AN ASPIRIN A DAY MAY LESSEN STROKE SEVERITY

Individuals who had taken at least one aspirin in the week before an ischemic stroke had milder strokes than did people who had not taken aspirin, according to a report in the December issue of Stroke.

The study compared stroke severity among aspirin users and nonusers with data from the Trial of Org 10172 in Acute Stroke Treatment (TOAST), a multicenter, randomized, placebo-controlled, double-blind clinical trial that ran from 1990 through 1996.

Among patients with ischemic stroke, researchers compared stroke severity between those who had been taking aspirin and those who had not. Of 1,275 patients in the study, 509—almost 40%—reported aspirin use during the week before stroke onset. Researchers found more strokes among the aspirin users, but stroke severity was significantly lower than that among nonusers.

Both the overall deficit and motor impairments were less severe in those who had recently used aspirin, according to the researchers. Using the National Institutes of Health Stroke Scale (NIHSS), 50.3% of aspirin users had mild strokes, compared with 43% of nonusers; only 9.6% of aspirin users had severe strokes, compared with 14.8% of nonusers.

On the Supplemental Motor Examination (SME) ranking, which measures the severity of muscle weakness in arms and legs, 55.6% of aspirin users had mild strokes, compared with 48.7% of nonusers; 19.8% of aspirin users had severe strokes, compared with 24.0% of nonusers.

Several different mechanisms factor in aspirin’s protective effect, said the researchers, including its antiplatelet effect, which may improve blood circulation in the brain; its antioxidant properties, which may reduce oxidative tissue damage; or some other possible anti-inflammatory, neuroprotective effect, which at this time is still under investigation.

No information was recorded about the amount or frequency of aspirin use, nor was information collected about the use of any other antiplatelet therapy or warfarin. Further, numerous factors that influence aspirin use also correlate with stroke severity; these factors may include age and prior cerebrovascular or cardiovascular history. These patients may also have received more medical attention and have been more aggressively pursuing risk factor reduction.

Suggested Reading
Wilterdink JL, Bendixen B, Adams HP, et al. Effect of prior aspirin use on stroke severity in the Trial of Org 10172 in Acute Stroke Treatment (TOAST). Stroke. 2001;32:2836-2840.

HYPOTENSION, HEART FAILURE, AND COGNITIVE IMPAIRMENT IN ELDERLY PATIENTS

A multicenter study of 13,635 patients found a correlation between cognitive impairment and heart failure among older patients. This finding is further evidence that arterial hypotension is associated with an increased risk of dementia.

Of the hospitalized elderly participants in the two-year study, 1,583 had heart failure. Among this subgroup 26% had symptoms of cognitive impairment, whereas 19% of the subjects without heart failure showed signs of cognitive impairment.

The study was conducted throughout Italy in 1995 and 1997 with 81 hospitals participating, according to study author Giuseppe Zuccala, MD, Chair of Gerontology at the Catholic University of the Sacred Heart in Rome. His team’s findings were reported in the December 11 issue of Neurology.

“We assessed whether arterial hypotension might be associated with cognitive impairment among older subjects with heart failure,” said Dr. Zuccala. “Arterial hypotension has been associated with increased risk of dementia in some large prospective studies, but it is still controversial. On the other hand, cognitive impairment is a common, potentially reversible condition among older patients with heart failure and depressed left ventricular function.”

The study found that systolic blood pressure levels below 130 could predict cognitive impairment among participants with heart failure. Low blood pressure alone was not a predictor of cognitive impairment, Dr. Zuccala reported. Notably, in this study the prevalence of cognitive impairment was more likely to be underestimated among participants with heart failure.

The study concluded that, as systolic hypotension might also be caused or aggravated by pharmacologic treatment, routine management of heart failure should include early systematic assessment of cognitive performance to detect any sign of cognitive dysfunction.

Suggested Reading
Zuccala G, Onder G, Pedone C, et al. Hypotension and cognitive impairment: selective association in patients with heart failure. Neurology. 2001;57:1986-1992.

HIGH TRIGLYCERIDES, HIGH STROKE RISK

Researchers have now shown that high triglycerides are a strong independent predictor of stroke risk, according to a report in the December Circulation. “High triglycerides are associated with ischemic stroke and transient ischemic attacks (TIA),” said David Tanne, MD, lead author of the study. “To the best of our knowledge, this study is the first to indicate that high triglycerides expose heart disease patients to increased risk for stroke beyond cholesterol.”

