Large Vessel Occlusions (LVOs)

« Back to Glossary Index

Large Vessel Occlusions (LVOs) are a type of ischemic stroke caused by the blockage of one of the major arteries in the brain. These blockages can have severe consequences, leading to significant brain damage if not treated promptly. Understanding the causes, symptoms, diagnosis, and treatment options for LVOs is critical for improving outcomes in stroke patients.

What are Large Vessel Occlusions (LVOs)?

LVOs occur when large blood vessels, typically in the anterior or posterior circulation of the brain, are obstructed by a blood clot. The most commonly affected arteries include the middle cerebral artery (MCA), internal carotid artery (ICA), basilar artery, and vertebral arteries. When these arteries are blocked, blood flow to large areas of the brain is compromised, leading to potentially extensive damage.

Causes of LVOs

The primary cause of an LVO is the formation of a blood clot or embolism that travels through the bloodstream and lodges in one of the brain’s large vessels. Some of the common risk factors that contribute to LVOs include:

1. Atherosclerosis: Plaque buildup in the arteries can lead to clot formation.
2. Atrial Fibrillation: An irregular heartbeat can cause clots to form in the heart, which may travel to the brain.
3. Hypertension: High blood pressure increases the risk of damage to blood vessels and clot formation.
4. Diabetes: Poor blood sugar control can contribute to the development of clots.
5. Smoking: This significantly increases the risk of arterial damage and clot formation.

Symptoms of LVOs

LVOs often present with symptoms that are more severe than those of smaller strokes. The hallmark signs of an LVO can include:

• Sudden weakness or paralysis on one side of the body (hemiparesis)
• Difficulty speaking or understanding speech (aphasia)
• Loss of vision or double vision
• Sudden confusion or inability to follow simple commands
• Severe headaches, particularly with posterior LVOs affecting the basilar artery
• Difficulty walking or maintaining balance (ataxia)

Due to the extensive damage that LVOs can cause, recognizing these symptoms and seeking immediate medical attention is crucial.

Diagnosis of LVOs

Timely diagnosis is essential to minimize brain damage. Medical professionals use several imaging techniques to diagnose LVOs:

1. CT Scan: A computed tomography (CT) scan provides an initial assessment of the brain and identifies any bleeding or significant damage.
2. CT Angiography (CTA): This specialized scan provides detailed images of the blood vessels and can pinpoint the location of the occlusion.
3. MRI: A magnetic resonance imaging (MRI) scan offers a more detailed view of the brain and can detect smaller areas of damage.
4. Doppler Ultrasound: In some cases, an ultrasound may be used to assess blood flow in the large vessels supplying the brain.

Treatment Options for LVOs

Effective treatment of LVOs requires rapid medical intervention to restore blood flow to the brain. Some of the most common treatment methods include:

1. Intravenous Thrombolysis (IV tPA): This clot-dissolving medication is administered within a specific time window (typically within 4.5 hours of symptom onset) to help break down the clot and restore blood flow.
2. Mechanical Thrombectomy: For patients with an LVO, mechanical thrombectomy is often the preferred method of treatment. In this procedure, a catheter is inserted through an artery in the groin or wrist and navigated to the site of the clot. A stent retriever or aspiration device is then used to physically remove the clot. This treatment is highly effective, particularly when performed within 6 to 24 hours of symptom onset.
3. Antiplatelet and Anticoagulant Medications: To prevent future strokes, patients may be prescribed medications like aspirin, clopidogrel, or warfarin to reduce the risk of blood clot formation.
4. Rehabilitation: After initial treatment, rehabilitation is crucial for stroke recovery. Depending on the severity of the stroke, patients may need physical, occupational, and speech therapy to regain lost functions.

Prognosis and Prevention

The prognosis for LVOs varies depending on how quickly treatment is administered and the extent of the brain damage. Early treatment significantly improves the chances of recovery, while delays can result in long-term disability or death.

Preventing LVOs involves managing risk factors such as high blood pressure, diabetes, and atrial fibrillation. Lifestyle changes like quitting smoking, maintaining a healthy diet, and regular exercise can also reduce the risk of stroke.

« Back to Glossary Index