Endovascular therapy outcomes in patients with the Global Limb Anatomical Staging System P2 modifier to identify the true no-option anatomic pattern in chronic limb-threatening ischemia.

Abstract

In patients with chronic limb-threatening ischemia (CLTI), the Global Limb Anatomical Staging System (GLASS) P2 modifier, defined by the absence of a target artery crossing the ankle and lack of a suitable pedal or plantar artery, indicates a no-option anatomic pattern. Although several studies have reported successful endovascular therapy (EVT) in such patients, EVT outcome predictors in this high-risk population remain unclear. This study aimed to identify factors contributing to procedural failure in patients with the GLASS P2 modifier undergoing EVT. It also evaluated the impact of inframalleolar angioplasty on clinical outcomes in patients with CLTI and the GLASS P2 modifier. This multicenter, retrospective, nonrandomized observational study was conducted at three cardiovascular departments in Hokkaido, Japan. Patients aged ≥20 years with CLTI (Rutherford classification 4-6) who underwent EVT for de novo inframalleolar occlusions with the GLASS P2 modifier during January 2016 to December 2023 were enrolled. In total, 160 limbs in 151 patients (mean age, 73.4 ± 10.9 years) were analyzed. At 2 years, the estimated amputation-free survival, limb salvage, and wound healing rates were 57.8%, 75.1%, and 60.1%, respectively. Procedural success was defined as recanalization of at least one dorsalis pedis, lateral plantar, or medial plantar artery with inline flow to the wound. Failure to meet this outcome was classified as procedural failure. Multivariate logistic regression identified pedal medial arterial calcification (pMAC) severity (mild/moderate/severe) and the absence of target inframalleolar vessel outflow as independent predictors of procedural failure. Notably, when severe pMAC coexisted with absent target inframalleolar vessel outflow, procedural failure occurred in 35 of 41 cases (85.4%), with infrapopliteal blood flow deterioration observed in nine of 41 cases (22.0%). Procedural failure significantly impacted clinical outcomes. In the successful vs failed IMA groups, 24-month amputation-free survival was 68.4% vs 41.1% (log-rank P < .001), limb salvage was 86.5% vs 56.1% (log-rank P < .001), and wound healing was 70.0% vs 43.1% (log-rank P = .001), respectively. Among patients with CLTI and the GLASS P2 modifier, the combination of severe pMAC and absent target inframalleolar vessel outflow indicates a true no-option anatomic pattern as well as elevated complication risk. In such high-risk cases, EVT may worsen outcomes rather than improve them. Therefore, alternative approaches such as deep venous arterialization should be considered when distal bypass is not an option.