As many as 80,000 stroke patients who arrive at the hospital in time may be eligible for treatment for disability-preventing therapy with clot-busting medications. Yet current estimates show that only three to five percent of all such eligible patients receive treatment, and it is clear that America faces a major public health problem.
The most common kind of stroke, known as ischemic stroke, occurs in 85 percent of the estimated 750,000 annual cases. These strokes are caused by blood clots forming in an artery that supplies blood to the brain. The part of the brain that is deprived of blood begins to die almost immediately.
Ischemic strokes can be treated using clot-busting medications such as tissue plasminogen activator or t-PA, which provides a 30 to 50 percent better chance of cure from stroke disability. However, delays to treatment and the unavailability of hospital equipment and staff can prevent many people from benefiting from this therapy.
The drug must be administered within three hours of stroke onset, and the presence of experienced treatment staff can greatly reduce the incidence of complications.
Delays Dampen Eligibility
Only about half of all ischemic strokes are recognized by witnesses or the patient when they occur. Many patients are alone, or become non-communicative, or for some reason do not understand that a stroke has begun. Failure to recognize stroke and get to a hospital can cause costly delays to receiving treatment when time is of the essence.
For those that do arrive at the hospital in time, many must be excluded from therapy for one of a variety of reasons. For example, if the patient is taking blood thinners like warfarin they cannot receive t-PA. Other exclusion criteria include severely elevated blood pressure or blood sugar, recent surgery, low platelet count, and end-stage liver or kidney disorders.
Yet delays in the hospital can also occur for those who arrive on time and are eligible for treatment. Some patients will arrive at a facility that is ill-prepared to provide t-PA. An immediate brain CAT scan is essential to rule out hemorrhagic strokes caused by the leakage of blood into the brain due to a ruptured artery, because giving a clot-buster to a person suffering this type of stroke would worsen it.
In some hospitals, CAT scans may be unavailable or there may be no one on hand that knows how to read them. In these situations, the patient would not be treated with t-PA.
Stroke Teams Save Lives
To assure that every possible patient receives t-PA, many medical centers have organized stroke teams. The members of the team come from many hospital departments and the team reviews in advance how to respond when a stroke patient arrives and then practices using drills. Critical review and feedback to team members leads to improvement.
The value of stroke teams was verified in recent studies. The proportion of stroke patients receiving t-PA increased from three or four percent to over 10 percent in several centers that implemented stroke teams. Importantly, more patients enjoyed a good response to the drug, with acceptable complication rates.
Even in the very best of centers, about six percent of patients treated with t-PA suffer a brain hemorrhage. This risk is clearly outweighed by the 30 to 50 percent chance of cure from stroke disability, but the risks are higher and the benefits lower when the therapy is not administered by a stroke team.
National agencies, including the National Institutes of Health, the American Heart Association and the National Stroke Association are currently calling for a national certification system for stroke teams.
An umbrella group, the Brain Attack Coalition, has published rules for deciding which medical centers qualify for stroke team designation and the Centers for Disease Control and Prevention is conducting surveys in several states to measure the performance of uncertified medical centers.
Within a few years, a nationally endorsed system for certifying stroke teams should be in place. This should cause a tremendous increase in the numbers of patients treated successfully after stroke, and a corresponding decline in the number of severely disabled stroke victims.
Dr. Patrick D. Lyden, chief of Neurology and director of the Stroke Center at University of California at San Diego Medical Center