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This study aimed to evaluate the subtle left ventricular function change in chronic aortic regurgitation (AR) patients using three dimensional strain imaging (3D STI) and to investigate the 3D STI value in predicting short-term outcome after aortic valve replacement surgery (AVR).
Conventional LV volume and function indexes, Global longitudinal strain (GLS), Global circumferential strain(GCS), Global radial strain(GRS), torsion, basal rotation (RoB), apical rotation (RoA) as well as all segmental strains by 3D STI were analyzed in 30 controls (age, 49.8±14.3 yrs, male 16), 31 chronic AR patients with preserved LV function (AR+PEF group, LVEF≥55%, age 50.4±14.2 yrs, male 18), and 36 chronic AR patients with LV dysfunction (AR+REF group, LVEF<55%, aged 48.0±14.1 yrs, male 23). Among them, 32 patients underwent AVR, with perioperative cardiac adverse events, pre and post operation echo recorded.
1. As compared to normal group, GLS(-19.93±1.82% vs. -17.87±2.43%), GRS(43.63±3.28% vs. 39.80±4.51%), torsion(2.31±0.60°/cm vs. 1.65±0.41°/cm) were significantly reduced in AR+PEF but GCS (-32.47±3.53% vs. -30.87±3.58%) was preserved. GLS(-19.93±1.82% vs. -12.56±2.62 %), GCS(-32.47±3.53%vs. -20.74±4.82%), GRS(43.63±3.28% vs. 27.13±5.90%), torsion (2.31±0.60 °/cm vs. 1.17±0.46°/cm) were all significantly reduced in AR+REF. 2. Strains from three directions were all decreased in middle segments (LS -18.44±3.34%vs. -15.21±3.50%, CS -37.03±5.51% vs -33.67±4.09%, RS 46.02±5.82% vs. 40.22±4.34%, respectively)and apical segments(LS -21.73±5.27 % vs. -19.18±7.85%, CS -39.07±5.32 %vs. -35.08±4.64 %, RS 50.73±6.74 % vs. 45.20±9.24 %, respectively) in AR+PEF. However, strains in basal segments LS(-17.96±3.27 % vs. -17.69±3.89%), CS(-29.80±5.30 %vs. -29.55±3.74%) and RS(38.48±5.00%vs.38.54±5.07%) were all preserved. RoA(10.42±2.92°vs.8.47±3.07°)was significantly reduced in AR+PEF, while RoB(-7.28±2.30°vs. -6.45±3.16°) was preserved (Table 1). 3.In our study, preoperative GLS was the only independent predictor of cardiovascular adverse events during and after the operation. The receiver operating characteristic curves showed that optimal cut-off point was -15.65% with the area under the curve 0.765 (sensitivity and specificity was 0.733 and 0.875, respectively).
3D STI can accurately evaluate subclinical left ventricular dysfunction in patients with chronic aortic regurgitation. For patients with preserved LVEF, GCS, basal ventricle strains and rotation played an important role to maintain normal LEVF. GLS can predict occurrence of adverse cardiovascular events during and after AVR, providing a critical role in selecting the appropriate timing of surgery.