The FDA and Centers for Disease Control and Prevention (CDC) warned that some LivaNova PLC Stöckert 3T heater-cooler devices used during open-heart surgery may have been contaminated during manufacturing. Patients exposed to such devices may be at risk for life-threatening infections.

The CDC said that approximately 60 percent of the 250,000 heart bypass procedures performed each year in the U.S. use the 3T heater-cooler device. The risk of a patient getting an infection from the bacteria is between approximately 1 in 100 and 1 in 1,000.

The alert mentioned that symptoms related to the infections might not appear for several months. However, patients should seek medical care if they are experiencing symptoms such as night sweats, muscle aches, weight loss, fatigue or unexplained fever.

It also told hospitals performing open-chest cardiac surgery to see if they are using 3T devices. If so, they should notify cardiothoracic surgeons, cardiologists and others about the risk of infection associated with 3T heater-cooler devices.

The FDA recommended that facilities with 3T devices manufactured before September 2014 should strongly consider to stop using them during open-chest cardiac surgery.

“It’s important for clinicians and their patients to be aware of this risk so that patients can be evaluated and treated quickly,” Michael Bell, MD, deputy director of CDC’s Division of Healthcare Quality Promotion, said in a news release. “Hospitals should check to see which type of heater-coolers are in use, ensure that they’re maintained according to the latest manufacturer instructions, and alert affected patients and the clinicians who care for them.”

In the latest CDC Morbidity and Mortality Weekly Report, the authors mentioned that these issues first arose in 2015 when Swedish investigators found that six patients who used heater-cooler devices while undergoing open-heart surgery had an invasive infection with bacteria known as Mycobacterium chimaera. Later that year, investigators from Pennsylvania’s Department of Health discovered the same bacteria in patients exposed to Stöckert 3T heater-cooler devices.

As a result of those investigations, approximately 1,300 patients were told they could have been exposed to the bacteria. The FDA and CDC also issued alerts at the time.

In June, an FDA safety warning mentioned that some patients who underwent cardiothoracic surgery with the Stӧckert 3T heater-cooler System could have been infected with M. chimaera.

The CDC and National Jewish Health recently completed whole genome sequencing on isolates from 11 patients and from five Stöckert 3T heater-cooler devices from hospitals in Pennsylvania and Iowa.

“These results strongly suggest a point-source contamination of Stöckert 3T heater-cooler devices with M. chimaera,” the authors wrote.

They also cited a report from Germany, in which preliminary results from heater-cooler devices used in three European countries were nearly identical to samples from the manufacturing sites. They added that additional sequence comparisons between patient specimens and device samples obtained from facilities from various regions in the U.S. were ongoing.

“Although thousands of patients in the United States have been notified regarding potential exposure to contaminated heater-cooler devices, the number who were exposed might be much larger,” they wrote. “CDC and FDA are continuing their efforts to increase provider and patient awareness of the risk.”