Stroke patients who received artery-widening brain stents had higher rates of stroke and death than patients who took only medication and received lifestyle change advice, researchers said.
High-risk patients treated with blood thinners and lifestyle coaching had lower rates of stroke and death than those who received Stryker Corp.’s (NYSE:SYK) Wingspan brain stent in addition to the medication and guidance, but researchers aren’t ready to give up on the technology just yet.
"Stroke specialists are all disappointed that stenting did not have the beneficial impact we thought it would have," principal investigator at the University Hospital Case Medical Center arm Dr. Cathy Sila said in a press release. "The group that received aggressive medical therapy alone did far better than predicted with a 30 day stroke and death rate of only 5.8 percent. However, the group that received a stent as well as aggressive medical therapy did worse than predicted with a rate of 14.7 percent."
After one year, the stroke and death rate rose to 12.2 percent for the non-stented group and 20 percent for the patients who received the device, according to a new study published in the online edition of the New England Journal of Medicine.
The study looked at patients with narrowed arteries in the brain who had suffered a stroke and were at high risk for another stroke based on the location and severity of the plaque in the arteries. The stent implantation procedure may have dislodged some plaque from the original brain site and set it loose to block other narrower arteries, researchers suggested.
Trial enrollment was cut off early when a high adverse effect proportion was found early on. The study was designed for up to 764 patients, but recruitment was halted when the Data Safety Monitoring Board determined there was enough evidence for a conclusive finding after 451 patients.
Stryker is currently the only company with the FDA’s okay to sell a brain stent for certain high-risk patients in the U.S., having acquired it as part of a $1.5 billion cash buyout of Boston Scientific Corp.’s (NYSE:BSX) neurovascular business in October of last year. Wingspan won FDA clearance through a humanitarian device exemption along with the Gateway balloon catheter for patients who didn’t respond to drug treatment in 2005, and thousands of patients have received the stent so far.
Similar stenting systems not currently cleared by the FDA are also used in clinical practice, researchers said, but those devices weren’t evaluated in the study.
"Stryker continues to support the Wingspan stent system and Gateway PTA balloon catheter as an FDA approved Humanitarian Use Device for improving cerebral artery lumen diameter in patients with intracranial atherosclerotic disease who have failed medical therapy," the company said in a statement sent to MassDevice.
Stryker also noted that the new study, funded by the National Institutes of Health and conducted at three U.S. sites, targeted patients earlier in the usual treatment cycle and used a more aggressive drug regimen than used in standard practice today. Researchers at Cedars-Sinai Medical Center in Los Angeles also pointed out that most patients in the study had blockages in smaller arteries and that the patients weren’t as sick as those considered in Wingspan’s original studies and thus didn’t fit the population considered most likely to benefit from stenting.
The original study was conducted on 45 patients and did not include a control group of non-stented patients for comparison, finding a 4.4 percent stroke rate after 30 days, the New York Times reported.
"Angioplasty and stenting procedures have become commonplace in treating blocked heart arteries, but stenting in the brain is more challenging because brain arteries are more delicate than those of the heart," Cedars-Sinai director Dr. Michael Alexander, a member of the initial NIH steering committee for the study and a consultant and device proctor for Stryker Neurovascular, said in prepared remarks. "For certain patients – particularly those for whom drugs are not effective – most experts believe stenting is a viable option. We have had many patients who have had dramatic, immediate improvement in neurologic function following intracranial stenting."
"We have always known that it is much more difficult to stent a blockage in the brain than in the heart but we cannot abandon this technology," Sila said. "We need to better understand the tolerances of the brain vasculature and continue to reengineer our tools."