American Stroke Association meeting report
SAN DIEGO, Feb. 5 – Angioplasty opened narrowed brain arteries, preventing strokes in patients for whom standard medication had failed, according to a study presented today at the American Stroke Association's 29th International Stroke Conference.
"Angioplasty improves the outcome over what we would expect to see with medication alone," said study author Michael P. Marks, M.D., associate professor of radiology and neurosurgery and chief of interventional neuroradiology at Stanford University Medical Center in Palo Alto, Calif. Additionally, "Stent treatment may not be necessary."
The study was not a head-to-head comparison of angioplasty and medical therapy. Researchers used data from other studies to make risk comparisons.
Angioplasty uses a tiny balloon threaded into the area of blockage. Once in this area, the balloon is inflated. As it expands, it forces the fatty plaque against the artery wall, opening the vessel. Balloon angioplasty is widely used to open blocked heart arteries but is not as commonly used for clearing neck and brain arteries. In some cases, a miniature wire tube called a stent is left behind after angioplasty to keep the artery propped open.
Blood thinners such as aspirin and anticoagulants such as warfarin are standard medical therapy for clogged brain vessels. Anticoagulants interfere with the blood's ability to clot.
The study examined both the overall rate of stroke and the rate of stroke in areas supplied by the treated vessel in patients with symptomatic intracranial stenosis (narrowing of a brain blood vessel) undergoing angioplasty.
Researchers studied 36 patients with significant intracranial stenosis, all of whom had unsuccessful medical therapy. Before angioplasty stenosis averaged 84.2 percent. After angioplasty, stenosis averaged 43.3 percent.
One ischemic stroke occurred during angioplasty but the patient recovered. No other ischemic strokes occurred within one month of angioplasty, the periprocedural period.
Two deaths occurred in the periprocedural period, one due to reperfusion hemorrhage and one due to vessel perforation. Follow-up was available in 34 patients and varied between four and 128 months (average follow-up 53 months) with 29 patients (or 85.3 percent) having greater than 24 months follow-up. The annual stroke rate in the area of the angioplasty was 3.36 percent. The annual rate for all strokes was 5.38 percent.
"One would expect 8 percent to 10 percent of these patients to have suffered a stroke in the territory of angioplasty annually had they been treated with medication," Marks said.
The researchers then looked at the subgroup of patients at high risk of stroke after angioplasty, which "has been used as an argument to use stents," he said. High-risk patients include those who still have significant vessel narrowing (residual stenosis) after angioplasty and those in whom the angioplasty caused a small tear, or dissection, in the vessel.
For patients with residual stenoses, some argue that the stent will open the vessel wider, Marks said. Some also believe stenting can help repair tears.
The subgroup of 18 patients with moderate but significant residual stenosis (50 percent to 75 percent) had an annual stroke rate of 3 percent – just as low as when there was no residual stenosis, Marks said. "So by opening the vessel even a small amount, we had a favorable effect on clinical outcome."
There does not appear to be any advantage to adding a stent to help prop the artery open after angioplasty for patients with symptomatic intracranial stenosis compared to angioplasty alone, he said.
Also, none of the 11 patients with evidence of a tear in their vessel after angioplasty had a stroke at follow-up. "The tear heals itself. Stenting is not necessary for these patients either," he said.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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