Preoperative, postoperative and 1-year follow-up N-terminal pro-B-type natriuretic peptide levels in severe chronic aortic regurgitation: correlations with echocardiographic findings

Abstract

B-type natriuretic peptide is synthesized in response to increased ventricular wall stress (WS) and hypertrophy. To serially evaluate amino-terminal-pro-BNP (NT-pBNP) serum levels in patients undergoing aortic valve replacement (AVR) for severe chronic aortic regurgitation (AR), blood samples were drawn preoperatively, 15 days postoperatively, at 6- and 12-month follow-up in 25 consecutive patients. Two-dimensional echocardiography was performed concomitantly, assessing left ventricular (LV) dimensional and functional parameters, including WS. Correlations between NT-pBNP, clinical and echocardiographic data were assessed by non-parametric statistics. Median preoperative NT-pro-BNP was 276 pg/ml (IQR=85-1056), being normal or mildly increased in 20 patients, overly increased in five. The most significant correlations of preoperative NT-pBNP were with diastolic (r=0.80, P<0.001) and systolic (r=0.75, P<0.001) meridional WS and inversely with time from symptom onset (r=-0.67, P=0.001). NT-pBNP increased 15 days postoperatively (568 pg/ml, P=0.006 vs. preoperative), then decreased at 6 months (144 pg/ml, P<0.001) to remain stable at 1 year (108 pg/ml, P=0.16). Long-term follow-up NT-pBNP showed direct correlation with diastolic WS (r=0.56, P=0.02). Higher preoperative levels of NT-pBNP predicted greater magnitude of total LV mass regression at follow-up (r=-0.65, P=0.002) independent of preoperative LV mass index, showing that NT-pBNP may have a potential prognostic usefulness in adjunct to echocardiography.