Clot-Buster Ultrasound Device May Become Best Treatment Option for Stroke Patients

The new technology fits on the head similar to a halo and delivers therapy to rapidly bust clots that cause stroke.

The device was developed by William Culp, MD, professor of radiology, surgery and neurology and vice chairman of research at the University of Arkansas for Medical Sciences (UAMS; Little Rock, USA), and Dr. Doug Wilson, assistant director at the Graduate Institute of Technology at UALR. One feature of Dr. Culp’s research included using ultrasound scanning in combination with the clot-busting drug tissue plasminogen activator (t-PA).

While studying the treatment to dissolve clots in blood vessels, Dr. Culp realized one problem is getting the ultrasound to operate through the skull. Ultrasound can be delivered anywhere in a patient’s body unless the waves hit something hard similar to bone or something very soft, similar to air. “We realized we had trouble delivering ultrasound to the vessels at the base of the brain,” Dr. Culp stated. “The skull stopped the ultrasounds.”

Dr. Culp collaborated with Dr. Wilson to devise strategies about how to get the ultrasound waves to reach the clot in stroke patients. “This is a great example of how faculty at both schools can partner to develop new technologies. The success of this research will foster ties between the two campuses,” Dr. Wilson said. “It makes me extremely proud to have contributed to a product with potential to help many people,” he said.

Dr. Culp received a grant from UAMS that provided him with the materials he needed to experiment. Wilson and Culp completed their first patent for “ultrasound for augmented clot lysis” in 2005. The patent was licensed in 2006 and has been in development by Cerevast Therapeutics (Redmond, WA, USA).

The ClotBust ER has 16 transducers distributed around the inside—designed to line up with the thin points in the skull: the temples and the foramen magnum in the base of the skull. This allows the ultrasound waves to move through the brain without interruption. After the patient is administered an intravenous (IV) solution containing t-PA, the circular device is positioned onto the patient’s head like a sports visor or halo. “The idea is to deliver ultrasound wherever the clot is and where the IV t-PA is working,” Dr. Culp said. “It makes t-PA work better—improving the clot-busting drug by 40% or 50%. It’s like taking a cooking pot and stirring it. The ultrasound stirs the drug around, making it work better.” The clot disappears more rapidly. “If we resupply blood, we resupply oxygen. The brain recovers quicker. Quicker is, of course, better,” Dr. Culp said.

Now in a phase three human trial, the ClotBust ER has been tested in more than 300 patients. None of the results have come back with substantial adverse effects. Since the trial periods began, 66 other university sites have signed up to be included in the testing. The device will also soon be available at some sites of the statewide stroke network called AR SAVES while it is in trial.

“Our goal is to test 840 patients,” Dr. Culp said. “But right now, the results are looking so promising that it is possible testing could be stopped early if the safety committee determines we don’t have to go any further.” He is hopeful the device will be approved by the start of 2016. “We’re here to find a cure,” Dr. Culp said. “This device is just one part of many things. We mustn’t forget prevention.”

Dr. Culp noted that there has been a significant decrease in strokes in the United States and in Arkansas during the past 20 years. This is especially good news for the state Arkansas, which ranks highest in the United States for rate of stroke deaths. Dr. Culp believes Americans generally now have a better awareness of the disease. “But for those 800,000 people who will have a stroke in the United States every year, we still have to have good therapy,” Dr. Culp concluded. “This device may well be the next step.”

Related Links:
University of Arkansas for Medical Sciences
Cerevast Therapeutics