Doppler echocardiographic assessment of left ventricular filling pressures in elderly patients with moderate/severe aortic stenosis

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.

Age-related changes in hemodynamics affecting valve performance

Degenerative processes result in changes in both the aortic and mitral valves. For example, degenerative changes may lead to significant aortic stenosis or myxomatous mitral valves. Flows through each valve are determined not only by the properties of the valve itself, but also by the properties of proximal and distal chambers, which also undergo changes with age and diseases associated with the elderly, such as hypertension and coronary artery disease. Assessment of valvular performance should consider the effects of atrial-ventricular coupling (for the mitral valve) or ventricular-arterial coupling (for the aortic valve). Design of therapy or intervention should accordingly consider effects on the system as a whole.