Recent studies have proven Abbott’s wireless pulmonary artery (PA) sensor CardioMEMS HF System to be successful in reducing heart failure hospitalizations and dramatically lowering medical costs, but a study published in the Journal of the American Medical Association this month questions the safety of the device.

The CardioMEMS HF System is the first wireless PA sensor approved by the U.S. Food and Drug Administration (FDA) that has been clinically proven to slash medical bills, reduce hospitalizations and improve the quality of life in heart failure patients. Still, Muthiah Vaduganathan, MD, MPH, and colleagues wrote in their study, not much safety data about the device is available. Since the success of the sensor—based on a randomized-single blinded study of 550 patients—was announced years ago, the device has been implanted in thousands of heart failure patients who are older and at higher risk for cardiovascular complications than those who participated in the initial study.

Vaduganathan and his team analyzed information from the Manufacturer and User Facility Device Experience (MAUDE) database to gauge the safety of the CardioMEMS system in a greater study sample. The MAUDE system collects data and reports about device malfunctions, injuries or deaths as reported by the FDA; Vaduganathan and colleagues searched the database for adverse event reports for the three years after May 28, 2014—the day the CardioMEMS device received premarket approval from the FDA.

During this three-year span, according to Vaduganathan’s research, more than 5,500 patients received CardioMEMS HF System implants in the U.S. Of these procedures, the researchers discovered 155 reports of 177 adverse events reported by CardioMEMS users. Most reports came around 42 days after patients experienced malfunctions and included anything from hemoptysis to tech malfunctions to death.

Of the 5,500 CardioMEMS implants between 2014 and 2017, 28 users reported PA injury or hemoptysis, which led to 14 intensive care unit stays, seven intubations and six fatalities. Eighteen patients reported technical challenges associated with implantation, and 46 individuals experienced sensor failure, malfunctions or migration of the device—recalibrations were necessary in 35 of those cases.

Twenty-two deaths in total were recorded in the MAUDE database, Vaduganathan and co-authors wrote, though 12 of those mortalities were due to unknown or unrelated causes. Six were linked to hemoptysis, and four were heart failure-related.

In their study, Vaduganathan and colleagues wrote that while the CardioMEMS HF System has seen success, the FDA’s ability to assess the safety of all regulated devices after their approval can be limited by volume and inaccurate reporting. They suggest the MAUDE system could use corroboration from different surveillance sources.

“Early detection of safety signals and general oversight of medical devices are challenging,” the authors wrote. “The FDA receives more than one million device-related reports annually but has limited resources, clinical reviewers and knowledge of total device use to understand their clinical significance. Future partnerships between regulators, industry sponsors and academia may help better triage available resources toward improving patient selection, operator experience or device technology to optimize device use in clinical practice.”