Impact of impaired myocardial deformations on exercise tolerance and prognosis in patients with asymptomatic aortic stenosis


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Abstract

AimsAs assessed by tissue Doppler velocities, longitudinal contraction is commonly altered at an earlier stage than radial contraction in patients with severe aortic stenosis (AS). However, its relationship to exercise tolerance or to prognosis has not been clearly established. By using two-dimensional (2D) echocardiographic strain, we sought to evaluate values of deformation components in the setting of severe AS and to correlate these values with exercise tolerance and with patients’ outcome.Methods and resultsSixty-five asymptomatic patients with severe AS (aortic valve area <1 cm2) were studied by echocardiography and exercise treadmill and were compared with controls. Conventional echographic parameters as well as longitudinal, radial, and circumferential deformations by 2D strain were measured at rest. During exercise treadmill, maximum tolerated workload, maximum heart rate, blood pressure, and EKG ST variations were recorded. Patients were then followed during 12 months. Compared with controls, despite similar ejection fractions, AS patients presented with a significantly lower global longitudinal strain (GLS) (−17.8 ± 3.5 vs. −21.1 ± 1.8%, P < 0.05) more pronounced in the basal segments (BLS) (−12.4 ± 2.9 vs. −18.4 ± 2.5%, P < 0.05). No difference was observed in terms of radial or circumferential strains. In a subgroup of AS patients with abnormal response to exercise, GLS and BLS were significantly lower (−14.7 ± 5.1 vs. −19.3 ± 4.0% and −10.7 ± 2.5 vs. −14.4 ± 2.1%, P < 0.05). With cut-offs of −18 and −13%, GLS and BLS were able to determine an inadequate exercise response with a sensitivity and specificity of 68 and 75% (AUC 0.77), and 77 and 83% (AUC 0.81), respectively. Finally, patients with a basal strain below −13% presented with more cardiac events in the follow-up.ConclusionIn asymptomatic patients with severe AS, impaired longitudinal contraction assessed by 2D strain is associated with abnormal exercise response and with an increased risk of cardiac events during follow-up.

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