Vascular neurology is concerned with the blood vessels that supply the brain and nervous system. The brain is critically dependent on blood flow and can incur damage within minutes of that flow being interrupted. Atherosclerosis, or “hardening of the arteries,” can narrow blood vessels that lead to the brain or are in the brain, causing transient ischemic attacks (TIAs or “mini-strokes”), and ischemic (blocked blood vessel) stroke itself. Hemorrhagic stroke, or bleeding in the brain, can be caused by weakened blood vessels that swell like a bubble in response to blood flow (aneurysm). In recent decades, much progress has been made in treating these disorders with minimally invasive techniques.
The most familiar cerebrovascular procedure is the carotid endarterectomy, in which excess plaque, a mixture of cholesterol, fat, and calcium, is removed from the inside of the carotid artery. The carotid arteries, one on each side of the neck, carry oxygenated blood to the brain, and are a frequent site of plaque build-up. An endarterectomy can be an open procedure, in which the carotid is surgically removed and replaced with a blood vessel graft, or is repaired with sutures. The plaque can also be removed with a surgical device called a curette, essentially a small scraping tool.
Carotid angioplasty and stenting uses a deflated balloon that is inflated when it reaches the blockage in the artery, leaving in place a stent, or mesh tube, that compresses the plaque and enlarges the blood vessel opening (lumen). Both carotid endarterectomy and angioplasty/stenting can be done by threading a wire through a major artery, such as the femoral artery in the upper thigh.
Cerebral aneurysms can be treated by clipping either side of the ballooned vessel, usually through an open surgery called a craniotomy. A minimally invasive approach called coiling, or coil embolization, can be used in selected aneurysm patients. This procedure entails placing a tiny coil in the ballooned portion of the vessel. The vessel closes around the coil, preventing rupture and bleeding of the aneurysm. As in carotid angioplasty, the coil is typically delivered through a major artery.
Cerebrovascular procedures similar to those used to treat carotid blockage and aneurysm can also be used to treat arteriovenous malformations (AVMs), where the blood vessels appear to be a tangle of wires, or a “bag of worms.” AVMs have a risk of rupturing and causing bleeding into the brain. They can be treated angiographically, using x-rays to monitor the placement of “occlusives” or biological glues to fill the AVM and close it off from the vessels around it; like carotid angioplasty, the filler substance is delivered through an artery. AVMs, when located in an appropriate site, can also be treated with [stereotactic radiosurgery. Some AVMs are treated with the use of microsurgery, which requires a craniotomy (opening of the skull), and a microscope for the visualization of individual blood vessels.