Pseudoaneurysm – Diagnosis and Treatment
Overview
A pseudoaneurysm is a blood sac that forms when a blood vessel wall is injured and bood leaks out, collecting in the nearby tissue. This problem can happen after certain medical procedures like cardiac catheterization, or after an artery is accidentally damaged.
Unlike a true aneurysm, a pseudoaneurysm does not involve all layers of the blood vessel wall. Many people have never heard of pseudoaneurysms, but recognizing them is important because they can lead to serious complications if not treated.
Common symptoms include pain, swelling, or a pulsating lump near where the artery was hurt. Doctors use imaging tests to diagnose a pseudoaneurysm and select the best treatment, which may include observation, pressure, or surgery.
What Is a Pseudoaneurysm?
A pseudoaneurysm, also called a false aneurysm, is a blood-filled sac that forms next to a blood vessel. It differs from a regular aneurysm and often occurs after an injury or medical procedure where blood leaks out and gets trapped by nearby tissues.
Pseudoaneurysm Versus True Aneurysm
A pseudoaneurysm and a true aneurysm are not the same. In a true aneurysm, the blood vessel wall itself bulges out but keeps all its normal layers. In a pseudoaneurysm, a break or hole forms in the vessel wall. Blood leaks out but gets trapped by surrounding tissue, not the vessel wall.
| Feature | True Aneurysm | Pseudoaneurysm (False Aneurysm) |
|---|---|---|
| Wall | All vessel layers involved | Wall made of surrounding tissue |
| Main Cause | Wall weakens (often long-term) | Injury, procedure, or trauma |
| Healing | Often grows slowly | May shrink, grow, or rupture |
Pseudoaneurysms sometimes develop after needle punctures or surgery. Blood collects outside the vessel, creating a soft, pulsating lump that can sometimes be felt under the skin. This is why they are called “false” aneurysms.
Common Causes
Medical procedures, injuries, and sometimes infections commonly cause pseudoaneurysms. Cardiac catheterization, used to examine the heart, is a leading cause. When a needle or tube enters an artery, like the femoral artery in the groin, a tiny hole may be left behind. Blood escapes and forms a sac outside the vessel.
Direct trauma, such as a car accident or a deep cut, can also create a pseudoaneurysm. Other causes are less frequent and include surgical scars or infections that weaken blood vessel walls. Sometimes, people may not notice symptoms right away. The main risk is that the hematoma (blood-filled sac) can burst and cause serious bleeding.
Pathophysiology
When a blood vessel is punctured or torn, blood leaks out and collects in nearby tissue. This forms a hematoma with a narrow neck connected to the artery. The body often tries to wall off this blood by creating a capsule made of clot and scar tissue.
Unlike a true aneurysm, a pseudoaneurysm’s “wall” does not contain the normal blood vessel layers. Instead, the sac consists of surrounding tissue, such as muscle or connective tissue. The high pressure inside arteries can push blood into the sac each time the heart pumps. Over time, the sac can get larger or stay the same size.
In some cases, the pseudoaneurysm will close off or heal by itself. In other cases, the sac can grow, become painful, or even rupture. If the blood starts to leak out again, it can cause swelling, bruising, or low blood pressure. Most pseudoaneurysms require medical testing and sometimes treatment to prevent complications.
Clinical Presentation
A pseudoaneurysm most often appears as a painful, pulsatile mass near the site of prior arterial puncture or trauma. The femoral artery is a common site, especially after procedures that use arterial access. Symptoms may include:
- Localized swelling
- Redness and warmth
- Throbbing pain
- Bruising around the affected area
Distal pulses in the affected limb may be weak or even absent if the pseudoaneurysm leads to thrombosis. This can result in decreased blood flow and signs of limb ischemia.
In some cases, the pseudoaneurysm may rupture, causing sudden, severe pain and rapid swelling. This event raises the risk for significant bleeding and can increase morbidity and mortality if not treated quickly.
A hematoma may also form if ongoing bleeding from the pseudoaneurysm enters the surrounding tissue. The mass usually develops within 24 hours after the arterial injury or procedure. The table below summarizes key features:
| Finding | Description |
|---|---|
| Pulsatile mass | Swelling that pulses with the heartbeat. |
| Pain and tenderness | Local discomfort at the site. |
| Bruising | Discoloration around the affected area. |
| Loss of pulse | Weak or absent pulse in the limb. |
| Rapid swelling | Can signal rupture or bleeding. |
Infections or blood clots (thrombosis) may complicate the clinical picture, increasing the risk of severe outcomes if not recognized early.
Diagnostic Methods
Doctors often diagnose pseudoaneurysm using imaging tests that help them see blood flow and vessel problems. Ultrasound is the most common first test. It uses sound waves to create images of the blood vessels.
Color Doppler ultrasound is especially helpful because it shows blood moving, which can reveal where blood escapes into the pseudoaneurysm. A duplex ultrasound combines both regular and Doppler ultrasound. This allows the doctor to see the structure of the vessel and measure blood flow at the same time. Doctors sometimes use other imaging tests if they need more detail.
