Exciting research involving the causes, treatment and recovery of stroke were presented last month during the International Stroke Conference in Los Angeles.

 Ischemic Stroke Hospitalizations Increase in Young

The number of acute ischemic stroke hospitalizations among middle-aged and older men and women fell between 1994 and 2007, but sharply increased among those under age 35 — including teens and children — according to research presented at the International Stroke Conference in February.

Analysts at the U.S. Centers for Disease Control and Prevention (CDC), reviewing hospitalization data by age and gender, identified declining stroke rates of 51 percent in girls 0-4 years, and 25 percent in men and 29 percent in women over age 45. However, the number of ischemic stroke hospitalizations increased 51 percent in males between ages 15 and 34 during the period studied.

The rate increased 17 percent in females between 15 and 34. Among children and teens, they found a 31 percent increase in boys between 5 to 14 years and a 36 percent increase among girls 5 to 14 years. Among the younger middle-aged set, they found a 47 percent increase among men 35-44 and a 36 percent increase among women 35-44.

“We cannot link anything in particular to the trend in younger patients, but I believe the role of obesity and hypertension will prompt a big discussion. Unfortunately, right now we can’t speculate on the causes,” said Xin Tong, MPH a health statistician for the CDC’s Division for Heart Disease and Stroke Prevention.

Experimental Agent Preferable to Aspirin for Stroke Prevention in Some AF Patients

A new anti-clotting agent has been found to be superior to aspirin at reducing stroke risk in atrial fibrillation (AF) patients unable to take stronger drugs, according to final data reported at the International Stroke Conference 2011. Researchers found the drug also worked better for people with a history of stroke or a warning stroke.

The AVERROES: Apixaban Versus Acetylsalicylic Acid (ASA) to Prevent Strokes trial was a randomized trial of 5,600 AF patients unwilling or unable to take oral vitamin-K antagonists (VKA) such as warfarin. Participants were treated at 520 medical centers worldwide. A May 2010 interim analysis found evidence that the investigational oral drug apixaban was superior to aspirin and advised researchers to end the trial early, according to Hans-Christoph Diener, MD, professor and chairman, Department of Neurology and Stroke Center, University Hospital Essen, Essen, Germany.  

The study’s primary endpoint was the reduction of ischemic stroke, hemorrhagic stroke and systemic embolism, and the primary safety endpoint was major bleeding incidents. The study patients, all over age 50, were at moderate-to-high risk because they had at least one stroke risk factor in addition to AF. Patients were randomized to receive either apixaban at 5 milligrams (mg) twice a day (2.5 mg twice a day in selected patients) or between 81 mg and 324 mg of aspirin per day. 

During an average of 1.1 years of follow up, the researchers found 51 strokes or systemic embolism events in the 2,808 patients taking apixaban compared to 113 strokes and systemic embolic events in the 2,791 patients taking aspirin. That represents an annual rate of 1.6 percent for apixaban vs. 3.6 percent for aspirin … or about half the relative rate of stroke or systemic embolism for apixaban compared to aspirin. Although bleeding events were slightly higher with apixaban, the difference fell short of statistical significance.

Diet Soda, Salt Linked to Vascular, Stroke Issues 

In findings involving 2,564 people in the large, multi-ethnic Northern Manhattan Study (NOMAS), scientists found people who drank diet soda every day had a 61 percent higher risk of vascular events than those who reported no soda drinking. 

“If our results are confirmed with future studies, then it would suggest that diet soda may not be the optimal substitute for sugar-sweetened beverages for protection against vascular outcomes,” said Hannah Gardener, ScD, lead author and epidemiologist at the University of Miami Miller School of Medicine.

In separate research using 2,657 participants also in NOMAS, scientists found that high salt intake, independent of the hypertension it causes, was linked to a dramatically increased risk of ischemic strokes. In the study, people who consumed more than 4,000 milligrams (mg) per day of sodium had more than double the risk of stroke compared to those consuming less than 1,500 mg per day.

