Not all U.S. stroke patients eligible for a clot-busting treatment actually receive it - and the odds of getting this therapy may depend on where they live, a large study finds. Researchers found wide variation in treatment for ischemic stroke, which results from an obstruction in a blood vessel supplying the brain. Patients who are diagnosed quickly may have less disability afterward if they receive an intravenous therapy known as thrombolysis to dissolve clots. Because this therapy generally must be completed within 4.5 hours of the onset of stroke symptoms, a major obstacle to treatment can be getting to the hospital fast enough, said lead study author Dr. James Burke, a neurologist at the University of Michigan and the VA Ann Arbor Health System.