Clot Retrieval Devices for Stroke Patients
The U.S. Food and Drug Administration today allowed marketing of two Trevo clot retrieval devices as an initial therapy for strokes due to blood clots (ischemic) to reduce paralysis, speech difficulties and other stroke disabilities. These devices should be used within six hours of symptom onset and only following treatment with a clot-dissolving drug (tissue plasminogen activator or t-PA), which needs to be given within three hours of symptom onset.
"This is the first time FDA has allowed the use of these devices alongside t-PA, which has the potential to help further reduce the devastating disabilities associated with strokes compared to the use of t-PA alone," said Carlos Peña, Ph.D., director of the division of neurological and physical medicine devices at the FDA's Center for Devices and Radiological Health. "Now health care providers and their patients have another tool for treating stroke and potentially preventing long-term disability."
The Trevo device was first cleared by the FDA in 2012 to remove a blood clot and restore blood flow in stroke patients who could not receive t-PA or for those patients who did not respond to t-PA therapy. Today's action expands the devices' indication to a broader group of patients.
Trevo is a clot removal device that is inserted through a catheter up into the blood vessel to the site of the blood clot. When the shaped section at the end of the device is fully expanded (up to three to six millimeters in diameter), it grips the clot, allowing the physician to retrieve the clot by pulling it back through the blood vessel along with the device for removal through a catheter or sheath.
Stroke kills nearly 130,000 Americans each year and is the fifth leading cause of death, according to the Centers for Disease Control and Prevention. About 87 percent of all strokes are ischemic strokes. Until now, the only first-line treatment for acute ischemic stroke was t-PA administered intravenously.
The FDA evaluated data from a clinical trial comparing 96 randomly selected patients treated with the Trevo device along with t-PA and medical management of blood pressure and disability symptoms with 249 patients who had only t-PA and medical management. Twenty-nine percent of patients treated with the Trevo device were functionally independent (ranging from no symptoms to slight disability) three months after their stroke, compared to 19 percent of patients who were not treated with the Trevo device.
Risks associated with using the Trevo device include a failure to retrieve the blood clot, device malfunctions including breakage and navigation difficulties, which can potentially damage blood vessels and cause perforation or hemorrhage.
The FDA reviewed the data for Trevo for stroke treatment through the de novo premarket review pathway, a regulatory pathway for devices of a new type with low-to-moderate-risk that are not substantially equivalent to an already legally-marketed device and for which special controls can be developed, in addition to general controls, to provide a reasonable assurance of safety and effectiveness of the devices.
SOURCE: FDA, September 2, 2016