Pseudoaneurysm

What is Pseudoaneurysm?

A pseudoaneurysm, also known as a false aneurysm, is an uncommon but known issue where turbulent blood flow at a site of arterial injury results in a local blood clot. The condition can occur after an artery is punctured, due to trauma or infection. The key difference between a true aneurysm and a pseudoaneurysm is that in a pseudoaneurysm, the blood does not balloon out the arterial wall. Instead, blood leaks from the injury site and is contained within a clot, forming a wall made from fibrin and platelets, a process referred to as clotting. These walls are usually weaker than true aneurysms. Most commonly, these false aneurysms are found in the heart, femoral (leg), organ-related, and aorta regions. They occur in various situations, necessitating unique examination and treatment procedures.

Most patients with a pseudoaneurysm notice a painful, throbbing swollen area, usually within 24 hours of the artery injury or procedure that caused it. These symptoms are often reported in cases where a pseudoaneurysm develops after an artery in the leg (femoral artery) has been accessed for a procedure involving the inner blood vessels (endovascular procedures). Quick detection and treatment are necessary. The imaging tests used to diagnose a pseudoaneurysm can vary based on its location. However, angiography (X-ray of the blood vessels) and duplex ultrasonography (a type of ultrasound) are frequently used to determine the size, structure, and origin of the pseudoaneurysm. Depending on the characteristics of the false aneurysm (like size, location, and type), doctors can choose the best treatment plan, especially for pseudoaneurysms in the femoral area.

What Causes Pseudoaneurysm?

A pseudoaneurysm is a strange bulge that occurs in the wall of the blood vessel. The causes of pseudoaneurysms can be categorized as either iatrogenic, which means caused by medical treatment, or noniatrogenic, which means not caused by medical treatment.

If you have a femoral pseudoaneurysm (in your thigh), the most common cause is a medical procedure that involves accessing your arteries, especially one called an endovascular procedure. This is quite rare, happening in less than 1% of cases. A failure in surgical linking of blood vessels might also cause a femoral pseudoaneurysm. Other rare causes that are not related to medical treatment can be trauma (like an accident), infection, and pancreatitis with a formation of a false cyst or abnormal connection in the pancreas.

An aortic pseudoaneurysm (in your main artery) is often due to trauma, infection, degenerating atherosclerotic lesions (damage to arteries), and surgical sites following a bypass or repair of your blood vessels.

A cardiac pseudoaneurysm (in your heart) can happen after a heart attack, after surgery on your mitral valve (a valve in your heart) or congenital heart surgery (surgery on a heart defect you’re born with), endocarditis (an infection of the heart), and trauma.

A visceral artery pseudoaneurysm (in the arteries of your organs) can be due to non-medical causes like pancreatitis with a false cyst and medical causes like catheter-based interventions (procedures using a long, thin tube).

Lastly, here are some risk factors to look for that could make you more likely to have a pseudoaneurysm caused by a medical procedure:

– High blood pressure
– Being a woman
– Taking blood-thinning drugs
– Having procedures in the left femoral artery
– Having hard, calcified blood vessels punctured
– Using a large sheath size, greater than 6 French (a unit of measure)
– Being overweight
– Not using ultrasound during access procedures
– Having to puncture the blood vessel several times.

Risk Factors and Frequency for Pseudoaneurysm

A pseudoaneurysm is a condition that can appear in various locations in the body. Its incidence differs based on the area it develops, such as the heart, thighs, body’s major artery called the aorta, or the gut’s arteries.

