External validation of the JR-CTO score in retrograde chronic total occlusion intervention: from the PROGRESS-CTO registry.

In complex chronic total occlusion (CTO) percutaneous coronary interventions (PCI), a retrograde crossing strategy is often necessary. Recently, the Japanese retrograde (JR) CTO score was developed using a simple 4-item tool. This score showed a good performance in predicting guidewire crossing failure in patients undergoing primary retrograde CTO PCI. We evaluated the JR-CTO score’s performance in patients treated at 44 centers between 2013 and 2024 as part of the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO). In an independent cohort, although the JR-CTO score showed an association with crossing and technical failure, its predictive ability for both outcomes was modest.