Narendra K. Kanuru, MD is an electrophysiologist with Kennestone Hospital in Marietta, Georgia. In this interview with EP Lab Digest, he discusses his methods for preventing and managing possible device implant infections. How many cardiac rhythm management device (CRMD) implants do you perform monthly, on average? It varies, but I would say it most likely averages between 500-700 implants per year at our institution. What is the rate, in general, of cardiac device infections or complications? Are there certain patients at higher risk for infection? The answer to the second part of your question is absolutely — there are certain patients who are at a much higher risk. The rate of device infections is generally a loose number, but numerous studies have indicated that the rate nationally is between 1–7 percent, with a mean rate between 2–4 percent. Device infection is a fairly significant problem. In fact, the rate of infections with cardiac devices and device placement is actually significantly higher than the rate of infection in knee implants. What are your methods for preventing possible device infections? It is essentially a multi-pronged approach. The first aspects to consider are whether or not there is an appropriate operating room with proper laminar air flow and if there are hospital staff who are properly trained in sterile technique before prepping patients. A second aspect is appropriate administration of intravenous antibiotics, including preoperative administration of antibiotics as well as intraoperative irrigation of the pocket with an antibiotic solution — both techniques have been shown to significantly reduce the risk of device infection, but the administration of perioperative antibiotics is considered to have a significant impact. The third aspect is physician technique and how long each case lasts; it is quite clear that the longer cases take on average, the greater the rate of infection. Also, physician technique is important in terms of keeping the field clean and keeping the actual surgical site free of blood. We know that the more bleeding that occurs both in surgery and post operatively (in terms of hematoma), can increase the risk of infection significantly. The fourth aspect deals in terms of patient selection: are you placing the device at the right time, meaning is it after obstruct, selective pneumonia, or some other type of blood-borne infection, and have you ensured that the patient is free of infection? In addition, where you put the device is also important. Many physicians are comfortable putting the device in more deeply. However, sometimes they place the device too superficially, and as you can imagine, the barrier from the outside to the inside of the skin becomes very narrow. The narrower that barrier is, the greater the risk of infection or rote, meaning that the device can migrate through the skin and expose itself or cause bleeding. Overall, these are the main factors involved in preventing infection. Do you also utilize TYRX’s AIGISRx™ anti-bacterial envelope? Tell us about your experience using this technology. Yes, we are actively using the AIGISRx (TYRX, Inc., Monmouth Junction, NJ) anti-bacterial envelope. We are also involved in the retrospective study looking at its use in humans to see how well it is working. There was positive data presented at HRS this year. We aren’t using the envelope in all cases, but in select populations. The benefit of the pouch is present in everyone, but there is probably a group of patients that you do not need to use it in — I think it all depends on what your institution’s infection rate is. If your infection rate is high, then those very factors I mentioned before need to be looked at, because they can all contribute to infection rates. The AIGISRx (TYRX, Inc.) anti-bacterial envelope is certainly novel, and thus far the data suggest that it very effectively helps reduce infection rates. The infection rate at our institution previously to the induction and availability of the anti-bacterial envelope was pretty low, so we’re using it for select cases, for example, 1) in patients who have already had a device infection, 2) in patients in which the location of the device is at a greater risk for device infection, 3) in patients who have experienced a long and possibly complicated hospital course, which presents the situation of would their immune system be optimal for operating or would they be at future risk of infection based on some of these other factors. It is relatively easy to select cases, and that has had a very good result. Fortunately in our center, the infection rates in general have been low for a variety of reasons, but I think the AIGISRx (TYRX, Inc.) has definitely been a very helpful adjunct to certain cases to lower the risk of infection in patients. In addition, using the AIGISRx (TYRX, Inc.) has not changed our implant procedure or procedure time in any manner. Once device infection has occurred, what steps are taken to treat and manage the patient? The consensus opinion is to immediately remove the device if possible. Then, based on the extent of the infection, the antibiotic course is determined. For example, if the infection is very limited (i.e., just in the pacemaker pocket), then the course of antibiotic therapy may be shorter. However, if the infection has spread into the bloodstream, then the antibiotic regimen may be longer, and the time from removal of the infected device to implantation of a new device may be much longer as well. In addition, we will of course never reimplant the device on the same side — the new implanted device will always be placed in another ‘fresh’ site. In the majority of patients, if you suspect that the device has become infected in any way, then everything — all the equipment — has to be removed; literature has been clear that abandoned equipment can be a site for reinfection or recolonization. So if an entire device system or if any part of the device system becomes infected, then it is important that everything be removed. How soon after device implantation will infection occur? Our expectation is that if a device is going to become infected, we would see that anywhere from 2-6 weeks after implantation. It is very rare that you would see a device getting infected 6-8 months later, and that the infection would be due to post implant. It may be due to some other infection that the patient had that colonized the device, but as far as the infection being related to the actual operation, it would occur within 2 months. What symptoms will the patient generally exhibit once a device infection is present? Some patients may report fevers and chills, but there may not be any other obvious source of infection such as pneumonia or UTI. Systemic symptoms such as fevers, chills, fatigue, anorexia, or unexplained weight loss may be present. More commonly when it is this type of implant infection, you will see at the pacemaker site itself a failure to heal at the original incision, perhaps redness or tenderness in the area of the pacemaker pulse generator, sometimes a continual bleeding because it hasn’t had time to heal, there may even be pus, and other times you will see the skin become discolored because the device is working its way through the infected tissue. In general, patients will experience systemic complaints if the infection has affected their body, or they may see that the incision site is not healing well or is draining fluid or is becoming red and tender. Why is it important to offer new methods to prevent device infections? It is important for a number of reasons. When dealing with device infection, it can be a very expensive proposition. The average cost is between $40,000-50,000, so there is a huge cost associated with these cases. Secondly, device infection is often life threatening. If there is just a limited infection at the pacemaker site, the patient will get through that, although they may need a hospital stay and have some other issues. However, if the infection spreads into the bloodstream, it can without question be a life-threatening problem. Therefore, it is very important, from an EP standpoint of mortality and morbidity, for the patient to avoid infection. In addition, there is a tremendous cost in terms of health care management of these infections. Is there anything else you’d like to add? In general, patients should ask their doctors these types of questions before they go into surgery. They should know what the rate of infection is at their hospital or from their physician — this is the kind of information that should be available. Secondly, it is important for patients to know that, in general, higher volume centers tend to have a much lower level rate of infection than smaller centers.