Title
Rare Vascular Anomaly Presenting With Bilateral Lower Extremity Claudication
Introduction
PSA is a rare anomaly found in 0.03%-0.06% of the population and originates from the embryonic sciatic artery, a branch of the umbilical artery. PSA occurs due to lack of regression of the embryonic sciatic artery which is the main blood source for the developing lower extremity. The majority of these rare cases present with unilateral anomaly, and bilateral persistent sciatic arteries are found in only 30% of all cases (1). PSA is typically asymptomatic, however, can result in aneurysm, occlusion, and stenosis, in decreasing order of frequency, occurring in 48%, 9%, and 7% of cases respectively (2). There are five types of PSA according to Pillet et al (3), and modified by Gauffre et al (4) (Figure 1).
Clinical Case
This case report involves a 64-year-old Caucasian female with a history of type 2 diabetes mellitus, atrial fibrillation and tobacco abuse, who presents with a six-month history of Rutherford class 3 bilateral calf claudication. Resting right ABI is 0.49 and left ABI is 0.57. The arteriogram of the lower extremities reveals bilateral persistent sciatic arteries, type 2A anomaly, in which the SFA is present but does not reach the popliteal artery (5). The right leg angiogram (Figure 2, Video 1) illustrates a right PSA with distal occlusion and reconstitution of the right popliteal artery via collaterals from the right SFA (Figure 3). The left leg angiogram demonstrates severe stenosis of the left CIA with apparent occlusion or underfilling of the left internal iliac artery (Figure 4) and delayed filling of the PSA (Video 2, 3). Subsequently, the patient underwent successful stenting of the left CIA (Figure 5, Video 4) resulting in flow normalization of the internal iliac artery and filling of the PSA (Figure 6, Video 5).
Discussion
Despite the rarity of the PSA anomaly, the clinical consequences can be severe with 31-63% of PSA cases presenting with lower limb ischemia and up to 25% with critical limb ischemia. Aneurysms are another common complication, which can result in radicular pain due to sciatic nerve compression, thrombosis, embolization and even rupture (6). Asymptomatic patients with PSA do not need any treatment and only require follow-up with duplex ultrasonography. Symptomatic individuals with PSA are treated either via surgical intervention or percutaneous endovascular procedures (7).