FDA Questions for Circulatory System Devices Panel
Acorn CorCap Cardiac Support Device
June 22, 2005
Evaluation of Device Safety
The patient operative reports indicate that performing a subsequent operation on CorCap patients was complicated by the presence of dense adhesions.
1. Please comment on whether placement of the CorCap device, and the resulting increased difficulty for follow-on surgery, especially coronary bypass operations, will compromise patient safety during a subsequent operation.
Forty two patients had evidence of constrictive physiology on at least one echocardiogram after CorCap implantation.
2. Please comment on whether there is adequate information to assess whether placement of the CorCap CSD causes clinically significant pericardial constriction.
The regulations under which a Pre Market Application is assessed for marketing approval require demonstration of a reasonable assurance of safety.
Evaluation of Device Effectiveness
As the protocol evolved during the course of the trial FDA requested that NYHA class be assessed by a blinded observer rather than by the site investigator. Blinded assessment of NYHA class at entry was not available for more than half of the patients; their NYHA class (for the purpose of the statistical analysis of the composite primary effectiveness endpoint) was imputed using a statistical model.
The primary determination of device effectiveness was assessed by a composite of mortality, NYHA score and the necessity of re-operation for worsening heart failure. As individual measures neither mortality nor NYHA class were statistically significantly improved in device as compared to control patients. However, CorCap patients experienced significantly fewer re-operations (to treat worsening heart failure) than did patients in the control group.
Secondary measures of device effectiveness included measures of ventricular geometry (e.g., left ventricular dimensions) and patient quality of life (MLHF and SF-36) and functional status (6 minute walk and MVO2).
One aspect of the pre-market evaluation of a new product is the review of its labeling. The labeling must objectively describe which patients are appropriate for treatment, indicate potential adverse events associated with the use of the device, and explain how the product should be used to maximize clinical benefit and minimize adverse events. If you recommend approval of the device, please address the following questions regarding product labeling.
a. The majority of patients studied had dilated cardiomyopathy and yet the number one cause of heart failure in the U.S. is ischemic cardiomyopathy. Please comment on whether the results of this study can be extrapolated to an ischemic cardiomyopathic population.
b. Do the proposed Indications for Use adequately define the patient population studied and for which the device will be marketed?
c. Are there any additional warning, precautions, or contraindications that you think should be included in the labeling to assist practitioners?
Selection of patients to receive heart failure therapy with, and surgical placement of, the CorCap CSD requires the referring cardiologist and the surgeon to assess multiple factors, some of which are unique to the device. The sponsor has not included a physician training program as part of the proposed labeling.
Post Approval Study
The sponsor has proposed a post-approval study to include up to 348 patients who will be followed for 5 years, the intent being to follow the long-term performance of the CorCap CSD in the general patient population.
Traditionally, the most common etiology of heart failure is ischemic disease, however, a majority of patients in the clinical trial had heart failure that was idiopathic (61%), and the trial included a much smaller number of patients with heart failure due to ischemic disease (10%).