CT scan (computed tomography) provides a clear cross-section of blood vessels. Computed tomographic angiography (CTA) uses a CT scan with a special dye to show details of arteries and veins. Ultrasonography is another term often used to describe these ultrasound-based imaging tests.
Common Diagnostic Tests for Pseudoaneurysm
| Test Name | What It Shows |
|---|---|
| Ultrasound | Vessel structure |
| Color Doppler ultrasound | Blood movement and leaks |
| Duplex ultrasound | Both structure and blood flow |
| CT scan | Detailed cross-sections of vessels |
| Computed tomographic angiography | Enhanced images of arteries and veins |
Healthcare teams choose the best test based on the pseudoaneurysm’s location and the patient’s health needs.
Treatment Options
Doctors manage pseudoaneurysms using a few main therapies. They choose treatment based on the size, location, symptoms, and overall health of the patient.
Ultrasound-Guided Compression
Doctors often use ultrasound-guided compression as the first step for small pseudoaneurysms. They use an ultrasound probe to press down on the spot where the artery is leaking. This pressure aims to close off the connection between the artery and the pocket of blood.
The doctor watches with the ultrasound to make sure it’s working. Each session may take up to an hour, and sometimes several sessions are needed. This method works best for pseudoaneurysms that are easy to reach and not too large. This method is less effective if the patient is on blood thinners, or if the pseudoaneurysm is deep or very wide. In these cases, doctors may use another method.
Thrombin Injection
Doctors use thrombin injection as a minimally-invasive treatment. Thrombin is a clotting medicine. The doctor injects it directly into the pseudoaneurysm under ultrasound guidance. The goal is to make the blood inside the pseudoaneurysm clot quickly.
This procedure works especially well for pseudoaneurysms at arterial puncture sites. Thrombin injection usually takes only a few minutes, and most people do not need sedation. The success rate is high, with a low risk of major complications.
Risks are rare but can include clotting of nearby arteries or allergic reactions. Thrombin injection is not recommended if the pseudoaneurysm connects to a large artery or has a wide neck.
Surgical Intervention
Doctors reserve surgical intervention for cases where less-invasive methods fail. They may also use it first if the pseudoaneurysm is large, infected, has burst, or is in a place that cannot be reached easily.
Surgeons can perform open repair by exposing the artery and repairing it directly. Alternatively, they may use an endovascular approach, accessing the artery through a small incision and using devices for embolization or stent placement to seal the pseudoaneurysm.
Open surgery usually requires a hospital stay and longer recovery. Endovascular repair or embolization is less invasive and may have a shorter recovery. The choice depends on patient needs, pseudoaneurysm characteristics, and available equipment.
Prognosis and Outcomes
The prognosis for pseudoaneurysm depends on its size, location, and the patient’s overall health. Small pseudoaneurysms may close on their own, while larger or fast-growing ones often need treatment. Main risks associated with pseudoaneurysms include:
- Rupture, which can cause life-threatening bleeding
- Infection at the site
- Compression of nearby nerves or blood vessels
Mortality from pseudoaneurysms is mostly linked to rupture, especially when not treated in time. Early detection lowers the chance of major complications. Most patients recover well with proper management.
Treatments like endovascular repair or surgery are often effective and have high success rates. Patients who have a history of pseudoaneurysm should learn the warning signs for recurrence. Prompt action if symptoms return can help prevent serious outcomes. A summary table:
| Outcome | Likelihood | Notes |
|---|---|---|
| Spontaneous closure | Possible in small | Needs close monitoring |
| Rupture | Moderate to high | Risk increases with size or delay |
| Morbidity (complications) | Depends on location | Infection, nerve or vessel injury |
| Mortality | Low with treatment | High if rupture occurs and untreated |
Prevention and Risk Minimization
Reducing risk factors during medical procedures helps prevent pseudoaneurysm. Medical professionals use careful technique during arterial puncture. Using the smallest possible introducer sheath and puncturing at the correct site lowers risk. Proper compression after catheterization prevents blood leaks.
Medical teams monitor for signs of bleeding or swelling near the puncture or surgical scar. Patients on blood thinners, such as anticoagulants or antiplatelet agents, require close monitoring. Healthcare providers may adjust these drugs before and after procedures to minimize risk. A checklist can help reduce complications:
- Correct puncture site selection.
- Use of proper equipment size.
- Adequate compression after procedure.
- Monitoring for pain, swelling, or pulsating mass.
Key Risk Factors
| Risk Factor | Effect on Risk |
|---|---|
| Anticoagulation | Increases |
| Large introducer sheath | Increases |
| Low puncture site | Increases |
| Faulty puncture technique | Increases |
| Inadequate compression post-procedure | Increases |
Medical teams handle patients with surgical scars in the area gently to reduce trauma to the blood vessel and nearby tissue. Patient education is important. Patients should report any new pain, swelling, or a pulsating mass near the puncture or surgical scar to a healthcare provider right away.
