The FDA issued a June 1, 2016, alert that some of the Mycobacterium chimaera infections acquired by cardiothoracic patients in the U.S. may be linked to the Stöckert 3T Heater-Cooler System manufactured by the Sorin Group in Germany.
“Currently, efforts are underway in to determine if the infections in U.S. patients and M. chimaera isolates from samples taken from the 3T are linked with M. chimaera isolates from European patients who were infected and the M. chimaera previously identified at the 3T manufacturer’s production and servicing facility in Germany,” the FDA stated.1
The FDA recently held a meeting to review available data and seek expert scientific and clinical opinion related to all heater-cooler device contaminations, associated patient infections, and mitigation strategies.
A recently published European study describes a link between M. chimaera clinical samples from several infected cardiothoracic patients with samples from the heater-cooler devices used during these patient’s procedures, and with environmental samples from the device manufacturer’s production and servicing facility in Germany. The results of this paper suggest a direct link between the M. chimaera to which the European patients were exposed and became infected during open-chest cardiac surgery, and one specific heater-cooler model: the 3T, the FDA reported.
The FDA did not cite the specific study, but it appears to be one2 described at a recent meeting in Atlanta of the Society for Healthcare Epidemiology of America — a meeting at which an FDA official was present. In addition to previous recommendations issued in a 2015 Safety Communication for facilities and staff using heater-cooler devices, the FDA recommends the following:
If your facility purchased and used the 3T prior to September 2014, be aware the units may have been shipped from the factory contaminated with M. chimaera. Such facilities should:
- Inform healthcare providers who have performed cardiothoracic surgeries that there is a possibility that their patients may have been infected with M. chimaera. Reports to date suggest there may be a higher risk of patient infection associated with surgeries that introduced a prosthetic product/material [e.g., heart valve, graft, LVAD], or heart transplants when the 3T was used.
- Determine a method for patient follow-up and establish patient surveillance in cases of potential exposure, per the recommendations in CDC’s Interim Guide for the Identification of Possible Cases of Nontuberculous Mycobacterium Infections Associated with Exposure to Heater-Cooler Units.
For facilities that purchased and used the 3T after September 2014, the FDA recommends continuing to follow the recommendations provided in the 2015 Safety Communication and the manufacturer’s most current instructions for use (IFU) for cleaning, disinfecting, and maintenance to reduce the risk to patients.
Healthcare professionals and patients are encouraged to report adverse events or side effects related to the use of these products to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program.
Company Letter
In a letter submitted to the FDA prior to the June alert, LivaNova Inc. (a U.S. affiliate of the Sorin Group Deutschland) said the company has instituted “changes to the device’s labeling, manufacturing and design, and will continue to evaluate potential further changes as our understanding and knowledge continue to develop.”3 The following are excerpts from the LivaNova company letter explaining its view of the situation and actions taken.
The literature currently available highlights that a key consideration with potential NTM transmission is the nature of the organism at issue. NTM is a ubiquitous environmental contaminant that is present in many water supplies, in the air, and in other non-sterile environments. NTM is also frequently identified in hospital environments. Consequently, in a non-sterile environment such as outside of the sterile field of an OR, NTM can certainly be present. NTM presence can result in postsurgical infection only if directly transmitted to the patient.
Generally, there are no reasonable alternatives to using of heater-cooler devices. While the literature is evolving, airborne NTM post-surgical infection appears to be exceedingly uncommon. For example, in an October 2015 publication, Public Health England stated: “This new risk is extremely small. Approximately 1 in 10,000 patients having this type of surgery might be affected. This level of risk is so small that surgery should not be delayed, as the risks of delaying surgery are greater than proceeding,” and that “[t]his risk identified above is extremely small compared to the background risk of infection recognized following this type of surgery.”
The potential risk of airborne NTM transmission from heater-cooler devices has only recently been recognized, and the understanding of this potential risk is continuing to evolve. At this time, the company believes that a properly maintained device poses minimal risk of disease transmission. LivaNova continues to actively seek appropriate solutions to mitigate any potential risk even further.
LivaNova is continuing to conduct extensive testing and data collection to better understand how airborne NTM infection may be occurring. In this process, the company consulted numerous experts to understand this phenomenon. The current thinking of the company is as follows:
- The failure to clean and disinfect a water circuit of a heater-cooler can allow biofilm formation. NTM is known to proliferate in biofilm and may lead to contamination of the heater-cooler water circuit.
- In operation of the device, air bubbles may be generated in the water tanks and then exit the device as aerosolized particles. The NTM present in the water may be carried by aerosolized particles out of the tank.
- Via air flow, the aerosolized particles may then be dispersed into the surrounding environment.
Labeling Changes
The company implemented a disinfection and drying process at the production facility in August 2014 to supplement the existing cleaning and disinfection process in the field. The company implemented additional manufacturing measures (e.g., disinfection of production equipment, use of sterile filtrated water). In addition, the company is implementing design changes for devices in production (e.g., replacing device tubing, plugging unused overflow outlet).
LivaNova communicated to customers the newly identified potential risk and importance of continuing to adhere to the cleaning and disinfection process. The company also provided information to customers regarding how to handle devices suspected of contamination and environmental monitoring.
Failure to perform adequate cleaning and disinfection per the IFU has the potential to lead to contamination, including NTM contamination. As more information has become available and while our investigation is ongoing, the device’s cleaning and disinfection regimen has been revised to require more frequent disinfection of the water circuit (disinfection every two weeks rather than quarterly) with specified disinfectant solutions; weekly water changes; and the addition of hydrogen peroxide solution to the water to act as a preservative and further prevent biofilm formation.
REFEREENCES
- FDA. Safety Alert for Human Medical Products. Stöckert 3T Heater-Cooler System by Sorin Group Deustchland GmbH: Safety Communication - Reports of Mycobacterium Chimaera Infections. June 1, 2016:http://1.usa.gov/1PfXSLX.
- Haller S, Höller C, Jacobshagen A, et al. Contamination during production of heater-cooler units by Mycobacterium chimaera potential cause for invasive cardiovascular infections: results of an outbreak investigation in Germany, April 2015 to February 2016. Euro Surveill 2016;21(17): http://bit.ly/1Tgb70l.
- LivaNova Inc. Letter: Docket No. FDA-2016-N-1126: Circulatory System Devices Panel of the Medical Devices Advisory Committee. May 19, 2016.
