Abstract WP137: Improvement of Cerebrovascular Reactivity After Carotid Stenting is Greater in Non-Diabetic than in Diabetic Patients: a Bold-FMRI Study.

Abstract

Background: Cerebrovascular reactivity (CVR) has been suggested as an independent predictor of stroke in patients with severe carotid stenosis. Functional-MRI (fMRI) can be used to assess CVR by comparing latency parameters of the neurovascular coupling, i.e. BOLD response at baseline and during hypercarbic challenge. We aim to compare BOLD amplitude and latency parameters in the ipsilateral (IH) and contralateral hemispheres (CH) induced by auditory stimulus, under different hypercapnia levels in diabetic and non-diabetic patients with symptomatic carotid stenosis, before and after carotid stenting. Methods: seven diabetic and eight non-diabetic patients with unilateral severe symptomatic carotid stenosis and similar clinical characteristics were evaluated. The protocol was undertaken one week before and three months after the endovascular intervention. Subjects were submitted to auditory stimulus (3s) under normocapnia and EtCO2 increase of 5 and 10mmHg. The images were acquired with a 3T MRI-scanner, preprocessed and BOLD response amplitude and latency parameters were analyzed. Results: We observed decreased BOLD amplitude in the IH compared to the CH (p<0.05) in non-diabetic patients in hypercapnic conditions, and was compromised bilaterally in diabetic patients before the stenting. In diabetic patients the mean change on BOLD latency parameters were not significant with CO2 increment. After carotid stenting, BOLD amplitude (p<0.05) under hypercapnic conditions and area under the curve (P<0.05) were increased for non-diabetic patients but not for diabetic patients. Conclusions: diabetic patients have diffuse baseline compromise of CVR and their cerebrovascular reactivity measured on BOLD fMRI does not respond to carotid stenting as non-diabetic patients.