A Pennsylvania hospital has warned 1,300 patients who underwent open-heart surgery there within the past four years that they may be at risk for a bacterial infection, hospital officials announced. The infections may have contributed to the deaths of four patients.
The U.S. Centers for Disease Control and Prevention has linked the infections to heater-cooler devices used during the operations.
WellSpan York Hospital, in York, Pennsylvania, alerted approximately 1,300 open-heart surgery patients by letter of possible exposure to a nontuberculous mycobacterium, or NTM, the hospital said in a statement. Patients at risk underwent open-heart surgery procedures performed between Oct. 1, 2011 and July 24, 2015.
The bug is commonly found in nature, including soil, water, and tap water, according to federal health officials, and it is typically not harmful, but in some rare cases,it can cause infections in patients who have had invasive medical procedures, especially in those with weakened immune systems.
WellSpan York Hospital said the infection has been identified in less than 1 percent of patients who had open-heart surgery during this period of concern.
"We know that the news of this potential risk of infection may be concerning to our open-heart patients, and we sincerely regret any distress that it may create for those patients and their families," Keith Noll, senior vice president of WellSpan Health and president of WellSpan York Hospital, said in the press statement.
The hospital said that patients who had other, noninvasive heart procedures such as stents, pacemakers, defibrillators and ablations, are not at risk. Physicians and hospital staff are also not at risk for infection.
Infectious disease experts at the hospital were alerted to the issue when a study published in July in the journal Clinical Infectious Diseases revealed a previously unknown risk of infection -- aerosolized NTM bacteria escaping from the heater-cooler devices used during open-heart surgery.
A short time after the study was published, WellSpan York Hospital staff became aware of several surgery patients with NTM infections of the type identified in the study and the Pennsylvania Department of Health was contacted, said the hospital. In collaboration with experts from the Centers for Disease Control and Prevention (CDC), an extensive review was conducted of all of the hospital's open-heart surgery cases in the at-risk group to confirm the source of the bacteria and take preventive steps.
"Based on our joint investigation, the CDC determined that the NTM infections identified in our patients are likely linked to the heater-cooler devices, paralleling the findings of the European study," said Dr. R. Hal Baker, an internal medicine physician and WellSpan Health's senior vice president for clinical improvement.
The CDC and the U.S. Food and Drug Administration have each issued safety advisories alerting health care providers about the potential link between NTM bacteria that can grow in heater-cooler devices and NTM infections in open-heart surgery patients.
According to the CDC, heater-cooler devices are used during cardiothoracic surgeries as well as other medical and surgical procedures to warm or cool a patient. The devices include water tanks that provide temperature-controlled water to external heat exchangers or warming/cooling blankets through closed circuits.
"Although the water in the circuits does not come into direct contact with the patient, there is the potential for contaminated water to enter other parts of the device or transmit bacteria through the air (aerosolize) through the device's exhaust vent into the environment and to the patient," the CDC wrote in a statement on their website.
Between January 2010 and August 2015, the FDA received 32 Medical Device Reports (MDRs) of patient infections associated with heater-cooler devices or bacterial heater-cooler device contamination.
The CDC shared their findings with WellSpan York Hospital officials on Oct. 15. As a result of the joint investigation, eight probable cases were identified where patients who underwent open-heart surgery at WellSpan York Hospital also subsequently acquired an NTM infection that was identified months or years following their surgery. Four of the patients in this group, who had a number of complex health conditions, are now deceased.
The CDC has not directly linked the deaths to the NTM infections associated with the heater-cooler devices, the hospital said, but they added that it is likely a contributing factor.
On its website, the hospital is encouraging open-heart surgery patients to consult with their primary care doctors to address any symptoms that might be associated with a possible NTM infection. The hospital has also been in contact with area physicians, briefing them on the situation and providing guidance in the monitoring and care of patients who may have been exposed to the bacteria.
WellSpan says the hospital replaced the heater-cooler devices with new equipment in late July 2015 and has meticulously maintaining the devices according to the enhanced cleaning procedures, Noll said.
Federal health authorities believe the device issue may be widespread and have issued health advisories to hospitals nationally in an effort to prevent infections. European hospitals have also reported infections tied to the heater-cooler devices.
"Astute clinicians paired with quick action to engage public health agencies has led to the identification of a firm link between patient infections and these devices," said Dr. Joseph Perz, lead epidemiologist on the investigation from the CDC.
The CDC said patients who have recently had cardiac or thoracic surgery should contact their health care provider if they have symptoms of NTM infection, including: fever, pain, redness, heat, or pus around a surgical incision; night sweats, joint pain, muscle pain, and fatigue.
Other medical device-associated infections have been reported in the past year, including "superbug"-related infections that lead to a number of deaths in patients who underwent endoscopic procedures in Los Angeles and Seattle hospitals.