Combined Treatment With Hyperbaric Oxygen Therapy and Endovascular Therapy for Patients With Chronic Limb-Threatening Ischemia　- Study Protocol for the HOTFOOT Multicenter Randomized Controlled Trial.

Background: Hyperbaric oxygen therapy (HBOT) is regarded as one of the therapeutic options added to standard care to improve lower-limb outcomes in patients with chronic limb-threatening ischemia (CLTI). However, the current guidelines specify that HBOT should not be offered instead of revascularization to prevent limb loss in CLTI patients. The aim of the HOTFOOT study is to examine the impact of HBOT on wound healing in CLTI patients after successful endovascular therapy (EVT). Methods and Results: The HOTFOOT study is a multicenter prospective randomized open blinded-endpoint trial that is to be conducted at 10 trial centers in Japan between February 2021 and February 2022. This study will enroll 140 patients with CLTI receiving successful EVT. Eligible participants will be allocated 1 : 1 to either the EVT+HBOT or EVT group; participants in the EVT+HBOT group will receive 30 HBOT sessions. The primary outcome is the time to complete wound healing over the 6-month follow-up. Secondary outcomes during the 6-month follow-up are the proportion of patients who achieved complete wound healing, freedom from major lower-limb amputation, amputation-free survival, and freedom from target lesion reintervention. Conclusions: This study is expects to assess whether HBOT, in combination with successful EVT, can improve lower-limb outcomes in CLTI patients.

Prediction of successful guidewire crossing of below-the-knee chronic total occlusions using a Japanese scoring system.

OBJECTIVE: To develop a scoring system that can adequately predict a successful guidewire crossing (S-GC) of below-the-knee (BTK) chronic total occlusions (CTOs) in angiographic evaluation. METHODS: A retrospective, multicenter, nonrandomized study examined 448 consecutive BTK CTOs in 299 patients treated with endovascular therapy in seven Japanese medical centers from April 2012 to April 2020. The cohort was classified into two groups: an S-GC group and a failed guidewire crossing group. RESULTS: The final logistic regression model created by a backward stepwise multivariate logistic regression model included five variables: "No outflow of the target vessel," "CTO length ≥200 mm," "Reference vessel diameter <2.0 mm," "Calcification at the proximal entry point," and "Blunt type at entry point." Optimisms were adjusted using 1000 bootstrap samples with replacement and candidate's risk score models developed according to optimism-adjusted correlation coefficients of risk factors. Choosing the best model as the Japanese-BTK (J-BTK) CTO score by comparing the optimism-adjusted area under receiver-operating characteristic curves it was decided to assign one point to "Blunt type at the proximal entry point," one point to "Calcification at the proximal entry point," one point to "Reference vessel diameter <2.0 mm," one point to "CTO length ≥200 mm," and two points to "No outflow of the target vessel." This rule was then used to categorize BTK CTOs into four grades with varying probabilities of S-GC: grade A (J-BTK CTO score of 0 and 1), grade B (score of 2 and 3), grade C (score of 4 and 5), and grade D (score of 6). Rates of S-GC in each grade (grades A, B, C, and D) were 97.3%, 76.8%, 19.3%, and 0%, respectively. Lesions categorized as grade C or D have a lower chance of S-GC. Internal validation was performed using the Hosmer-Lemeshow test (P = .99). CONCLUSIONS: The J-BTK CTO score predicts the probability of an S-GC of BTK CTOs and stratifies the difficulty of endovascular therapy for BTK CTOs in angiographic evaluation.