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

Infra-inguinal bypass surgery vs endovascular revascularization for chronic limb-threatening ischemia in average- and high-risk patients

OBJECTIVE

This study aimed to evaluate treatment outcomes after bypass surgery or endovascular therapy (EVT) in average- and high-risk patients with chronic limb-threatening ischemia (CLTI).

METHODS

We retrospectively analyzed multicenter data of patients who underwent infra-inguinal revascularization for CLTI between 2015 and 2022. A high-risk patient was defined as one with estimated 30-day mortality rate ≥5% or 2-year survival rate ≤50%, as determined by the Surgical Reconstruction vs Peripheral Intervention in Patients With Critical Limb Ischemia (SPINACH) calculator. The amputation-free survival (AFS), limb salvage (LS), wound healing, and 30-day mortality were compared separately for the average- and high-risk patients between the bypass and EVT with propensity score matching.

RESULTS

We analyzed 239 and 31 propensity score-matched pairs in the average- and high-risk patients with CLTI. In the average-risk patients, the 2-year AFS and LS rates were 78.1% and 94.4% in the bypass group and 63.0% and 87.7% in the EVT group (P < .001 and P = .007), respectively. The 1-year wound healing rates were 88.6% in the bypass group and 76.8% in the EVT group, respectively (P < .001). The 30-day mortality was 0.8% in the bypass surgery and 0.8% in the EVT group (P = .996). In the high-risk patients, there was no differences in the AFS, LS, and wound healing between the groups (P = .591, P = .148, and P = .074). The 30-day mortality was 3.2% in the bypass group and 3.2% in the EVT group (P = .991).

CONCLUSIONS

Bypass surgery is superior to EVT with respect to the AFS, LS, and wound healing in the average-risk patients. EVT is a feasible first-line treatment strategy for high-risk patients with CLTI undergoing revascularization, based on the lack of significant differences in the 2-year AFS rate, between the bypass surgery and EVT cohorts.

Validation of JCLIMB, SPINACH, and VQI Calculators for Prediction of Two Year Survival in Patients With Chronic Limb Threatening Ischaemia After Infra-Inguinal Surgical or Endovascular Revascularisation

OBJECTIVE

This study aimed to evaluate three survival prediction models: the JAPAN Critical Limb Ischaemia Database (JCLIMB), Surgical Reconstruction Versus Peripheral Intervention in Patients With Critical Limb Ischaemia (SPINACH), and Vascular Quality Initiative (VQI) calculators.

METHODS

Multicentre data of patients who underwent infrainguinal revascularisation for chronic limb threatening ischaemia between 2018 and 2021 were analysed retrospectively. The prediction models were validated using a calibration plot analysis with the intercept and slope. The discrimination was evaluated using area under the curve (AUC) analysis. The observed two year overall survival (OS) was evaluated by the Kaplan - Meier method. The two year OS predicted by each model at < 50%, 50 - 70%, and > 70% was defined as high, medium, and low risk, respectively.

RESULTS

A total of 491 patients who underwent infra-inguinal revascularisation were analysed. The rates of surgical revascularisation, endovascular therapy, and hybrid therapy were 26.5%, 70.1%, and 5.5%, respectively. The average age was 75.6 years, and the percentages of patients with diabetes mellitus and dialysis dependent end stage renal disease were 66.6% and 44.6%, respectively. The tissue loss rate was 85.7%. The intercept and slope were -0.13 and 1.18 for the JCLIMB, 0.11 and 0.82 for the SPINACH, and -0.15 and 1.10 for the VQI. The AUC for the two year OS of JCLIMB, SPINACH, and VQI were 0.758, 0.756, and 0.740, respectively. The observed two year OS rates of low, medium, and high risk using the JCLIMB calculator were 80.1%, 61.1%, and 28.5%, respectively (p < .001), using the SPINACH calculator were 81.0%, 57.0%, and 38.1%, respectively (p < .001), and using the VQI calculator were 77.8%, 45.8%, and 49.6%, respectively (p < .001).

CONCLUSION

The JCLIMB, SPINACH, and VQI survival calculation models were useful, although the OS predicted by the VQI model appeared to be lower than the observed OS.