The role of biomarkers in valvular heart disease: focus on natriuretic peptides.

The optimal timing of valve surgery remains controversial. Biomarkers can be serially monitored and are objective laboratory measurements. Plasma B-type natriuretic peptide (BNP) and its N-terminal pro-form are well known predictors in heart failure. Diastolic stretch induces cardiomyocyte BNP expression in volume-loaded conditions like aortic or mitral regurgitation (MR) or pressure-loaded conditions like aortic stenosis (AS). Here, we review the value of natriuretic peptide measurements in valve disease. Cardiac decompensation is reflected by increased BNP in AS and in MR. Repeated marked increases in natriuretic peptides are a potential indication for valve replacement in severe asymptomatic AS with normal ejection fraction and exercise test results. High BNP level also predicts postoperative outcome. Increased BNP level is associated with low-flow AS, impaired left ventricular longitudinal strain, and myocardial fibrosis. The BNP ratio to the reference value for age and sex incrementally predicts mortality in AS. Increased BNP reflects the hemodynamic consequences of MR and is associated with exercise-induced pulmonary-arterial hypertension and reduced contractile reserve. In severe primary MR, increased and serially increasing BNP or N-terminal pro-form BNP might be helpful in guiding early mitral replacement. In conclusion, baseline (N-terminal pro-form) BNP should be obtained in all severe valve disease patients and interpreted together with clinical and echocardiography findings. Very high BNP values are associated with increased mortality and should lead to close monitoring peri- and postoperatively. Progressively increasing BNP in asymptomatic patients points to advancing valve disease. BNP adds important incremental prognostic information that is useful for valve patient management and for optimal timing of surgery in particular.