The Japan–Chronic Total Occlusion (J-CTO) score, widely used to estimate procedural difficulty in percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs), may have limited predictive accuracy in in-stent lesions. Findings from this study, published in The American Journal of Cardiology, suggest that in-stent CTOs behave differently from de novo occlusions when using intraplaque guidewire tracking techniques.

The study included 508 patients (mean age 64 years, 88% men) undergoing CTO intervention, of whom 74 had in-stent CTOs and 434 had de novo CTOs. Overall procedural failure occurred in 7.5% of patients. For de novo CTOs, procedural success declined significantly when the J-CTO score was ≥3 (85% vs. 97% for ≤2; p < 0.001). In contrast, success rates for in-stent CTOs remained consistently high regardless of score (96% vs. 100%; p = 0.400).

In multivariate analysis, in-stent CTOs required shorter guidewire crossing times (odds ratio 0.40; 95% CI 0.18-0.86). Independent determinants of longer crossing time included blunt stump morphology and occlusion length ≥20 mm. The results underscore that while the J-CTO score remains useful for de novo CTOs, its interpretation should be individualized for in-stent CTO procedures performed with intraplaque wiring strategies.