In a letter to cardiologists and transplant surgeons, the FDA said it is evaluating recent interim post-approval study results which suggest a higher mortality rate for patients treated with the Abiomed Impella RP System than the rate previously observed in the premarket clinical studies. The Impella RP System is a temporary right heart pump system intended to help patients maintain stable heart function without open chest surgery, the agency explained. “The FDA wants to ensure you are aware of the mortality rate that has been observed in the ongoing PAS,” the letter stated. It added, “Although the FDA is concerned about the high mortality rate from the interim PAS results, we believe that when the device is used for the currently approved indication in appropriately selected patients, the benefits of the Impella RP system continue to outweigh the risks.”