In January 2005, the oversight responsibility of the Post-Approval Studies Program was transferred to the Division of Epidemiology (DEPI) of the Office of Surveillance and Biometrics (OSB)/Center for Devices and Radiological Health (CDRH).
The CDRH Post-Approval Studies Program encompasses design, tracking, oversight, and review responsibilities for studies mandated as a condition of approval of a premarket approval (PMA) application, protocol development product (PDP) application, or humanitarian device exemption (HDE) application. The program helps ensure that well-designed post-approval studies (PAS) are conducted effectively and efficiently and in the least burdensome manner.
CDRH has established an automated, internal tracking system that efficiently identifies the reporting status of active PAS studies ordered since January 1, 2005 based on study timelines incorporated in study protocols and agreed upon by the CDRH and applicants. This system represents CDRH's effort to ensure that all PAS commitments are fulfilled in a timely manner.
In addition, CDRH launched this publicly available webpage to keep all stakeholders informed of the progress of each PAS. The webpage displays general information regarding each PAS, as well as the overall study status (based on protocol-driven timelines and the adequacy of the data) and the applicant's reporting status for each submission due.
The primary objective of the study was to determine whether morbidity and mortality for high-risk
surgical patients treated with the NexStent Over the Wire in conjunction with the FilterWire EXIEZ System Distal Protection Device will be less than an Objective Performance Criterion derived from historic controls undergoing surgical intervention with carotid endarterectomy.
Study Population Description
The NexStent Carotid Stent System used in conjunction with the FilterWire EZ System, is indicated
for treatment of patients at high risk for adverse events from carotid endarterectomy who require carotid revascularization and meet the criteria outlined below 1) Patients with neurological systems associated with >50% stenosis of the common or internal carotid artery OR patients without neurological symptoms and >80% stenosis of the common or internal carotid artery by ultrasound or angiogram AND 2) Patients must have a reference vessel diameter within the range of 4 mm and 9 mm at the target lesion and a stenosis less than 30 mm in length. The subject population being studied included subjects indicated for NexStent Carotid Stent System placement.
488 patients including 454 registry patients and 34 Roll-In patients, 21 sites
Primary safety endpoints include: 1) Major clinical events at one-year defined as any death, stroke
or myocardial infarction, and 2) 30 day event rate defined as any death, stroke or myocardial infarction at 30 days post-procedure. 12 month event rate defined as the 30 day event rate plus any ipsilateral stroke and/or death as a result of an ipsilateral stroke.
Followup Visits and Length of Followup
Follow-up at 30 days and one year post procedure
Final Study Results
Actual Number of Patients Enrolled
Actual Number of Sites Enrolled
Patient Followup Rate
Final Safety Findings
On June 6, 2008, BSC initiated a voluntary recall of all units of the NexStent
Carotid Stent System due to reported complaints involving detachment of the tip from the stent delivery System.
Study Strengths and Weaknesses
Strengths: The post-approval study was able to detect an early problem involving detachment of the
tip from the stent delivery system. Weaknesses: There was no predetermined hypothesis for postapproval analysis.
Recommendations for Labeling Changes
Nexstent carotid stent was taken off the market due to adverse events that have occurred
as part of the SONOMA post-approval study. Labeling changes were not recommended since the device is no longer marketed.