Below-the-Ankle Lesion Intervention and Amputation and Survival Rates

Researchers sought to investigate clinical outcomes following below-the-ankle intervention in patients with chronic limb-threatening ischemia.

Patients with chronic limb-threatening ischemia (CLTI) who have intervention for below-the-ankle lesions have a higher rate of major amputation but improved survival compared with those who have below-the-knee intervention alone, investigators reported in the Journal of Endovascular Therapy.

The prospective, observational, multicenter LIBERTY 360 study evaluated predictors of clinical outcomes in symptomatic patients with peripheral arterial disease (PAD) who were receiving lower extremity endovascular device intervention with use of a US Food and Drug Administration–approved or cleared endovascular device.

A total of 1189 patients were analyzed and stratified according to Rutherford Classification (RC) 2 to 3 (n=500), RC 4 to 5 (n=589), and RC 6 (n=100) from May 2013 to February 2016. The post hoc subanalysis included patients with CLTI (RC 4-6) who received below-the-knee intervention. Participants were stratified into 2 treatment groups based on whether at least 1 lesion was below the ankle (n=66; 66.7% men) or not (n=273; 67.8% men).

The main clinical outcome measures were freedom from major amputation, from target vessel revascularization, from major adverse limb events or peri-operative death, and from major adverse events, as well as amputation-free survival, procedural success, and severe angiographic complications.

Patients who had below-the-ankle intervention had a mean age of 66.3±13.3 years, compared with 70.5±10.8 years for those who received below-the-knee intervention alone (P =.006).

No differences were observed in procedure success rate or severe angiographic complications. Participants in the below-the-knee group had a higher rate of freedom from major amputation (95.0% vs 86.9%; hazard ratio [HR], 2.87; 95% CI, 1.17-7.03), a higher rate of freedom from target vessel revascularization (80.1% vs 66.9%; HR 1.94; 95% CI, 1.14-3.32), and a higher rate of freedom from major adverse limb events or peri-operative death (94.6% vs 86.9%; HR 2.65, 95% CI, 1.10-6.41) compared with the below-the-ankle group at 1-year postprocedure. However, at 3 years, these differences were no longer statistically significant.

Below-the-knee group participants had a higher rate of freedom from major adverse events at 1 year (76.0% vs 60.1%; HR 2.00; 95% CI, 1.24-3.22) and 3 years postprocedure (67.5% vs 55.8%; HR 1.69; 95% CI, 1.08-2.65). The below-the-knee group had a significantly lower rate of overall survival at 3 years compared with the below-the-ankle group (74.3% vs 91.1%; HR 0.35, 95% CI, 0.14-0.87).

After risk adjustment, a higher all-cause death rate was found in the below-the-knee group compared with the below-the-ankle participants at 3 years postintervention (19.4% [15.2%, 24.5%] vs 9.1% [4.6%, 17.5%]; P =.023). A lower rate of major amputation (4.5% [2.7%, 7.3%] vs 7.7% [3.8%, 15.1%]; P = .03), major adverse events (21.8% [17.3%, 27.3%] vs 37.5% [27.8%, 49.3%]; P = .002), and major adverse limb events or peri-operative death (5.2% [3.3%, 8.4%] vs 8.2% [4.1%, 15.9%]; P = .041) was observed in the below-the-knee group compared with the BTA group at 1 year.

Among several study limitations, the subanalysis comparison of below-the-ankle and below-the-knee cohorts is not powered, and the choice for below-the-ankle intervention is not specified and is operator-dependent. In addition, extensive mandatory testing requirements may have led to selection bias, and the study does not track potential confounders such as severity and type of wound infections.

“[Below-the-ankle] revascularization remains a challenge in improving clinical outcomes for patients with CLTI,” wrote the researchers. “Future studies will need to further elucidate the optimal patient selection, lesion selection, and device-based strategy to improve outcomes and limb salvage in patients with CLTI and BTA lesions.”

Disclosure: This research was supported by Cardiovascular Systems, Inc. Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Metser G, Puma J, Mustapha J, et al. Clinical outcomes of additional below-the-ankle intervention compared to below-the-knee intervention alone: a post-hoc analysis of a prospective multicenter study. J Endovasc Ther. Published online May 3, 2022. doi: 10.1177/15266028221092981