Predictores de recurrencia clínica en los pacientes con ataque isquémico transitorio

Abstract

Since its first description in 1951 many clinical studies had been performed. Following a transient ischemic attack (TIA), up to 17% of patients have an stroke within the next 90 days. Although many studies attempted to determine prognostic factors among these patients strong predictors of recurrence had not been well defined. TIA are defined classically as reversible episodes of neurologic deficits of vascular origin that resolve completely within 24 hours. Recently, a new definition of a TIA has been proposed, based on the duration of symptoms (<1h) and imaging data (absence of ischemic lesion). Most TIA are resolved within 60 minutes, and the likelihood that symptoms will be resolved is <15% if symptoms last for >1h. New MRI techniques like diffusion-weighted imaging (DWI) demonstrated that almost half of all patients with clinical TIA syndrome have a ischemic lesion. OBJECTIVES 1. To determine the short and medium-term risk of ischemic events after emergency department diagnosis of TIA. 2. To investigate the value of DWI data on the prognoses of TIA patients 3. To determine the value of combined carotid/transcranial ultrasound testing (UST) on the prognosis of TIA patients 4. To investigate the relationship between high-sensitivity C-reactive protein (hs-CRP) and the risk of stroke recurrence in TIA patients. METHODS Inclusion criteria comprised: consecutive TIA patients attended by the neurologist in the emergency room. Clinical data, symptom duration, radiological and UST findings were collected. In the first work 83 consecutive classical TIA patients were followed-up. DWI findings were collected. In the second work 311 TIA patients were included. Large-artery occlusive disease were detected by UST in 70 patients (22,5). In the last work, 135 TIA patients were included. Hs-CRP level was determined within 24 hours after symptoms onset. Cox regression models and survival analyses were performed to evaluate predictors of ischemic events. RESULTS 1. DWI: A total of 27 (32. 5%) patients revealed focal abnormalities on DWI, whereas 37(44. 6%) had symptoms lasting <1 hour. Twenty (24. 1%) patients experienced an endpoint: 2 myocardial infarctions, 16 cerebral ischemic events, and 2 cases of peripheral arterial disease. Cox proportional hazards multivariate analyses identified the association of symptoms>1h with DWI abnormalities as independent predictors of further cerebral ischemic events or any vascular events (HR, 5. 02; CI, 1. 37 to 18. 30; P=0. 015; and HR, 3. 77; CI, 1. 09 to 13. 00; P=0. 029). 2. UST: A total of 20 patients suffered an stroke within 7 days of symptoms onset. During the next 90 days after index TIA, 51 (16. 4%) patients experienced an endpoint. Cox proportional hazards multivariate analyses identified the presence of intracranial stenoses (HR, 3. 05; CI, 1. 21 to 7. 70; p=0. 018) and carotid territory implication (HR, 15. 91; CI, 2. 11 to 120. 04; P=0. 007) as independent predictors of stroke within the first 7 days after index TIA. Moreover, at 90 day follow-up, large-artery occlusive disease was an independent predictor of stroke (HR, 3. 07; CI, 1. 76 to 5. 38; p<0. 001). 3. Hs-CRP: A total of 28 (20. 7%) patients experienced an end-point event. Cox proportional hazards multivariate analyses identified age (HR 1. 07, CI 1. 01 to 1. 12, p=0. 01), large-artery occlusive disease (HR 2. 73, CI 1. 16 to 6. 41, p=0. 02) and hs-CRP> 4. 1 mg/L (HR 2. 81, CI 1. 12 to 7. 10, p=0. 03) as independent predictors of stroke. CONCLUSIONS 1. The short and medium-term risk of stroke and other adverse events after emergency department diagnosis of TIA is high. 2. TIA patients with DWI abnormalities associated with duration of symptoms <1 hour have a higher risk of further vascular events. 3. Routine use of UST will be useful for identifying TIA patients at high risk 4. HS-CRP serum level, determined <24h after symptoms onset, predicts further ischemic events following TIA.

Date of Award	25 Jul 2005
Original language	Spanish
Supervisor	Joan Montaner Villalonga (Director) & Jose Alvarez Sabin (Director)