and functional class but not hospital readmission after cardiac surgery.

OBJECTIVES
N-terminal brain natriuretic peptide (NT-proBNP) is an established biomarker of heart failure and has been found to predict mortality and morbidity after cardiac surgery. The aim of this study was to investigate whether preoperative NT-proBNP can predict postoperative New York Heart Association (NYHA) functional class and hospital readmission in addition to morbidity and mortality.


DESIGN
Retrospective.


SETTING
University hospital.


PARTICIPANTS
All patients undergoing aortic valve replacement for aortic stenosis and coronary artery bypass grafting from January to December 2008 (n = 390).


MEASUREMENTS AND MAIN RESULTS
Preoperative NT-proBNP was recorded prospectively. Five-year mortality was obtained through national registries. Postoperative functional class, morbidity, and hospital readmission were obtained through telephone interviews. Patients were divided into quartiles based on preoperative NT-proBNP; the medians of each quartile were 103 ng/L, 291 ng/L, 825 ng/L and 2,375 ng/L. Increased preoperative NT-proBNP was associated with reduced postoperative functional class. In the first quartile, 7% (7/97) were in NYHA functional class III-IV compared to 26% (25/97) in the fourth quartile (p<0.01). Increased preoperative NT-proBNP was also associated with reduced long-term survival (p<0.01). The covariate adjusted hazard ratio for mortality in the fourth quartile was 2.9 (1.61-5.08; p<0.01) compared to the other quartiles. No association was found between preoperative NT-proBNP and postoperative hospital readmission.


CONCLUSIONS
Increased preoperative NT-proBNP is associated with reduced long-term survival and functional class but not hospital readmission post-cardiac surgery. Thus, NT-proBNP might have additive value to established risk factors in the preoperative assessment of patients undergoing cardiac surgery.