Among the emerging stroke treatment trends presented last week at the American Stroke Association's (Dallas) International Stroke Conference in San Antonio, Texas, was a relatively new approach for hemorrhagic stroke which combines clot-busting drugs with ultrasound waves to drain bleeding in the brain.

Up to 40% of people who experience a hemorrhagic stroke die within a month. Survivors are often left severely disabled.

David Newell, co-executive director, Swedish Neuroscience Institute (SNI; Seattle) presented a small study known as SLEUTH (Safety of Lysis with Ultrasound in the Treatment of Intracerebral [ICH] and Intraventricular Hemorrhage [IVH]) in which tissue plasminogen activator (rt-PA) was delivered through an ultrasound microcatheter directly into spontaneous IVH or ICH to facilitate evacuation of the hemorrhage with the aid of ultrasonic waves.

“If you Google sonophoresis [using ultrasound to increase drug absorption] there are two decades of research,“ Robert Hubert, president/CEO of Ekos (Bothell, Washington), the company behind the study and ultrasonic accelerated thrombolysis technology, told Medical Device Daily. “The science is extremely well vetted. Clots are made of fiber and strands; a tightly woven substance. When you apply rt-PA it has to go to a receptor. Ultrasound opens up the clot and thins out the fiber and strands and makes it porous so when the drug hits the clot you have more surface area. Ideally if you can get the drug to all receptor sites immediately, you can dissolve the clot.“

Newell reported that 35 patients presented at SNI with ICH and IVH who were screened between November 2008 and July 2009 for entry into the study. Entry criteria included the spontaneous onset of ICH and/or IVH producing ventricular obstruction. Nine of the patients who met the entry criteria were entered into the trial.

A ventricular drainage catheter and an ultrasound microcatheter were stereotactically delivered together, directly into the IVH or ICH. rt-PA and 24 hours of continuous ultrasound were delivered and gravity drainage was performed. In patients with IVH a total of 3 mg of rt-PA was injected, and in patients with intraparenchymal hemorrhages a total of 0.9 mg rt-PA was injected, in three doses over 24 hours.

All of the patients had significant volume reductions of the treated hemorrhage. The mean percentage volume reduction after 24 hours of treatment, compared to the pre-treatment stability scans, as determined by CT, were 59% for ICH and 45% for IVH. One ICH patient was excluded from analysis due to catheter breakage.

There were no intracranial infections and there were no significant episodes of re-bleeding by clinical or CT assessment. One patient died within 30 days after admission.

“The data are pretty compelling,“ Hubert said. “I would suggest that we move further with this as a result. We will now develop a device specific to hemorrhagic stroke. Today there is no good therapy for hemorrhagic stroke. When you contrast it to ischemic stroke, the patient needs to be treated within six to eight hours. With hemorrhagic, it's the pressure from bleeding that does the damage and data show you can delay therapy up to 72 hours, so patients have a lot more time to get to the hospital for treatment.“

In a more remarkable case that was part of the study, and a best result, a police officer, age 38, was enrolled at 71 hours post stroke.

“A couple of weeks later, he walked out of the hospital and is now back on the job,“ Hubert said. “It's very encouraging. It's a small study and now there needs to be a larger study. This could be a major paradigm shift in how we treat stroke. The technology and the science are well grounded. Nobody disputes that ultrasound has a positive effect.“

Ekos developed the same technology it uses for peripheral vascular disease for stroke.

“We took the ischemic catheter and used it for hemorrhagic using image guidance and then delivered rt-PA,“ Hubert said. “But it's not ready for prime time or the average surgeon. We will likely start development [of the final product] in a month and in 18 months we'll have a product. We may have a couple of iterations come out to start some trials sooner.“

The company's technology is already being used successfully in peripheral vasculature with more than 16,000 devices sold.