Open heart surgery complications may include a mycobacterial infection introduced by the use of a heater-cooler device used in the operating room.

While similar to the bacteria that causes the highly contagious disease of tuberculosis, according to the Merck Manual, non-tuberculosis mycobacteria (NTM) introduced in this manner bring on open heart surgery complications such as a lingering cough, unexplained fever, and significant weight loss that can’t be attributed to another cause.

Aside from exposure from use of the heater-cooler device in surgery, mycobacterium chimaera—the specific bacterium in question–is typically harmless. It is frequently present in soil and water which we encounter daily. This mycobacterium was also found to be capable of growing inside certain makes and models of cardiac heater cooler devices.

Heater Cooler Devices

Cardiac heater cooler devices are used to maintain the body temperature of a patient undergoing most open chest-type surgeries. The water in the tank itself, as indicated by the U.S. Food and Drug Administration (FDA), doesn’t actually come into contact with the patient’s blood. The blood circulates near the enclosed heated water tank and absorbs its heat indirectly.

However, use of these devices in open heart surgery has reportedly led to NTM infections. The source of the infection has been attributed to a process known as aerolization—when the contaminated water is released into the operating room’s air in a vaporous state via the machine’s own venting system.

Contamination can be spread into the open chest cavity or mist onto a prosthetic valve or surgical instruments used for the medical intervention. Use of a prosthetic piece has been associated with a higher risk of infection contraction.

Mycobacterial Infections

According to the Centers for Disease Control (CDC), open heart surgery complications from mycobacterium chimaera became linked with the LivaNova PLC Stockert 3T heater cooler device which may have been contaminated during the manufacturing process at the company’s Germany plant.

The CDC indicates that the risk of contracting mycobacterium chimaera and dying from related open-heart surgery complications is small compared to the risks presented by the kinds of heart conditions that necessitate surgery. Nevertheless, flu-like symptoms such as muscle aches, fever, night sweats, and weakness by a former heart surgery patient should never be ignored.

According to Washington State’s Department of Health, the trouble with mycobacterium chimaera infections is that they are slow-growing and can be presenting problems up to four years after the associated surgery. This makes the connection somewhat difficult to make diagnostically.

Additionally, the NTM infection can present itself in several ways including infection of the surgical wound itself. This includes renal system compromise, hepatitis, or an infection of the bones known as osteomyelitis. Unless the physician seeing the patient specifically orders certain mycobacterial cultures, it is unlikely that identification of the infection will come to light.

Washington’s Department of Health recommends that health care providers seek consultation with specialists of infectious disease when they have a patient presenting with symptoms that could potentially be mycobacterium chimaera.

LivaNova Heater Cooler Settles U.S. Lawsuits

In March 2019, LivaNova said it was ready to settle nearly ¾ of the lawsuits the company faces in the U.S. regarding the NTM infections.

The company said it could pay up to $225 million to settle claims that include a multi-district litigation in U.S. Federal Court in addition to other class action lawsuits and individual lawsuits in state courts across the United States. Up to $135 million will be paid no later than July 2019 and the remaining amount in January 2020.

According to a company press release, “LivaNova makes no admission of liability under the agreement and can void the agreement if certain conditions, including participation rates by 95 percent of each of the categories of plaintiffs, are not met.”

The company, headquartered in London, continues to stand behind the 3T heater cooler medical device. LivaNova also said it established a reserve of $294 million in the fourth quarter of fiscal year 2018 to handle the 3T heater cooler litigation issues.

CDC Establishes NTM Infect Registry

In an effort to track the cases of NTM infections around the U.S., a CDC Safety and Healthcare Epidemiology Prevention Research Development (SHEPheRD) contract was awarded to the University of Iowa to create a national registry of patients diagnosed with NTM infection after undergoing cardiothoracic surgical procedures that made use of a heater cooler device.

The registry will be a tool used to collect and distribute information about the epidemiology, clinical manifestations, treatment, and outcomes of affected patients, whose identities will remain confidential.

The University of Iowa will note the heater cooler units that were used, the patients’ symptoms, the clinical findings, method of diagnosis, treatments, response to treatments and outcomes. The NTM Infect Registry was approved by the Institutional Review Board of the University of Iowa Carver College of Medicine.