Impact of residual coronary lesions on outcomes of myocardial infarction patients with multi-vessel disease

Background The residual burden of coronary artery disease (CAD) after percutaneous coronary intervention (PCI) drew a growing interest. The residual SYNTAX Score (rSS) was a strong prognostic factor of adverse events and all-cause mortality in patients who underwent PCI. In addition, the SYNTAX Revascularization Index (SRI), a derivative of rSS, was used to figure out the treated proportion of CAD and could be used as a prognostic utility in PCI for patients with multi-vessel disease (MVD). Purpose We aimed at the assessment of the use of rSS and the SRI as predictors of in-hospital outcomes and up to two-year cumulative follow-up outcomes in patients with MVD who had PCI for the treatment of ST-Elevation Myocardial Infarction (STEMI) or Non-STEMI (NSTEMI). Methods We recruited 149 patients who had either STEMI or NSTEMI while having MVD and received treatment with PCI. We divided them into tertiles based on their rSS and SRI values. We calculated baseline SYNTAX Score (bSS) and rSS using the latest version of the calculator on the internet, and we used both scores to calculate SRI. The study end-points were In-hospital composite Major Adverse Cardiovascular Events (MACE) and its components, in-hospital death, and follow-up cumulative MACE up to 2 years. Results Neither rSS nor SRI were significant predictors of in-hospital adverse events, while female sex, hypertension, and left ventricular ejection fraction were independent predictors of in-hospital MACE. At the two-year follow-up, Kaplan-Meyer analysis showed a significantly increased incidence of MACE within the third rSS tertile (rSS > 12) compared to other tertiles (log rank p = 0.03). At the same time, there was no significant difference between the three SRI tertiles. Unlike SRI, rSS was a significant predictor of cumulative MACE on univariate Cox regression (HR = 1.037, p < 0.001). On multivariate Cox regression, rSS was a significant independent predictor of two-year cumulative MACE (HR = 1.038, p = 0.0025) along with female sex, hypertension, and left ventricular ejection fraction. We also noted that all patients with complete revascularization survived well throughout the entire follow-up period. Conclusions Neither rSS nor SRI could be good predictors of in-hospital MACE, while the rSS was a good predictor of MACE at two-year follow-up. Patients with rSS values > 12 had a significantly higher incidence of cumulative MACE after 2 years. The best prognosis was achieved with complete revascularization.