The influence of the Ini­tial Severity of Coronary Artery Lesion (by the Syntax Score) on the Midterm Prognosis of Patients With Acute Myocardial Infarction Without ST Segment Elevation

Abstract

Aim To study the effect of the baseline severity of coronary artery damage according to the SYNTAX scale (baseline score of coronary lesions, BSCL) on the mid-term prognosis in patients with non-ST segment elevation acute myocardial infarction (AMI) (NSTEMI), and to identify the threshold BSCL value that determines high and low risks of adverse cardiac outcomes.Material and methods A retrospective analysis was performed for the hospital treatment of patients with NSTEMI (n=421) who had undergone percutaneous coronary intervention (PCI). 256 patients with a repeated hospitalization in mid-term (11.6±3.2 months) were selected for the study. These patients were followed up for the incidence of acute coronary syndrome (ACS), unscheduled repeated myocardial revascularization (URR), and of the composite endpoint (CEP) that included at least one the following events: death, recurrent AMI, unstable angina (UA), and URR. The effect of BSCL on the incidence of these events in mid-term was proven (р<0.05), and then the BSCL threshold value was determined, which allowed segregation of patients into groups of high and low risk of adverse cardiac outcomes.Results The threshold BSCL value for the risk of ACS was determined as score 14 (odds ratio, OR, 2.79; 95 % confidence interval, CI: 1.32-5.89); for URR and CEP, score 13 (OR, 2.21; 95 % CI: 1.22-4.01 and OR, 2.38; 95 % CI: 1.32-4.31, respectively). Since these threshold values were comparable, for the composite category of events (CEP), the BSCL threshold comprised score 13, and namely this value was taken as a base. According to the multifactorial Cox regression at BSCL score ≥13, the probability of earlier CEP in mid-term was 2.44 times higher than at lower BSCL values (OR, 2.44; 95 % CI: 1.41-4.21; р=0.001). Furthermore, according to the Kaplan-Meier estimate, the effect of BSCL on the survival without adverse cardiac outcomes becomes significant starting from the second half-year (р=0.001, log-rank test).Conclusion In NSTEMI patients, the SYNTAX baseline score of coronary lesions >13 is an independent predictor of adverse cardiac outcomes in mid-term starting from the second half-year. Thus, patients with BSCL ≥13 should undergo a follow-up examination no later than at 6 months independent on their clinical condition..