The FDA has updated a letter to health care providers about a lower survival rate with a temporary right heart pump system in patients from a postapproval study who would not have been eligible for the premarket clinical studies compared with the survival rate from the premarket clinical study.
The current letter is an update from the Feb. 5 letter from the FDA about the temporary right heart pump system (Impella RP system, Abiomed). As Cardiology Today previously reported, the letter from the FDA alerted health care providers about the increased rate of mortality in patients who have received a temporary right heart pump system in a recent interim postapproval study compared with what was previously observed in premarket clinical studies.
Postmarket approval study
The most recent postapproval study results found that 28.6% of patients survived to 30 days after device explantation or hospital discharge or to the initiation of the next long-term therapy, according to the letter. Premarket clinical studies had a survival rate of 73.3%.
Patient selection may have played a role in the difference in survival outcome. The subgroup of patients from the postapproval study who would have been eligible for the premarket clinical studies would have had a survival rate of 64.3%, which was similar to the survival rate in the premarket clinical study. Those who would not have qualified for the premarket clinical study had a survival rate of 10.7%, according to the letter.
Before the system was implanted, patients from the postapproval study who would not have qualified for the premarket clinical studies were more likely to have a cardiac arrest, cardiogenic shock for longer than 48 hours or a preimplant hypoxic or ischemic neurologic event vs. those who would have been eligible for the premarket clinical studies.
The FDA is continuing its evaluation of the postapproval study for the system, according to the letter. The FDA approved updated labeling in April with information on patient selection. Changes to the system’s design were also required by the FDA. The survival rate in the postapproval study will continue to be monitored by the FDA and Abiomed.
The FDA recommends that health care providers are made aware that the approval of the system was based on premarket clinical studies with patients who were in cardiogenic shock for less than 48 hours before implantation, according to the letter. None of the patients from the premarket clinical studies were treated with an intra-aortic balloon pump, had an in-hospital cardiac arrest or had an ischemic or hypoxic neurologic event before device implantation.
“Although these clinical events may not preclude a clinical decision to use the device, physicians should be aware that the occurrence of one or more of these events prior to Impella RP implantation may decrease expected survival rate,” the FDA wrote in the letter.
Health care providers should also consider survival results from the postapproval study when deciding what treatment option to proceed with and to have a benefit-risk discussion with their patients, according to the letter. Any events related to the system should be reported to the FDA.
“Based on our current analysis, the FDA believes 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,” the FDA wrote in the letter.