Early activation of intracranial collateral vessels influences the outcome of spontaneous internal carotid artery dissection.

BACKGROUND AND PURPOSE: the effectiveness of different treatments for internal carotid artery (ICA) dissection has not been well defined. Lack of early prognostic indicators may represent a major problem in adequately identifying the most appropriate option for treatment. This study aimed at evaluating the influence of patients' vascular risk profiles and of early cerebral hemodynamic changes in determining the clinical evolution after ICA dissection. METHODS: sixty-six stroke patients with ICA occlusion due to spontaneous artery dissection were included. Transcranial Doppler was performed within 24 hours from symptom onset to examine cerebral arteries and the patency of the 3 major intracranial collateral vessels (ophthalmic artery and anterior and posterior communicating arteries). Possible recanalization of the occluded ICA within the first month was evaluated. Stroke severity at onset was assessed with the National Institutes of Health Stroke Scale, whereas outcome was defined according to the modified Rankin Scale score at 90 days after stroke onset. RESULTS: forty patients had at least 2 activated intracranial collateral vessels. The remaining 26 patients, with none or only 1 collateral vessel, showed a significant increased risk of poor recovery (modified Rankin Scale score ≥ 2; adjusted relative risk=14.9; 95% CI, 3.24 to 68.46). Poor recovery was not associated with the occurrence of recanalization, with stroke severity at onset, or with vascular risk profile. CONCLUSIONS: early assessment of cerebral hemodynamic status and, in particular, the activation of intracranial collateral vessels, may help in predicting the outcome of stroke patients with ICA lumen occlusion as a result of spontaneous dissection.