Femoral Artery Aneurysm

True vs false femoral aneurysm

True femoral aneurysms

They are uncommon. They are strongly linked to other aneurysms: a large share of people with a femoral aneurysm also have an abdominal aortic aneurysm, and many have aneurysms on both sides or in the popliteal artery behind the knee. Anyone diagnosed should be screened for these.

False aneurysms (pseudoaneurysms)

The femoral artery is the most common access point for heart catheterization and many other procedures. After the catheter is removed, the puncture can fail to seal, and blood leaks into a pocket outside the artery that stays connected to it. Risk factors include large catheters, blood thinners, obesity and puncture below the ideal site. Pseudoaneurysms also follow groin injuries, injecting drugs into the groin, and leaks at the join of a previous bypass graft (anastomotic aneurysm). Infected (mycotic) pseudoaneurysms are particularly dangerous.

Symptoms

• a pulsating lump in the groin that throbs with the heartbeat
• groin or thigh pain
• bruising and swelling, especially after a procedure
• leg swelling if the aneurysm presses on the femoral vein
• numbness or tingling in the front of the thigh if it presses on the femoral nerve
• signs of reduced blood flow: leg pain on walking, cold or pale foot, or sudden severe pain if a clot blocks the artery
• many true aneurysms cause no symptoms and are found on scans or during an exam

Not every groin lump is an aneurysm. Hernias, swollen lymph nodes and abscesses are more common. A pulsating lump, or a lump after a groin procedure, needs an ultrasound.

Complications

• thrombosis: a clot forms inside the aneurysm and blocks the artery, causing acute limb ischemia, an emergency that threatens the leg
• embolism: clot fragments travel down to block smaller arteries in the leg or toes
• rupture: more common with pseudoaneurysms and infected aneurysms than with true femoral aneurysms
• compression of the femoral vein (causing swelling or deep vein thrombosis) or nerve
• infection

Diagnosis

• Duplex ultrasound: the main test. It measures the size, shows blood flow in and out of a pseudoaneurysm (a "to-and-fro" pattern) and detects clot.
• CT angiography: maps the aneurysm and other arteries before surgery, and checks for aortic and popliteal aneurysms.
• Ankle-brachial index: compares blood pressure in the ankle and arm to assess leg circulation.

Treatment

True femoral aneurysms

• Small, symptom-free aneurysms: regular ultrasound monitoring, smoking cessation, blood pressure control, statins and antiplatelet medicine to lower cardiovascular risk.
• Repair is usually recommended for aneurysms around 3.5 cm or larger, or any size that causes symptoms, contains clot or causes embolism. The standard repair is open surgery, replacing the aneurysm with a graft or bypass. Stent grafts are used less often in the groin because the hip joint bends there.

Pseudoaneurysms

• small ones (under about 2 to 3 cm) after catheterization may close on their own and can be watched with repeat ultrasound
• ultrasound-guided thrombin injection: the most common treatment. Thrombin injected into the pocket clots it within seconds
• ultrasound-guided compression: pressing on the neck of the pseudoaneurysm. Less used now because it is painful and slower
• surgery for large, rapidly expanding, infected or ruptured pseudoaneurysms, or those with skin damage or nerve compression

Infected aneurysms

These need surgery to remove infected tissue, reconstruction often routed away from the infected area, and long-term antibiotics.

Prevention

• do not smoke, and control blood pressure and cholesterol
• after a groin catheter procedure, follow instructions about lying flat, pressure on the site and avoiding heavy lifting
• report a new lump, swelling or bruising at the puncture site promptly
• men over 65 who have ever smoked are recommended a one-time ultrasound screen for abdominal aortic aneurysm

Frequently asked questions

What is a femoral aneurysm?

A femoral aneurysm is an abnormal bulge in the femoral artery in the groin or thigh. True aneurysms involve the whole artery wall and are usually caused by atherosclerosis. False aneurysms are contained leaks, most often after procedures that use the groin artery.

What does a femoral pseudoaneurysm feel like?

It usually feels like a tender, swollen, pulsating lump in the groin, often with bruising, appearing hours to days after a procedure such as a heart catheterization. Some people notice leg swelling or thigh numbness. A doctor can confirm it with ultrasound.

How is a femoral pseudoaneurysm treated?

Small ones may heal on their own and are monitored. Most are treated with an ultrasound-guided injection of thrombin, which clots the pocket within seconds. Large, infected or rapidly growing pseudoaneurysms may need surgery.

Is a femoral aneurysm dangerous?

It can be. The main risks are a clot blocking blood flow to the leg, small clots traveling to the toes, rupture and bleeding, and pressure on nearby nerves or veins. Many small true aneurysms are safely monitored, but large or symptomatic ones need repair.

Does a femoral aneurysm mean I have other aneurysms?

It might. True femoral aneurysms often occur with abdominal aortic aneurysms or popliteal aneurysms behind the knee, and in both legs. Anyone diagnosed with a true femoral aneurysm should be screened for aneurysms elsewhere.