1032-121 Utility of B-type natriuretic peptide assay in the assessment of symptomatic state in hypertrophic cardiomyopathy

Background. Hypertrophic cardiomyopathy (HCM) is a common genetic cardiovascular disease with a diverse clinical spectrum which often includes functional disability due to progressive heart failure symptoms at any age. Assessment of symptom severity may be highly subjective and encumbered by the heterogenous clinical presentation of HCM. Plasma B-type natriuretic peptide (BNP) has been used widely as an objective marker for the severity of heart failure and clinical outcome predominantly in coronary heart disease with ventricular dilatation and systolic dysfunction. We considered the possibility that BNP would be an accurate and independent predictor of heart failure severity in HCM, a disease characterized by intact ventricular function in the absence of chamber dilatation. Methods. We prospectively assessed plasma BNP as a quantitative clinical marker of heart failure severity in 107 consecutive HCM patients. Results. BNP showed a statistically significant relationship to the magnitude of functional limitation assessed by New York Heart Association (NYHA) functional class: I: 136 ± 159 pg/ml; II: 338 ± 439 pg/ml; III/IV: 481 ± 334 pg/ml (p 200 pg/ml was the most reliable predictor of heart failure symptoms with positive and negative predictive values of 65% and 79%, respectively. Conclusions. Plasma BNP is independently related to the presence and magnitude of heart failure-related symptoms in patients with HCM. The clinical power of BNP as a marker for heart failure in HCM is, however, restricted by the overlap in BNP values between symptom-related subgroups, due largely to the important confounding variables of advancing age and substantial left ventricular wall thickness characteristic of this heterogeneous disease.