B-type natriuretic peptide and left ventricular dysfunction on exercise echocardiography in patients with chronic aortic regurgitation

Objective: To determine whether plasma levels of B-type natriuretic peptide (BNP) predict left ventricular (LV) dysfunction on exercise echocardiography in patients with moderate to severe aortic regurgitation (AR). Design: Case-control study. Setting: Outpatient cardiology departments. Patients: 39 asymptomatic or mildly symptomatic patients with chronic moderate to severe AR and a normal LV ejection fraction (> 50%), and 10 normal controls. Main outcome measures: Plasma level of BNP and echocardiographic measures of LV function at rest and immediately after treadmill exercise. Results: LV end systolic volume index (LVESVI) was significantly increased in AR patients with normal BNP (<= 12 pmol/l) compared with controls (mean (SD) 32 (13) vs 17 (7) ml/m(2), p = 0.002) but was similar for AR patients with normal and elevated BNP ( 38 ( 16), p = 0.14). In AR patients there was no association between plasma BNP and measures of LV function on echocardiography at rest (r < 0.30, p > 0.05 for all). However, there were modest but statistically significant associations between the plasma level of BNP and severity of AR indicated by a greater AR: LV outflow tract width ratio (r = 0.37, p = 0.02) and lower diastolic blood pressure (r = -0.44, p = 0.004). Increased BNP was also associated with a greater LVESVI (r = 0.33, p = 0.04) and lower LV longitudinal strain rate (r = -0.037, 0.02) on echocardiography after exercise. Conclusions: In moderate to severe AR compensatory LV remodelling can occur with no increase in plasma BNP. Increased BNP is associated with more severe regurgitation and changes consistent with early LV dysfunction on exercise echocardiography.