Experimental validation of circumferential, longitudinal, and radial 2-dimensional strain during dobutamine stress echocardiography in ischemic conditions.

OBJECTIVES The aim of this study was to assess and validate 2-dimensional (2D) strain for the detection of ischemia during dobutamine stress echocardiography (DSE). BACKGROUND Evaluation of abnormalities of left ventricular (LV) function from wall thickening during DSE is unsatisfactory and requires a high level of expertise. METHODS In 10 open-chest anesthetized pigs, myocardial deformation was studied before and during dobutamine infusion, under control and ischemic conditions produced by various degrees of coronary artery constriction: 2 of nonflow-limiting stenoses (NFLS) of increasing severity reducing left anterior descending artery hyperemic flow by 40% and 70% and 2 flow-limiting stenoses (FLS) reducing resting coronary flow by 25% and 50%. Agreement between 2D strain echocardiography and sonomicrometry (reference method) was evaluated by linear regression and Bland-Altman analysis. RESULTS Good correlation and agreement were observed between 2-dimensional strain and sonomicrometry at rest and during dobutamine infusion; longitudinal strain: r = 0.77, p < 0.001 and r = 0.80, p < 0.001; radial strain: r = 0.57, p < 0.05 and r = 0.63, p < 0.05; and circumferential strain: r = 0.74, p < 0.001 and r = 0.58, p < 0.001. Circumferential and longitudinal strains in the risk area were significantly decreased at rest in the presence of FLS and during dobutamine infusion in the presence of NFLS. By contrast, radial strain was significantly decreased in the presence of severe FLS only during dobutamine infusion. CONCLUSIONS The 2D strain provides accurate assessment of LV regional function. Evaluation of circumferential and longitudinal strains during DSE has real potential for quantitative evaluation of LV deformation in the routine assessment of ischemia.