BACKGROUND Although the success rate of percutaneous coronary intervention (PCI) of chronic total occlusive (CTO) lesions is rising recently, the nature and behavior of these revascularized lesions in the real-world practice are unknown.

METHODS Data was collected from a prospective cohort of patients with successfully revascularized CTO lesions using drug-eluting stent (DES). Among these, patients with angiographical in-stent restenosis (ISR) were analyzed.

RESULTS 58% (n=149) of the total patients (n=255) with successful PCI of CTO received 6-9 months' angiographical follow-up. Angiographic ISR was identified in 36 lesions from 36 patients. There was a strong tendency towards diffuse ISR (61% of total ISR lesions) in these lesions, as compared with ISR after implantation of DES for non-CTO lesion in previous literatures. Multivariate analysis showed that post-procedural minimal lumen diameter (MLD) and total stent length were the only reliable predictors of diffuse ISR (HR 0.527 per 0.5 mm increment of MLD, HR 1.262 per 10mm increment of stent length). Compared with the group with larger post-procedural MLD (> 1.9 mm) and shorter stent length (≤ 55 mm), the group with smaller post-procedural MLD (≤ 1.9 mm) and longer stent length (> 55 mm) carried a 9-fold higher risk of diffuse restenosis. In addition, diffuse ISR was more frequently associated with symptoms or signs of myocardial ischemia.

CONCLUSION Revascularized CTO lesions using DES may carry a high risk of diffuse ISR, which is associated with more frequent myocardial ischemia compared with focal ISR. Post-procedural MLD and total stent length are significant predictors of these types of ISR after successful CTO intervention.