NT pro B type natriuretic peptide levels in constrictive pericarditis and restrictive cardiomyopathy

Background: The differentiation of constrictive pericarditis (CP) from restrictive cardiomyopathy (RCM) may be clinically difficult and may require multiple investigations. Even though brain natriuretic peptide (BNP) is shown to be higher in patients with RCM as compared to CP, the clinical utility is not fully established especially in Indian patients known to have advanced CP and myocardial involvement. Methods and results: We measured NT-pro-BNP levels in 49 patients suspected of having either CP or RCM, diagnosed on the basis of echocardiography, computed tomography, magnetic resonance imaging, endomyocardial biopsy and cardiac catheterization data as needed. Twenty nine patients (Mean age – 26 yrs, 24 males) had CP and 20 patients (Mean age – 39 yrs, 14 males) had RCM. The median plasma NT-pro-BNP levels were significantly higher in RCM as compared to CP [1775 (208–7500) pg/ml vs 124 (68–718) pg/ml, respectively; p = 0.001]. A cut off value of 459 pg/ml had sensitivity, specificity and overall accuracy of 90%, 86% and 88% respectively, for differentiating CP from RCM. Conclusions: The NT-pro-BNP levels are significantly elevated in RCM as compared to CP