Abstract
Purpose : The purpose of the present study was to evaluate the availability of transcranial color-coded duplex sonography (TCDS) for detecting hemispheric hyperperfusion syndrome after carotid endarterectomy (CEA). Methods : This prospective study included 100 consecutive patients who underwent CEA for severe carotid stenosis. TCDS studies were serially performed to evaluate MCA flow velocity before and after CEA. Echo contrast agents were used when we could not detect MCA by conventional TCDS. Transoral carotid ultrasonography (TOCU) was also performed to evaluate the distal portion to the carotid stenosis before and 2 weeks after CEA. Regional CBF of MCA territory was evaluated quantitatively before and 4 and 14 days after CEA using single photon emission computed tomography (SPECT). Vasodilatory capacity was evaluated before CEA using SPECT with acetazolamide (ACZ) challenge. Results : By TCDS with echo contrast agents, we detected MCA in 90 (90%) among 100 patients. Twelve (13%) of them showed clinical symptoms of hyperperfusion syndrome after CEA. In patients with hyperperfusion syndrome, affected MCA mean flow velosity ratio (after CEA/before CEA) was higher than that in patients without hyperperfusion (2.19 ± 0.47 vs 1.28 ± 0.27 times, p<0.000l). All 12 patients with hyperperfusion syndrome had remarkable change (> 1.5 times) in MCA mean flow velocity at any time point 1 to 4 days after CEA. Affected MCA mean flow velosity ratio between before and 4 days after CEA were significantly correlated with that in rCBF(R=0.47, p < 0.0001). Symptomatic carotid stenosis (p < 0.05), severe carotid stenosis by NASCET method (p < 0.05), retrograde flow of the ophthalmic artery ipsilateral to CEA detected by cerebral angiography (p< 0.001), the narrow diameter of the ipsilateral distal carotid artery by TOCU (/><0.0l), and reduced ACZ reactivity (/>< 0.001) in the ipsilateral MCA territory all contributed to prediction of hyperperfusion syndrome. Multivariate analysis revealed that the grade of reduced vasodilatory capacity (OR ・ 0.13, 95% CI: 0.02-0.95) was an independent risk factor for hyperperfusion syndrome. Conclusions : TCDS with echo contrast agents is available for evaluation of hyperperfusion syndrome after CEA.
