People who manage to recover from the effects of a stroke aren't out of the woods yet, Canadian experts say, because they remain at an elevated risk level for a second event or serious medical complication up to 5 years after the initial event.

That suggests stroke survivors should be given closer and longer-lasting follow-up monitoring to prevent health problems, said researchers reporting their work at the Canadian Stroke Congress in Vancouver.

A University of Toronto study looked at data from 34,000 patients who had suffered a stroke or a mini-stroke, also called "transient ischemic attack."

The patients, who had strokes or mini-strokes between 2003 and 2011, had survived what has usually been considered a 90-day "high-danger" stage following their discharge from a hospital.

Most Canadian stoke patients are monitored closely by specialized clinics for those 90 days.

However, in the first year following their stroke survival, 9.3 percent of the patients who made it through the 90-day danger period suffered a repeat event of stroke, mini-stroke or heart attack, were admitted for long-term care or died from other causes.

"This high long-term risk was surprising and shows that we need to develop better strategies and interventions for these patients to prevent as many of these serious problems as we can," says study leader Dr. Richard Swartz.

The rate of the event risks present in the first years remained at 5 percent in the following 4 years, the researchers said.

"We now need to identify ways to determine which people, among those who have made it through the riskiest period, remain most at risk for serious events so we can develop appropriate preventive interventions," Swartz says.

Longer periods of close monitoring are needed, even in stroke clinics cannot provide such follow-up, says Ian Joiner, director of stroke for the Heart and Stroke Foundation.

"If it's not feasible, due to lack of resources, to follow patients longer in stroke clinics, we must do more to educate patients, their families and their family physicians and nurse practitioners to be more alert to the ongoing risks," Joiner says. "Even those who seem to recover very well after a stroke or TIA must be followed closely."

Swartz and his colleagues are carrying out investigations of factors that may be involved in a risk of serious health problems or death for stroke survivors, including depression, mental impairment or obstructive sleep apnea.