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The basilar artery is a blood vessel involved in transporting oxygenated blood away from the heart and to the brain. It is located at the base of the brain where two vertebral arteries converge. Along with these vertebral arteries, the basilar artery is part of the system known as the vertibrobasilar system. This system is part of a network of arteries known as the Circle of Willis that supplies blood to the brain. The basilar artery diverges into the left and right posterior cerebral arteries, which are also part of the Circle of Willis.
Blood from the basilar artery mainly supplies the brain stem, cerebellum, and occipital lobes of the brain. The brain stem is responsible for such things as consciousness and attention. Visual acuity and spatial perception are controlled primarily by the occipital lobes. The cerebellum is involved in balance, coordination, and other motor skills.
Lack of sufficient blood to these areas can result in symptoms such as dizziness, vertigo, confusion and visual impairment. Patients may experience these symptoms anywhere from a few minutes at a time to continuously. In the most extreme cases, basilar artery dysfunction can lead to brain damage or even death.
There are two basic modes of basilar artery dysfunction: blockage and bulging. Blockage of the basilar artery may be partial or complete and often results from buildup of plaque in the artery. Such plaque may restrict blood flow either by narrowing the artery or by a piece of the plaque breaking free and causing a blockage downstream. Abnormal bulging of the artery, known as an aneurysm, indicates a weakness in the wall of the artery and a risk of rupture of the artery. An aneurysm may be caused by an acute condition such as physical trauma to the head or by chronic problems such as high blood pressure or birth defects.
Diagnosis of such conditions may be made using minimally invasive or completely noninvasive procedures such as computed tomography angiography (CTA) or magnetic resonance angiography (MRA). In a CTA procedure, a contrasting dye is injected into the patient’s blood vessels, and X-rays taken after the dye has circulated through the area of interest are then analyzed on a computer for abnormalities. MRA procedures may be either minimally invasive or totally noninvasive. Injection of a contrasting dye for an MRA procedure is optional and may or may not be done at the discretion of the health care provider. For an MRA, the area of interest is imaged using a magnetic field rather than radiation.
Doctors can repair the basilar artery through a variety of surgical techniques. They can remove plaque from the artery or make alternative paths to route blood around the blockage. For example, a new blood vessel may be used to circumvent the blockage in a procedure known as bypass grafting. Surgeons can strengthen an aneurysm by surgically wrapping another material around the weakened vessel wall.