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

Abstract

Background: 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.

Methods: 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.

Results: A total of 287 distal bypasses were performed in 230 patients (153 males; median age, 74 years; 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 30 days. During a mean follow-up period of 33 ± 29 months, 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.

Conclusions: 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 2 years suggest that the decision-making for VQI medium- and high-risk patients may be carefully considered.