P1012Post systolic strain during dobutamine stress and myocardial ischemia.


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Abstract

Purpose: Dobutamine stress echocardiography (DSE) is an established, noninvasive method for the detection of myocardial ischemia induced by coronary artery disease (CAD). Quantification of systolic and post-systolic myocardial strain by speckle tracking echocardiography has been proposed as a potential tool to aid visual assessment of wall motion abnormalities induced by ischemia. The aim of this study was to evaluate feasibility of speckle tracking during DSE.Methods: Study group consisted of 36 patients of 62 ± 7 years of age with intermediate likelihood of CAD who underwent diagnostic DSE. Strain images were obtained using GE Vivid 7 at 4 time points: rest, low dose (20 μg/kg/min) of dobutamine, peak stress (40 μg/kg/min of dobutamine +/- atropine) and 3 minutes post-stress. All patients had invasive coronary angiography and haemodynamically significant coronary stenosis was defined as >70% by quantitative coronary angiography or in the presence of intermediate stenosis by fractional flow reserve (FFR) <0.80. Myocardial strain, strain rate and post systolic strain (PSS) of areas supplied by these arteries were measured blinded to the results of angiography.Results: There were 13 significant stenoses in 108 vessels. Overall PSS was higher in low dobutamine dose than in rest (4.7 ± 5.1% vs. 3.4 ± 3.7%, p=0.05) but did not change significantly at low dose, peak stress and post-stress (4.7 ± 5.1%, 5.9 ± 9.8% and 5.5 ± 8.8%, respectively). Logistic regression analysis including strain, strain rate and PSS showed that PSS was the strongest predictor of significant coronary stenosis. Compared with the vessels with significant stenosis, PSS was comparable in the non-stenosed vessels at rest (5.8 ± 6.6 vs. 3.1± 3.1, p=0.07). At low dose, peak stress and post-stress, PSS was higher in stenotic than non-stenotic vessels (8.3 ± 8.0 vs. 4.2 ± 4.3, p= 0.03, 13.1 ± 15.3 vs. 4.9 ± 8.4, p=0.03, 17.3 ± 19.4 vs. 3.8 ± 4.3, p=0.02, respectively).Conclusions: The amount of post systolic myocardial strain during dobutamine infusion is a strong predictor of the presence of flow-limiting coronary artery stenosis. Further studies are warranted to determine the value of PSS measured with speckle tracking for the detection of significant CAD during DSE.

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