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NEW YORK -- Community-based interventionalists and surgeons can be trained to perform catheter-based carotid stenting in high-risk patients just as well as those who tested the devices in the studies that led to FDA approvals, researchers reported.
NEW YORK, Dec. 15 -- Community-based interventionalists and surgeons can be trained to perform catheter-based carotid stenting in high-risk patients just as well as those who tested the devices in the studies that led to FDA approvals, researchers reported.
A large study of the post-approval transfer of carotid stenting with embolic protection found that rigorous training prepared community interventionalists and surgeons with varying experience to handle the new therapy effectively, according to an online report to appear in the January 2007 issue of Catheterization and Cardiovascular Interventions.
In 2004, the FDA approved the first carotid stenting system, the RX Acculink Carotid Stent, a self-expanding nitinol device, and the RX Accunet Embolic Protection System (Abbott Vascular), a filter to capture potential released emboli.
The agency required a standard post-approval "conditions of approval" study to supplement pre-market data by evaluating clinical outcomes with the use of a specific device in a larger patient cohort under "real world" circumstances, according to William A. Gray, M.D., of Columbia University here, and colleagues.
From October 2004 to March 2006, 3,500 patients with asymptomatic and symptomatic atherosclerotic disease, not suited for carotid endarterectomy, were enrolled by 353 physicians at 144 sites.
The study, known as the Carotid Acculink/Accunet Post-Approval Trial to Uncover Unanticipated or Rare Events (CAPTURE), was a prospective, multicenter trial to assess the safety of carotid stenting by physicians with varying levels of experience. The goal was to measure the adequacy of physician training and to identify possible rare and unexpected device-related complications.
Physicians were classifed from the most experienced carotid interventionalists (level 1, participated in carotid stenting studies), to the less experienced (level 2, having done 10 carotid stent procedures as the primary operator), to the least experienced (level 3, having done 25 carotid angiograms as well peripheral procedures with self-expanding stents).
Although most patients were treated by physicians with level 2 experience, the majority of level 2 and 3 physicians and sites had not participated in carotid stenting studies, the researchers said.
Only a small percentage of the patients (8.1%) were treated by the most experienced operators and at the most experience sites. Most (55%) of the study procedures were performed by interventional cardiologists, 21.8% by vascular surgeons, and 23.2% by neurosurgeons, interventional radiologists, or neuroradiologists, the researchers reported.
The primary endpoint of the CAPTURE trial was a composite of death, any stroke, or myocardial infarction within 30 days of the procedure.
The 30-day composite rate was 6.3% (95% CI: 5.5-7.1%) and did not differ among the three experience levels (5.3%, 6.0%, and 7.4%; P=0.31) from most to least experienced, respectively, the researchers reported.
After adjusting for two significant predictors, symptomatic status and age, no statistically significant difference across the three levels was found for death (P=0.64) or any other outcome.
There were no differences in outcomes among physician specialties, when adjusted for case mix, and there were no unanticipated device-related adverse events (events not identified in the device labeling or occurring at high rates), Dr. Gray said.
Ten rare device-related events (<0.1%) included stent thrombosis in one patient, and seven reports of RX Accunet filter basket separation. After the device was modified in May 2005, there were no adverse events, the researchers reported.
These data also provide objective evidence that the manufacturer's device-specific training program was effective in preparing physicians to do carotid artery stenting, the researchers said.
All physicians in the training program received manufacturer-conducted mandatory training, including hands-on training with the Acculink and Accunet devices.
Less experienced physicians had a structured two-day carotid training program of didactic sessions, case reviews, and hand-on device and simulator training focused on clinical management, imaging, and procedural education. After that, the manufacturer supported the physicians' first three cases, and proctoring by an expert physician was available.
Discussing the study's limitations, the researchers wrote that because this was an observational study, no formal statistical hypothesis comparing pre-market and commercial experience had been previously established.
Furthermore, they said, there were no central core laboratories to confirm severity of carotid artery disease, angiographic outcomes, or confirmation of coronary events. Lastly, the symptomatic patient population and Level 1 physicians were relatively under-represented in this trial, the investigators said.
The results of the CAPTURE study demonstrate that the post-approval transfer of this new therapy to the community practice by way of training programs is effective, with outcomes that match those of more experienced physicians, the researchers said.
"This model of rigorous FDA-mandated training combined with careful post-marketing study, may be applicable to the introduction of other new medical technologies," Dr. Gray and his team concluded.