Untreated transient ischemic attacks put 21,000 Canadians at increased risk of death, stroke or heart attack

The Canadian Heart and Stroke Foundation warns that untreated transient ischemic attacks (TIAs) are putting nearly 21,000 Canadians at increased risk of death, stroke or heart attack.  Yet there is evidence that only a minority of TIA patients receive appropriate medical follow-up, according to a new study published today in the journal Neurology.

Heart and Stroke Foundation spokesperson Dr. Alastair Buchan says, “This study and other recent evidence shows TIA should be treated every bit as urgently as chest pain and angina are in the prevention of heart attacks.  Between 10 to 20% of patients with TIA will have a stroke within the next three months.”

“We must make sure the public and medical professionals do not dismiss TIAs, but recognize them for what they are – a medical emergency and a precursor of stroke,” says Dr. Buchan, a neurologist.

Most strokes are caused by a blood clot interrupting the flow of blood to the brain. This produces symptoms such as weakness, paralysis or numbness, in the face, arm or leg, trouble speaking or understanding speech, confusion, vision problems, sudden severe, unusual headache and dizziness.  The symptoms of a TIA are similar but tend to go away quickly.

“Because the symptoms of a mini-stoke or TIA can go away in a few minutes or hours, people don’t realize just how serious they are,” says Dr. Michael Hill, Heart and Stroke Foundation researcher and the study’s lead author. “TIAs are under-recognized, under-estimated and under-treated.  As a result, we’re losing the opportunity to prevent thousands of strokes.”

Applying the rates observed in the study, there may be at least 21,000 TIAs each year in Canada.  Many people with TIA fail to report their experience to their doctor or go to the hospital.  “All patients with TIA require urgent evaluation; approximately 20% may require admission to prevent stroke,” says Dr. Hill, who is Director of the Stroke Unit at the Foothills Medical Centre. “The tragedy is that less than 50% of patients are seen urgently, either because they don’t recognize their symptoms as important, or because acute medical services are not available to them.

Prompt, appropriate treatment of TIA could reduce the risk of stroke and death for these patients, says the Heart and Stroke Foundation.  A recent study published in March in the Canadian Medical Association Journal indicated that many TIA patients in Ontario did not receive adequate diagnostic testing or follow-up treatment – but new information indicates some dramatic changes.

Using data from the Ontario Stroke Registry (May – December 2000), a computerized database established by the Heart and Stroke Foundation as part of the Coordinated Stroke Strategy, investigators studied 371 TIA and 418 ischemic stroke patients diagnosed in the emergency departments of four regional stroke centres.  The study found that compared with stroke patients, those experiencing a TIA were significantly less likely to have diagnostic CT or MRI testing, to be examined by a neurologist, or to be discharged with clot-preventing medication.

  Source: HSF’s Ontario Stroke Strategy, December 2000

    * Difference between the two groups is statistically significant (p<0.001)

New Strategy, Dramatic Change

  That was the picture in 2000, but recent dramatic changes to these figures are encouraging.  “A coordinated stroke strategy makes a huge difference in the way TIAs are treated,” says Dr. Frank Silver, Heart and Stroke Foundation spokesperson, and Co-Principal Investigator for the Registry of the Canadian Stroke Network.

Latest figures show that in 2003[1], 78% of TIA patients arriving at regional stroke centres in Ontario received CT or MRI neuroimaging in the emergency department, up from 43% in 2000.  The percent discharged with medication to reduce the risk of blood clot also increased significantly, from 63% in 2000 to 79% in 2003.  

“With strong support from the Ministry of Health and Long Term Care and the Heart and Stroke Foundation, Ontario’s Coordinated Stroke Network has already demonstrated impressive improvements in stroke care in this province,” says Dr. Silver.

“Clearly these changes show that organized stroke care can have a dramatic impact on treatment and care in a relatively short period,” says Dr. Alastair Buchan.  Other provinces are also recognizing the value of coordinated stroke strategies – in their latest budget, the government of Nova Scotia announced funding to further the work of their provincial Stroke Strategy Committee.

The Heart and Stroke Foundation, the Canadian Stroke Network and with other partner organizations are building on these experiences to develop a national stroke strategy that will support the development of coordinated stroke strategies in all provinces, so that all Canadians can benefit from improved stroke care.