New stent bridges wide-neck aneurysms for embolization
A highly flexible, self-expanding neurovascular stent has been successfully used as a bridge to keep the parent artery open while detachable coils were inserted into a wide-neck aneurysm, according to a German study.
Preliminary results from Dr. Isabel Wanke and colleagues at the University of Essen attest to the safety and efficacy of the Neuroform microdelivery stent system from Boston Scientific, the first FDA-approved neurovascular stent.
"The major advantage of this stent is its self-expanding character, allowing deployment without balloon assistance, and its distinctively characteristic flexibility," said the study, published in the July issue of the American Journal of Neuroradiology.
Researchers treated four consecutive patients presenting with wide-neck intracranial aneurysms with a combined endovascular approach. This involved bridging the aneurysm's opening with the stent, followed by insertion of detachable coils into the aneurysm. Previous attempts with conventional endosaccular coil packing alone failed in all four cases.
Researchers found the technique achieved complete or nearly complete aneurysm occlusion in all patients. An aneurysm perforation with the microcatheter was the only complication. A six-month follow-up showed no neurological damage, except slight memory dysfunction in the patient with complications.
"Even when the stent bridged very tiny vessels, like pontine branches originating from the basilar artery, we did not observe any ischemic event in these vascular supply areas. In all patients, the stent prevented coil herniation into the parent vessel," the authors said.
The stent also contains platinum markers at the distal and proximal ends for sufficient visualization under fluoroscopy. It did not cause any artifacts on MR images and MR angiograms.
Study findings were followed by an FDA announcement in August clearing the Guglielmi Detachable Coils (Boston Scientific) to treat all types of brain aneurysms. Although introduced in 1991, the GDC had not been indicated for wide-neck aneurysms until now.
"In a period of slightly more than a decade, there has been a phenomenal increase in the amount of endovascular procedures performed," said Dr. Joshua A. Hirsch, director of interventional neuroradiology and endovascular neurosurgery at Massachusetts General Hospital.
The International Subarachnoid Aneurysm Trial (Lancet, Oct. 2002), which involved 2143 patients from 43 (mostly European) centers, focused attention on the different options for aneurysm therapy. It made a strong case for endovascular treatments, in terms of both morbidity and mortality, compared with traditional surgical clipping, Hirsch said.
"Coil treatment is therefore likely to assume an even larger role in treating ruptured and unruptured cerebral aneurysms," he said.
But the German researchers said the bridging and coiling treatment option for wide-neck aneurysms should be reserved for patients without other options until additional morbidity data are acquired.
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