The Impact of Performing Lower-Extremity Angiographic Intervention Beyond the Pedal Plantar Loop: A Case Study

The patient was a 57-year-old Caucasian male with a >20-year history of insulin-dependent type 2 diabetes mellitus accompanied by severe peripheral neuropathy and a prior history of slow-healing, diabetic foot ulcers. Additional past medical history was significant for hypertension, hyperlipidemia on statin therapy, prior transient ischemic attack in 2010, and human immunodeficiency virus. During evaluation of social history, the patient identified as a non-smoker, denying prior usage of tobacco.

He presented to our clinic on December 23, 2020 for evaluation of an open, right hallux plantar ulceration (Figures 1A-1C) along with a “blister-like” ulceration to the base of the right, fifth digit (Figure 1D). The patient had been combating a current infection to the right hallux ulcer and was treated at the hospital with an irrigation and debridement procedure a few weeks prior, followed by administration of intravenous antibiotics.

In the clinic, the patient stated that both of the wounds on his right foot had been non-healing for the past 5-6 weeks. The etiology of these wounds was unknown to the patient, but he speculated that the wounds might have originated as shoe blisters. Since the inception of these digital ulcers, the patient’s wound care had been managed by his podiatrist, who referred the patient to our clinic for a vascular evaluation due to the patient’s impaired wound healing, prompting concern for compromised arterial flow in the foot.

The patient also complained of severe paresthesia to the bilateral feet, which was most prominent in the ulceration site of the right hallux. The patient stated that his podiatrist advised him to limit weight-bearing activities with the right foot, preventing him from keeping up with his activities of daily living. The patient also struggled with his balance and coordination on a daily basis due to the ulceration site at the right hallux. Upon further interview, the patient denied any prior revascularization procedures.

Physical examination revealed severe peripheral neuropathy with the patient scoring a 0/10 bilaterally on the Semmes-Weinstein monofilament test. There was loss of protective sensation from the mid tibia and downward, with the right lower extremity being worse than the left. Pedal pulses were easily palpable at the dorsum and the ankle bilaterally, scoring a 2+. Examination of the right foot demonstrated redness and non-pitting edema to the ulceration site at the right hallux and extending up the first metatarsal. The wound at the base of the right fifth digit was dry with eschar.

Diagnostic, non-invasive testing performed in the office was benign in nature, with the arterial duplex ultrasound revealing triphasic waveforms bilaterally (Table 1). No significant stenosis was detected via ultrasound in the bilateral femoropopliteal region, tibial arteries, and dorsalis pedis arteries (Table 1). The resting ankle-brachial indexes (ABIs) were 1.14 (right) and 1.60 (left). A toe-brachial index was not performed due to the right hallux ulceration.

In spite of the patient’s normal ultrasound and ABIs, given the chronic, non-healing nature of the wounds on the right foot along with the patient’s long-standing history of diabetes, a right lower-extremity angiogram with possible intervention was recommended. With diabetes being known to be associated with inframalleolar arterial disease, it was of utmost importance to proceed with angiographic evaluation due to the duplex ultrasound and ABIs limiting the vascular evaluation only up to the level of the ankle.

Approximately 1 week later, the patient presented to our office-based lab and a right lower-extremity  angiogram was performed. Ultrasound-guided, antegrade access of the proximal superficial femoral artery was obtained since the patient’s aortoiliac inflow was patent, as indicated by his physical exam and duplex ultrasound findings (Figure 2A andTable 1). The initial angiographic run-off revealed no significant disease in the superficial femoral artery (Figures 2A, 2B) and popliteal artery (Figure 3), with a patent 2-vessel run-off involving the anterior tibial artery and the peroneal artery (Figures 4A, 4B). The patient’s posterior tibial artery was congenitally absent, with the peroneal artery continuing as the plantar vessels in the foot (Figures 5A, 5B). Pedal angiography revealed a patent dorsalis pedis artery, medial plantar artery, and lateral plantar artery, forming a complete pedal plantar loop (Figures 5A, 5B). At first glance, the angiographic findings seemed convincing enough to rule out a PAD diagnosis.

However, super-selective angiography beyond the pedal plantar loop demonstrated severe, critical stenosis involving the medial branch arising from the superficial branch of the medial plantar artery (Figures 6A, 6Band Figures 7A, 7B, 7C). Additional angiography demonstrated critical stenosis involving the distal aspect of the lateral phalangeal branch arising from the first dorsal metatarsal artery of the dorsalis pedis artery (Figures 6A, 6B and Figures 8A, 8B). The medial phalangeal branch coming off the first dorsal metatarsal artery of the dorsalis pedis artery was chronically occluded (Figures 9A, 9B).

Following angiographic evaluation, the stenotic medial branch arising from the superficial branch of the medial plantar artery was successfully treated with percutaneous transluminal angioplasty using both a 1.5 x 120 mm Takeru balloon dilation catheter (Terumo) (Figures 10A, 10B) and a 2.0 x 150 mm Coyote balloon dilation catheter (Boston Scientific) (Figure 10C). Postangioplasty angiogram revealed good flow coming off the superficial branch of the medial plantar artery into the medial branch (Figures 11A, 11B). With restoration of patency to the medial branch, a complete “arterial loop” was angiographically observed in the region of the hallux, where there was continuous flow from the medial branch to the lateral branch, both arising from the superficial branch of the medial plantar artery (Figures 11A, 11B).

Prolonged balloon angioplasty was also performed on the critically stenosed lateral phalangeal branch coming off the first dorsal metatarsal artery from the dorsalis pedis artery, using a 1.5 x 15 mm Takeru balloon catheter (Figures 12A, 12B). The occluded medial phalangeal branch coming off the first dorsal metatarsal artery of the dorsalis pedis artery was successfully recanalized with a guidewire and angioplastied with a 2.0 x 40 mm Extra Support Coyote balloon catheter (Figure 12C), followed by a 2.0 x 150 mm Coyote balloon catheter (Figure 12D). The follow-up angiogram revealed significant improvement of flow into the distal phalanx of the right great toe (Figures 13A, 13B), including restoration of patency to the medial phalangeal branch, arising from the first dorsal metatarsal artery of the dorsalis pedis artery (Figures 13C, 13D). Postangioplasty angiogram further demonstrated good arterial blush within the region of the hallux wound (Figure 13A).

There was no peripheral sheath placed in the proximal SFA access site during the procedure. Instead, there was a 3 Fr inner dilator from the micropuncture kit inserted at the time of access, but all of the interventional balloons were bare backed. During the procedure, a total of 4000 units of heparin were administered intravenously. At the conclusion of the treatment, all wires and catheters were removed from the access site. Manual compression was held for approximately 5-6 minutes to achieve satisfactory hemostasis. Following the procedure, the patient was instructed to start dual-antiplatelet therapy, including acetylsalicylic acid 81 mg once daily for life and clopidogrel 75 mg once daily for 6 months.

To track the progression of the wound-healing process, the patient was followed on a consistent basis by both our clinic and his podiatrist. With each monthly visit, the patient’s right foot wounds, particularly his right hallux ulceration, noticeably improved in appearance while decreasing in size (Figure 14, Figure 15, Figure 16). At 6-month follow-up angiogram, the patient’s right plantar hallux ulceration had fully healed (Figure 17). The “blister like” ulceration at the base of the right, fifth digit healed more quickly than the right hallux ulceration status post angiogram.