Five-Year Risk of Stroke After TIA or Minor Stroke
How common is recurrent stroke, acute coronary syndrome (ACS), or cardiovascular death by 5 years after an initial transient ischemic attack (TIA) or minor ischemic stroke?
This is a registry-based study (TIAregistry.org) of 3,847 patients with a TIA or minor ischemic stroke (modified Rankin scale score [mRS] of 0 or 1) within 7 days before enrollment. Patients were enrolled from 2009 to 2011 and were followed prospectively with interviews at 1 month, 3 months, 12 months, and every 12 months thereafter for 5 years. The primary outcome was a composite of stroke (ischemic or hemorrhagic), ACS, or death from cardiovascular causes. The 1-year data were previously published (Amarenco P, et al., N Engl J Med 2016;374:1533-42), and the present study serves as a follow-up analysis.
Of 3,847 patients at 42 sites, mean age at enrollment was 66.4 years, 59.8% were male, 70.3% had hypertension, and 8.7% had a diagnosis of atrial fibrillation. At 5 years, the primary outcome (stroke, ACS, or cardiovascular death) had occurred in 469 patients (estimated cumulative event rate, 12.9% over 5 years; 95% confidence interval [CI], 11.8%-14.1%) with 235 (50.1% of the events) occurring during years 2-5. At 5 years, 345 of the patients had had a recurrent stroke (estimated cumulative event rate, 9.5%; 95% CI, 8.5%-10.5%), with 149 (43.2% of the total strokes) occurring during years 2-5.
The 5-year rates of the primary outcome (12.9%) and of stroke (9.5%) in this registry were lower than the rates suggested by historical cohorts (22% and 17%, respectively). The risk of stroke, ACS, and death from cardiovascular causes is highest in the first year, but persists in the 2-5 years after minor stroke or TIA.
The observed lower rate of recurrent stroke in this registry compared to historical cohorts may be due to improved secondary prevention measures in the modern era. Although only 42 of the initial 61 1-year follow-up sites provided long-term data for this analysis, the excluded patients tended to be “healthier” (less hypertension, less smoking, more with mRS of 0, and more with ABCD2 scores of 0-3) than the included patients, which—if anything—would suggest that the 5-year rates in the current study may overestimate the true risk in the population.
Keywords: Acute Coronary Syndrome, Atrial Fibrillation, Brain Ischemia, Hypertension, Ischemic Attack, Transient, Primary Prevention, Risk, Secondary Prevention, Smoking, Stroke, Vascular Diseases
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