Salvage Percutaneous Transluminal Angioplasty of the Superficial Femoral Artery in the Diabetic Foot With Deteriorating Limb Ischemia

Diabetic foot, a complex pathological condition resulting from PAD and/or sensory neuropathy, affects approximately 6% of individuals with diabetes worldwide.¹ Given the poor vascular perfusion of the lower extremities, management of diabetic foot can be challenging and time-consuming. Without proper management of the lesion at an early stage, infection and extensive tissue destruction can ensue, potentially leading to amputation of the involved structure. 

Lower extremity complications including claudication, rest pain, ulceration, and gangrene are prevalent in patients with diabetes and are often associated with PAD, which poses significant challenges for surgeons treating diabetic foot conditions. The prevalence of PAD varies based on the diagnostic methods used, but it is estimated to affect up to 30% of patients with diabetes.² 

The ABI is frequently used to ascertain the presence and severity of PAD, which is diagnosed when the ABI is less than 0.9. The ABI is reliable in the general population; however, debate persists regarding its utility as a diagnostic tool for PAD in patients with diabetes, owing to potential inaccuracies resulting from diabetes-associated atherosclerosis and vessel wall calcification, which can lead to false ABI results.³ Nevertheless, a recent study demonstrated that the ABI is reasonably accurate and reliable for the evaluation of PAD in individuals with type 2 diabetes, demonstrating strong concordance with duplex ultrasonography.⁴ In conjunction with ABI, duplex ultrasonography is commonly used as the first-line imaging modality for PAD, enabling identification of the location and severity of arterial obstruction.⁵ In cases of diagnostic uncertainty following noninvasive testing or in which an intervention is probable, advanced vascular imaging techniques, such as computed tomography angiography, magnetic resonance angiography, and catheter-based arteriography, are usually indicated.

Key components of medical management of PAD include smoking cessation, regular exercise, antihypertensive therapy, glycemic control, lipid-lowering therapy, and antithrombotic therapy. These measures collectively serve to alleviate symptoms, while reducing the risk of future cardiovascular events and limb complications. In cases of CLI, a more aggressive management strategy is required. Vascular bypass surgery remains an important treatment option for patients with advanced disease. However, there has been a discernible shift toward endovascular treatments over surgical bypass owing to the low periprocedural risk of endovascular treatment in patients with multiple comorbidities and the increased efficacy of these procedures in the management of complicated foot ulcers. 

The current article reports the successful surgical repair of extensive heel necrosis after emergency PTA of the SFA in a 67-year-old male with diabetes and deteriorating limb ischemia following surgical stress.

A 67-year-old male with a 5-month history of right heel necrosis presented for further management following unsuccessful treatment at a local clinic. His medical history included type 2 diabetes managed with oral hypoglycemic agents for over 15 years, and a long-term smoking history of over 3 decades. Although the patient’s recent blood glucose levels were stable, his HbA_1c was 8.2%. He also reported intermittent claudication and pain at rest in the right leg since the previous year, which had occasionally affected his daily activities. Physical examination revealed a 4-cm eschar on the lateral aspect of the right heel, along with an ulcerative lesion on the right great toe and dorsum of the foot.

Two months prior to admission, a diagnostic catheter arteriography performed in the authors’ cardiology department showed arteriosclerosis obliterans in both SFAs, with diffuse chronic total occlusion on the right side and segmental chronic total occlusion on the left. Based on the angiographic findings, the cardiologist (B.L.) performed a successful PTA using a drug-coated balloon in the right SFA. This intervention led to improvement in the right lower extremity ABI from 0.64 to 0.86.

Upon admission, however, the right ABI was 0.81 with monophasic Doppler waveforms, and a handheld vascular Doppler device revealed weak pedal pulse sounds. Initial treatment involved surgical debridement of the necrotic tissue on the patient’s heel to assess the depth and extent of the wound, leading to exposure of the calcaneal bone and significant soft tissue loss (Figure 1A). Postoperatively, negative pressure wound therapy was applied to encourage the formation of granulation tissue and to prepare the wound for delayed skin grafting. Despite these measures, the necrotic tissue continued to progress during wound treatment. 

On postoperative day 6, a sudden drop in the right ABI to 0.36 was observed, accompanied by dampened monophasic waveforms on Doppler images. Emergency PTA was performed, during which the cardiologist (B.L.) placed 2 Supera self-expanding interwoven nitinol stents (Abbott Vascular), measuring 5.5 mm × 150 mm and 6.5 mm × 150 mm, within the occlusive lesions of the right SFA. Imaging studies performed immediately after this procedure revealed good vascular patency within the previously occlusive lesions (Figure 2).

