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U.S. Department of Health and Human Services

Post-Approval Studies (PAS) Database

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The FDA has the authority to require sponsors to perform a post-approval study (or studies) at the time of approval of a premarket approval (PMA), humanitarian device exemption (HDE), or product development protocol (PDP) application. Post-approval studies can provide patients, health care professionals, the device industry, the FDA and other stakeholders information on the continued safety and effectiveness (or continued probable benefit, in the case of an HDE) of approved medical devices. This database allows you to search Post-Approval Study information by applicant or device information.

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Study Status Progress Adequate
Application Number /
Requirement Number
P200037 / PAS001
Date Original Protocol Accepted 07/27/2021
Date Current Protocol Accepted  
Study Name ACE-PAS
Device Name ASSURE Wearable Cardioverter Defibrillator (WCD) System
General Study Protocol Parameters
Study Design Active Surveillance
Data Source Sponsor Registry
Comparison Group Objective Performance Criterion
Analysis Type Analytical
Study Population Adult: >21
Detailed Study Protocol Parameters
Study Objectives Active surveillance study using real-world data collected in the ASSURE Registry. Outcome measures are based on analysis of ASSURE Registry data including data recorded by the ASSURE system which has been annotated by clinical experts in electrophysiology.
Study Population Adult patients prescribed the ASSURE system who have consented to participate in the ASSURE registry
Sample Size A total of 271 appropriate shock episodes for VT/VF is required to provide the desired level of statistical precision for the primary efficacy endpoint (overall shock conversion rate). It is estimated that a total of 5,179 patients will be required to provide data on 271 appropriate shock episodes.
The required sample size is based on the following assumptions:
• Performance goal of 89% for overall shock conversion rate
• Estimated ASSURE system overall shock conversion rate of 94%
• Endpoint will be met if lower bound of a 2-sided 95% exact confidence interval greater than or equal to the performance goal of 89%
The estimated number of patients required was derived from a literature review of prospective studies (6) that presented shock data for LifeVest. In these studies, 27/804 (3.36%) patients had a total of 42 appropriate shock episodes, or an average of 1.555 (42/27) shock episodes per patient. It is expected, therefore, that 174 (271/1.555) ASSURE Registry patients will account for the 271 required appropriate shock episodes. If only 3.36% of the ASSURE Registry patients will experience one or more appropriate shock episodes, a total of 5,179 (174/0.0336) patients are required to provide data on 271 appropriate shock episodes for VT/VF.
Key Study Endpoints Effectiveness
Objective: To evaluate shock effectiveness in converting ventricular tachycardia/ventricular fibrillation (VT/VF)

Primary Endpoint: Overall shock conversion rate [percent of spontaneous episodes of ventricular tachycardia/ventricular fibrillation (VT/VF) successfully converted with one or more shocks] =89.0%

Secondary Endpoint: First shock conversion rate [percent of spontaneous episodes of ventricular tachycardia/ventricular fibrillation (VT/VF) converted with a single shock] (report only)

Rationale for Effectiveness Performance Goal: The overall performance goal is based on results from LifeVest German Registry data in which the overall shock conversion rate was 94.0% for 163 appropriate shocks delivered in a population of 6,043 patients. Applying a non-inferiority margin of 5% results in a performance goal of 89%.

Objective: To evaluate the prevalence of inappropriate shocks

Primary Endpoint: Inappropriate shocks per patient-month of use [total inappropriate shocks/cumulative months of device use for all patients] = 0.0075
Secondary Endpoint: Inappropriate shock rate [percent of patients who experience at least one inappropriate shock] (report only)

Rationale for Safety Performance Goal: Based on results from two registry studies and the manufacturer reported rate which cumulatively report 0.0071 inappropriate shocks per patient month (1363 inappropriate shocks/191,743 months of cumulative wear time). The upper bound of a two-sided 95% confidence interval around 0.0071 is 0.0075.

• Appropriate shock rate per month
• Percent of patients who experience at least one appropriate shock
• Total shocks delivered
• Shocks diverted by Alert Button press

• False Positive Shock Alarm rate
• True Positive Shock Alarm rate
• Adverse Events

• Average Daily Usage (hours)
• Device usage in days
Follow-up Visits and Length of Follow-up The device will be used temporarily (days of use), and the data will be obtained from that period of use. No additional patient follow-up is required.
Interim or Final Data Summary
Interim Results N/A because outcome measures will be reported after 500 patients are enrolled
Actual Number of Patients Enrolled 382
Actual Number of Sites Enrolled N/A because the study is using real world data.
Patient Follow-up Rate N/A because this study uses RWE

ACE-PAS Reporting Schedule

Reporting Schedule
Date Due
FDA Receipt
Applicant's Reporting Status
6 month report 01/25/2022 01/28/2022 Overdue/Received
1 year report 07/27/2022 07/27/2022 On Time
18 month report 01/25/2023    
2 year report 07/27/2023    
3 year report 07/26/2024    

Contact Us

Mandated Studies Program
Food and Drug Administration
10903 New Hampshire Ave.
Silver Spring, MD 20993-0002
Email: MandatedStudiesPrograms@fda.hhs.gov

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