Association Between Wound Healing and the Japanese Below-the-Knee Chronic Total Occlusion Score in Patients With Chronic Limb-Threatening Ischemia After Endovascular Therapy.

Introduction: In the current study, we hypothesized that the Japanese below-the-knee chronic total occlusion score could be used to stratify the lesion difficulty of endovascular therapy for below-the-knee chronic total occlusion through angiographic evaluation. We thus aimed to evaluate the prognostic impact of the Japanese below-the-knee chronic total occlusion score in patients with chronic limb-threatening ischemia after successful endovascular therapy for below-the-knee chronic total occlusion.

Methods: This was a retrospective, single-center observational study. We enrolled 139 consecutive patients with chronic limb-threatening ischemia (149 limbs), who underwent successful endovascular therapy for chronic total occlusion between February 2008 and December 2017. The Japanese below-the-knee chronic total occlusion score was assessed based on the definition of the target arterial path. The evaluation items were the rate of amputation-free survival and wound healing at 1 year, and the association between wound healing at 1 year and the Japanese below-the-knee chronic total occlusion score.

Results: The rates of amputation-free survival and wound healing at 1 year were 88.0 and 56.4%, respectively. Multivariate Cox proportional hazard analysis identified direct flow to the wound (hazard ratio: 2.34, 95% confidence interval: 1.28-4.66; p<0.01); Wound, Ischemia, and foot Infection stages 1-3 (hazard ratio: 2.81, 95% confidence interval: 1.63-5.18; p<0.01); and a Japanese below-the-knee chronic total occlusion score ≤1 (hazard ratio: 1.70, 95% confidence interval: 1.02-2.98; p=0.04) to be predictors of wound healing.

Conclusions: A Japanese below-the-knee chronic total occlusion score ≤1, direct flow to the wound, and Wound, Ischemia, and foot Infection stages 1-3 were found to be associated with wound healing after successful endovascular therapy for below-the-knee chronic total occlusion in patients with chronic limb-threatening ischemia.

Clinical impact: This study was conducted to evaluate the prognostic impact of the Japanese below-the-knee chronic total occlusion (J-BTK CTO) score in patients with chronic limb-threatening ischemia (CLTI) after successful endovascular treatment (EVT). The results showed that the J-BTK CTO score not only evaluates the difficulty of EVT but also can predict limb prognosis. Using the J-BTK CTO score, it seems possible to predict the limb prognosis and make it useful in clinical practice.