Overview of Common Neurovascular Disorders and Introduction of Minimally Invasive Endovascular Therapies

Director Yen-Jun Lai, M.D.

Interventional Neuroradiology, also known as Neurointerventional Surgery, is a technique that uses minimally invasive methods to treat neurovascular diseases. The procedure involves delivering a catheter through a small skin incision to perform the treatment. Compared to open surgery, this technique has less risk, smaller wounds, and quicker recovery.

Conditions such as cerebral aneurysms, acute strokes with major vessel occlusion, intracranial arterial stenosis, arterial dissection, arteriovenous malformations (AVM/AVF), and carotid artery stenosis can all be treated with endovascular therapy.

Cerebral Aneurysms

A cerebral aneurysm is a localized bulging of the cerebral blood vessel wall caused by thinning or weakening of a segment of the artery. Most small unruptured aneurysms may not produce symptoms.

However, rupture of an aneurysm can cause subarachnoid hemorrhage, leading to severe headache, nausea, vomiting, visual disturbance, loss of consciousness, and even death. This life-threatening condition requires emergency treatment.

Treatment options depend on the aneurysm’s size, location, configuration, and the patient’s clinical condition. When aneurysms are located in deep or surgically inaccessible areas, endovascular therapy is often preferred.

Common treatments include:

• Coil embolization to promote thrombosis inside the aneurysm
• Flow diverter placement to redirect blood flow and seal the aneurysm

Cerebral Artery Occlusion (Ischemic Stroke)

When a thrombus forms within a blood vessel and travels to the brain, it can block cerebral arteries and lead to ischemic stroke. Stroke can significantly impair neurological function and affect essential life activities.

Mechanical thrombectomy has become an important treatment. Using aspiration catheters or stent retrievers, physicians can remove the clot within the therapeutic time window, restoring blood flow to the brain and reducing neurological damage.

Intracranial Arterial Stenosis

Intracranial arterial stenosis occurs when major brain arteries become narrowed due to atherosclerosis or other causes. The condition commonly affects vessels such as:

• Basilar artery
• Middle cerebral artery
• Internal carotid artery
• Vertebral artery

Reduced blood flow can lead to transient ischemic attacks (TIA), sometimes called “mini-strokes.” Symptoms may include blurred vision, speech difficulty, numbness, or limb weakness.

Severe stenosis may progress to ischemic stroke, causing paralysis, speech impairment, or memory problems.

Endovascular treatments such as angioplasty and stent placement can widen the artery, improve blood circulation, and reduce stroke risk.

Arteriovenous Malformation (AVM) and Arteriovenous Fistula (AVF)

Arteriovenous malformations are abnormal vascular networks where arteries connect directly to veins without normal capillaries. Blood flow through these structures is usually rapid and irregular.

Arteriovenous fistulas represent direct abnormal connections between arteries and veins within the brain, which may cause reversed venous blood flow.

Both AVM and AVF may lead to serious complications such as:

• Intracranial hemorrhage
• Seizures
• Pulsatile tinnitus
• Increased intracranial pressure
• Severe headaches

Many patients remain asymptomatic until complications occur. Endovascular therapy can occlude abnormal vessels through catheter-based techniques to reduce hemorrhage risk.

Carotid Artery Stenosis

Carotid artery stenosis is usually caused by atherosclerosis or arterial dissection. The carotid arteries supply oxygenated blood to the brain, and narrowing of these vessels increases the risk of stroke.

Minimally invasive procedures such as carotid artery stenting can restore blood flow and reduce stroke risk.

Risks and Safety of Neurovascular Interventions

Although neurovascular interventions are generally safe, some risks remain. Possible complications include:

• Brain hemorrhage
• Nerve injury
• Blood vessel damage
• Vessel rupture or occlusion
• Infection

Overall complication risk is estimated to be approximately 3%–6%. Treatment decisions should always be evaluated by experienced neurovascular specialists.