Recanalization Results After Carotid Stent Placement
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Patient Selection
Between 1997 and 2000, 52 extracranial carotid stent procedures were performed in 51 patients in whom high-grade carotid artery stenoses had been diagnosed at clinical neurologic examination and Doppler and duplex sonography. Prior to therapeutic decisions, all patients underwent diagnostic angiography and CT or MR imaging of the brain. The carotid stent was approved by our local ethics committee. Our institutional review board approved the study protocol, and all patients provided written informed consent.
The indication for endovascular treatment was determined by means of an interdisciplinary conference between neurologists (A.D., M.S., H.S.), vascular surgeons (T.S-R.), and neuroradiologists (J.B., B.T.). We selected digital subtraction angiographic (DSA) and Doppler sonographic studies of 40 consecutive interventions performed in 39 patients with high-grade atherosclerotic stenoses for retrospective imaging analysis of the vascular anatomy before and after stent placement. Patients with restenoses after carotid endarterectomy (n = 7) and other nonatheromatous lesions (n = 5) were excluded. The mean age of the selected patients (22 men, 17 women) was 67 years (range, 53-84 years). All stenoses chosen for review were 70% or greater, as measured angiographically according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria (8). In addition to the 34 symptomatic lesions, we treated six asymptomatic plaques that caused progressive stenosis of luminal narrowing of 80% or greater. Because of obstructions in several cerebral vessels, concomitant diseases, or old age, the patients scheduled for endovascular treatment were supposed to be high-risk candidates for carotid endarterectomy. For these reasons, 27 (69%) of them would not have met the NASCET inclusion criteria (8).
Interventional Technique
All stent procedures were performed with anesthesiologic monitoring and neurologic control. The patients received antiplatelet therapy, with a combination of 100 mg acetylsalicylic acid and 75 mg clopidogrel, which was started 3 days before the intervention and continued for 3 months. A bolus of heparin, 150 IU/kg, was given only during the stent procedure. After 3 months, monotherapy with acetylsalicylic acid, 100 mg, was administered permanently.
All stents were implanted via a transfemoral approach through an 8F or 9F guiding catheter with balloon protection, according to the technique initiated by Thйron et al (2). Angioplasty was performed and the stent deployed with temporary balloon occlusion of the distal ICA. Blood flow was not restored until potential emboli had been aspirated or flushed into the external carotid artery (ECA) territory. In the first 24 procedures, we used a 3-mm-long custom-made microcatheter (Cordis, Miami, FL) with a hand-mounted latex balloon (Nycomed, Paris, France) at its tip for protection. A steerable guidewire with an integrated balloon (Guard Wire; Percu-Surge, Sunnyvale, CA) was used to replace the handmade catheter during the last 16 stent procedures. The stenosis was predilated with a percutaneous transluminal angioplastic (PTA) balloon catheter (3-mm diameter, 20-mm length) if the caliber of the stent delivery system exceeded the diameter of the residual lumen.
Self-expanding Easy Wallstents (Schneider-Boston-Scientific, Galway, Ireland) (n = 18); rolling membrane Wallstents (n = 6); and carotid Wallstents (n = 18) with nominal sizes of 8-mm diameter, 20-mm length (n = 4); 8-mm diameter, 30-mm length (n = 21); 10-mm diameter, 30-mm length (n = 9); and 10-mm diameter, 40-mm length (n = 8) were implanted to cover the entire plaque. Two patients received two stents. After stent deployment, all stenoses were postdilated with 5-mm to 2-cm PTA balloons. Preinterventional high-resolution color-coded duplex sonography (Elegra; Siemens, Erlangen, Germany) with a 7.5-MHz linear probe was performed to determine the diameters of the CCA, ICA, and residual lumen, as well as the length of the stenosis for correct sizing of the stents and PTA balloons. All stent diameters were adapted to the diameter of the CCA or carotid bulb and oversized in relation to the ICA diameter.
Anatomic Results of Treatment
Two neuroradiologists (J.B., H.L.) without knowledge of the corresponding sonographic findings reviewed the pre- and postinterventional angiograms. Two certified operators (B.T., A.D.) performed high-resolution sonography. The same operator (J.B.), who had knowledge of all angiographic findings and who collected the data from the sonographers after the evaluation of the angiograms, implanted all stents. Angiographic images were discussed with a second angiographic evaluator (H.L.) who was not involved