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

ObjectiveTo evaluate the ability of BNP to identify a subset of patients with asymptomatic significant rheumatic MS, who get symptoms on stress exercise testing.MethodsSeventy 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.ResultsBNP 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%.ConclusionBNP 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.