Procedural and Long‐Term Outcomes of Percutaneous Coronary Intervention for In‐Stent Chronic Total Occlusion

BACKGROUND: This study examined procedural success and long-term outcomes of percutaneous coronary intervention (PCI) for in-stent chronic total occlusion (IS-CTO) compared with de novo CTO. While contemporary techniques have improved acute success rates for IS-CTO PCI, data on long-term outcomes remain limited. AIMS: We aimed to examine procedural success rates for IS-CTO PCI using contemporary techniques, evaluate long-term clinical outcomes with extended follow-up, identify independent predictors of major adverse cardiac events, and compare our findings with recent multicenter registries. METHODS: We analyzed 501 consecutive CTO PCI procedures in 456 patients at our institution between January 2018 and December 2023. Patients were stratified into IS (n = 82, 16.4%) and de novo CTO (n = 419, 83.6%) groups. The primary endpoint was a composite of in-stent restenosis requiring revascularization, heart failure hospitalization, myocardial infarction, and stroke at median follow-up of 713.5 days. Cox proportional hazards regression identified predictors of adverse events. RESULTS: Patients with IS-CTO had a higher prevalence of diabetes (58.5% vs. 47.5%, p = 0.067) and prior myocardial infarction (46.3% vs. 27.5%, p = 0.001). Procedural success was similar (86.6% vs. 79.5%, p = 0.136) with comparable in-hospital complications. However, at median follow-up of 713.5 days, patients with IS-CTO experienced higher rates of the composite endpoint (26.4% vs. 12.8%, p = 0.003), driven by in-stent restenosis (20.8% vs. 5.2%, p < 0.001). After adjustment, IS-CTO showed a trend toward increased risk for composite outcome (HR 2.03, 95% CI 1.00-4.11). Independent predictors of composite outcome included heart failure (HR 2.15, 95% CI 1.17-3.94) and male sex (protective: HR 0.49, 95% CI 0.26-0.90). CONCLUSIONS: Despite achieving procedural success comparable to de novo CTO, IS-CTO PCI is associated with significantly worse long-term outcomes over extended follow-up, particularly recurrent restenosis. These findings underscore the need for improved therapeutic strategies in this challenging population.