Comparison of multiple risk scores in assessing medium-to long-term clinical outcomes in unstable angina / non-ST-elevation myocardial infarction patients undergoing multi vessel percutaneous coronary intervention: An observational, registry-based study in India

OBJECTIVE: Post-revascularization mortality in multivessel coronary artery disease (MVCAD) has been explored via several risk scores. Here, we assessed and compared various risk scores in predicting medium to long-term clinical outcomes in unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) patients with MVCAD undergoing percutaneous coronary intervention (PCI). METHODS: We analyzed a cohort of a tertiary care center registry enrolling patients in South India, Kerala, with MVCAD (N = 200) who had undergone PCI between 2010 and 2018. The outcomes evaluated were all-cause mortality and major adverse cardiac events (MACE). The risk scores assessed included SYNTAX score (SS), residual SYNTAX score (rSS), SYNTAX revascularization index (SRI), age, creatinine, and ejection fraction (ACEF) score, clinical SYNTAX score (cSS), and SYNTAX score II (SSII). RESULTS: Of the analyzed risk scores, SSII had the best predictive capability with the area under the curve (AUC) of 0.79 in c-statistics, followed by ACEF score and cSS with AUCs of 0.74 and 0.65, respectively for all-cause mortality (p < 0.01). Kaplan-Meier survival curves and multivariate analysis by Cox regression showed SSII with cut-offs of >35.15 and > 29.55 to be the only score associated with higher mortality and MACE, respectively. CONCLUSIONS: In UA/NSTEMI patients with relatively less complex MVCAD treated by PCI, the SSII, ACEF and cSS risk scores could predict the outcomes better. The SSII showed the best predictive performance for all-cause mortality and MACE. Scores based on baseline and residual atherosclerotic burden (SS, rSS, and SRI) performed poorly in predicting the mortality and MACE.