Simultaneous estimation of NT-proBNP on top to mitral flow Doppler echocardiography as an accurate strategy to diagnose diastolic dysfunction in HFNEF

Abstract

Background: Conventional echocardiography has limited accuracy in detecting diastolic dysfunction and NT-proBNP is known to be a reliable biomarker to rule out heart failure. Therefore NT-proBNP on top to conventional mitral flow Doppler might improve the diagnostic of diastolic dysfunction in patients with heart failure despite normal EF (HFNEF) without using tissue Doppler.

Methods and results: Diastolic function of 46 patients with HFNEF was determined by pressure-volume loop obtained by conductance-catheter measurements. LV stiffness correlated with the amount of collagen types I and III analyzed from endomyocardial biopsies (EMBs). NT-proBNP plasma levels correlated with LV stiffness, LVEDP and the collagen amount from EMBs (p<0.01). In another set of patients with HFNEF (n=107, 53 [45-62] years), diastolic dysfunction was confirmed by left and/or right heart catheterization. Their Doppler indices and plasma marker NT-proBNP values were compared with those of 73 controls (186 [70-342] vs 54[30-75] pg/ml, p<0.001). Mitral flow Doppler was impaired in 70/107 (65%) of the HFNEF. When additional criterium NT-proBNP>125 pg/ml was used 96/107 (90%) patients with impaired diastolic function were recognized. Sensitivity of tissue Doppler indices E'/A' and E/E' were improved by 4-6% using NT-proBNP on top. NT-proBNP recognized HFNEF patients with higher hospitalization rate indicated by phone questionnaire, whereas Doppler indices alone did not.

Conclusion: Plasma NT-proBNP levels are associated with increased LV stiffness and cardiac collagen content. On top measurements of plasma NT-proBNP improve the echocardiography diagnostic of diastolic function and prognostic of rehospitalization in HFNEF.