Early detection of left ventricular dysfunction by Doppler tissue imaging and N-terminal pro-B-type natriuretic peptide in patients with symptomatic severe aortic stenosis.

BACKGROUND: Patients with severe aortic stenosis (AS) require valve replacement before development of irreversible left ventricular (LV) dysfunction. It has been postulated that Doppler tissue imaging (DTI) parameters are more sensitive to detect subtle LV dysfunction compared with conventional echocardiographic parameters.
OBJECTIVE: We sought to assess early LV dysfunction with DTI-derived echocardiographic parameters and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with severe AS and normal LV ejection fraction.
METHODS: A total of 29 patients (mean age 65 +/- 12 years, 15 male) with symptomatic severe AS and 17 control subjects were included in the study. DTI was performed at the level of the mitral lateral (m(lat)) and septal (m(sep)) annulus. Systolic (Sm), early (Em), and late (Am) diastolic velocities were measured, and E/Em ratio was calculated. NT-proBNP was determined by an electrochemiluminescence immunoassay.
RESULTS: Baseline characteristics between patients and control subjects were similar regarding LV ejection fraction and mitral inflow E/A ratio. However, patients with AS had significantly lower DTI values (Sm, Em, Am) compared with control subjects. Moreover, LV filling pressures, expressed by the E/Em ratio, were significantly higher in patients. Correlation analysis showed a relationship between the natural logarithm of NT-proBNP and aortic valve area, Sm(lat), and E/Em((sep)) ratio. Using stepwise multiple linear regression, Sm(lat) was found to be independently related to NT-proBNP.
CONCLUSIONS: In patients with severe AS and normal LV ejection fraction, DTI showed LV systolic and diastolic dysfunction compared with control subjects. DTI-derived variables, and especially Sm(lat), were correlated with NT-proBNP levels.