Holistic review and meta-analysis of independent impact of the residual SYNTAX score on prognosis in patients with acute coronary syndrome

<i>Objectives</i>. The appropriate extent of revascularization following primary intervention is unknown. We conducted a systematic review and meta-analysis of residual Syntax score (rSS) to predict the outcomes and provide guide to optimal management of revascularization following primary intervention. <i>Designs</i>. Previously published studies from 2007 to 2020 assessing the prognostic impact of rSS after ACS were included for this meta-analysis. The primary endpoint was defined as the major adverse clinical events (MACE) in multivariable analysis. The risk ratios (RRs) with 95% confidence intervals (CI) were calculated using the RevMan 5.4 software. <i>Results</i>. A total of 8,157 participants complicated with ACS from 12 clinical studies were included in this analysis. Based on the wide range of rSS studies available, we classified it into two major groups: rSS &lt; 8 and rSS ≥ 8. In multivariate analysis, the rSS was an independent risk marker for MACE [RR = 1.04 (95%CI; 1.00–1.08)], all-cause mortality [RR = 1.05 (1.03–1.07)] and cardiovascular death [RR = 1.05 (1.03–1.07)]. Patients with incomplete revascularization (ICR) showed higher prevalence of MACE along with all-cause mortality, cardiovascular morality, and recurrent myocardial infarction without significant heterogeneity [RR = 1.60 (1.03–1.07), 2.30 (1.57–3.38), 3.57 (2.09–6.10) and 1.70 (1.38–2.09), respectively]. The patients with rSS ≥ 8 presented higher frequency of all-cause mortality [RR = 2.99 (2.18–4.09)], cardiovascular death [RR = 3.32 (2.22–4.95)], and recurrent myocardial infarction [RR = 1.64 (1.34–2.02)]. <i>Conclusion</i>. The meta-analysis indicated that an rSS value of 8 could be a reasonable cut-off for incomplete revascularization after ACS and is an efficient tool to guide revascularization. In future, detailed research should focus on investigation of the optimal value of the rSS score.