Four weeks after stent placement, the right ABI improved to 1.06, and a handheld vascular Doppler device revealed strong pulse sounds along the lateral calcaneal artery. The following day, a 4.5-cm × 9-cm lateral calcaneal artery flap, including the vascular pedicle, was elevated under general anesthesia. After additional debridement, the flap was used to cover the heel lesion. Full-thickness skin harvested from the left groin was grafted onto the flap donor site (Figure 1B). Despite a localized loss of the skin graft, the flap successfully settled into the heel lesion. 

At 1-year follow-up, the patient exhibited durable heel coverage and the restoration of weightbearing function (Figure 1C). No signs or symptoms indicative of restenosis were evident in the blood vessel managed with stent angioplasty. Additionally, the right ABI remained well-maintained at 1.07 with multiphasic waveforms, and the pulse sounds of the flap pedicle were strongly audible on a handheld vascular Doppler device.

Endovascular treatment is typically considered in patients with 1 of the following conditions: lifestyle-limiting claudication that is no longer responsive to conservative therapy, ALI, or CLI.⁶ ALI is a sudden decrease in limb perfusion within 14 days that threatens limb viability. It carries a poor prognosis, with amputation rates ranging from 12.7% to 14% and mortality rates between 9% and 12%.⁷ The most common cause of ALI is peripheral embolization of an intracardiac thrombus, usually caused by atrial fibrillation. CLI is characterized by chronic ischemic rest pain, ulceration, or gangrene owing to critically reduced perfusion and is often accompanied by an ABI of less than 0.4 and toe pressure below 30 mm Hg. 

Endovascular treatments have greater long-term durability for aortoiliac disease than for femoropopliteal disease.⁶ The SFA is the longest artery with the fewest branches, and it is uniquely exposed to complex external mechanical stresses, such as flexion, compression, and torsion. These recurring mechanical stresses significantly affect primary patency and clinical outcomes of endovascular revascularization in this area. Infrapopliteal revascularization is typically performed in the management of CLI and ALI.

The 2 mainstays of endovascular therapy are stents and balloon angioplasty. Several types of stents are used clinically, including self-expanding stents, drug-eluting stents, and covered self-expanding stents. Drug-eluting stents and drug-coated balloons are 2 newly substantiated advancements in this field. Marmagkiolis et al⁸ reported that in patients with SFA disease, 12-month “[p]rimary patency rates were (weighted average) 82.6% for drug-eluting stents, 77.2% for drug-coated balloons, 75.2% for covered stents, 73.9% for nitinol self-expanding stents, 66.1% for atherectomy, and 44.5% for bare balloon angioplasty.” However, outcomes after balloon angioplasty alone are similar to those of self-expanding stents in short SFA lesions (≤ 100 mm).⁹ 

In the case reported herein, a state of deteriorating ischemia developed in the right lower extremity after surgical debridement, accompanied by a sudden reduction in ABI to 0.36. Untreated CLI has an all-cause mortality rate of 22% and a major amputation rate of 22% during a median follow-up of 12 months.¹⁰ Consequently, the authors of the current case report promptly evaluated the patient’s vascular status and swiftly restored perfusion to the ischemic zone by performing emergency PTA, with the goal of preventing irreversible tissue damage or major amputation. 

Restenosis is a major concern after endovascular treatment. In a study by Meloni et al,¹¹ approximately 24% of patients with ischemic diabetic foot ulcers required repeat PTA following their initial treatment, with a mean time to repeat PTA of 3.5 months. Recurrence of symptoms accompanied by decreases in ABI of more than 0.15 and duplex ultrasound demonstrating a greater than 3-fold incremental increase in the peak systolic velocity ratio between adjacent arterial segments are indicative of significant restenosis.⁶ The case in the current report manifested a critical ischemic state in the right lower extremity approximately 2 months after drug-coated balloon angioplasty. However, the sudden escalation of ischemic conditions indicative of ALI may be attributable to thrombosis secondary to surgical stress rather than postprocedural restenosis, considering that this occurrence followed surgical debridement of necrotic heel tissue. During the postoperative period, a propensity for hypercoagulability is typically observed, as demonstrated by changes in several coagulation parameters; a thrombotic event may occur if  hypercoagulability is not offset by some protective mechanism.¹²

Endovascular treatment has the potential to relieve ischemic pain, close foot ulcers, reduce amputation rates, and improve patient functionality and quality of life. However, the long-term mortality associated with the use of these devices remains subject to debate.¹³ Thus, after successful intervention it is imperative to establish appropriate drug therapy and standardized follow-up protocols to prevent restenosis, unfavorable limb events, and cardiovascular events.

This is a single case report with limited follow-up. Although the findings are based on only 1 patient and a 1-year follow-up period, they may contribute to more effective management of ischemic complications in patients with diabetic foot.

This case report suggests that proper evaluation and timely endovascular intervention are pivotal in the management of the critically ischemic limb. These elements are key to preventing deterioration of vascular conditions in the diabetic foot and mitigating the risk of serious complications.