Residual syntax score and long-term outcomes among patients who underwent CTO-PCI

Abstract

Backgrounds: Although favorable outcomes have been reported, role of CTO-PCI is still controversial because of its difficult procedure and unpredictable benefit. Assessment of patients with CTO by syntax score may help to establish appropriate indication and strategy of CTO-PCI. Methods: We investigated consecutive 245 patients who underwent CTO-PCI adjunctive to medical therapy. All those patients were assessed by syntax score based on their initial angiogram. We divided them into the three groups by tertiles of SYNTAX score analysis (low score ( 32), and investigated occurrence of major adverse cardiac event (MACE) during subsequent follow-up periods. We employed residual syntax score (define as score after the PCI) for assessment of revascularization. MACE comprises from all cause death, non-fatal myocardial infarction, initially unplanned revascularization including bypass surgery. Results: Mean age (y) was 65.0±11, 65.7±10, and 69.3±10 (P=0.04). Ejection fraction (%) was 57.5±15, 55.8±15, and 51.5±16 (P=0.04). According to baseline syntax score, syntax score of each groups was 14.2±5, 25.4±4, and 44.1±10 (P<0.001), specific score at CTO site was 10.2±3, 15.2±7, and 15.4±7 (P<0.001). Procedural success rate among those groups was 85.7%, 90.8% and 80.0% (P=0.16) and their residual syntax score after the PCI was 3.5±6, 4.3±7, and 13.6±16 (P<0.0001). According to survival analysis, success of CTO-PCI was effective to reduce occurrence of MACE compared to failure cases among patients with high and intermediate syntax score, in contrast to the low syntax score group (median 769 days, success vs. failure (%); 12.4 vs. 0: P=0.967, 18.5 vs. 61.9: P=0.008, and 22.9 vs. 53.8: P=0.004). By multivariate analysis, residual syntax score after PCI was only independent predictor of occurrence of MACE (hazard ratio: 1.05, 95% confidence interval: 1.02-1.08, P=0.002). Conclusion: Independent predictor of long-term outcome among patients who underwent CTO-PCI was residual syntax score after PCI. Specific score of CTO segment may be useful to identify optimal indication of CTO-PCI, and efficacy of CTO-PCI among patients with low syntax subset needs further investigation.