Medical device maker Covidien (NYSE:COV) touted 2-year study results demonstrating the safety and efficacy of its Solitaire FR revascularization system, combating another recently published study that questioned whether devices like Solitaire in provide long-term benefits to stroke patients.
The Solitaire FR device helps restore blood flow to the brain by removing blood clots that hinder circulation. Stroke patients with blood clots can suffer brain damage or even death if the brain is deprived of proper blood flow for too long.
Covidien’s study demonstrated that the Solitaire FR was successful in reopening blocked blood vessels with low rates of adverse events or patient deaths, but a government-funded study questioned whether manual blood clot removal was ultimately better for patients than treatment with drugs alone.
The current standard of care for stoke patients involves treatment with clot-busting drugs that help dissolve blood clots over time. In a study funded by the National Institutes of Health and the National Institute of Neurological Disorders & Stroke found that patients who underwent manual clot removal, or thrombectomy, didn’t see much improvement in overall outcomes when compared with patients who only received a clot-busting drug, IV t-PA, an intravenous tissue plasminogen activator.
Manual thrombectomy was 40% more likely to get rid of blood clots, according to the NIH/NINDS trial, the only study of its kind to directly balance the risks and benefits of adding medical device intervention to acute stroke treatment. However, the reopening of the blocked artery didn’t improve patients’ disability due to stroke when compared with patients who only received drugs to dissolve the clots, according to the report.
"This is the largest trial of an intra-arterial intervention for acute ischemic stroke, and is important because it shows that the addition of devices to treat clots within the brain artery was no more effective than treatment with IV t-PA alone," NINDS deputy director Dr. Walter Koroshetz said in prepared remarks. "Such devices are already widely used in clinical practice based on dramatic improvements seen in individuals, but without evidence supporting their overall clinical effectiveness in a large group."
The researchers ceded that their study, unlike pilot more successful studies that came before, featured an important difference in patient treatment – a delay. Patients on average waited about 32 minutes longer between initial drug therapy and manual clot removal than patients in previous trials.
"We probably did not open the arteries quickly enough," lead researcher Dr. Joseph Broderick said in prepared remarks. The report noted, however, that real-world patient treatment is rife with delays.
"Most patients do not have immediate access to the level of care required to perform intra-arterial procedures," according to a press release. "Instead, they are often treated with IV t-PA at a local hospital then transferred to another hospital, all of which further delays the time to treatment."
Covidien researchers were quick to respond to the study results with results of their own from a 2-year follow-up of patients who received treatment with the Solitaire FR revascularization system in the Solitaire FR Thrombectomy for Acute Revascularization (STAR) study.
More than 84% of the 190 patients with complete data sets achieved the highest levels of recanalization, a measure of the openness of the blood vessel. Nearly 60% of patients reported functional independence 90 days after treatment, indicating little to no disability, according to the Covidien press release.
The company brought on an independent Core Lab to assess patient outcomes and and independent Clinical Events Committee to assess adverse events. The committee reported a 6.9% mortality rate and a 1.5% symptomatic intracranial hemorrhage rate.
"In the wake of the failed IMS III Study, a NINDS-funded randomized controlled trial, there will be some physicians who will question the benefit of mechanical thrombectomy," principal STAR investigator Dr. Vitor Mendes Pereira said in prepared remarks. "The results of the STAR prospective, multi-center clinical study demonstrate that mechanical thrombectomy is both safe and effective for the treatment of acute ischemic stroke when treating the right patients, in comprehensive stroke centers, with the Solitaire FR device."
