The US FDA has sent a letter to transplant surgeons and cardiologists about the Syncardia temporary Total Artificial Heart (TAH-t) Companion 2 Driver. The letter states the final results of the post-approval study of the system indicate that it is associated with a higher stroke rate than a previous generation of the driver (the Circulatory Support System [CSS] Console). Therefore, the FDA is now recommending that transplant surgeons and cardiologists “carefully consider” the final results.
According to the letter, the FDA previously apprised the healthcare community about interim results comparing C2 Driver System patients to CSS console patients. On 15 June 2015, the FDA posted a letter indicating that interim data suggested a higher mortality rate for a subgroup of patients requiring pre-implant circulatory rescue interventions when using the C2 Driver System. On 26 October 2016, the FDA posted an update about the continued increased mortality rate for a subgroup of patients requiring pre-implant circulatory rescue interventions when using the C2 Driver System as well as additional interim study results that indicated a higher risk of neurological adverse events for C2 Driver System patients. On 25 September 2017, an update informed the health care community of a higher rate of cerebrovascular accidents (stroke) for C2 Driver System patients.
The letter goes on to detail the final mortality and stroke results from the post-approval study. These results show that survival for patients initially supported with the C2 Driver System was significantly lower than survival for patients initially supported with the CSS Console at three months and six months’ post-implant, and the study’s non-inferiority hypothesis was not met.
Furthermore, the letter notes, there was a higher mortality rate at six months’ post-implant for C2 Driver System patients who did not require pre-implant circulatory rescue interventions (such as intra-aortic balloon pump or extracorporeal membrane oxygenation) compared with those who received the CSS console—even though at three months’ post-implant the mortality rates were similar. For the subgroup of patients who did require pre-implant circulatory rescue interventions, the final results confirm the previously communicated finding of a higher mortality rate with the C2 Driver System at three months and six months’ post-implant.
Additionally, the stroke rate (a secondary endpoint) for patients initially supported with the C2 Driver System was statistically significantly higher than the stroke rate for patients initially supported with the CSS Console at three months and six months’ post-implant. Other neurological adverse event rates were similar between the two groups.
The FDA letter states: “The information provided in this letter is meant to assist physicians in understanding the performance of the TAH-t using the C2 Driver System as seen in the post-approval study. We recognise that the CSS Console is no longer available as a driver option for TAH-t patients, and that consequently, physicians may determine that the C2 Driver System is the most appropriate option for patients with severe biventricular failure in need of mechanical circulatory support.”
The key recommendations are:
- Carefully consider these mortality and stroke results from the TAH-t post-approval study when making treatment decisions, and discuss the risks and benefits of the C2 Driver System with patients.
- Report any adverse events or suspected adverse events experienced with the SynCardia TAH-t and Driver Systems. Voluntary reports can be submitted through MedWatch, the FDA Safety Information and Adverse Event Reporting program. Device manufacturers and user facilities must comply with the applicable Medical Device Reporting (MDR) regulations. Healt care personnel employed by facilities that are subject to the FDA’s user facility reporting requirements should follow the reporting procedures established by their facilities. Prompt reporting of adverse events can help the FDA identify and better understand the risks associated with medical devices.
- Return all devices associated with, or suspected to be associated with, any adverse events to the manufacturer for evaluation to help them and the FDA better understand the issue.
Syncardia’s TAH-t functions as a bridge to a heart transplant in a small population of heart failure patients with severe bi-ventricular failure. The TAH-t replaces a patient’s native ventricles and valves to completely take over pumping of blood to both the pulmonary and systemic circulation. The TAH-t is used with an external pneumatic driver which activates the implanted device. The C2 Driver System is one of the available external pneumatic drivers.
The TAH-t was initially approved for use by the FDA in 2004, with the CSS Console as its initial driver system. The FDA approved the smaller C2 Driver System in 2012. Both driver systems were approved for use only in the hospital setting. In addition to the in-hospital driver systems, the FDA approved the portable Freedom Driver System in 2014. The Freedom Driver System can be used outside of the hospital, allowing some TAH-t patients to return home while on the device.
