The cerebrovascular accident (CVA, more commonly called ‘stroke’) is the third largest cause of death, killing over 150,000 people every year, and a major cause of long-term disability.
A stroke is caused by a broken or blocked blood vessel in the brain. This interruption of the blood supply to parts of the brain starves cells of oxygen, causing them to die. The symptoms of stroke are a result of this cell death; common symptoms include aphasia (the inability to speak) and hemiplegia (paralysis on the right side of the body), which occur because most people suffer a stroke in the left hemisphere of the brain, which contains the speech centres and controls the muscles on the opposite side of the body (contralateral control).
Certain factors, such as hypertension and diabetes, increase the risk of a stroke, and transient ischaemic attacks (TRAs, or ‘mini-strokes’, in which there is a temporary constriction of blood vessels in the brain) indicate that a more serious cerebrovascular accident may be imminent.
Recently developed minimally invasive (endovascular) stroke treatments could soon revolutionize the way surgeons treat stroke, and also help them reduce the likelihood of high-risk patients suffering strokes. This is already being achieved without surgeons ever having to open the patient’s skull.
A major advantage of minimally invasive techniques is that they can be used to treat patients for whom surgery would be too traumatic or risky.
One of these new treatments is intracranial stent angioplasty, in which a device called a Wingspan intracranial stent (left) is used to open up clogged blood vessels in the brain.
The device, manufactured by Boston Scientific, consists of a tiny wire mesh tube. A ballon catheter is first inserted through an incision in the leg and threaded up through blood vessels in the chest and neck to the damaged vessel in the brain. This is used to dilate the blocked vessel. The stent is then inserted into the damaged vessel in the same way and left there to keep it dilated, so that blood flow to that part of the brain is restored.
The treatment cannot, of course, reverse any damage already caused by a stroke, but quick treatment could minimize any further damage that would be caused by continued interruption of blood flow.
Doctors at the University of Michigan Health System are among the first in the world to use the Wingspan stent to treat stroke patients. They use the technique on up to 30% of patients who have suffered cerebrovascular accidents.