Aberrant course of the superficial femoral artery and profunda femoris artery: A rare vascular anomaly identified during peripheral artery disease intervention

INTRODUCTION

The American College of Cardiology (ACC) and American Heart Association (AHA), in their 2024 guidelines, describe three main anatomical segments for the arterial blood supply of the lower extremities: (1) Aortoiliac – composed of the infrarenal abdominal aorta, common iliac, external iliac and internal iliac arteries; (2) Femoropopliteal – composed of common femoral, profunda femoris (PFA), superficial femoral, and popliteal arteries; and (3) Infrapopliteal – composed of tibial-peroneal trunk, anterior tibial artery, posterior tibial artery, peroneal artery, plantar pedal loop, and pedal vessels.^[1]

The American ACC/AHA, Society for Cardiovascular Angiography and Interventions, and the Society of Interventional Radiology define the superficial femoral artery (SFA) as the continuation of the common femoral artery (CFA). The SFA begins at a bifurcation where the PFA branches emerge. Typically, the SFA courses inferiorly, along the anteromedial aspect of the thigh, traveling within the femoral triangle and then through the Hunter’s canal. The SFA concludes its course at the level of the adductor hiatus, where it develops into the popliteal artery on the posterior surface of the knee. Over the length and breadth of its course, the SFA is proportionately deep and efficiently protected by surrounding musculature, even though its name seems to indicate otherwise.^[2,3]

The PFA normally emerges from the lateral aspect of the femoral artery (FA), 3.75 cm from the mid-inguinal point. This artery crosses behind the FA and femoral vein at the level of the pectineus and exits the femoral triangle by passing through the gap between the pectineus and adductor longus, after that it slopes in the junction between adductor longus and magnus, thus ending as the fourth perforator.^[4]

Several variations in the origins and course of the CFA, SFA, and PFA have been documented, with significant implications during interventional or surgical procedures.^[5] We present a rare anatomical variation in which the SFA demonstrated a variant course, presenting more laterally and superficially than expected during right lower extremity (RLE) arterial intervention.

CASE REPORT

A 65-year-old female with past medical history of type 2 diabetes, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, and peripheral artery disease status post right hallux amputation presented with lifestyle-limiting bilateral critical limb ischemia (CLI).

Duplex ultrasonography demonstrated monophasic waveforms in the bilateral common femoral, PEA, popliteal, and posterior tibial arteries. The superficial femoral [Figure 1] and anterior tibial arteries appeared occluded.

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Figure 1: (a) 65 year old female with bilateral Chronic limb-threatening ischemia (CLTI) duplex ultrasound of the arterial system of the medial thigh demonstrates the absence of the SFA (white head arrow) within its expected anatomic location. (b) Color Doppler duplex ultrasound of the arterial system of the medial thigh demonstrates the absence of the SFA within its expected anatomic location, with no detectable color flow signal (blue square) in the anticipated vascular course (white arrow). SFA: Superficial femoral artery. OCC: Occluded.

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An RLE arterial angiogram was performed during planned left leg angiography. The patient was positioned supine in the angiography suite under conscious sedation. Ultrasound-guided retrograde access was successfully performed using the modified Seldinger technique, and a 5 F Slender sheath in the right groin in the presumed “CFA” [Figure 2]. Initial intra-arterial contrast injection showed PFA-type branches which extended medially in the thigh [Figure 3]. The angiogram further revealed an unexpected vascular anomaly: The SFA course was deviated laterally and posteriorly, assuming an unusual position relative to expected anatomy [Figure 4]. A subsequent angiogram on a different day (this time obtained through retrograde right PT access) showed the central and peripheral portions of the right SFA extending laterally in the thigh [Figure 5]. It continued its aberrant course through the thigh before terminating as the popliteal artery at the posterior knee [Figure 6]. No associated venous or neural anomalies were identified.

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Figure 2: 65 year old female with Chronic limb-threatening ischemia (CLTI) selective posteroanterior digital subtraction angiography of the right lower extremity on the proximal segment, through retrograde arterial access. Based on ultrasound, the operator felt that they were in the common femoral artery; however, the angiography shows that access was in fact in the right profunda femoris artery profunda femoris (PFA) (black head arrow), consistent with an aberrant course of this artery.

