'Silent' brain damage points to greater stroke risk: Study

Patients in their 40s were more likely to have brain lesions, as were those with high blood pressure, coronary artery disease or a history of angina or heart attack.

Seemingly healthy Canadians under 50 are unknowingly walking around with pre-existing brain damage that puts them at increased risk of a full-blown stroke, Canadian researchers are warning.
In a study believed to be a world first, Montreal researchers who investigated 168 stroke patients age 18 to 50 discovered that 29 per cent had old brain lesions — small clusters of dead brain cells.
Brain lesions are most often caused by "silent" brain infarcts — tiny strokes caused by blocked blood supply to the brain that can be seen on brain scans but that produce no symptoms. Those with silent lesions were three times more likely to suffer another stroke during an average two-plus years of followup.
"These are young patients who we think are healthy until they present with their first stroke," says lead investigator Dr. Alexandre Poppe, a neurologist at the Cerebrovascular Disease Centre at Montreal's Notre-Dame Hospital, who will present his study Tuesday at the Canadian Stroke Congress in Quebec City.
"But then they end up having signs of having had an accumulation of silent (brain) damage over time."
Patients in their 40s were more likely to have brain lesions, as were those with high blood pressure, coronary artery disease or a history of angina or heart attack.
In a surprising finding, patients with migraines with aura also had a higher incidence of these "silent" brain lesions.
"We tend to think of stroke as a disease of older people but about 10 per cent of stroke patients are under 50," Poppe said. "Even young people should take their risk factors very seriously, because they might be accumulating silent damage that could one day manifest itself as a real stroke."
The warning comes as another Canadian research team will report Tuesday that the economic burden of treating stroke in Canada is double previous estimates.
The costs of caring for a stroke patient in just the first six months post-stroke alone adds up to more than $2.5 billion a year in Canada, according to the Canadian Stroke Network's Burden of Ischemic Stroke (BURST) study.
By contrast, the most recent data from Health Canada put the total cost of stroke in Canada at $2.4 billion a year for both new stroke patients as well as long-term survivors.
There are 300,000 stroke survivors in Canada. About 50,000 new strokes occur in Canada each year. The study, based on 232 stroke patients from 12 hospitals across the country, found that the costs for every new stroke add up to an average $50,000 in the six-months following a "brain attack."
The bulk of the costs were health-care costs — hospitalizations and medications. But 20 per cent were costs people bear on their own, says stroke neurologist Dr. Mike Sharma, director of the Ottawa Hospital's regional stroke program, who co-led the BURST study with Dr. Nicole Mittmann, of Toronto's Sunnybrook Health Sciences Centre.
That can include medications not covered by drug plans, canes, wheelchairs, braces and lost income. Costs for families ranged from $2,000 for a "non-disabling" stroke, to as much as $200,000 for the most severely affected — people "who need to be institutionalized in a setting where they have 24-hour care. Really, all of their basic needs to be met," says Sharma.
Stroke is the third-leading cause of death in Canada. Experts are warning the absolute number of strokes will increase as the baby boom generation enters the ages when their stroke risk increases.
But even young people are not immune to stroke. The Montreal study focused on a group that has been largely ignored: 18- to 50-year-olds.
The study involved patients at Notre-Dame Hospital. When the researchers checked their MRI scans, overall, 29.4 per cent had old brain lesions. Most had silent brain infarcts — small areas of damage to the brain "that probably imply a small stroke," Poppe said.
Others had more diffuse damage to the brain's white matter.
The patients were followed for an average of 27 months. Those with old brain lesions had a threefold increased risk of another stroke during the followup period compared to patients without lesions. Overall, 22 per cent of patients who had silent brain lesions had a recurrent stroke, versus seven per cent without lesions.
Those with lesions also had a higher risk of heart attack during the followup period — six per cent, versus one per cent for those lesion-free.
Young stroke patients should have a brain MRI, Poppe said. Those with silent lesions should be followed more closely, and their risks factors — such as hypertension, smoking, diabetes and cholesterol — aggressively controlled, he said.