Traditional dogma states that the primary goal of infrapopliteal revascularization is the restoration of at least one straight line of pulsatile blood flow to the distal foot to reperfuse the ischemic tissue.
In diabetic patients, obstructive lesions tend to be located in the distal tibial arteries at the malleolus level and might extend below the ankle and involve the dorsalis pedis and plantar arteries. As a result, distal bypass can be technically challenging or even impossible to perform, mainly because there is no appropriate healthy vascular segment for distal anastomosis, according to Dr. Konstantinos Katsanos.
Because patency outcomes after angioplasty of the femoral artery are negatively affected by compromised and/or poor tibial runoff, infrapopliteal and distal outflow lesions must be treated accordingly. Published data regarding angioplasty or stenting of the arteries below the ankle are scarce, noted Dr. Katsanos at the Veith symposium on vascular medicine sponsored by the Cleveland Clinic.
He reported on the feasibility of percutaneous angioplasty and optional bail-out stenting of distal below-the-ankle arterial occlusive disease in patients with critical limb ischemia.
Dr. Katsanos, a lecturer of radiology at the department of radiology, Patras University Hospital, Rio, Greece, and his colleagues evaluated the long-term angiographic and clinical results of such interventions based on a retrospective analysis of 17 patients who underwent infrapopliteal endovascular procedures, including angioplasty and optional bailout stenting of the dorsalis pedis and/or the plantar arteries (20 lesions in 19 limbs).
Most patients (82%) were diabetic, and most had ischemic ulcers and tissue loss. About 75% of the lesions were calcified, and 40% were initial total occlusions.
Ultralow-profile 2.0- to 2.5-mm wide and 0.014-inch over-the-wire compatible long balloon platforms were applied. In 55% of the lesions, adjunctive bail-out stenting with balloon-expandable drug-eluting stents was also performed.
Results were encouraging: a cumulative limb salvage rate of 88% at up to 4 years' follow-up and just two major amputations. Repeat angioplasty was needed in five cases (29%) because of recurrent symptoms.
Dr. Katsanos and his colleagues also evaluated stent integrity with x-ray imaging during regular follow-up and found four deformed and/or collapsed stents and one severe stent fracture. Primary patency of the distal below-the-ankle outflow lesion was significantly, positively correlated with sustained patency of the proximal infrapopliteal lesion. Median infrapopliteal primary patency was 14 months in the case of a patent runoff vessel versus 7 months in the case of distal occlusion - a significant difference, Dr. Katsanos said.
He discussed the safety and feasibility of below-the-ankle angioplasty for limb salvage and the improved outflow runoff, which was associated with better patency rates of the proximally treated lesions.
"According to our findings, below-the-ankle placement of balloon-expandable stents should only be reserved for bailout in exceptional cases of suboptimal postangioplasty results because of the superficial anatomical location [which renders] them highly susceptible to external compression and occlusion (almost half of the stented cases in our series).
"Previous studies from our center have also shown increased stent deformity of balloon-expandable stents placed in the distal third of the anterior tibial artery. Therefore, if it is deemed necessary, we would generally recommend using self-expanding stents at the malleolar and inframalleolar level of the tibial vasculature," Dr. Katsanos said in an interview.