Laser Therapy and the Stroke Window
MADISON - Sometime in the next few weeks, an ischemic stroke patient at UW Hospital will be enrolled in a new clinical trial. The patient’s head will be shaved and a special cap precisely fitted on it. Both the patient and the treating neurologist will put on laser-safety glasses. Then the neurologist will pick up a handpiece equipped with an optical lens, and direct invisible laser beams, through openings in the cap, directly into the patient’s brain.
The NEST-2 Trial, in which near-infrared energy is delivered directly to brain tissue, is designed to test the safety and efficacy of the NeuroThera system, under development for 10 years by a California biomedical company.
Justin A. Sattin, MD,
a UW Health stroke neurologist, is principal investigator of the study at UW. The international study aims to enroll 660 patients.
The Food and Drug Administration approved the trial based on the results of NEST-1, the initial randomized trial of 120 patients. NEST- 1’s results, published in Stroke online in April 2007, showed that significantly more patients in the active treatment group versus controls had successful neurological outcomes at 90 days post-stroke, as assessed by several measures.
UW Health neurologists are particularly enthusiastic about the system’s potential to expand the treatment window for ischemic stroke. Intravenous tPA - the only FDA-approved treatment for ischemic stroke - must be given within three hours of symptom onset. While UW Hospital offers sophisticated endovascular treatments that can be effective within somewhat longer time windows, the hope is that the NeuroThera system could prove effective up to 24 hours after symptoms appear.
“Failure to arrive at the hospital within the current time window is a major factor in the difficulty we face in reducing brain damage from stroke,” says Sattin. “If the trial proves this approach effective, it would be a tremendous addition to our arsenal.”
Another potential advantage of the laser therapy is fewer bleeding complications.
“Many stroke patients do not receive tPA because of its associated risk of hemorrhage, especially if they are taking blood thinners or have recently undergone surgery,” says Sattin. “Laser therapy may be a safe treatment for such patients.”
The theory behind the system is that a particular enzyme in the mitochondria of brain neurons absorbs the near-infrared energy and spurs the formation of ATP. That process, according to the hypothesis, improves energy metabolism and reduces neuronal death in the ischemic penumbra, the vulnerable area that remains salvageable with appropriate treatment.
Patients must have their heads shaved because hair absorbs laser light. The treatment involves pressing the experimental device onto the scalp at 20 treatment sites, through open tabs in the cap. Because the study is randomized and double-blind, however, neither the physician nor the patient will know if the patient is actually receiving the laser treatment.
The study’s primary objective will be to compare treatment with the device versus placebo treatment, based on the patient’s scores on commonly used stroke scales. All study subjects will receive standard medical management. Patients with hemorrhagic, brainstem or cerebellar stroke will not be eligible.
Date Published: 09/07/2007