Elevated triglycerides are independent of normal cholesterol levels, said Dr. Tanne, who is Director of the Stroke Unit, Department of Neurology, at Sheba Medical Center, Tel Hashomer, Israel. “More effective screening and detection of high blood triglycerides and treatments to modify this stroke risk factor could further reduce the health burdens of stroke,” said Dr. Tanne.

For six to eight years, researchers followed 11,177 patients with coronary heart disease but no history of stroke or TIA. Medical histories were obtained and blood lipid levels assessed. Participants were ages 40 to 74, and 78% were men. Researchers identified 941 individuals with cerebrovascular disease, of whom 487 had ischemic stroke or TIA.

Individuals who had a stroke or TIA had higher than average levels of triglycerides and lower levels of HDL cholesterol. About one fourth of individuals in the study had triglyceride levels of 200 mg/dL or higher, a level that increased their risk for stroke by nearly 30%. The increased risk associated with high triglycerides was found across subgroups of age, gender, patient characteristics, and cholesterol.

“Our main finding in this study is that elevated blood triglycerides increase a person’s risk of suffering an ischemic stroke,” Dr. Tanne said. “Those with high blood triglycerides over 200 mg/dL have a nearly 30% higher risk of suffering a stroke, after taking into account other risk factors for stroke such as high blood pressure, cigarette smoking, or diabetes.” A secondary finding was that individuals with coronary heart disease and high HDL levels were less likely to have a stroke.

The link between triglycerides and stroke is still under investigation, said Dr. Tanne. “However, in addition to the direct atherogenic effect of triglycerides, these lipids appear to be a marker of a series of other changes that could worsen atherosclerosis or cause blood clots. High triglycerides are associated with several abnormalities of the body’s clotting systems, which may contribute further to their association with cardiovascular disease.”

Suggested Reading
Tanne D, Koren-Morag N, Graff E, Goldbourt U. Blood lipids and first-ever ischemic stroke/transient ischemic attack in the Bezafibrate Infarction Prevention (BIP) registry: high triglycerides constitute an independent risk factor. Circulation. 2001;104:2892-2897.

WERNICKE’S AREA PREDICTS SEMANTIC DEFICIT IN ACUTE STROKE

Researchers at Johns Hopkins University have found new support for the crucial role of Wernicke’s area (left Brodmann’s area 22)—in lexical semantics. That is, adequate perfusion for tissue function in BA 22 is necessary for lexical–semantic tasks, such as word/picture verification.

Argye E. Hillis, MD, MS, and colleagues observed that among stroke patients without infarct in Wernicke’s area, a strong correlation existed between the rate of errors on a word comprehension test and mean number of seconds of delay in time-to-peak concentration of contrast in Wernicke’s area, relative to the homologous region in the right BA 22. Furthermore, Dr. Hillis’ team concluded that the magnitude of delay on perfusion-weighted imaging (PWI) may be a gross indicator of tissue dysfunction.

The study’s findings, reported in the November Annals of Neurology, are consistent with previous research demonstrating that the percentage of Wernicke’s area that is infarcted predicts the severity of word comprehension in chronic stroke. The investigators believe that these results do not imply that all, or perhaps any, semantic information is represented in BA 22, but that this region is essential in linking the phonologic representations of words (the learned pronunciation of the words) to their meanings (semantic information). However, to link this distributed semantic information to a specific phonologic representation, to name the item, or to verify the name of the item, the auditory input must first be processed in BA 22.

Eighty patients met the inclusion criteria of clinical diagnosis of acute left hemispheric ischemic stroke within 24 hours of symptom onset or symptom progression and right-handed and premorbid proficiency in English. The subjects underwent diffusion-weighted imaging, perfusion-weighted imaging, and conventional magnetic resonance imaging sequences and were administered a battery of language tests. Age ranged from 23 to 86, and time after onset or worsening of symptoms was 0.5 to 24 hours.

In an accompanying editorial, Howard S. Kirshner, MD, of the Vanderbilt University School of Medicine, said that the implications of this research are important both for the understanding of language function and for the scientific basis of acute stroke therapy. “Methods such as those of [Dr.] Hillis and coworkers should be at the forefront of research into this treatment strategy, and neurologists interested in cognitive function should emulate their practical application of these techniques in the emergency room,” he said.

NR