Diagnostic value of postsystolic shortening of the left ventricular myocardium assessed during speckle tracking stress echocardiography on the treadmill in patients with coronary artery disease

Abstract

Aim      To evaluate the diagnostic capacity of left ventricular (LV) postsystolic shortening (PSS) values obtained by speckle-tracking stress-echocardiography (stress-EchoCG) using a treadmill test in determining the functional significance of the degree of coronary artery (CA) stenosis.Material and methods  The study included 132 patients (80 men aged 65.0±9.3 years) with suspected or previously verified diagnosis of ischemic heart disease. Stress-EchoCG with the treadmill test was performed for all patients. Strain parameters were determined by two-dimensional speckle-tracking on gray-scale images before and after the exercise. Values of LV postsystolic index (PSI) and LV mean postsystolic time (PST) were calculated. Coronary angiography was performed for all patients. Patients were divided into 3 groups based on the severity of CA stenosis according to the G. G. Gensini score.Results LV PSS values at rest did not significantly differ between the patient groups. After completion of the exercise, the mean LV PSI was significantly higher for patients with pronounced CA stenosis than in the group without CA stenosis or with moderate CA stenosis: 8.9 %  [3.8; 10.7 %] vs. 3.8 % [2.2; 6.8 %] (p=0.012) and 3.4 %  [2.2; 6.2 %] (p=0.012), respectively. The mean LV PSI after completion of the exercise indicated the presence of pronounced CA stenosis with a sensitivity of 75 % and a specificity of 61 % (area under the curve, AUC, 0.74±0.06; р<0.001). After completion of the exercise, the mean LV PST was significantly greater for patients with pronounced CA stenosis than in the group without CA stenosis or with moderate CA stenosis: 27.4 [18.7; 34.7] ms vs. 18.4 [10.8; 26.5] ms (p=0.036) and 20.9 [14.2; 29.5] ms (p=0.036), respectively. The mean LV PST after completion of the exercise exceeding 23.5 ms suggests pronounced CA stenosis with a sensitivity of 71 % and a specificity of 65 % (AUC 0.69±0.06; p=0.004). A complex evaluation of the LV PSI, the LV local contractility disorder (LCD) index, the LV PST, and LV LCD index allows enhancement of the test sensitivity in diagnozing pronounced CA stenosis.Conclusion      Determination of LV PSS in speckle-tracking stress-EchoCG may be useful for evaluating the functional significance of the degree of CA stenosis to enhance the sensitivity of stress-EchoCG in patients with pronounced CA stenosis.