Cerebral hemodynamics in asymptomatic and symptomatic patients with high-grade carotid stenosis undergoing carotid endarterectomy Soinne L, Helenius J, Tatlisumak T, et al. Stroke 2003;34:1655-61

AbstractConclusionHemodynamic adaption to high-grade carotid stenosis is inferior in patients with symptomatic carotid stenosis compared with those with asymptomatic carotid stenosis, and there are differences in the cerebral hemodynamic response to carotid endarterectomy (CEA) in patients with symptomatic and asymptomatic carotid stenosis.SummaryThe authors used dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI ) and transcranial Doppler scanning techniques to investigate hemodynamic changes in cerebral perfusion induced by carotid stenosis and how they were affected by CEA. In addition, they sought to determine whether there were differences between patients with asymptomatic and symptomatic carotid stenosis. Finally, they examined differences between gray and white matter, and watershed regions with respect to these hemodynamic changes.Twenty three patients with asymptomatic high-grade unilateral carotid stenosis and 23 patients with symptomatic high-grade unilateral carotid stenosis were examined with DSC-MRI and transcranial Doppler ultrasound scanning before CEA and subsequently 3 and 100 days after CEA. Patients with symptomatic carotid stenosis, in comparison with patients with asymptomatic carotid stenosis, had increased preoperative transit time of the MRI contrast bolus and lower cerebral blood flow values in the hemisphere ipsilateral to the high-grade carotid stenosis. These flow abnormalities were more pronounced in white matter and watershed regions than in gray matter regions. Asymmetric flow patterns between hemispheres were abolished with CEA. Improvements over time were greater in patients with symptomatic carotid stenosis. With regard to changes with transcranial Doppler scanning, a breath-holding index, a measure of cerebrovascular reactivity, improved in the symptomatic carotid stenosis patients after CEA. There was no change in the asymptomatic patients after CEA.CommentThe improved ability of patients with asymptomatic carotid stenosis to hemodynamically adapt to the high-grade carotid lesion may partially account for a lesser benefit of surgery in patients with asymptomatic carotid disease