(RxWiki News) Time is of the essence when it comes to stroke. While clot-busting drugs work for about half of patients, scientists have had high hopes for mechanical devices designed to break up clots.
Mechanical embolectomy is a novel procedure that uses a tool to go into a blocked artery and remove a blood clot (thrombus).
Compared to standard therapy, the new approach did not enhance overall recovery for stroke patients, according to recent research.
"Get treatment fast at the first sign of stroke."
Reza Jahan, MD, an associate professor of interventional neuroradiology and a member of the UCLA Stroke Center in California, shared the role of principal investigator on this study with Chelsea Kidwell, MD, professor of neurology and director of the Stroke Center at Georgetown University in Washington, DC.
In this 22 center trial, 118 patients with an average age of 65 and one-half years old were treated within eight hours of experiencing an ischemic stroke in one of the large blood vessels carrying blood to the front of the brain.
Ischemic stroke is an interruption of blood flow to the brain caused by a blockage in a blood vessel. Hemorrhagic stroke, on the other hand, is caused by a ruptured blood vessel (aneurysm) or leaky venous malformation (a group of abnormally connected blood vessels).
Ischemic strokes account for 87 percent of all stroke cases, according to the American Heart Association.
To treat the ischemic stroke, tissue plasminogen activator (tPA) is often used, but it must be given within three hours of the onset of stroke symptoms, according to the National Stroke Association. tPA is an enzyme found naturally in the body that helps dissolve a blood clot.
The medication does not always work. When patients fail to respond to tPA (brand name Activase), they may receive standard post-stroke care or be considered for an embolectomy.
Standard post-stroke care includes monitoring blood pressure and ensuring the brain is receiving oxygen
To perform an embolectomy, doctors may use either a MERCI Retriever (a tiny corkscrew-like device developed at UCLA that "grabs" clots) or the Penumbra System (a device that sucks clots out). Both devices work by inserting a catheter through the patient's groin to the blocked brain artery.
Patients in this study were randomly assigned to receive either standard medical treatment or to have their clot removed by embolectomy.
The results showed that the level of disability 90 days after suffering a stroke was no different between those patients who underwent the clot-removal procedure and those who received standard care. Rates of death and bleeding in the brain were also the same.
Investigators also noted that imaging techniques (CT scans and MRI) used to measure the amount of salvageable brain tissue in these patients did not predict which patients might benefit from mechanical clot removal.
"We found no data showing that imaging could help select patients for treatment, nor did we show an overall benefit of performing an intervention to physically remove the clot," said Dr. Jahan.
"So that was disappointing. On the other hand, there are new devices that open up vessels better and faster, and with fewer complications, than the first generation devices used in our trial."
In relation to this study, Dr. Kidwell said, “If you experience signs of stroke, the important thing is to get to a stroke center in time to qualify for the only proven treatment—tPA.”
The study was published in March in The New England Journal of Medicine and was sponsored by the National Institutes of Health.