Cerebral ischemia after carotid intervention

PURPOSE

To determine the incidence of symptomatic and asymptomatic cerebral ischemic lesions found on diffusion-weighted magnetic resonance imaging (DW-MRI) after carotid interventions.

METHODS

A prospective study was conducted to assess new cerebral ischemic lesions using DW-MRI in symptomatic patients with carotid artery disease undergoing protected carotid artery stenting (CAS) or carotid endarterectomy (CEA). DW-MRI was performed before and after the intervention in 44 patients (21 CAS and 23 CEA). Two experienced radiologists not involved in the carotid procedures or neurological assessment compared the postprocedural DW-MR images with those acquired before the intervention.

RESULTS

Three (6.8%) of the 44 patients suffered strokes: 1 major and 1 minor stroke after CEA and 1 minor stroke after CAS. DW-MRI showed 15 new hyperintense lesions in 2 (9%) of 23 CEA patients; 31 new hyperintense lesions were found in 9 (43%) of the 21 CAS patients. The majority of new lesions were located in the ipsilateral vascular territory; 2 CAS patients also showed 6 new hyperintense lesions in the cerebellum. The mean lesion load per patient was 2.52 cm(3) (range 0.31-4.74) in the CEA group and 1.74 cm(3) (0.03-9.72) in the CAS group (p=0.35). The volume of the individual lesions in CEA patients was 0.39 cm(3) (range 0.01-2.16) compared to 0.52 cm(3) (range 0.01-5.47) in the CAS group (p=0.23). Patients who were asymptomatic after the intervention had fewer lesions (p=0.03) and a smaller lesion load than symptomatic patients.

CONCLUSIONS

Ischemic lesions were more frequently seen on DW-MRI after carotid stenting than after endarterectomy. The majority of the detected lesions did not cause neurological deficits.

Comparison of Catecholamine Hormone Release in Patients Undergoing Carotid Artery Stenting or Carotid Endarterectomy

PURPOSE

To investigate the pattern of catecholamine response in patients undergoing carotid endarterectomy (CEA) or carotid artery stenting (CAS).

METHODS

Adrenaline, noradrenaline, and renin levels were measured at 5 time points in 12 patients undergoing 13 CEAs (1 bilateral) and 13 patients undergoing unilateral CAS. Arterial blood samples were taken at the following time points: (1) after induction in CEA patients or 5 minutes following first contrast injection in CAS patients, (2) 5 minutes following ICA clamp release in surgical patients or deflation of the balloon in the CAS cohort, (3) 60 minutes following ICA clamp release in surgical patients or deflation of the balloon in the CAS cohort, and (4) 24 hours following the procedure. Intraoperative blood pressure and heart rate were recorded using radial arterial monitoring. Changes in adrenaline, noradrenaline, and renin levels are expressed as ratios versus baseline.

RESULTS

Patterns of adrenaline and noradrenaline release were significantly different in patients undergoing CAS and CEA, with much higher and more variable surges of adrenaline and noradrenaline occurring in CEA patients. Adrenaline and noradrenaline levels increased significantly over baseline following carotid artery clamping in patients undergoing CEA (noradrenaline ratio before clamping: 1.54+/-1.25, 24 hours after unclamping: 8.38+/-16.35 [p<0.001]; adrenaline ratio before clamping: 1.12+/-0.49, 60 minutes after unclamping: 17.59+/-19.14 [p<0.001]). Conversely, in patients undergoing CAS, catecholamine levels remained unchanged (noradrenaline ratio before dilation: 0.96+/-0.23, 24 hours after the procedure: 0.92+/-0.32 [p=NS]; adrenaline ratio before dilation: 0.83+/-0.33, 60 minutes after balloon deflation: 0.56+/-0.32 [p=NS]).

CONCLUSIONS

CAS is associated with a significantly less marked catecholamine response than CEA, which may reflect down-regulation of the sympathetic nervous system in response to carotid sinus stimulation during carotid angioplasty.