Chuck Bednar for redOrbit.com – @BednarChuck
Patients who are treated with a new clot-removal device after suffering an acute ischemic stroke have significantly reduced disability levels after the event, according to new research led by Dr. Jeffery Saver of the UCLA Stroke Center and the David Geffen School of Medicine.
Dr. Saver, a professor of neurology at the California-based university, and his colleagues report in Friday’s edition of the New England Journal of Medicine that combining use of a clot-busting drug with that of a stent retriever device significantly increased the number of patients who were capable of independent daily function after three months.
Ushering in a “new era” of stroke care
According to the study authors, the findings represent the first new treatment of acute ischemic strokes since the development of the clot-busting drug tissue plasminogen activator (tPA) some 20 years ago, and could lead to a new era in the care of a condition characterized by the sudden loss of blood circulation to a part of the brain caused by the blockage of a blood vessel.
“These findings are a paradigm shift, a new era in stroke care and we are ecstatic. We will be able to treat many more patients, who will have much better outcomes,” Dr. Saver explained in an emailed statement Thursday. “This is a once-in-a-generation advance in acute stroke care.”
“While these findings won’t help all stroke patients, it will help those who have the most disabling strokes,” added Dr. Sidney Starkman, co-director of the UCLA Stroke Center and a professor of emergency medicine and neurology at the university. “Right now, they get tPA and it helps a third of them, but the other two thirds end up disabled or don’t survive the stroke.”
Trial shows effectiveness of clot-removal device
The research was conducted at 39 hospitals throughout the US, Canada and Europe and involved 196 patients, though it was originally scheduled to involve 833 before being halted early due to the early positive results, according to Dr. Saver. The study was examining a second-generation stent clot retrieval device known as Solitaire, which is manufactured by Medtronic.
Dr. Saver said that the first-generation devices had been tested previously and showed no benefit over medical therapy alone, which he called disappointing. The new device was used on patients within six hours of the first symptoms, and participants were divided into two groups of 98, each randomly receiving either tPA alone or tPA with stent retrieval of the clot.
Three months after experiencing their strokes, 60 percent of the patients that received tPA along with clot retrieval were said to be functionally independent and free from disability, compared to just 35 percent of the patients receiving only tPA. While tPA is effective, it only reopens blood vessels approximately 30 percent of the time, Dr. Saver said, while the stent retriever device used in the trial was able to open the arteries 88 percent of the time.
Preclinical research used to help develop the Solitaire device was performed at the university by UCLA radiology professor Dr. Reza Jahan, who explained in a statement that the device was able to reopen the arteries far more frequently than tPA, and with less injury to the blood vessel, less bleeding and less difficulty engaging and entangling clots.
Attempting to improve upon tPA’s success rate
To put the significance of this finding into perspective, Dr. Starkman described what it was like to be an emergency physician and a neurologist (one of the few doctors to be trained and board-certified in both specialties) two decades ago and having to treat a person with stroke symptoms.
“Despite stroke being labeled a neurological emergency, there was essentially nothing that could be done to help the patient other than supportive care,” he explained to redOrbit via email. “A severe stroke patient would typically be admitted to the hospital then eventually die or be discharged disabled for the remaining years. Then, because of the new understanding of the biology of stroke… the very first therapy for stroke was approved by the FDA.”
That therapy was tPA, a clot-buster drug that had been approved to treat heart attacks 10 years before hand. The belief was that, since most ischemic strokes were caused by a blood clot that suddenly occluded a cerebral blood vessel resulting in stroke symptoms, administering this drug within three hours would improve a patient’s opportunity for recovery.
“However, tPA was not a cure-all, it was not perfect,” Dr. Starkman said, noting that when a clot could be visualized using neuroimaging, the blood vessel would only be open one-third of the time after tPA had been administered intravenously. Two-third of the time, he explained, the tPA did “nothing… the blood vessel did not open before there was irreversible brain injury caused by the offending blood clot, and the patient was not helped.”
The invention and evolution of clot-removing devices
He and his colleagues continued to be frustrated with the lack of progress until one of the team member “invented a device which specifically was navigated from the groin artery to the blocked blood vessel, engaged the clot with a corkscrew coil, and retrieved the clot from the brain and out of the body,” Dr. Starkman told redOrbit.
The instrument, the MERCI (mechanical embolus retrieval in cerebral ischemia) device, was the first device approved by the FDA for ischemic stroke, which happened 15 years ago. However, it too was imperfect – patients in which the clot was retrieved in time were saved, but other died or were disabled for the remainder of their life. A more sophisticated device was needed.
“The stent devices were developed for opening coronary blood vessels in patients who were having a heart attack,” the UCLA research explained. “When stents were placed into clots in the brain blood vessels, it was clearly determined that the architecture of the stents permitted the clot to be readily engaged. Thus the stent was seen to be far superior to all other prior devices and means utilized for opening the cerebral blood vessels.”
Fighting for a “paradigm shift” in stroke care
The success of the new Solitaire device is clearly something that Dr. Starkman and his UCLA colleagues are very passionate about. He explains that the stent retriever had been used at the university’s facilities for more than a decade, and that he hopes that there will be a “paradigm shift” that seems them available at stroke centers all over the country.
“It was unequivocally demonstrated that the device resulted in a far better recovery for the stroke patients who received the device compared with those who were randomized for the purpose of the study to not receive the device,” the professor told redOrbit.
“This subject has become very important to me and to us at UCLA,” he added. “It’s exhilarating when all’s in place, all goes smoothly, the clot is retrieved, and the patient is immediately ‘on the table” made normal, [saved] from the hands of death or disability. It’s a Lazarus effect. We look forward to have many more care providers and patients have such an experience.”
—–
Follow redOrbit on Twitter, Facebook, Google+, Instagram and Pinterest.
Comments