New Study Finds Minimally Invasive Aneurysm Treatment Produces Better Outcomes

Compelling Results Prompt Discussion of Best Treatment Protocols

December 16, 2002

Results from a recent study that compared brain surgery to a less-invasive endovascular procedure may dramatically change the way brain aneurysms are treated in the future. Recently published in the peer-reviewed medical journal The Lancet, the International Subarachnoid Aneurysm Trial (ISAT) demonstrated that the less-invasive endovascular treatment using detachable platinum coils produces better outcomes for patients suffering from ruptured brain aneurysms than neurosurgical clipping, the standard treatment for treatment of brain aneurysms.

The study showed that the risk of death or significant disability at one year for patients treated endovascularly with coils was 22.6 percent lower than for those treated neurosurgically with clipping. Results from interim analysis of the data was so compelling that the trial was halted early after enrolling 2,143 of the planned 2,500 patients. The Trial Steering Committee determined it was no longer ethical to randomize patients to neurosurgical clipping.

Health care analysts suggest that as many as 75 percent of patients with brain aneurysms in the United States are currently treated by neurosurgical clipping, which involves removing a section of the skull and placing a surgical clip at the neck of the aneurysm. Endovascular treatment, which was introduced in the early 1990s, involves insertion of a catheter into the femoral artery in the patient’s leg and navigating it through the vascular system under X-ray guidance, into the head and into the aneurysm. Tiny platinum coils are then threaded through the catheter and into the aneurysm, obstructing blood flow into the aneurysm and preventing further damage.

Henry Wang, M.D., associate professor of radiology at the University of Rochester Medical Center, and the only Rochester-area neuroradiologist trained to perform the endovascular coiling method, has performed approximately 50 procedures at Strong Memorial Hospital. Wang said that the ISAT study confirms the positive results he has had here.

“The endovascular coiling procedure offers tremendous benefits to our patients,” Wang said. “The coils are like miniature slinkies that are folded gently into the aneurysm one by one to stop the bleeding. With coiling we can prevent an aneurysm from rupturing.”

Wang cautioned that not all patients with aneurysms are candidates for the procedure, noting that the size, location and status of the aneurysm are all taken into account when recommending a treatment protocol.

 “A team of neurosurgeons and neuroradiologists work together to determine if a patient is a candidate for the coiling procedure,” Wang said. “For patients suitable for both treatments, we do encourage the endovascular coiling procedure because it is so much less invasive and gets the patient home much sooner—with the same or better results than clipping.”

Deadly Stroke

When a brain aneurysm ruptures, blood flows into the space surrounding the brain, resulting in a subarachnoid hemorrhage, the deadliest form of stroke. In the United States, it is estimated that as many as 18 million people will develop a brain aneurysm during their lifetime, and that every year approximately 30,000 people suffer from ruptured brain aneurysms. Ten to 15 percent of these patients will die before reaching the hospital. More than 50 percent will die within the first 30 days after rupture. Of those who survive, approximately half suffer some permanent neurological deficit.

Funded by the Medical Research Council of Great Britain in 1997, ISAT systematically compared endovascular coiling to neurosurgical clipping. Forty-three neurosurgical centers in Europe, North America and Australia participated, enrolling patients who were deemed suitable for either treatment. The study’s primary objective was to determine whether endovascular coiling reduces the number of patients with poor outcomes compared to neurosurgical clipping.

Following a planned interim review by the Data Monitoring Committee, the Trial Steering Committee halted the trial on May 2 because the difference in outcomes between the two procedures was so great that it was no longer deemed ethical to randomize patients to neurosurgical clipping.

While the Lancet article on ISAT reflects survival and disability data, additional data on cost effectiveness, quality of life, angiographic findings and rebleed rates are still being collected and analyzed for release in 2003. In order to continue evaluating the long-term follow-up data, the Medical Research Council of Great Britain has granted funding for ISAT through 2007.

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