UAMS/UALR-Developed Clot Buster Device Helps in Stroke Treatment

By Holland Doran


Wilson demonstrates how to apply the clot-busting device invented by Culp.

LITTLE ROCK — A patent awarded to the University of Arkansas for Medical Sciences (UAMS) could soon help lead to a new treatment for ischemic stroke.

The ClotBust ER® fits on the head like a halo and delivers ultrasound energy to the brain to help break up clots that cause ischemic strokes.

The inventors on the patent are William Culp, M.D., professor of radiology, surgery and neurology and vice chairman of research at UAMS, and Doug Wilson, assistant director at the Graduate Institute of Technology at the University of Arkansas at Little Rock  (UALR).

Culp has spent many years studying therapy for stroke. One element of Culp’s work included using ultrasound (high-frequency sound waves) in combination with the clot-busting drug tissue plasminogen activator (t-PA).

While looking into the treatment to dissolve clots in blood vessels, 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 like bone or something very soft, like air.

“We realized we had trouble delivering ultrasound to the vessels at the base of the brain,” Culp said. “The skull stopped the ultrasound.”

He teamed with Wilson to brainstorm ideas 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 advance new technologies. The success of this research will foster ties between the two campuses,” Wilson said. “It makes me extremely proud to have contributed to a product with potential to help many people.”

Culp received an $8,000 grant from UAMS that provided him with the materials he needed to conduct initial experiments. 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.  

The ClotBust ER® has 16 transducers located on the inside of the headframe – designed to line up with the thin points in the skull— the temples and the foramen magnum in the base of the skull — thus allowing the ultrasound waves to pass through the skull bone. After the patient is administered an IV containing t-PA, the circular device is placed 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,” Culp said. “Results from prior clinical studies, have suggested that ultrasound may help promote the breakdown of clots. It’s like taking a cooking pot and stirring it. We believe that the ultrasound creates a gentle stirring effect in the region of the clot. If we resupply blood, we resupply oxygen. The brain recovers quicker. Quicker is, of course, better.”

Now in a Phase 3 human trial, the ClotBust ER® has been tested in more than 400 patients. Since the trial began, more than 60 other university sites have signed up to be included in the study. The device will also soon be available at some sites of the statewide Arkansas stroke network called AR SAVES while it is in trial.  The trial is designed to enroll up to 830 patients.

If the Phase 3 trial is successful, Culp is hopeful the device will eventually be approved as a new treatment for patients that suffer an ischemic stroke.

“We’re here to find a cure,” Culp said. “This device is just one part of many things. We mustn’t forget prevention.”

Culp says there has been a significant decrease in strokes nationally and in Arkansas during the past 20 years. This is particularly good news for Arkansas, which ranks highest in the nation for rate of stroke deaths. Culp believes Americans as a whole 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,” Culp said. “This device may well be the next step.”

UAMS is the state’s only comprehensive academic health center, with colleges of Medicine, Nursing, Pharmacy, Health Professions and Public Health; a graduate school; a hospital; a statewide network of regional centers; and seven institutes: the Winthrop P. Rockefeller Cancer Institute, the Jackson T. Stephens Spine & Neurosciences Institute, the Myeloma Institute, the Harvey & Bernice Jones Eye Institute, the Psychiatric Research Institute, the Donald W. Reynolds Institute on Aging and the Translational Research Institute. It is the only adult Level 1 trauma center in the state. UAMS has 2,890 students and 782 medical residents. It is the state’s largest public employer with more than 10,000 employees, including about 1,000 physicians and other professionals who provide care to patients at UAMS, Arkansas Children’s Hospital, the VA Medical Center and UAMS regional centers throughout the state. Visit www.uams.edu or uamshealth.com.