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Although it is known that left ventricular function is impaired in subjects with severe aortic stenosis (AS), it is unclear whether the same is true in patients with in asymptomatic mild to moderate AS. In the present study, we aimed to evaluate the utility of speckle tracking echocardiography (STE) in asymptomatic mild to moderate aortic stenosis at rest and during supine bicycle exercise test which has not been studied previously.
The study sample consists of 25 patients with asymptomatic mild to moderate AS and 13 healthy controls. All patients underwent detailed echocardiographic evaluation at rest and during supine bicycle exercise test. Left ventricular functions were evaluated with two dimensional STE at rest and during peak exercise. Additionally C-reactive protein (CRP), brain natriuretic peptide (BNP) and troponin values of the groups were recorded.
Conventional echocardiographic parameters were similar between groups (ejection fraction, pulmonary artery pressure, heart chamber diameters). Aortic velocity was significantly higher (2.1 m/s vs 1.3 m/s, p=0.001) in the group with AS and the difference increased at peak exercise (2.7 m/s vs 1.7 m/s, p<0.001). Left ventricular global longitudinal strain (GLS) was not only significantly lower in the group with AS (18.6±2.7 vs 21.2±2.8, p=0.034) when compared with the control group but also the difference became more pronounced during peak exercise (18.1±2.7 vs 23.8±2.3, p<0.001). Resting GLS inversely correlated with BNP (p:0.033, r:-0.419), CRP (p:0.014, r:-0.474), troponin (p:0.009, r:-0.505). Peak exercise GLS demonstrated better correlation with BNP, CRP and troponin (p:0.010, r:-0.496; p:0.004, r:-0.547; p:0.001, r:-0.633 respectively). Peak exercise GLS (p:0.035, r:-0.415) but not resting GLS correlated with aortic velocity.
Despite normal left ventricular ejection fraction, GLS is not only significantly decreased in patients with asymptomatic mild to moderate AS but also the difference is more pronounced during peak exercise. Results of the present study suggest that STE is a reliable tool in early detection on left ventricular involvement in mild to moderate AS.