Myocardial function in aortic stenosis--insights from radial multilayer Doppler strain

Area of Science:

• Cardiology
• Medical Imaging
• Echocardiography

Background:

• In healthy individuals, left ventricular (LV) radial tissue Doppler imaging (TDI) strain shows a gradient, increasing from subepicardial to subendocardial layers.
• Previous studies suggest this strain gradient diminishes with increasing aortic stenosis (AS) severity.

Purpose of the Study:

• To investigate the impact of AS severity and hypertension on LV radial TDI strain in different myocardial layers.
• To assess layer-specific strain patterns in patients with AS using TDI.

Main Methods:

• TDI strain was measured in 84 patients with AS (mean age 73 ± 10 years, 56% hypertensive).
• Peak systolic radial TDI strain was analyzed in subendocardial, mid-myocardial, and subepicardial layers of the basal inferior LV wall.
• Patients were categorized into non-severe (n=38) and severe AS (n=46) based on aortic valve area corrected for pressure recovery.

Main Results:

• Subepicardial radial strain (33.4 ± 38.6%) was significantly lower than mid-myocardial (50.3 ± 37.3%) and subendocardial (53.0 ± 40.0%) layers (p < 0.001).
• Severe AS patients exhibited lower subendocardial and mid-myocardial radial strain compared to non-severe AS patients (p < 0.05).
• Multivariate analysis revealed hypertension and AS severity attenuated mid-myocardial strain (β = -0.23 and -0.26, respectively; p < 0.05), while only AS severity affected subendocardial strain (β = -0.35; p < 0.01).

Conclusions:

• Both AS severity and hypertension contribute to reduced radial TDI strain in the inferior LV wall.
• Subendocardial radial strain is predominantly influenced by AS severity.
• Midmyocardial radial strain is attenuated by both the severity of AS and the presence of hypertension.