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Figure 3: 65 year old female with Chronic limb-threatening ischemia (CLTI), Selective posteroanterior digital subtraction angiography of the right lower extremity on the SFA territory shows profunda femoris branches extend medially in the femur region (black head arrow). Subtle lateral deviation in the course of the SFA (black arrow). SFA: Superficial femoral artery.

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Figure 4: 65 year old female with Chronic limb- threatening ischemia (CLTI), Selective postero-anterior digital subtraction angiography of the right lower extremity on the proximal segment of the femur shows a closer look at the right superficial femoral artery (black head arrow) with high take off and a posterior fashion that then extends laterally, and profunda femoris branches (black arrow) extend medially.

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Figure 5: 65 year old female with Chronic limb-threatening ischemia (CLTI), Selective posteroanterior digital subtraction angiography of the right lower extremity at the level of the medial femur demonstrates a closer look at the right superficial femoral artery which deviates laterally (black arrow head). The distal branches of the profunda femoris are also visualized extending medially (black arrow).

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Figure 6: 65 year old female with Chronic limb-threatening ischemia (CLTI), selective posteroanterior digital subtraction angiography of the right lower extremity at the level of the popliteal region demonstrates the final portion of the superficial femoral artery (black arrow head), which becomes the right popliteal artery (asterisk) and the tibial arteries.

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Following recognition of this variation, appropriate technical adjustments were made to safely perform angiography and revascularization. The procedure was completed without complication, and the patient recovered uneventfully.

DISCUSSION

FA anomalies are exceedingly rare. The most frequently reported include aplasia and hypoplasia of the SFA, duplication of the FA, trifurcation of the FA, and duplication of the SFA. As of the time of this manuscript, the aberrant course of the SFA described here – lateral and posterior – and PFA going medially in the thigh, has not been specifically mentioned in a PubMed search, though some case reports and textbooks do discuss embryologic defects that can trigger some vascular anomalies.^[6]

The embryologic development of the lower limb blood vessels and their branches involves several steps, such as the fusion and regression of multiple arteries. The development of the blood vessels begins at roughly the 6 mm stage embryo (35–37-day gestational age) and ends around the 14 mm stage embryo (42–45 days gestational age). Variations in the course of the SFA and PFA likely represent a failure in appropriate interactions between them and the sciatic artery. When altered, variants occur such as the dorsal thigh being supplied by the PEA as a branch of the FA.^[7]

The clinical significance of a vascular anomaly has been reported in a few cases, with notable case reports including bilateral duplications of the SFA^[6] and a persistent sciatic artery (PSA), where the CTA of the patient demonstrated that the right inferior gluteal artery and right popliteal artery of the right internal iliac artery were connected.^[8] PSA, an embryologic remnant with important clinical implications, differs from the present case in both anatomical and clinical presentation. In our case, PFA and SFA are present, with the SFA continuing into the popliteal artery. In contrast, in PSA, the sciatic artery provides the dominant inflow to the popliteal artery. In addition, the SFA in the described case follows a posterior and lateral course, whereas PSA typically demonstrates a more medial trajectory. PSA is also associated with a higher risk of complications, particularly aneurysm formation, reported in up to 47% of cases. Clinically, PSA may present with sciatic nerve compression, which was not observed in our case.^[9]

Aberrant positioning may increase the risk of iatrogenic injury during surgical exposure, orthopedic procedures, trauma, or endovascular interventions. Pre-operative imaging, particularly with duplex ultrasound, computed tomography angiography, or conventional angiography, is essential to identify such variants and inform procedural planning.

CONCLUSION

This case illustrates a previously undescribed vascular anomaly of the SFA, with a lateral and posterior trajectory through the thigh and a variant of the PFA with a medial trajectory. Recognition of such variations is critical for interventional radiologists, vascular surgeons, interventional cardiologists, and orthopedic surgeons to avoid inadvertent injury and to optimize procedural outcomes. Pre-procedural imaging remains the cornerstone of safe intervention in patients with suspected or known vascular anomalies. These case reports can help to develop some skills to identify vascular anomalies and improve future diagnoses.