• Aortic pseudoaneurysms – These usually result from major bodily harm, puncture injuries to the aorta, or infections of the aortic valves. They’re serious conditions and many people (around 85%) don’t survive to reach the hospital. They’re mostly (90%) found just below the aorta’s narrower segment, often caused by sudden deceleration injuries. They’re typically treated with a less invasive surgery (endovascular repair) than open surgery. Rarely, they can be caused by advanced tuberculosis. Occasionally, they can form after bypass surgery to the aorta and thighs at an incidence of 3.8%.
• Cardiac pseudoaneurysms – These often develop after a major heart attack. A study from the Mayo Clinic found 55% of cardiac pseudoaneurysms occurred after a heart attack. These often affect the lower wall of the heart more than the front wall. Other common causes include surgeries to fix the mitral valve in the heart or heart defects, which make up for 33% of cases, as well as infection of the heart lining, trauma, and unknown causes. Some heart transplant patients have also developed coronary artery pseudoaneurysms.
• Femoral pseudoaneurysms – These generally happen after inserting a catheter for heart or other procedures. Their occurrence varies from 0.6% to 4.8%, but recent reports suggest they happen in under 1% of all procedures. The use of ultrasound to help guide catheter insertion has made them less common, and rates following this method should ideally be less than 0.2%.
• Visceral artery pseudoaneurysms – These are often seen in patients with long-standing pancreatitis. They’re most commonly formed in the spleen’s artery but are least likely to burst. Uterine artery aneurysms have been reported to occur after the uterus has been stitched to prevent miscarriage.

Signs and Symptoms of Pseudoaneurysm

Identifying pseudoaneurysms, or false aneurysms, which are outpouchings of a blood vessel wall, can be based on where they occur and what type they are. Here’s a brief overview:

Femoral Pseudoaneurysm

Most femoral pseudoaneurysms, which primarily occur in the superficial femoral artery, typically appear as a painful, pulsating lump. These lumps usually develop within 24 hours of a damaging event to the artery. If the doctor listens to this region, they might hear an unusual sound called a bruit. An ultrasound can often confirm the diagnosis, showing unique blood flow patterns. If the pseudoaneurysm gets bigger, it can pressure the skin, causing redness, pain, and potentially leading to skin tissue death and bleeding. A pulsating lump in the groin is a particularly reliable sign of a femoral pseudoaneurysm. If any of the following conditions are present, immediate surgical assessment is needed:

• Growth of a bruise
• A related motor or sensory neurological deficit
• A related pulse deficit
• Unstable blood pressure and heart rate
• Significant skin and underlying tissue damage
• Nearby infection (such as an abscess, purulent drainage, cellulitis, fever, increased white blood cells)

Historically, aortic and femoral pseudoaneurysms rarely happen spontaneously. There’s often a recent history of an interventional procedure, or the person may use intravenous drugs. Both of these pieces of historical information can be crucial to managing the issue.

Cardiac Pseudoaneurysm

A cardiac pseudoaneurysm is one that occurs in the heart. The common symptoms are chest pain and shortness of breath, although some people may not report any symptoms. In rare cases, it can lead to cardiac arrest. When examined, a heart noise that sounds like a leaking heart valve might be heard in roughly two-thirds of patients. There might also be various changes on an EKG and masses may be visible on a chest x-ray.

Visceral Artery Pseudoaneurysm

Nearly 91% of visceral artery pseudoaneurysms, found in the abdominal region, do not cause symptoms until they burst. This situation has been called abdominal apoplexy in the past.

Testing for Pseudoaneurysm

When a patient has a suspected or confirmed pseudoaneurysm, which is a balloon-shaped bulge in a blood vessel, the type of imaging that’s recommended depends on where the bulge is located in the body. For pseudoaneurysms located in the femoral artery, duplex ultrasonography is considered the best diagnostic method. This technique helps doctors see the size, anatomy, and origin of the pseudoaneurysm. Research suggests that this kind of ultrasound is 100% accurate at detecting these types of bulges in the blood vessels.

If more information is required, a computer tomography angiogram (CTA), which is a special type of CT scan that provides detailed pictures of blood vessels, can be used. It can give a closer look at the pseudoaneurysm and how it relates to the surrounding structures. However, a regular CT scan isn’t essential for diagnosing or evaluating a pseudoaneurysm in the femoral artery.

In the aortic region, a CTA or a conventional arteriography, which is an x-ray of blood vessels, is typically applied for diagnosis. These aortic blood vessel bulges might show up in patients who have had previous surgeries or treatments for dissection or aneurysm (a weak, bulging spot in an artery wall), trauma, infection, or certain genetic disorders like Marfan syndrome or Ehlers-Danlos syndrome that can make the aorta degrade.

