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 post-approval study is a 6-month, multi-center, single arm, prospective cohort study. All subjects in
the study receive the device.
Study Population Description
Study Population: Patients with an accepted indication for an implantable cardioverter defibrillator implant. Indication: The
device is indicated for use in patients who are at high risk for sudden death due to ventricular tachyarrhythmia who have experienced at least one episode of cardiac arrest due to tachyarrhythmia or who have recurrent poorly tolerated, sustained ventricular tachycardia.
60 subjects at 5 sites
Endpoints include incidence and nature of device related adverse events through 6 months follow-up (safety)
and the percentage of patients with two successful reductions of ventricular fibrillation (VF) at 24Joules (10 Joules below maximum output) at implant (effectiveness).
Followup Visits and Length of Followup
Patients will be evaluated at implant, 3 months, 6 months, and at unscheduled visits as
needed for adverse events and effectiveness of device therapy.
Final Study Results
Actual Number of Patients Enrolled
Actual Number of Sites Enrolled
77 successful implants (85 enrolled)
Patient Followup Rate
84.4% (65 patients completed study of 77 implanted)
Final Safety Findings
There were 12 applicable system complications in 8 patients for a 6-month system complication free
rate of 89.6% (95% lower confidence bound: 85%). There were 4 deaths; none were device related. There were 12 serious, implant- or device-related events (complications) including: 2 pocket infections, 3 lead dislodgement/migrations, 1 non-conversion of ventricular tachycardia (VT) or ventricular fibrillation (VF), 3 lead losses of capture, 1 elevated pacing threshold, 1 pocket erosion, and 1 cardiac perforation. All were resolved within one day, except the 2 pocket infections which required explant of the device.
Final Effectiveness Findings
Two successful reductions of VF occurred in 72 of the 77 implanted patients (93.5%; 95%
CI 89-98%). Four patients received 7 shocks for spontaneous VT or VF in the six months following implant. All had successful reductions of VT or VF. The sensitivity for correctly detecting and shocking induced VT or VF was 99.5%. The sensitivity for spontaneous VF was 100%. The sensitivity for spontaneous VT was 100%. And, the specificity for (correctly detecting and not shocking) supraventricular tachycardia or sinus tachycardia was 99.1%.
Study Strengths and Weaknesses
The purpose of the study was to follow at least 60 patients for 6 months
and to report on complications and successful shocks during that time. There was no stated hypothesis or specified maximum attrition rate. Thus, the results are descriptive and representative of the patients who completed the 6 month follow-up and not necessarily all patients who utilize this device.