Transient Ischemic Attacks

Abstract

In recent years, it has become clear that the risk of stroke after a transient ischemic attack (TIA) or minor ischemic stroke is higher than was previously supposed, with consistent reports of 7-day stroke risks of up to 10%,1–4 and other evidence of the very short time-window for prevention of stroke after a TIA.5 However, patients with TIA and minor stroke are a highly heterogeneous group in terms of symptoms, risk factors and underlying pathology, and the early risk of recurrent stroke is likely to vary between different clinical and etiological subtypes. In order to appropriately target secondary prevention, we therefore need reliable data on risk in particular subgroups and ideally in individuals. Recent studies have provided some useful data, although many important issues are still unresolved. There is good evidence that the presenting clinical features of a TIA provide considerable prognostic information. Johnston and colleagues identified 5 risk factors independently associated with a higher 3-month risk of recurrent stroke in a large emergency department–based TIA cohort: age >60 years (OR=1.8; 95% CI, 1.4 to 2.9), symptom duration >10 minutes (2.3, 1.3 to 4.2), weakness (1.9, 1.4 to 2.6), speech impairment (1.5, 1.1 to 2.1), and diabetes mellitus (2.1, 1.1 to 2.7).1 A simple index with 1 point for each risk factor was useful in estimating risk at 3 months, which varied from 0% in patients with no risk factors to 34% in those with 5 risk factors, and also differentiated between risk groups during the first few days after the TIA.1 Isolated sensory or visual symptoms were associated with a low risk of stroke, and sex, ethnicity, previous diagnoses of coronary artery disease or hypertension, current cigarette smoking, antiplatelet or anticoagulant-use at presentation and presentation blood pressure did not predict early stroke.1,6 Rothwell and …