Strategies for Preventing Cardiac Device Implant Infections: Interview with Heather Bloom, MD

Heather L. Bloom, MD, FACC, is an Assistant Professor of Medicine at the Emory University School of Medicine and Director of Cardiac Electrophysiology Services at the Atlanta VA Medical Center. Do you think the rate of infection in cardiac rhythm management devices (CRMD) is on the rise? Why? Infection rates for device implantation vary significantly between studies but are commonly reported between 1% and 7%.1 Overall rates of device implantation have increased significantly in the last decade, particularly due to expanded indications for internal cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) devices. Unfortunately, it has been well documented that the rates of infection are increasing out of proportion to the rates of implantation. For example, between 1990 and 1999, device infection rates in Medicare beneficiaries increased by 124%.2 The reason for this increase appears to be the fact that older, sicker patients now meet criteria for device implantation (e.g., class IV CHF patients for CRT-D). We at Emory identified renal insufficiency as an independent risk factor for CRMD infection, which has a prevalence of 11% in the general population.3 Several other risk factors have been identified, including oral anticoagulation medications, corticoid steroid use, complexity of the procedure, and revision procedures. Two other key factors that may be responsible for increasing frequency of infections are: 1) There is increasing incidence of methicillin-resistant S. aureus and Coag (-) Staph (per SCOPE and NNIS data), which are resistant to traditional prophylaxis with Ancef (cefazolin). 2) As CRT increases, there are increasing numbers of patients with > 2 leads, which is an independent risk factor for CRMD infection.4 How many CRMD implants do you perform monthly, on average? I personally implant about 25-30 devices a month. What are your methods for preventing CRMD infections in your patients? Data suggests that contamination during the surgical procedure is the primary source of device-related infections, with Staph (coagulase-negative or S. aureus) being the most common pathogen identified. Thus, the factors that I consider the most important are the surgical prep, sterile technique and empiric antibiotic therapy. At my hospital, we use ChloraPrep for our surgical preps. We also double-dose procedural antibiotics, giving one full dose of Ancef prior to making the surgical incision. We then give a second dose during the procedure. We flush with gentamycin-infused saline, and always give 3 days of oral antibiotics on discharge. Interestingly, there is only one prospective, randomized controlled trial that shows prophylaxis of any kind works: in the Circulation: Electrophysiology and Arrhythmia, Dr. Julio Cesar de Oliveira et al5 demonstrated that IV cefazolin (Ancef) at the time of the procedure reduces CRMD infections. Interestingly, all infections in the cefazolin-treated group were methicillin sensitive (i.e., cefazolin sensitive), indicating that single-dose IV therapy may be insufficient prophylaxis. Have you also used TYRX’s AIGISRx anti-bacterial envelope for preventing infection? Tell us about your experience with this technology. Yes, I have been using TyRx’s AIGISRx anti-bacterial envelope for preventing infection for about a year and a half now. I find it to be easy to implant. It requires very minimal expansion of the pocket and incision to accommodate. I use this because data shows that the minocycline/rifampin combination is effective against methicllin-resistant S. aureus and S. epidermidis, and multiple randomized controlled trials demonstrate this antibiotic combination prevents other medical-device associated infections in central venous catheters, hemodialysis catheters, and CSF ventricular shunts. How has the AIGISRx helped reduce device infection? I have not had a single device infection that I am aware of since I started implanting the AIGISRx envelope in my patients. The year prior to that, we had several infections, which was what led me to reassess our technique and decide to start implanting AIGISRx. Give us an example of a memorable implant case. One memorable ICD implantation case started routinely, with a cephalic cut-down. Then the ICD lead abruptly stopped advancing, and a sheath wire revealed a persistent left SVC. With the assist of a long sheath, the right atrium was easily entered, via the coronary sinus, but getting the ICD lead to make the back-handed turn into an adequate position in the right ventricle took a lot of manipulation and time. At the end of the case, the lead was very apical, but unfortunately, the lead dislodged overnight. In the re-do procedure, I implanted the lead closer to the RVOT, making more of a "C" shaped curve, rather than the cursive L shape the lead had previously taken. Since the early reopening of the pocket increased the risk of infection, I was particularly happy that I had the AIGISRx envelope available to help mitigate that risk. That patient has not returned with any further problems. What are your techniques for successfully treating infected CRMDs if they occur? Guidelines specify that infected CRMDs require removal of all hardware and 10 days to 6 weeks of IV antibiotics, prior to reimplantation. What impact do device infections have on hospitals? The impact is huge. These infections require extraction procedures which can be fatal, especially with older pacing and defibrillator leads. Patients who are pacemaker dependent require temporary pacemakers and usually ICU beds. All patients require significant courses of IV antibiotics, and a second surgical procedure for reimplantation. Cost analysis suggest that the hospital cost for one patient may range from $25k-50k to treat major infections (i.e., generator pocket and endocarditis that require explants). Why is it important to offer new methods to prevent device infections? The morbidity associated with CRM device infection is extremely high, and there is risk of mortality with extraction procedures. The cost of prolonged hospitalizations is huge. Is there anything else you’d like to add? I do have one more very important comment regarding device infections. Currently none of the national organizations — AHA, ACC or HRS — have guidelines regarding prophylaxis of CRMD infections. Thus, standard of care varies widely between different institutions and regions of the country. There is a relative dearth of data to help clinicians make their decisions about their technique. Therefore, ongoing research trials that are looking at these issues, such as Biotronik’s REPLACE and TYRX’s AIGIS retrospective trial, are critically important.