Long-Term Risk of Stroke After Transient Global Amnesia in Two Prospective Cohorts

Abstract

Background and Purpose— Transient global amnesia (TGA) is known as a benign syndrome, but recent data from neuroradiological studies support an ischemic cause in some cases, which might suggest an increased susceptibility to cerebrovascular events. We determined the long-term risk of stroke after a first TGA in 2 independent prospective cohorts. Methods— In 2 independent prospective cohorts of patients with TGA (OXVASC [Oxford Vascular Study], population-based; NU (Northern Umbria) cohort, TGA registry), cardiovascular risk factors and long-term outcomes, including stroke and major cardiovascular events, were identified on follow-up. Cardiovascular risk factors were treated according to primary prevention guidelines. In OXVASC, the age-/sex-adjusted risk of stroke during follow-up was compared with that expected from the rate in the underlying study population. Results— Among 525 patients with TGA (425 NU and 100 OXVASC), mean (SD) age was 65.1 (9.5) years and 42.5% male. Hypertension (58.1%), dyslipidemia (40.4%), and smoking (36.4%) were the most frequent cardiovascular risk factors. The risk of stroke was similar in the 2 cohorts, with a pooled annual risk of 0.6% (95% CI, 0.4–0.9) and a 5-year cumulative risk of 2.7% (1.1–4.3). Moreover, the stroke risk in OXVASC cases was no greater than that expected in the underlying study population (adjusted relative risk=0.73; 0.12–4.54; P =0.74). Conclusions— TGA does not carry an increased risk of stroke, at least when cardiovascular risk factors are treated according to primary prevention guidelines.