For identifying pseudoaneurysms in other parts of the body, including the heart and the visceral (internal organs) region, angiography is usually the best method. It can accurately identify more than 85% of such cases. While a type of ultrasound of the heart (known as transthoracic echocardiography) can sometimes find cardiac pseudoaneurysms, it only confirms the diagnosis in about 25% of cases. Another heart ultrasound technique, transesophageal echocardiography, is more accurate with a sensitivity of around 75%. In these ultrasounds, doctors look for a narrow neck on the aneurysm as a sign that it’s a pseudoaneurysm. True aneurysm has a wide neck at the top. Other techniques like cardiac CT and MRI can also help in distinguishing between true and pseudo-aneurysms.

For patients with pseudoaneurysms in the visceral region, who can experience signs of bleeding and abdominal pain, a CT angiography or conventional angiography can be used to confirm the diagnosis and understand the pseudoaneurysm better.

Treatment Options for Pseudoaneurysm

Your treatment for the false aneurysm, a condition where the wall of an artery becomes weakened and bulges outward, will be guided by its specific characteristics such as size, location, and type (whether it’s complicated or not).

If you have aortic pseudoaneurysms, a certain type of false aneurysm found in the aorta, your doctor would likely use methods that are less invasive, such as thoracic endovascular aortic repair (TEVAR) or endovascular aneurysm repair (EVAR). Even if the false aneurysm is caused by an infection or tuberculosis, these approaches can still save lives by avoiding larger surgeries, which can be particularly beneficial for patients not in good health.

Now, if you have a femoral artery pseudoaneurysm, which is situated in the artery that supplies blood to the leg, your treatment plan will consider various factors, including size, location, and whether the condition is classified as complicated or not. Complicated femoral artery pseudoaneurysms are characterized by conditions like a rapidly expanding lump (hematoma), noticeable loss in motor or sensory function, loss of pulse, unstable blood pressure, extensive skin damage, or signs of nearby infection. For these situations, immediate surgical assessment is recommended.

Earlier, a femoral artery pseudoaneurysm that happens because of endovascular access, a route to reach and treat the inside of arteries, was always treated with surgery. Nowadays, less invasive methods have become more common. For uncomplicated pseudoaneurysms, possible management strategies include observation, compression guided by ultrasound, injection of a clotting substance called thrombin guided by ultrasound, and surgical repair. A femoral artery aneurysm with a diameter less than 2 to 3 cm usually spontaneously closes and regresses, so monitoring the condition or opting for ultrasound-guided treatments is usually followed. Those with a diameter greater than 3 cm typically require intervention, even if they are not causing symptoms.

Using ultrasound to guide the injection of thrombin is a widely accepted, minimally invasive treatment for pseudoaneurysms that are easy to reach. This is often the first choice, before considering open or endovascular surgical repair. This approach has shown very high success rates, even among patients on blood-thinning or anti-clotting medication, with risks like embolization (blockage of a blood vessel by a clot) and pulmonary embolus (a clot in the lungs) being quite low.

Pseudoaneurysms that continue to grow, become acutely symptomatic, or are still bigger than 1 cm after six weeks are recommended for intervention. Surgery is only considered for patients where ultrasound-guided compression or thrombin injection has been unsuccessful and for those with certain types of surgical connections.

If you have a visceral artery pseudoaneurysm, located in the artery that supplies blood to the gut and its organs, endovascular methods are typically used first (as they are less invasive), with surgery only considered as a backup plan. This approach is highly effective and includes techniques like coiling, injections of substances that promote clotting, and deploying a covered stent to seal the origin of the pseudoaneurysm.

What else can Pseudoaneurysm be?

When trying to diagnose a femoral pseudoaneurysm, doctors will consider several other conditions that have similar symptoms. These conditions include:

• Hematoma (a solid swelling of clotted blood within the tissues)
• Seroma (a pocket of clear serous fluid that sometimes develops in the body after surgery)
• Infection or abscess (a localized collection of pus)
• True aneurysm (an enlargement of an artery caused by a weakening of the artery wall)

What to expect with Pseudoaneurysm

The overall outlook for most pseudoaneurysms (false aneurysms) is usually good, but it depends on where it’s located in the body. If you have a small pseudoaneurysm—less than 3 cm—in your femoral (leg) artery, doctors often choose a “wait and see” approach. This strategy has a success rate of anywhere between 50% to 100%. However, people who are on dual antiplatelet therapy (a type of treatment that helps prevent blood clots) may not have the same high success rates—the failure rates can reach up to 44%.

