Stroke risk remains elevated 5 years after TIA or minor stroke
The risk of stroke remains elevated 5 years after a transient ischaemic attack (TIA) or minor ischaemic stroke, with around half of the cardiovascular (CV) events occurring during years 2–5, data from the TIAregistry.org project have shown.
The study included 3,847 patients from 21 countries who had a TIA or minor stroke. The rate of CV events (a composite of nonfatal stroke, nonfatal acute coronary syndrome [ACS], or death from CV causes), the primary outcome of the study, was 6.4 percent in the first year and 6.4 percent in years 2–5. [N Engl J Med 2018, doi: 10.1056/NEJMoa1802712]
“Half of the events occurred during years 2–5, which raises the question of whether prevention strategies could decrease the risk of stroke after a TIA or minor ischaemic stroke beyond 1 year,” the investigators highlighted. “There may be potential for reducing recurrent strokes by ongoing secondary prevention measures.”
The TIAregistry.org project was designed to prospectively enrol patients with a recent TIA or minor stroke to determine the short-term (3 months and 1 year) and long-term (5 years) outcomes. The 1-year data from 4,789 patients, reported previously, showed a CV event rate of 6.2 percent. [N Engl J Med 2016;374:1533-1542]
After 5 years, a primary outcome event occurred in 469 patients (death from CV cause, n=96; nonfatal stroke, n=297; nonfatal ACS, n=76), corresponding to an estimated cumulative event rate of 12.9 percent. Among these events, 50.1 percent occurred during years 2–5. Stroke occurred in 345 patients (9.5 percent), with 43.2 percent of these patients experiencing a stroke at years 2–5.
All-cause death, recurrent stroke, ACS and bleeding occurred in 10.6 percent, 16.8 percent, 2.4 percent and 1.5 percent of the patients at 5 years, respectively.
In sensitivity analysis, ipsilateral large-artery atherosclerosis, cardioembolism, and an ABCD2 (age, blood pressure, clinical features, duration of TIA, diabetes) score of ≥4, but not the presence of a brain lesion on neuroimaging, were independent predictors of recurrent stroke during years 2–5 after a TIA or a minor ischaemic stroke.
The rates of medication use at hospital discharge after the first stroke and at 5 years were: Blood pressure (BP)-lowering therapy, 68.7 percent and 70.5 percent, respectively; lipid-lowering therapy, 70.5 percent and 63.9 percent; glucose-lowering therapy, 18.8 percent and 17.7 percent; antiplatelet therapy, 90.6 percent and 71.1 percent; anticoagulant therapy, 16.2 percent and 17.0 percent. At 5 years, the patients’ mean BP was 132/77 mm Hg, while the mean and median LDL-cholesterol levels were 92 mg/dL and 86 mg/dL, respectively.
“The 12.9 percent risk of the composite CV outcome and 9.5 percent risk of stroke at 5 years were approximately twice the previously reported 1-year rates of 6.2 percent and 5.1 percent, respectively,” the investigators noted. “These rates were lower than the rates of 22 percent and 17 percent, respectively, in historical cohorts before the widespread adoption of aggressive risk-reduction measures for vascular disease.”
“Our registry was composed primarily of patients at moderate-to-high risk of stroke, as more than two-thirds of the cohort had an ABCD2 score of ≥4 at the time of their first stroke,” they added.