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Fear the Biofilm

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Scott Feitell, DO
Drexel College of Medicine
Philadelphia, PA, USA

This afternoon's Concurrent Symposium 26: Infections in Mechanical Circulatory Support Devices—Understanding and Conquering the Beast provided a harrowing and eye-opening look at what we are up against as we help our LVAD patients with long-term survival. The session started off with a great case presentation that we are all too familiar with, provided by Dr. Pavan Atluri, of the unfortunate gentleman who presented with MRSA bacteremia six months after LVAD placement. After multiple treatments were provided including surgical intervention, the patient presented with bacteremia again and will require lifelong antibiotics. This provided a great opening to our next speaker who explained why we are confronted with such difficult cases in our clinical practice.

Now normally I don't offer much praise to folks from Boston, as I myself am a lifelong Yankees fan, but Dr. Robert Padera provided great insight into the LVAD infection quandary. His talk on "Biofilm Basics" provided a kind of "biofilm 101" on what a biofilm is, and why we have such difficulty treating it. The biofilm is the product of 3.5 billion years of bacteria evolution to protect itself in the environment it lives. In a simple five-step diagram, Dr. Padera demonstrated how attachment and production of an extracellular matrix leads to the development of an early biofilm within minutes of a bacteria touching down on a surface, which then organizes into a mature biofilm from which further bacteria can reproduce and disperse into the host (our LVAD patient!). Breaking through or dissolving this biofilm sadly does not solve the problem as a few select "persister cells" bacteria manage to stick around, and as soon as the offending agents (our antibiotics) are removed, these little suckers rev back up again and infect our patient. As Dr. Padera pointed out, this will remain an ongoing problem as long as LVADs are in use and will likely require a multifactorial approach to treat and ultimately solve this problem.

Linda Staley, an LVAD coordinator at the Mayo Clinic, then took to the stage and offered insight into managing patient drivelines, and how to aggressively manage and triage any issues that can arise with the driveline. She reviewed a great four-stage assessment that patients, family and clinicians alike can use to help quantify the degree of inflammation/infection seen at the driveline site. She reviewed some great techniques to prevent infections as well, including pre-surgery selection of driveline sites by the patient and some simple dressing change protocols in place to maximize sterility and ease of use for the patient.

Dr. Margaret Hannan was tasked with outlining what an LVAD infection actually is, and did an outstanding job outlining terminology and standardization that is being applied through the IMAC database to ensure proper reporting and descriptions of LVAD infections. She also reviewed an LVAD "Duke's Criteria" type approach to work up and diagnose LVAD infections including labs, imaging and clinical picture which will be very useful in patient management.

Unfortunately, Dr. Benjamin Medalion could not make it to his talk, as he was in a helicopter over Israel saving a patient's life with ECMO. Thus, his partner was able to fill in and provide an overview to surgical approaches to driveline and pump infections. He reviewed several cases from his hospital and demonstrated different surgical techniques that can be used to salvage existing pumps, and how to approach reimplants. The pictures were gruesome, but the results were outstanding. Luckily I had a light lunch.

Finally, Dr. Matthew Romano provided insight into LVAD imaging techniques that can help evaluate driveline and pump infections. His work up often includes a simple ultrasound to start with to evaluate for fluid collections that can be tapped for cultures. He will then follow with a CT scan for further evaluation. While little data exists on the use of PET or WBC scans, he shared some of his experience with these imaging modalities and demonstrated how they may be useful with further study.

This was a great session, with many thought provoking questions posed to the presenters after thier talks, and it is clear this will be an ongoing field that will require a lot of research, time and cost to solve.

Disclosure Statement: the author has no conflicts of interest to report.

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