Aims: Diastolic heart failure is a frequent entity but difficult to diagnose. N-terminal pro-B type natriuretic peptide (NT-proBNP) was therefore investigated as a possible non-invasive parameter to diagnose isolated diastolic dysfunction.
Methods and results: Sixty-eight symptomatic patients with isolated diastolic dysfunction and preserved left ventricular ejection fraction (LVEF) (> or =50%) and 50 patients with regular left ventricular (LV) function were examined by conventional echocardiography, tissue Doppler imaging (TDI), and left and right heart catheterization. Plasma NT-proBNP levels were determined simultaneously. Median NT-proBNP plasma levels were elevated [189.54 pg/mL (86.16-308.27) vs. 51.89 pg/mL (29.94-69.71); P<0.001] and increased with greater severity of the diastolic dysfunction (R=0.67, P<0.001). According to the recevier operating characteristic analysis, LV end-diastolic pressure [area under the curve (AUC) 0.84] was the most specific parameter, which had a low sensitivity (61%), however. The reliability of NT-proBNP was similar to TDI indices (AUC 0.83 vs. 0.81) and improved when compared with conventional echocardiography (AUC 0.59-0.70). NT-proBNP levels had the best negative predictive value of all methods (94%) and correlated strongly with indices of LV filling pressure, as determined by invasive measurements. Multivariable linear regression analysis confirmed NT-proBNP as an independent predictor of diastolic dysfunction with an Odds ratio of 1.2 (1.1-1.4, CI 95%) for every unit increase of NT-proBNP.
Conclusion: NT-proBNP can reliably detect the presence of isolated diastolic dysfunction in symptomatic patients and is an useful tool to rule out patients with reduced exercise tolerance of non-cardiac origin.