CDC Warns of Infection Risk after Open Heart Surgery; When to Worry

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A federal investigation has concluded that a device used during open-heart (open-chest) surgery that infected at least 12 patients at a Pennsylvania hospital last year was probably contaminated at the plant in Germany where it was made. At least four patients in the US have died, according to The Wall Street Journal.

Investigation shows device used during open-heart surgery was contaminated where it was made Click To Tweet

The device, called a heater-cooler machine, uses water to regulate the temperature of patients having heart surgery. The water does not come into contact with the patient, but bacteria can be transmitted through the air from the device’s exhaust vent. Called Sorin Stöckert 3Ts, the highly specialized devices are used in about 60% of the 250,000 heart bypass procedures that require such machines each year, and there are few alternatives.

In a report published Thursday by the US Centers for Disease Control and Prevention, the researchers said a genomic analysis “strongly” suggests that the infections arose from such devices. They are manufactured by London-based LivaNova PLC, according to an account of the research published in the CDC’s Morbidity and Mortality Weekly report.

The CDC report is the latest development in an 18-month effort to solve a mystery over the origin of the unusual infection, which surfaced in a cluster of patients in Switzerland in the spring of 2015. Some patients in Germany have also been infected, says The Journal.

Since the Swiss outbreak, the CDC has learned of 28 cases in the US, including 21 in Pennsylvania, five in Iowa and two in Michigan, a spokeswoman said. The four associated deaths were in Pennsylvania.

Late last year, the US Food and Drug Administration blocked imports into the US of the LivaNova device, manufactured in Germany, after issuing a warning letter related to manufacturing violations at the company. The FDA didn’t ask hospitals to stop using existing units, though the agency and the CDC have issued recommendations for reducing risk of the infections. The FDA issued a new safety communication regarding the heater-coolers in conjunction with the CDC report Thursday.

LivaNova was recently formed by the merger of Milan-based Sorin SpA and Houston-based Cyberonics Inc.

The company said Thursday it was aware of the new report and is “working with regulators to develop a solution that addresses their concerns and assures continued clinician access to this important device, which enables lifesaving cardiac surgery.”

The perpetrator of the infection is an organism called Mycobacterium chimaera, one species of what are called nontuberculous mycobacteria that are common in nature and found in water, soil and tap water. Generally they aren’t harmful to people, but the FDA says they can cause serious infections in patients who are severely ill or who have weakened immune systems.

For the new report, researchers sequenced samples of M. chimaera taken from 11 patients infected in Iowa and Pennsylvania and from five of the devices used in hospitals in those states. All had the “identical fingerprint,” said Dr. Michael Bell, deputy director of the CDC’s division of healthcare quality promotion. “We definitely have a multistate outbreak related to this one machine.” The results almost certainly mean “the machines were shipped with the contamination,” he said.

How many patients may have been infected by the contaminated device is difficult to determine. The infection is especially slow-growing, said Charles Daley, chief of the division of mycobacterial and respiratory infections at National Jewish Health, Denver, and often doesn’t cause symptoms for months or even years. Neither patients nor doctors even connect symptoms to the operation.

Daley said open-heart-surgery patients who experience such symptoms as chills, fatigue, fever, and unintended weight loss even long after their operation should be tested for the infection. Most of the confirmed patients had a valve or other prosthetic tissue implanted during their surgery, said Dr. Daley, who is a co-author of the report.

“Once valves get seeded with these organisms, it becomes very difficult to treat,” he said. The bacteria are not usually harmful, but they can infect patients who are seriously ill or who have compromised immune systems, causing fever, weight loss, joint pain and energy loss. But the infection is slow, growing over months or years, and it can be treated if it is caught, according to The New York Times.

There is no test to determine whether a person has been exposed to the bacteria, says the CDC. Infections can be diagnosed by detecting the bacteria by laboratory culture; the slow growing nature of the bacteria can require up to two months to rule out infection.

The evidence so far suggests that somewhere between one in 100 and one in 1,000 patients whose surgeries involved the device might develop an infection. Caught early, it is generally easy to treat, he said. “It may be low-risk, but once it happens, it’s very bad for the patient.”

LivaNova, the London-based company that owns the German manufacturer, said it was “proactively and voluntarily contacting 3T heater-cooler users to inform them of the new information.”

Steve’s Take: I recall seven years ago being wheeled into the OR at the University of California, San Diego, Medical Center for replacement of my aortic valve, root and stem. Lying on my back, the ceiling lights were bright…faces of the nurses were grim as they caught my eye while silently scrubbing up. Shower caps and masks had been donned. As the anesthesia quickly dimmed the room to black, the least of my worries was a bacterial infection from the above-referenced heart device, and that I could still be at risk for the infection now. How could this happen?

Well, Bruce Y. Lee, MD, MBA, a contributor at Forbes, penned an excellent piece on this sudden warning from the CDC that calmed me just enough to write this post. A graduate of Harvard Medical School, Dr. Lee says anyone who’s had open heart surgery since 2011 should beware: You could have a deadly infection brewing in your chest.

Lee says, “Sort of like the movie Alien, the bacteria can quietly grow over weeks or months, creating a sticky film around your heart that can eventually cause all sorts of complications including death.”

When thorough cleaning could not remove the malevolent germ, health officials suspected that the devices had been contaminated in the factories while being assembled.

What should one do if you’ve had open-heart (open-chest) surgery over the past several years?

Lee says, “Well, like the end of every pharmaceutical commercial following the four million warnings of side effects, see your doctor. Certainly any sign of infection, such as fever, fatigue or unintended sweating or weight loss should be extra cause for concern.”

Since the infection can remain dormant, even for years, by the time one gets symptoms, it may be too late. Therefore, the best advice is check with your doctor, Lee advises.

The other thing to keep in mind is that M. chimaera is by no means the only microorganism that can cause an infection after open-heart surgery. With such a major surgery involving various devices and equipment, different microorganisms have different possible pathways into an open chest.

My final thought about this worrisome warning is there’s an exceedingly simple way to lessen your chances of the type of infection reported in this post: In addition to being extremely finicky about the surgeon you select, choose a better hospital.  A recent study shows that many patients have already done so, driving up the market shares of higher-quality hospitals.

Steve's Take: Studies show that #heartattack survival goes up with hospital quality Click To Tweet

A great deal of the decrease in deaths from heart attacks, for example, over the past two decades can be attributed to specific medical technologies like stents and drugs that break open arterial blood clots. But a study by health economists at Harvard, MIT, Columbia and the University of Chicago showed that heart attack survival gains from patients selecting better hospitals were significant, about half as large as those from breakthrough technologies.

That’s a big improvement for just driving a little further to a higher-quality hospital. Infection control, meanwhile, is something that all hospitals perform pursuant their own particular protocols which are monitored by health officials and generate data they must share with the public. With the emergence of superbugs, that’s something to think about and investigate before undergoing any surgery, especially given this new CDC warning about a relatively innocuous microbe.

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