Relation between E/e ' ratio and NT-proBNP levels in elderly patients with symptomatic severe aortic stenosis

Background: Symptoms in the elderly patients with severe aortic stenosis (AS) and co-morbidities seem to lack in specificity. Therefore, objective parameters for increased left ventricular(LV) filling pressures are needed. The aim of this study was to investigate the correlation between the septal, lateral and average E/e' ratio and the value of the N-terminal pro-hormone of brain natriuretic peptide (NT-proBNP). Methods: Two-hundred-fifty consecutive symptomatic patients (mean age 80 +/- 8 years, 52 % men) with severe AS underwent transthoracic echocardiography and NT-proBNP measurement. Results: In the overall population the septal E/e' (r = 0,459, r(2) = 0,21, P < 0,0001), lateral E/e' (r = 0,322, r(2) = 0,10, P < 0,0001), and the average E/e' (r = 0,432, r(2) = 0,18, P < 0,0001) were all significantly correlated to NT-proBNP. After the exclusion of patients with confounders (more than mild aortic or mitral regurgitation, severe renal dysfunction, obesity or severe COPD) the septal E/e' (r = 0,584, r(2) = 0,34, P < 0,0001), lateral E/e' (r = 0,377, r(2) = 0,14, P < 0,0001), and the average E/e' (r = 0,487, r(2) = 0,24, P < 0,0001) were all significantly better correlated to NT-proBNP. In obese patients no significant correlations were seen. Previous bypass surgery did not alter the correlations. Conclusions: In elderly patients with severe symptomatic AS there is a significant correlation between the E/e' ratio and NT- proBNP, in particular after exclusion of confounders. The correlation was best for the septal E/e' ratio and was preserved in patients with a history of bypass surgery.