The ARCHeR Trial: 30-Day Results
Experience with carotid stenting in high surgical risk patients compares favorably with historical CEA outcomes.
By Alicia Fagan
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The ARCHeR (ACCULINK for Revascularization of Carotids in High Risk Patients) trial is designed to evaluate the safety and efficacy of carotid artery stenting as a minimally invasive alternative for treating carotid artery disease in patients in whom CEA poses a high risk for perioperative complications. Mark Wholey, MD, presented the preliminary 30-day ARCHeR results at the recent American College of Cardiology meeting. The following is adapted from his presentation.
MATERIALS AND METHODS
Forty-one investigational sites enrolled a total of 437 consecutive patients who underwent stenting of the internal carotid artery using the ACCULINK Carotid Stent System (Guidant Corporation, Indianapolis, IN) (Figure 1A), including 278 patients treated with the ACCUNET Embolic Protection System (Guidant Corporation) (Figure 1B). The mean age for the study was 69.4 ± 9.6 years. Sixty-seven percent of patients were male; 33% were female. Eligible patients were either symptomatic or asymptomatic and met rigorous study criteria for high-risk surgical patients and/or nonsurgical patients. Clinical follow-up visits are scheduled for 1 month and at every 6 months thereafter. Follow-up visits include a carotid ultrasound and an independent neurological evaluation. An independent committee adjudicates all primary endpoint adverse events, and an independent core laboratory conducts angiographic analysis.
The primary endpoints of the ARCHeR trial are 1) a composite of stroke, death, and MI at 30 days and ipsilateral stroke between 31 days and 1 year; and 2) ACCUNET device success. Key secondary endpoints include ACCULINK device success, target lesion revascularization at 6- and 12-month follow-up examinations, and duplex carotid ultrasound evaluation at the 6-, 12-, and 24-month follow-up examinations.
High-Risk Inclusion Criteria
Patients were considered “high-risk” if they exhibited two or more of the following: two or more coronary vessels with &Mac179;70% stenosis; MI within 30 days, concurrent requirement for CABG or valve surgery within 30 days; unstable angina; or contralateral occlusion of the internal carotid artery. High-risk inclusion criteria also comprised patients with one or more of the following: ejection fraction <30% or New York Heart Association Functional Class &Mac179;III; forced expiratory volume 1 <30% (predicted); dialysis-dependent renal failure; uncontrolled diabetes; restenosis after previous CEA; previous radical neck surgery and/or radiation therapy; surgically inaccessible lesions; spinal immobility; tracheostomy stoma; or contralateral laryngeal nerve paralysis (Table 1).
The ACCULINK self-expanding nitinol stent is manufactured in straight and tapered models; straight model diameters range from 5 mm to 10 mm, and tapered model diameters taper from 8 mm to 6 mm or 10 mm to 7 mm. Straight ACCULINK stents are available in lengths of 20 mm, 30 mm, and 40 mm, and tapered models are manufactured in lengths of 30 mm and 40 mm. The ACCULINK is currently limited by federal law to investigational use only.
The investigational ACCUNET device is a guidewire-based filter basket comprised of a polyurethane filter over a nitinol basket. It is available in diameters ranging from 4 mm to 8 mm. The filter’s pore size is &Mac178;150 µm. The ACCUNET is also currently limited by federal law to investigational use only.
Patients were administered 325 mg of aspirin b.i.d. and 75 mg of clopidogrel b.i.d. for 48 hours prior to undergoing the procedure. During the procedure, heparin was used to maintain an ACT of &Mac179;250 seconds. After the procedure, patients were prescribed a daily regimen of 325 mg of aspirin for a minimum of 1 year and 75 mg clopidogrel for a minimum of 2 to 4 weeks.
The preliminary 30-day total major adverse event rate, which was defined as all-cause stroke, death, and myocardial infarction, was 7.8%. ACCULINK device success, defined as successful deployment of the stent and <50% residual stenosis, was 97.8%. The success rate for delivery, placement, and retrieval of the ACCUNET device was 92.7%. Fifty-seven percent of the filter baskets were retrieved with debris inside. Comprehensive 30-day event rates are displayed in Table 2.
The ARCHeR trial is one of the first trials to study carotid artery stenting in those patients who are high-risk surgical and nonsurgical candidates for CEA. Its preliminary 30-day major adverse event rate of 7.8% compares favorably with historical CEA outcomes; in similar high-risk CEA patient cohorts, stroke, death, and MI exceed 10%. These preliminary results demonstrate that carotid stenting with filter protection can be safely performed in high-risk surgical patients.
Alicia Fagan is a freelance medical writer. She holds no financial interest in any product or manufacturer mentioned herein. Material adapted from Mark H. Wholey, MD’s, presentation entitled, “The ARCHeR Trial: Results for Carotid Stenting in High Surgical Risk Patients: Preliminary 30 Day Results,” given on March 30, 2003, at the American College of Cardiology Scientific Meeting in Chicago.