Potential use of Brain Natriuretic Peptide in patients with asymptomatic significant mitral stenosis

Abstract

Objective: To evaluate the ability of BNP to identify a subset of patients with asymptomatic significant rheumatic MS, who get symptoms on stress exercise testing. Methods: Seventy asymptomatic patients with significant rheumatic MS (MVA ⩽1.5 cm2) were included in the study. All patients underwent resting echo-Doppler study, exercise echocardiography and BNP level assessment pre- and one week post-balloon dilatation (for group I patients who had PMC). Patients were divided into two groups. Group I included 33 patients who became symptomatic on exercise and had low exercise capacity. Group II included 37 patients who were asymptomatic on exercise and had reasonable exercise capacity. Results: BNP level in group I was 92 ± 12 compared to 40 ± 10 pg/ml in group II, P < 0.001. Post PMC, BNP in group I significantly decreased (92 ± 12, compared to 31 ± 9 pg/dl, P < 0.001). LA dimension was significantly different between both groups (50 ± 2.9 in group I compared to 46 ± 3.1 mm in group II, P < 0.001). Post-exercise SPAP was 72 ± 12 in group I compared to 46 ± 13 mmHg in group II, P < 0.001. Post-exercise MV gradient was 28 ± 9 compared to 20 ± 12 mmHg, P = 0.002. BNP significantly correlated with post-exercise SPAP (r = 0.635; P < 0.001). Area under the ROC curve for BNP as a predictor of low exercise capacity and development of symptoms on exercise was 0.98 [CI 95% 0.96–1.0]. When using a cutoff value of 55 pg/mL for BNP, sensitivity was 93.9% and specificity was 91.9%. Conclusion: BNP may be used to approach asymptomatic patients with significant MS. BNP may identify a subset of patients with exercise-induced clinical and echo-Doppler criteria that meet the contemporary guidelines for intervention.

Keywords

• Brain Natriuretic Peptide
• Rheumatic mitral stenosis
• Exercise echocardiography
• Balloon commissurotomy