Bruce Ovbiagele, MD, professor of neurosciences at the University of California, San Diego School of Medicine and Avindra Nath, MD, of Johns Hopkins University, analyzed data on hospital patients primarily diagnosed with stroke between the years 1997 and 2006 and found that while stroke declined among the general population by seven percent, incident rates increased 67 percent among HIV-infected patients.
The rise in strokes in HIV patients was entirely attributable to one type of stroke-- ischemic strokes, caused by inhibited blood flow to the brain resulting from clots. Ischemic strokes account for about 87 percent of all strokes in the general population.
A recent study looking at the clot-dissolving treatment for acute ischemic stroke, called intravenous tissue plasminogen activator (tPA), found that the greatest benefit is achieved after 4.5 hours from stroke onset. The study also indicated, for the first time, increased death risk from late treatment, between 4.5 hours to 6 hours following onset.
Stroke remains the third leading cause of death in the U.S. with more than 143,000 fatalities annually. The cardiovascular event is also the leading cause of disability among Americans.
Ovbiagele said strokes in HIV patients are rare, however, "so the rise is notable."
The link between stroke and HIV might stem from metabolic complications as a side effect of highly active antiretroviral therapy (HAART), which has been proven to greatly extend the lives of HIV patients. (HAART affects lipid and glucose levels, which are biomarkers linked to stroke risk.)
Or the stroke-rate increase might simply be because HIV patients are living longer, Ovbiagele said, since risk doubles every decade past age 55.
Research is providing hope for stroke patients in the form of new treatments and discoveries. Two pilot studies, for example, found that lowering blood pressure aggressively within six hours of stroke onset can inhibit growth of intracerebral hemorrhage (bleeding into the brain).
Doppler ultrasound has been shown to help identify silent "microclots" traveling to the brain. This technique could help patients with asymptomatic narrowing of the carotid artery (the artery that supplies the head and neck with oxygenated blood), who might benefit from stint surgery.