Long-term incidence and predictors of in-stent restenosis after chronic total occlusion percutaneous coronary intervention: a cohort study

Background In-stent restenosis (ISR) remains a major limitation after percutaneous coronary intervention (PCI) with drug-eluting stents (DESs). However, long-term patency data after chronic total occlusion (CTO) PCI are limited despite high ISR risk. We evaluated long-term ISR incidence and predictors after CTO PCI. Methods This prospective single-centre study (NCT07473596) included patients with successful CTO PCI and DES implantation in 2014–2021. Selected survivors underwent protocol-driven surveillance with coronary computed tomography angiography ≥3 years after the index procedure, with suspected ISR confirmed by invasive coronary angiography (ICA). ISR was also identified through clinically indicated ICA during follow-up in all patients. Patient-, lesion-, and procedure-related ISR predictors were analysed. Results The study included 294 patients (median age 66 years (IQR 57–74), 79.9% male) and 294 analysed CTO stents. Median clinical and imaging follow-up were 7.1 (IQR 5.1–8.9) and 4.4 (IQR 3.2–6.2) years, respectively. Follow-up imaging covered 186 patients and 186 analysed CTO stents (63.3%). ISR was diagnosed in 40 stents (13.6%). Aalen–Johansen cumulative ISR incidence was 4.8% (95% CI 2.9–7.9), 10.2% (95% CI 7.1–14.5), and 12.9% (95% CI 9.3–18.0) at 3, 5, and 8 years, respectively. Atrial fibrillation (HR 3.71, 95% CI 1.74–7.91, p < 0.001) and in-stent CTO (HR 3.51, 95% CI 1.53–8.04, p = 0.003) were independently associated with ISR. Conclusions Long-term ISR after CTO PCI was infrequent in this high-risk cohort, although estimates should be interpreted in the context of selected imaging follow-up among survivors. ISR was independently associated with atrial fibrillation and in-stent CTO at the index procedure.