Ultrasound-guided thrombin injections—a procedure to clot off the blood flowing into the pseudoaneurysm—has a high success rate of up to 97% to 100% for femoral pseudoaneurysms caused by vascular access (a procedure where a tube is inserted into the blood vessels). This applies even to those who are taking medications to thin the blood or prevent clotting. If the first attempt doesn’t work, it can be tried again. Very few cases will require surgical correction.

On the other hand, we don’t know much about endovascular repair (a procedure where a stent or a graft is placed inside the blood vessel to prevent rupture) of a pseudoaneurysm in your viscera (your internal organs). However, in smaller studies, this procedure seemed to have a high success rate. Still, open surgery and ligation (tying off the blood vessel) are often considered more durable and may be a better option for younger patients.

Cardiac pseudoaneurysms (false aneurysms in the heart) are extremely dangerous if left untreated, with an almost 45% risk of rupture. Also, there is a 50% risk of death if they aren’t treated surgically but with medications alone.

Lastly, if you have a pseudoaneurysm in your aorta (the main artery in your body) caused by trauma and it’s treated with TEVAR (a type of endovascular repair), the success and complication rates are excellent. Only 2.4% of such cases experience problems related to the device, and only 2.4% end up needing an open procedure. However, if the procedure covers the left subclavian artery (a major artery in the upper body), there is a 6% chance that revascularization (restoring blood flow) may be required at a later stage.

Possible Complications When Diagnosed with Pseudoaneurysm

Pseudoaneurysms, or false aneurysms, can lead to a range of complications. Some of the possible issues include the breaking off and travelling of a blood clot in the bloodstream (called distal embolization), rupture of the pseudoaneurysm, bleeding, and even death. Notably, femoral pseudoaneurysms, which occur in the large artery in the thigh, may rupture into the retroperitoneal space (an area at the back of the abdomen), potentially causing significant yet hidden bleeding, and this could sadly lead to fatal outcomes.

Certain complications may also arise from the use of ultrasound-guided thrombin injection, a procedure used to treat pseudoaneurysms. Distal embolization, as mentioned before, can occur in up to 2% of patients undergoing this procedure. However, very few people require any further treatment for this issue.

The complications related to the endovascular repair of visceral and aortic pseudoaneurysms – those occurring in the body’s central artery and the arteries supplying the digestive organs – mainly involve issues concerning the endovascular devices used in the procedure – we’re not going into details about these specific complications here.

Common Complications:

• Distal embolization (blood clot breaking off and travelling in the bloodstream)
• Rupture of the pseudoaneurysm
• Bleeding
• In the case of a femoral pseudoaneurysm, bleeding in the retroperitoneal space (back of the abdomen)
• Death
• For ultrasound-guided thrombin injections: distal embolization

Recovery from Pseudoaneurysm

When a femoral pseudoaneurysm, or a vein in the thigh with a false aneurysm, is treated through an open repair, the post-surgery care is uncomplicated. It’s essentially the same as the standard care given to patients who have a vascular operation, and the need for physical therapy after surgery mostly depends on the patient’s overall health before the procedure.

On the other hand, a procedure called endovascular repair, which is a nonsurgical procedure typically performed inside the blood vessels, is usually tolerated well by patients. After this procedure, it’s essential for patients to stay flat for 2 to 4 hours while health professionals watch for pseudoaneurysm development at the insertion site of the surgical instruments.

If there’s a need to insert a stent (a tiny mesh tube that keeps blood vessels open) or a graft device (a synthetic tube used to replace or repair blood vessels) during the repair, then patients will need regular check-ups with a vascular surgeon. At these appointments, they will undergo imaging tests to check the stent or graft, ensuring it’s functioning correctly and supporting the blood vessels as intended.

Preventing Pseudoaneurysm

There are no specific guidelines on how to prevent pseudoaneurysms, which are false aneurysms where blood collects outside of a blood vessel wall. However, if a patient has had a pseudoaneurysm in the past, it’s crucial for them to know what the signs and symptoms look like in case it happens again. Also, before any procedures involving the blood vessels, patients should be educated about the signs and symptoms of a pseudoaneurysm because there is a chance it could occur.