What is Femoral Artery Pseudoaneurysm?
A Femoral artery pseudoaneurysm is a condition where part of the wall of the femoral artery, a large blood vessel in the leg, bulges outward. This is different from a true aneurysm, where all three layers of the blood vessel wall are involved. It may cause symptoms like a pulsating lump, pain, bruising, or active bleeding. In chronic cases, when a fibrous capsule has formed around the pseudoaneurysm, it may keep creating a connection with the blood vessel. The risks involved with a pseudoaneurysm depend on its size, how it was caused, how long it has been there, the patient’s other health conditions, and the width of its neck. These risks may include expansion, rupture, blockage, bleeding compressing the arterial wall, and lack of blood supply. It is very important to pay attention to the possibility of a pseudoaneurysm when a pulsating lump can be felt, especially if the patient had a recent procedure.
The common iliac artery, a major blood vessel in the lower body, splits into two branches: the internal iliac artery, which supplies blood to the pelvis, and the external iliac artery, which carries blood to the foot. When the external iliac artery crosses the inguinal ligament (a band of fibrous tissue in the lower abdomen), it becomes the common femoral artery. This artery then further divides into two other arteries. Before attempting to puncture an artery, it’s very important to have a clear understanding of these anatomical landmarks. Using ultrasound-guided techniques to locate the arteries and for safe insertion of the needle into the artery is a common practice. Inserting the needle into the femoral artery above the femoral head (the part of the thigh bone that fits into the hip socket) is recommended to avoid complications.
For this, one can identify the common femoral artery by drawing two lines. The first line is roughly the width of one finger below a second line drawn from the top of the hip bone (anterior superior iliac spine) to the pubic bone in the lower part of the abdomen. By feeling for the area where the pulse is strongest, one can find the location for arterial entry that will also allow for easy compression in case of complications.
What Causes Femoral Artery Pseudoaneurysm?
Femoral Pseudoaneurysms (PSA), a type of abnormal bulging in a blood vessel, can be caused by procedures that use the femoral artery (a major artery located in the thigh) as their entry point. These might include procedures like inserting a heart catheter to place a stent in a coronary artery. However, any procedure that involves puncturing the femoral artery can potentially lead to damage of the artery wall and cause a PSA. Therefore, using ultrasound and a special technique called the Seldinger technique under real-time X-ray (fluoroscopy) can be an important part of these procedures.
Some factors may increase the possibility of developing a PSA. These include using a large-sized sheath (a thin tube used during the procedure), poor procedure technique, being overweight, needing blood thinner medication, being female, or being a patient on dialysis. Additionally, procedures performed for treatment purposes are sometimes found to be associated with a higher number of PSA formations than the procedures done only for diagnosing, because of using larger sheath size.
True aneurysms in the femoral artery are really rare and are typically found in individuals who are older than 65. They usually occur on one side but can be on both sides in 10% of cases. In about 30% of cases, if a person has a real aneurysm in the femoral artery, they may also have an aneurysm somewhere else in the body. Unlike the PSA, the chance of these true aneurysms breaking open is low. However, they can sometimes form a blood clot and cause poor blood flow to the limb.
Risk Factors and Frequency for Femoral Artery Pseudoaneurysm
It is well noted that Pseudoaneurysms, or PSAs, are the most common complication after a specialist surgeon performs certain procedures via skin-puncture, known as percutaneous procedures. These are often performed by professionals such as cardiologists, interventional radiologists, or vascular surgeons. Depending on the case, the incidence rate for these complications can vary anywhere from 0.5% to as high as 9%. There can be other less common causes too, such as surgical interventions or blunt and penetrating injuries. In some unusual cases, treatment for a specific hip condition, known as slipped capital femoral epiphysis, has resulted in this issue with the femoral artery. However, it’s important to note that percutaneous interventions are the primary cause of PSAs.
Signs and Symptoms of Femoral Artery Pseudoaneurysm
If a patient needs to be examined for a femoral pseudoaneurysm (a bulging blood vessel in the leg), here’s the process the doctor would usually go through:
- Review the patients’ full medical history, including high blood pressure, smoking habits, high cholesterol, any procedures on their blood vessels, or recent injuries.
- Conduct a comprehensive examination of the patient’s blood circulation. This typically involves a full cardiovascular examination.
- Check in the neck for any unusual sounds called bruits, which could indicate a problem with blood flow.
- Measure the strength of pulses in the arms and legs.
- Look for any unusual pulsating masses in the abdomen.
The doctor should pay particular attention to patients showing signs of a pulsating mass in the groin. It’s important to avoid confusing this with an inguinal hernia, which can also cause pain and bulging. These two conditions can be differentiated by checking for a bruit in the groin area, as this would be characteristic of a pseudoaneurysm but not a hernia.
Testing for Femoral Artery Pseudoaneurysm
If your doctor suspects you might have a pseudoaneurysm (PSA), a kind of bulge in your artery, they’ll likely perform a duplex ultrasound (DUS) first. A DUS is really good at detecting PSAs, with a successful detection rate of 92% to 96%.