Rat Response Opens Interesting Options for Human Study

• Although it has been documented that docosahexaenoic acid (DHA), an essential omega-3 fatty acid, is vital for proper brain function and can lower the risk of cerebrovascular diseases, researchers at Louisiana State University were interested in knowing if DHA might be effective in post-stroke treatment and recovery. Either DHA or a placebo was administered at 3, 4, 5, and 6 hours after the onset of stroke in rats. Treatment with DHA significantly improved behavior in the days following the stroke in comparison to the placebo group. The volume of the area of destroyed tissue was reduced by an average of 40 percent when DHA was administered at 3 hours, 66 percent at 4 hours, and 50 percent at 5 hours. MRI found DHA treatment reduced brain swelling. Lipidomic analysis found DHA treatment potentiates neuroprotein D1 synthesis in the penumbra and promotes cell survival when administered up to five hours after focal cerebral ischemic stroke in rats.
• Scientists at Advances Technologies and Regenerative Medicine found cells derived from human umbilical tissues (hUTC) helped restore greater motor-sensory functions in older rats affected by stroke. After inducing stroke in the right middle cerebral artery in 18-to-20-month-old rats (considered aged for rats), the hUTC-treated group showed significant improvement in neurological function compared to the placebo group. The improved results were observable as early as one month post-stroke.
• Out of the University of California - Irvine, it was discovered that whisker stimulation helps rats recover from stroke. Previous research reported stimulating a rat’s whiskers after stroke helped protect the brain by diverting blood flow to the area where the stroke occurred. The new research finds the benefits of whisker stimulation depend on the amount of stimulation but not the particular pattern in which it is delivered. For humans, this might suggest a noninvasive therapy to reduce or prevent stroke damage by stimulating parts of the body that send messages to the cortex, such as the lips or fingers.

Robot Therapy Seems to Improve Arm, Shoulder Mobility After Stroke

Therapy in which robots manipulate paralyzed arms, combined with standard rehabilitation, could improve arm and shoulder mobility in patients after stroke, according to recent research out of Kitasato University East Hospital in Kanagawa, Japan.

Patients on robotic therapy showed marked improvement in two measures of upper extremity function: the Fugl-Meyer flexor synergy score and the Fugl-Meyer shoulder/elbow/forearm score. The study involved 60 stroke survivors, average age 65, with hemiplegia treated at six rehabilitation centers in Japan. The patients, who had suffered a stroke in the previous four to eight weeks, all received standard rehabilitation therapy from an occupational therapist. Half received robotic therapy daily for six weeks in 40-minutes sessions with the balance using the same daily time period to engage in a standard self-training program.

The group assigned to robotic therapy used a Reo Therapy System by Motorika Ltd. in Israel. Based on initial mobility scores, patients with severe hemiplegia were more likely to benefit from the robotic therapy. The finding is consistent with the notion that higher-functioning patients already can correctly carry out self-training programs, while patients with lower function — only reflex and minor voluntary movement — are more likely to benefit from the support and aid of robots, according to the lead author.

Acute Anemia Linked to Silent Strokes in Children

Silent strokes, which have no immediate symptoms but could cause long-term cognitive and learning deficits, occur in a significant number of severely anemic children, especially those with sickle cell disease. One-quarter to one-third of children with sickle cell disease have evidence of silent strokes in their brains, according to Michael M. Dowling, MD, PhD, lead author of the study and assistant professor of pediatrics and neurology at the University of Texas Southwestern Medical Center in Dallas.

“These are 5- to-10-year-old children who have brains that look like the brains of 80-year-olds,” Dowling said. “These strokes are called ‘silent’ because they don’t cause you to be weak on one side or have any obvious neurologic symptoms. But they can lead to poor academic performance and severe cognitive impairments.”

Using MRI on the brains of 52 hospitalized children with hemoglobin concentrations dropping below 5.5 g/dL, they identified silent strokes in about 20 percent of children with sickle cell disease who were experiencing acute anemia and also found evidence, though not as often, of silent stroke in the severely anemic group without sickle cell disease.  Dowling said these brain injuries go unnoticed by doctors unless the children have testing with special MRI. He added the findings suggest that all children with severe anemia need careful examination for silent strokes.

Improved recognition and timely transfusion to increase blood hemoglobin levels could potentially prevent permanent brain damage in children with silent strokes. Dowling said future studies with larger groups of children could help clarify the information found in this early study.

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