Effectiveness of the Vascular Quality Initiative Chronic Limb-Threatening Ischemia Mortality Prediction Model in Patents with Distal Bypass

Abstract

The purpose of this study is to evaluate the effectiveness of mortality prediction using the Vascular Quality Initiative (VQI) chronic limb-threatening ischemia (CLTI) model in patients with distal bypass. Patients who underwent distal bypass for CLTI from 2009 to 2020 at a single center were retrospectively reviewed. Distal bypass was defined as any bypass with a distal anastomosis to the posterior tibial, anterior tibial, dorsalis pedis, plantar, or peroneal artery. Baseline characteristics, operative details, hospital outcomes, and medium-term outcomes were compared among patients with a low-, medium-, and high-risk of mortality based on a VQI CLTI calculation. The primary endpoints were survival and limb salvage. A total of 287 distal bypasses were performed in 230 patients (153 males; median age, 74years; diabetes mellitus, 70%; end-stage renal disease [ESRD] with hemodialysis, 38%). These patients were stratified into 153 (66%) low-, 35 (15%) medium-, and 42 (18%) high-risk cases based on the VQI CLTI model. There were two hospital deaths (1%) within 30days. During a mean follow-up period of 33±29months, 105 patients died and 26 limbs (9%) required major amputation. The 2-year survival rate of 81% in the low-risk group was significantly higher than those of 41% in the medium-risk group and 46% in the high-risk group (both P<0.001). The 2-year survival rates did not differ significantly between the medium- and high-risk groups (P=0.81). The 2-year limb salvage rate of 93% in the low-risk group was significantly higher than those of 81% in the medium-risk (P=0.023) and those of 87% in the high-risk (P=0.039) groups. There were no significant differences in graft patency and wound healing among the three groups. These results suggest that distal bypass is optimal treatment for patients with a low VQI-predicted risk of mortality. However, the lower limb salvage and higher mortality rates at 2years suggest that the decision-making for VQI medium- and high-risk patients may be carefully considered.