Relation between frequent transient ischemic attacks and intracranial or extracranial artery lesions

Objective To investigate the relationship between the stenosis of clinically relevant artery or the characteristics of carotid plaques and frequent transient ischemic attacks(TIA).Methods Seventy-nine consecutive patients sufiered TIA attribute to carotid territory in the acute phase(within 7 days )who had been admitted to neurology department of Xuanwu Hospital from August 2005 to January 2007 were retrospectively analyzed.Patients with nonatherosclerotic vasculal disease were excluded.According to the times of TIA from the first attack to the day of hospitaliztion(within 7 days)patients were divided into two groups:those who had sparse TIA(onsets＜3 times),and those who had multiple TIA(onsets≥3 times).All patients underwent the examination of DSA.carotid ultrasound and transcranial doppler.The degree of stenosis of clinically relevant artery and the characteristics of carotid plaques were compared between the two groups.According to degree of stenosis of relevant artery,we defined as normal or＜50%stenosis.50%-69%stenosis.70%-99%stenosis or occlusion.According to the characteristics of carotid plaques we divided into stable or unstable plaques.Resuits Patients with TIA in carotid territory had more intracranial artery diseases.The middle cerebral artery was the most commonly involved artery(5 1.2%).the extracranial internal carotid artery was the next(37.2%).Multiple TIA were more likely to have a short duration of symptoms≤10 min than sparse TIA(x2=5.343,P=0.021).A significant stenosis of clinically relevant artery(≥50%)was demonstrated more frequently in the multiple TIA group(66.7%)than in the sparse TIA group(35.3%,x2=7.655,P=0.006).No significant correlation was observed between the multiple TIA and characteristics of carotid plaques in the focus side(x2=0.939,P=0.332).Conclusions Frequent TIA is significantly associated with a short duration of symptoms and≥50% stenosis of clinically relevant artery.Transient flow reduction by hemodynamic compromise may he an important mechanism of frequent TIA. Key words: Ischemic attack,transient; Constriction,pathologic;  Carotid arteries; Hemodynamic phenomena