The Association Between Postsystolic Index and SYNTAX Score in Hospitalized Patients With Non-ST-Elevation Acute Coronary Syndrome

Objective: Non-ST-elevation acute coronary syndrome (NSTE-ACS) is a heterogeneous disorder including subgroups with a low or high risk for myocardial ischemia. The presence of postsystolic index (PSI) is associated with myocardial ischemia. The focus of this study was to find probable association between PSI and severity of coronary artery disease (CAD) in a cohort of patients. Materials and Methods: This was a cross-sectional study that consisted of 83 patients with unstable angina, non-ST-segment myocardial infarction (UA/NSTEMI), and a left ventricular ejection fraction ≥50%, without visible regional wall motion abnormalities. All patients underwent echocardiography, and global longitudinal strain (GLS), PSI, and mitral annular peak systolic (s′) and early diastolic (e′) velocities were measured. Coronary angiography was then performed, and a SYNTAX score was calculated. Results: The patient cohort was divided into two groups based on their high and low SYNTAX scores. PSI and GLS were higher in those patients with a higher SYNTAX score than in individuals with a lower score (85.04% ± 67.02% vs 46.67 ± 39.03, P = .001 and −16.09 ± 3.70 vs −17.99 ± 2.87, P = .012, respectively). Among the different variables assessed, only PSI was an independent predictor of a high SYNTAX score ( B = 1.014, 95% confidence interval [CI]: 1.001–1.027, P = .034). Conclusion: This cohort study demonstrated that a cumulative PSI may be predictive of much more complex and extensive CAD, especially in patients with UA/NSTEMI.