Atherosclerosis Impacts Vascular Event Risk in TIA, Ischemic Stroke

The risk for vascular events is significantly higher among patients with a transient ischemic attack (TIA) or minor ischemic stroke with atherosclerosis when compared with those without atherosclerosis, according to study findings published in The Lancet Neurology.

Data are limited on the long-term outcomes following a TIA or minor ischemic stroke. Additionally, previous studies tend to group together all noncardioembolic strokes despite the underlying pathology. For the study, researchers assessed the 5-year risk for major vascular events in patients with TIA or minor ischemic stroke compared with patients without atherosclerosis.

The researchers used TIAregistry.org, an international registry of patients with a recent TIA or minor ischemic stroke, for analysis. Patient data was collected from 61 centers in 21 countries in Asia, Europe, Latin America, and the Middle East. Follow up occurred at 1, 3, and 12 months after the baseline, and yearly for 5 years.

Participants were adult patients with either focal retinal or brain ischemia with a resolution of symptoms or a minor ischemic stroke modified Rankin scale (mRS) score of 0 to 1.

Patients were assessed for the 5 disease categories in the ASCOD grading system (atherosclerosis, small vessel disease, cardiac pathology, other causes, and dissection). Only patients with grade A1 (atherosclerosis with luminal stenosis of 50% or greater) and A2 (atherosclerosis with luminal stenosis of greater than 30% and less than 50%) were considered for analysis.

The primary outcome was a combined incidence of nonfatal stroke, nonfatal acute coronary syndrome, or cardiovascular death within 5 years. Secondary outcomes were individual factors from the primary outcome, bleeding, all-cause death, and mRS score.

Of the 4,789 patients in the database, 3,847 patients from 42 centers participated in the 5-year follow-up period. There were 1,406 (36.5%) of 3,847 patients with no atherosclerosis (grade A0) and 998 (25.9%) with atherosclerotic stenosis ipsilateral to the ischemic area (grade A1 or A2).

For the primary outcome, the researchers found an event rate of 7.7% (95% CI, 6.3-9.2; 101 events) for patients with an ASCOD of A0 and 19.8% (95% CI, 17.4-22.4; 189 events) for patients with an ASCOD of grade A1 or A2.

When compared with patients with grade A0, patients with grade A1 or A2 had an increased risk for the primary composite outcome (Hazard ratio [HR], 2.77; 95% CI, 2.18-3.53; P <.0001) and an increased risk for stroke (HR, 2.74; 95%CI, 2.07-3.62; P <.0001).

Aside from age, male sex, and multiple infarctions confirmed by neuroimaging, most risk factors associated with an ASCOD score of A1 or A2 were modifiable. Examples of these factors include hypertension, dyslipidemia, being overweight, and smoking cigarettes (all P <.025).

Preventative treatment should focus on targeting patients with atherosclerosis, rather than giving the same treatment to those with TIA or minor ischemic strokes regardless of atherosclerotic status.

“Our findings could facilitate the design of future clinical trials evaluating drugs addressing complications of atherosclerosis in patients with TIA or minor ischaemic stroke, supporting a focus on patients with atherosclerosis rather than including all patients in these trials,” study authors concluded. Study limitations were including only highly specialized TIA and stroke study centers and incomplete atherosclerotic information for many patients.