Should interventional radiologists be involved in acute stroke intervention

STROKE is the third leading cause of death in North America, Europe, and Japan. According to the American Heart Association and American Stroke Association, there are over 750,000 new strokes per year, resulting in over 250,000 deaths per year in the United States alone (1). Stroke is the leading cause of adult disability and the leading cause for inpatient Medicare expenditure for long-term care. The average cost per case is over $50,000 (2,3). This year, the National Institutes of Health (NIH) estimates that stroke costs will exceed $40 billion US health care dollars. Perhaps most importantly, however, is that stroke is probably the most feared of all medical conditions. The NIH, the pharmaceutical industry, medical device companies, and large numbers of physicians have invested hundreds of millions of dollars and years of research to develop new drugs and therapies to treat this devastating disorder. However, all large-scale, multicenter, controlled clinical trials involving oral or intravenous neuroprotectants, calcium channel blockers, and intravenous lytics have failed, except for the NIH-sponsored acute stroke trial involving intravenous recombinant tissue plasminogen activator (tPA; Activase, Genentech, South San Francisco, CA) (4–6). The only other emergency therapy of any kind that that has shown statistical benefit is catheter-directed intraarterial lytic therapy, as demonstrated by the PROACT I and II trials (7–9). The results of the National Institute of Neurological Disorders and Stroke trial of intravenous tPA for acute stroke were reported more than 5 years ago. This study demonstrated that intravenous tPA administered to appropriately selected patients with stroke within 3 hours of acute symptom onset was statistically beneficial, improving clinical outcome at 3 months by 31% compared to the untreated control group. Based upon this two-part study, the Food and Drug Administration approved recombinant tPA for acute ischemic stroke in 1996 (6). However, current estimates are that fewer than 2%–3% of all potential stroke patients are benefiting from this therapy. The major obstacle to providing therapy is the very short time to treatment of less than 3 hours, compounded by inadequate knowledge of the general public regarding the signs and symptoms of stroke and the appropriate decision concerning medical therapy. Major organizations are now actively attempting to educate the public about “Brain Attacks” (stroke warning signs/symptoms) and encouraging them to seek immediate treatment at their local hospital by dialing 911. The American Society of Interventional and Therapeutic Neuroradiology (ASITN) and the Society of Cardiovascular & Interventional Radiology (SCVIR) fully endorse the recommendations for “Emergency Interventional Stroke Therapy” (7). The results of PROACT I and II indicate that there is compelling evidence that catheter-directed intraarterial thrombolytic therapy given to patients within 6 hours of symptom onset with angiographically identified clot in the middle cerebral artery (the most common location for large vessel stroke) will recanalize and reperfuse 66% of vessels (vs 18% in the control group). More importantly, 40% of those treated (vs 25% in the control group) will have significant improvement with slight or no neurologic disability at 90 days, resulting in a 58% relative imFrom the Department of Neuroradiology (R.T.H.) University of California San Francisco Medical Center, 505 Parnassus Avenue, L-352, San Francisco, CA 94143-0628 and Department of Radiology (J.J.C.) INOVA Fairfax Hospital, Fairfax, Virginia. Address correspondence to R.T.H.