This prospective analysis of 79 patients with transient carotid ischemic attacks (TIAs) showed that only 15% of them subsequently had strokes causing serious disability or death. They were followed up from one to nine years. All had arteriography during initial evaluation. Most of the patients who suffered strokes had at least one additional risk factor for stroke, such as hypertension or a cardiac problem.
Today it is probably impossible to collect data on the natural history of untreated TIAs, inasmuch as virtually all patients are receiving either specific medical or surgical therapy.
(JAMA 235:2608-2610, 1976)
Fields WS, Lemak NA. Joint Study of Extracranial Arterial OcclusionIX. Transient Ischemic Attacks in the Carotid Territory. JAMA. 1976;235(24):2608–2610. doi:10.1001/jama.1976.03260500024020