The results from the DUS can show whether the blood flow between the inner part of the artery and the main leg artery (femoral artery) is typical of a PSA. It can also measure the size of the bulge and the neck (the point where the arterial wall starts to bulge out), which helps your doctor decide on the best treatment. The DUS scan can also spot any blood clots (thrombus) sticking out from the bulging sac in the arteries above and below the suspected PSA.
If surgery needs to be done, a CT angiography, which is an X-ray that can see the blood in your arteries, could be used to help plan the operation.
Treatment Options for Femoral Artery Pseudoaneurysm
Femoral pseudoaneurysms, or PSAs, are a complication that can occur after a procedure involving the femoral artery. The treatment options for this condition include open surgery, pressure applied with the guidance of ultrasound, injection of a clotting protein (thrombin) under ultrasound guidance, use of coils or stents to block blood flow to the aneurysm, and the placement of a specialized stent in case of true aneurysms.
Open surgery is suggested when the PSA has led to an abnormal connection between the artery and a vein, the patient’s blood pressure is unstable, or the patient’s limb isn’t receiving enough blood. The surgery involves gaining control of the blood flow from the artery, repairing the damaged part of the artery, and sometimes using a piece of a vein to repair the artery if it can’t be done directly. In severe cases, if the patient goes into shock from blood loss, the area may need to be compressed to stop the bleeding before any other steps are taken.
Direct pressure to the PSA, known as ultrasound compression, is used to close off the aneurysm. Care is taken to make sure the femoral artery isn’t compressed while doing this. This method is usually successful when the aneurysm’s neck is short. However, there may be technical failures with this method for around 10-30% of the time, prompting the need for alternative treatments.
Ultrasound-guided thrombin injection is a less invasive technique that involves injecting the clot-inducing protein thrombin into the aneurysm to promote clotting and closure of the aneurysm. This requires an aneurysm with a narrow and long neck that is viewable with an ultrasound. Failure with this method is seen in around 5-10% of cases, given that the anatomy of the aneurysm is cooperative.
Similarly, minimally invasive endovascular treatments, like coil embolization and covered stent placement, also aim to stop blood flow to the aneurysm. However, there might be a risk of a new aneurysm forming since these methods often involve inserting devices into the artery from the opposite side of the groin.
While these treatment options are typically effective, there can be complications, such as the formation of clots in the blood vessels (thrombosis) or the movement of the clot to other parts of the body (embolism). Hence, healthcare professionals should meticulously examine the patient’s pulse before and after the treatment. If there’s a suspicion of a clot moving into the smaller arteries (distal embolization), a specialist catheter can be used to clear the blockage and restore blood flow. After this, the healthcare professional performs a pulse check at the patient’s feet.
If the patient is diagnosed with a true aneurysm, a different approach is recommended. In this case, the aneurysm is surgically removed, and a synthetic graft is used to replace and restore the function of the removed section.
What else can Femoral Artery Pseudoaneurysm be?
When trying to diagnose a femoral artery pseudoaneurysm, doctors have to consider other conditions that show similar signs and symptoms. These might include:
- Constipation
- Diverticulitis
- Ectopic testis
- Femoral artery aneurysm
- Gastroenteritis
- Inguinal lymph nodes
- Lipoma
- Osteoarthritis
- Psoas abscess
- Psoas bursa
- Saphena varix
Physicians will generally conduct medical tests to exclude these possibilities and make an accurate diagnosis.
What to expect with Femoral Artery Pseudoaneurysm
The outcome is generally good for most patients when they receive treatment. Without it, a pseudoaneurysm (an abnormal blood-filled pocket caused by a leak in the wall of a blood vessel) can keep growing and there’s a chance that it could burst. True aneurysms (balloon-like bulges in an artery that can stretch and burst) can potentially block blood flow in the limbs.
Patients who have a procedure done at the groin area often experience significant bleeding that can take months to subside. Since this blood is in the connective tissue, putting in a drain won’t help. It’s important to realize that most patients who go through a nonsurgical procedure for heart disease also have other health issues. Due to this, they typically need careful and regular monitoring.
Possible Complications When Diagnosed with Femoral Artery Pseudoaneurysm
The possible complications that can occur with a pseudoaneurysm in the femoral artery are:
- Embolization
- Ischemia and gangrene of the leg
- Blue toe syndrome
- Rupture of the pseudoaneurysm
- Compression of the veins
Recovery from Femoral Artery Pseudoaneurysm
Typically, after undergoing a medical procedure, doctors will check and record your pulse to compare it to your pulse before the procedure. About 1 hour after your treatment, an ultrasound test will be conducted to confirm that the sac, which is a fluid-filled space in your body, has successfully closed. Moreover, your doctor will want to see you for a follow-up appointment one week after your treatment. This is to check if there’s any tissue death on your skin (known as skin necrosis), examine your pulse status, and confirm through a handheld ultrasound device that the sac remains closed.
