Notice to Cardiac patients
Open heart surgery – risk of mycobacterial infection

What is the issue?

There is a risk that some heater-cooler devices (HCDs) used in open-heart surgery may have been contaminated with a rare environmental bacterium called Mycobacterium chimaera and that exposure to aerosols from these devices may lead to infections in patients that can appear months to years after surgery. These devices are widely used around the world, including in Australia.

Infection of open-heart surgery patients with M. chimaera associated with a particular type of HCD was first recognised in Switzerland and there have now been a number of cases reported from countries in Europe and the United States. As at 10 February 2017, there have been three patients in Australia who have been identified with M. chimaera infection associated with HCDs.

No patients in Western Australia have developed this infection and, as a precautionary measure, those patients at risk of this infection will be provided with information about the risk.

What is Mycobacterium chimaera?

M. chimaera is one of a group of bacteria known as non-tuberculous mycobacteria (NTM), which are commonly found in the environment, including soil and water. NTM are not usually harmful, however, in very rare cases, they can cause infections in surgical patients. The bacteria are slow-growing and can take months, and up to five years, for an infection to develop.

What are heater-cooler devices?

Heater-cooler devices are used during open-heart surgery to warm or cool a patient’s blood during the procedure. It has been recognised that there is the potential for M. chimaera to grow in a water tank in the device. Although the water in the HCDs does not come into contact with the patient’s blood, it is possible for the bacteria in contaminated water drops to become airborne and then settle on a patient during open-heart surgery.

What are the chances that I have, or will get, an infection?

It appears that the risk may be higher in certain surgeries that involve the insertion of artificial heart valves or grafts. A person may be at risk if they had such an operation in Fiona Stanley Hospital, Fremantle Hospital, Princess Margaret Hospital, Royal Perth Hospital, the Mount Hospital or St John of God Subiaco Hospital in the last five years.

Patients who had surgery performed at Sir Charles Gairdner Hospital (SCGH) are not believed to be at any risk of M.chimaera infection as the HCDs at SCGH have repeatedly tested negative for M.chimaera.

What are the signs of infection?

Symptoms of a possible M. chimaera infection may include:

• unexplained fevers
• unexplained weight loss
• increasing shortness of breath
• night sweats
• joint or muscle pains
• nausea, vomiting or abdominal pain
• pain, redness, heat or pus around the surgical site.

What do I need to do if I am at risk?

If you have one or more of these symptoms and have had heart surgery within the past five years at one of the hospitals listed, it is recommended that you make an appointment with your family GP for review and referral to a specialist, if necessary. As signs and symptoms are not limited to those listed above, it is important for you to speak to your family GP if you are concerned about any unexplained illness.

What will happen to me?

Your doctor will conduct initial examinations and you may be referred to an infectious diseases physician or clinical microbiologist for further assessment. M. chimaera infections can be treated with antibiotics. There is no role for antibiotics if you are well and there is no vaccine available.

What is the WA health system doing about the problem?

All WA public and private hospitals that perform open-heart surgery have tested their HCDs to determine if the bacterium is present. Hospitals with contaminated devices have implemented processes to reduce the risk of patients acquiring an infection. In addition, the contaminated HCDs have either been disinfected to remove the bacterium or have been replaced with new HCDs. Regular testing of the HCDs is ongoing at all hospitals and no further positive results have been identified.

Is there a risk to my family and friends?

No. M. chimaera is not contagious. This means that, even if you had the infection, it cannot be spread from person to person through contact.

Department of Health Western Australia