Association between global longitudinal strain and post-systolic shortening of left ventricle with the severity of coronary artery disease in patients with acute coronary syndrome without ST elevation

Introduction For patients presenting with non-ST-elevation acute coronary syndrome (NSTE-ACS) who are not considered to be at very high mortality risk at the time of admission, current clinical guidelines advocate for coronary angiography (CAG) to be performed during hospitalization. Therefore, in these patients, introduction of novel non-invasive methods for prediction of severity of coronary artery disease is needed in order to identify patients who could benefit from CAG earlier during their hospital stay. Purpose The aim of this study was to evaluate the association between severity of CAD and echocardiographically assessed global longitudinal strain (GLS) and post-systolic shortening (PSS) of left ventricular myocardium in patients with NSTE-ACS. Methods This prospective cross-sectional study included patients admitted to the cardiology clinic with the diagnosis of NSTE-ACS. Inclusion criteria were: preserved left ventricular ejection fraction (>50%), absence of regional wall motion abnormalities and indication for CAG set by interventional cardiologist and performed during the hospital stay. Patients who were estimated to be at very high mortality risk were excluded from the study. In addition to conventional echocardiography parameters, post-systolic shortening index (PSI), LAD specific PSI (PSI-LAD) and GLS were measured. PSI was calculated as the average PSS across all 17 myocardial segments, generated from strain curves, while PSI-LAD was calculated as the average PSS across 10 myocardial segments vascularized by LAD. The severity of CAD was assessed using the SYNTAX score. Significant coronary artery stenosis was defined as ≥90% narrowing in one of the three main epicardial arteries. Results Among the 70 enrolled patients, 45.7% (n=32) were diagnosed with unstable angina, while 54.3% (n=38) were diagnosed with NSTEMI. There was a significant positive correlation between SYNTAX score and both GLS (rho=0.504; p<0.001) and PSI (rho=0.249; p=0.035). Patients with significant LAD stenosis had higher GLS values (-14.88±2.53% vs. -17.02±3.23%, p=0.001) and higher PSI-LAD values (10.65 [3.13–18.53] vs. 4.2 [2.53–8.3], p=0.015) compared to those without significant LAD stenosis. GLS emerged as an independent predictor of significant stenosis on one of three main epicardial arteries (p=0.001; OR 1.43; 95% CI: 1.16–1.76). Both PSI-LAD and GLS demonstrated significant predictive value for LAD stenosis, with AUCs of 0.672 (p=0.020) and 0.675 (p=0.019), respectively. Conclusion In addition to other known clinical factors, GLS and PSI may serve as feasible non-invasive echocardiographic parameters for additional risk stratification in NSTE-ACS patients who are not at very high risk. These measures could help identify individuals who might benefit from earlier CAG during hospitalization. Further research is warranted to develop precise risk assessment models incorporating these parameters.