Subendocardial dysfunction in patients with chronic severe aortic regurgitation and preserved ejection fraction detected with speckle-tracking strain imaging and transmural myocardial strain profile

Abstract

It remains difficult to detect subtle left ventricular (LV) myocardial dysfunction in chronic aortic regurgitation (AR) patients with the preserved ejection fraction (EF). We studied 36 chronic severe AR patients undergoing surgical correction with the EF of 58 ± 6% (all ≥ 50%). Echocardiography was performed before and 12 ± 8 months after surgical correction. We used two-dimensional speckle-tracking strain imaging to evaluate global radial strain in the inner-half (GRSinner), outer-half (GRSouter), and total (GRStotal) layer from the mid-LV short-axis view. We also evaluated the transmural strain profile in the LV posterior wall by using myocardial tissue Doppler radial strain, and the location of peak strain was determined as the percentage of the distance from the endocardium to the epicardium accounted for by the wall thickness. Fifteen EF-matched normal volunteers were studied for comparison. GRSinner for AR patients was significantly smaller than that for controls (28.9 ± 12.9 vs. 37.1 ± 9.1%, P = 0.032), and the location of peak strain had significantly shifted to the epicardial side compared with that in controls (27.1 ± 14.0-13.2 ± 4.8%, P = 0.001). In contrast, GRStotal and GRSouter were similar for the two groups. After surgical correction, EF increased from 58 ± 6 to 62 ± 7% (P = 0.018), GRSinner from 27.8 ± 12.5 to 37.7 ± 14.6% (P < 0.0001), and the location of peak strain significantly shifted to the endocardial side (26.9 ± 13.9-19.1 ± 11.9%, P = 0.028). However, GRStotal and GRSouter did not change. The LV endocardium side, impaired in chronic AR patients with the preserved EF, improved after surgical correction. Our observations may prove useful for evaluating subtle early changes in such patients.