Early cerebral hemodynamic changes following unilateral carotid artery stenting in patients with different degrees of carotid stenosis

BACKGROUND: Few studies have focused on cerebral hemodynamics in the early stage following carotid artery stenting (CAS). This retrospective cohort study aimed to investigate cerebral hemodynamic changes within 6 hours of unilateral CAS in patients with different degrees of carotid stenosis. METHODS: A total of 104 patients who underwent CAS accompanied by transcranial color-code Doppler or transcranial Doppler were enrolled in the study. The participants were divided into the following 3 groups based on the degree of carotid stenosis: severe stenosis group, extreme stenosis group, and near occlusion group. Bilateral middle cerebral artery (MCA) peak systolic velocity (PSV) and pulsatility index (PI) were measured using transcranial color-code Doppler before and 1 and 3 hours following CAS. Blood pressure, MCA-PSV, and PI were compared among the 3 groups. RESULTS: At 1 hour following CAS, ipsilateral MCA-PSV increased compared to the baseline in the severe stenosis group [84±21 vs. 93±27 cm/s; 8.1%; interquartile range (IQR), 1.4–20.1%; P<0.001]. A similar hemodynamic change, but of a larger magnitude, was observed in the extreme stenosis group (83±24 vs. 100±29 cm/s; 20.8%; IQR, 5.3–33.1%; P<0.001) and near occlusion group (73±24 vs. 109±29 cm/s, 45.8%; IQR, 24.3–73.1%; P<0.001). At 3 hours after CAS, the hemodynamic changes were the same as those at 1 hour. PI increased in all 3 groups following CAS. A subgroup analysis was performed according to symptoms, sex, smoking status, history of hypertension, and presence of hyperlipidemia or diabetes, and the increase in ipsilateral MCA-PSV was not significant. In terms of adverse events, only 4 patients in the near occlusion group experienced transient post-CAS hyperperfusion. CONCLUSIONS: The ipsilateral MCA-PSV and PI in patients following unilateral CAS increased significantly in the initial hours. The increase in ipsilateral MCA-PSV was considerably higher in patients with a severe degree of stenosis. Near occlusion of the carotid artery was an independent risk factor for hyperperfusion after unilateral CAS.