Two-dimensional speckle tracking echocardiography derived post systolic shortening in patients with unstable angina and normal left ventricular systolic function

Objective: Post-systolic shortening (PSS) has been shown to be sensitive in detecting ischemia on stress echocardiography. In this study, we aimed to assess the diagnostic potential of resting PSS and post-systolic index (PSI) in patients with suspected unstable angina (UA). Methods: A total of 159 participants with suspected UA without any wall motion abnormalities were recruited. They all underwent speckle tracking echocardiography (STE) and coronary angiogram (CAG). Global longitudinal strain (GLS); presence or absence of pathological PSS; PSI17 and PSI12, and PSI in left anterior descending, left circumflex, and right coronary artery territories were assessed. On the basis of CAG, those who had more than 70% stenosis were labelled to have obstructive CAD. Results: Obstructive disease was noted in 54.7% patients. The prevalence of PSS (62.1% vs. 13.9%), mean PSI17 (5.4 vs. 3.3), and PSI12 (6.2 vs. 3.7) were significantly higher in those with CAD compared with patients without obstructive disease. Both PSS [odds ratio (OR) 10.145; 95% confidence interval (CI) 4.577-22.489; p=0.001] and PSI17 (OR: 1.217; 95% CI: 1.064-1.393; p=0.004) were predictors of CAD by multivariate regression analysis. PSS had a sensitivity of 62.1% and specificity of 86.1% with a positive predictive value of 84.4%. PSI17 [area under curve (AUC): 0.637; p=0.003] and PSI12 (AUC: 0.661; p=0.001) have moderate accuracy in identifying obstructive CAD. Conclusion: In patients presenting with suspected UA, STE derived PSS has reasonable sensitivity and good specificity in diagnosis of obstructive CAD. Patients identified to have PSS can be subjected to CAG without further stress testing because of its high positive predictive value.