If untreated or unsalvageable, the diabetic foot requires surgical interventions to address the risks to its viability. However, recent advancements in the field suggest that surgeons may not always have to sacrifice a limb to save a life.
During the 2021 virtual American College of Surgeons Clinical Congress, Lucas M. Ferrer, MD, described the use of endovascular venous arterialization for limb salvage, and William P. Robinson, MD, discussed the timing of foot amputation after revascularization.
Chronic Limb-Threatening Ischemia
According to Dr. Ferrer, an assistant professor of surgery at Dell Seton Medical Center at The University of Texas Hospital, in Austin, approximately 185,000 amputations are performed annually in the United States, and the primary cause is vascular disease (54%).
But for many patients, the specific vascular disease driving their chronic limb-threatening ischemia remains unclear. While most studies on peripheral artery disease have focused on above-the-ankle artery disease, for example, less is known about foot artery disease.
In a 2018 study, Ferraresi and colleagues hypothesized that patients with peripheral artery disease can be afflicted with both big artery disease and small artery disease, overlapping at the foot level (J Cardiovasc Surg (Torino) 2018;59[5]:655-664). Their retrospective analysis showed that small artery disease was strongly and independently associated with critical limb ischemia, diabetes and dialysis. Of the 1,613 patients with symptomatic peripheral artery disease who underwent angiography, approximately 25% had significant small artery disease.
“For patients with disease in both major vessels and small arteries, there really are no great options, either with an endovascular or open approach,” Dr. Ferrer said. “We need to start looking for new solutions.”
Endovascular Venous Arterialization for Limb Salvage
When all classic methods have failed or are impossible, Dr. Ferrer noted that arterialization of the distal veins of the foot may be considered a useful revascularization technique for limb salvage. In one study of 60 arterializations, 36 were successful (60%), while the other 24 patients had poor results followed by a major amputation. No deaths were associated with the reversed circulation (Ann Chir 2001;126[7]:629-638).
This technique was adapted in the PROMISE I trial. Using a proprietary LimFlow stent-graft system to achieve foot vein arterialization in an endovascular fashion, the investigators demonstrated a limb salvage rate of approximately 70% at 12 months (J Vasc Surg 2021;74[5]:1626-1635).
“We observed decreased wound area over time and an increased percentage of completely healed wounds,” said Dr. Ferrer, who acknowledged that the procedure is still in the early stages of development. “The technique still needs more refinement, and there are more questions than answers at this stage.
“Foot vein arterialization requires dedicated collaboration between vascular surgery, internal medicine, podiatry and wound care to be successful because the learning curve is very steep,” he concluded.
Timing of Foot Amputation After Revascularization
For patients with diabetes who require minor amputation of noninfective necrotic tissue and revascularization, the risk for major amputation approaches 50% at one year. According to Dr. Robinson, a vascular surgeon at Southern Illinois University School of Medicine, in Springfield, time is tissue, and in these situations, “aggressive debridement, including amputation, if necessary,” must be undertaken without delay.
Although Dr. Robinson acknowledged a lack of clear, high-level evidence to support definitive recommendations, he emphasized that revascularization should precede definitive minor amputation and closure.
“When revascularization provides a good, palpable pulse of the foot and the tissue at the proposed level of amputation is good quality, concurrent amputation is advised,” he said. “However, when the perfusion increase after a revascularization is marginal or the tissue level at the amputation is marginal, a delayed amputation is recommended to allow the maximum perfusion benefit.
“Endovascular perfusion may be different, and in these cases, it probably makes sense to delay the minor amputation, if possible,” Dr. Robinson added. “But clearly given the lack of evidence in this field, we need more research on these outcomes to drive our patient selection and optimize limb salvage in these patients.”
This article is from the March 2022 print issue.
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