OBJECTIVES: Plain old balloon angioplasty (POBA) is a common endovascular therapy for below-the-knee lesions in patients with critical limb ischemia (CLI). However, restenosis often develops, resulting in amputation. This study examined the risk factors for below-the-knee amputation (BKA) in CLI patients that underwent POBA.

METHODS: A Japanese database including data from acute care hospitals (April 2008–September 2020) was used. Patients with first CLI diagnosis during the observation period, with POBA after first CLI diagnosis, without amputation before first POBA (defined as index), and with neither stent nor drug-coated balloons at the index were analyzed. The hazard ratio (HR) of BKA by anatomical location was estimated using a proportional hazard analysis with the age at the index, sex, presence of hypertension, dyslipidemia (treated with lipid modifying agents), chronic kidney disease (CKD), diabetes (treated with insulin), cerebrovascular disease, cardiovascular disease, and chronic obstructive pulmonary disease before the index, and smoking status at the index as explanatory variables. We considered p <0.05 as statistically significant.

RESULTS: Of 13,737 patients with first CLI diagnosis during the observation period, 7,289 underwent POBA and 2,408 were analyzed. The mean (standard deviation) age was 75.1 years (10.9) and 36% were women. Hypertension (67.9%) was most common followed by CKD (53.5%), diabetes (42.1%), and dyslipidemia (30.6%) among the diseases included in the explanatory variables. The incidence of BKA by anatomical location varied: finger (316), foot (151), lower leg (229), and any of them (558). The HRs of any BKA were significantly >1 for diabetes (1.968) and CKD (1.282) and significantly <1 for age (0.992) and dyslipidemia (0.723) . A similar HR tendency was observed for lower leg; whereas only diabetes showed significant HR (2.777) for foot.

CONCLUSIONS: Diabetes was suggested as a risk factor for BKA regardless of below-the-knee anatomical location in CLI patients who underwent POBA.