AORTIC VALVE AREA CAN DETERMINE MYOCARDIAL CONTRACTILE DETERIORATION IN SEVERE AORTIC STENOSIS: STUDY WITH TISSUE DOPPLER

Abstract

Introduction: After‐load increase in aortic stenosis does not alter the left ventricular ejection fraction (LVEF), even in advanced stages of the illness. We analyzed the ventricular long‐axis velocities and amplitude using tissue Doppler (TD) imaging of the mitral annulus, as this perhaps provides a more sensitive index of systolic function than LVEF. Objectives: (1) To evaluate the left ventricular function in patients with chronically high afterload and (2) determine the effective aortic valve area able to produce changes in left ventricular contractility. Methods: We studied 111 subjects, mean age 68.7 years (range 29–90 years). Of these, 106 (88%) had a valvular area smaller that 1 cm2, and there were 18 age‐matched normal controls (mean age 63.9 years, range 71–81 years) representing the control group (C). The Doppler sample volume was placed at the lateral and septal margins of the mitral annulus. We measured the peak of the systolic apically directed (S‐wave), early diastolic (E), and late diastolic (A) myocardial velocities, the isovolumetric relaxation time (IVRT), and isovolumetric contraction time (IVCT). Patients were classified in groups representing valvular areas 1.1–1.5 cm2 (Group 1, n = 13), 0.71–1 cm2 (Group 2, n = 42),: and <0.7 cm2 (Group 3, n = 64). Statistics: Data are expressed as mean (SD). Group data were compared using the unpaired Student's t test or analysis of variance (ANOVA) with Fisher's PLSD test where appropriate. Linear regression analysis was used (stepwise) to compare continuous variables. A probability value of p < 0.05 was considered significant. Results: The only significant difference observed among groups C and 1 was an increase in the time of ventricular relaxation (103 ± 22 vs.137 ± 35, p < 0.003). Group 2 had a significantly smaller S‐wave than group 1 (5.71 ± 1.15 vs. 6.9 ± 0.91, p < 0.001). Group 3 had significantly smaller A‐wave (6.45 ± 2.5 vs. 8 ± 2.1, p < 0.002), and S‐wave (5.06 ± 1.02 vs. 5.71 ± 1.15, p < 0.005) velocities than group 2, as well as a significant increase in the E/A ratio compared to group 2 (1.00 ± 0.62 vs. 0.74 ± 0.35, p < 0.018). In the regression analysis, we observed a moderate direct relationship between the aortic area and the S‐wave of the TD (r = 0.49, p < 0.0001). LVEF diminished significantly more in group 3 than in group 2 (56 ± 16 vs. 63 ± 15, p < 0.015) but were within normal values. Conclusions: (1) AS first deteriorates the left ventricular diastolic function, prolonging the IVRT. (2) Left ventricular contraction (S‐wave) deteriorates when the aortic valve area decreases below 1 cm2, and this deterioration has a direct relationship with aortic valve area. LVEF decreases when the valvular area is smaller than 1 cm2, but remains inside what is considered normal values.