Ontario-wide study finds reduction in stroke following 'mini-strokes'

A new study from Sunnybrook Health Sciences Centre and Heart & Stroke has found that long-term stroke occurrence and death after a transient ischemic attack (TIA) — which are often called mini-strokes and are a warning that a more serious stroke could occur — declined significantly from 2003 to 2015 in Ontario.

The study, published in the Canadian Journal of Neurological Science, utilized data from the Canadian Institute of Health Information (CIHI) National Ambulatory Care Reporting System (NACRS) database and the Discharge Analysis Database to link incidences of TIAs and stroke across the province.

TIAs happen when blood supply to the brain is briefly blocked, typically lasting only minutes. Although TIAs don’t cause permanent damage, they can be a significant precursor to a stroke, with approximately one in eight acute strokes being preceded by a TIA.

“Over the past 15 years the management of TIAs has changed significantly, with improved recognition and diagnostic strategies, better implementation of secondary prevention strategies and greater efforts to educate the public,” says Dr. Rick Swartz, principal investigator of the study and a neurologist at Sunnybrook Health Sciences Centre. “However, few studies have examined trends over time at a provincial level. Our study shows the significant impact these changes can have.”

Researchers looked at data from 61,710 patients with an emergency department diagnosis of TIA in an Ontario-wide hospital-based cohort. From 2003 to 2015, they found a 32 percent reduction in stroke and a 61 percent reduction in mortality at one-year post-TIA. However, the early high risk of stroke remains, with the majority of strokes occurring in the first seven days. Risk of stroke decreased from 6.0 percent to 3.4 percent for one-year risk.

The authors caution that it remains unclear whether recent interventions are simply delaying stroke or actually reducing occurrence longer term. “There are a number of potential factors that may have contributed to the observed reduction in stroke: improved management of TIA due to improvements in stroke care implemented as a result of the Canadian Stroke Strategy, better early diagnostics strategies, greater awareness of stroke signs (resulting in faster hospital arrivals), and decreasing rates of atherosclerosis,” says Dr. Patrice Lindsay, Director, Health Systems Change, Heart & Stroke. “The reduction is likely caused by a synergy of factors, but what we’re seeing is data that suggests we’re headed in the right direction and it’s important to remain vigilant in these practices to see continued improvement in patient outcomes.”

Dr. Swartz says the results showcase the importance of timely identification of TIAs. “If we’re able to reduce the risk of a stroke following a TIA, we’re hopeful we can prevent more acute strokes, reducing costs to the health care system and most importantly — saving patient lives.”

Researchers emphasize their study demonstrates the importance of continuing aggressive risk factor management for on-going improvement in stroke reduction after TIA in the future.

This study was supported with grants from Heart & Stroke Foundation, The Ontario Brain Institute, the Canadian Institutes for Health Research (CIHR) and Ontario Genomics.

Read the full study: Reduction in Stroke after TIA in a Province-wide Cohort Between 2003-2015

Media Contacts:

Samantha Sexton
Communications Advisor
416-480-4040
samantha.sexton@sunnybrook.ca

Jennifer Palisoc
Communications Advisor
416-480-4040
jennifer.palisoc@sunnybrook.ca

Stephanie Lawrence
Senior Manager, Communications, Heart & Stroke
613-290-4236
stephanie.lawrence@heartandstroke.ca