Electrophysiologic Management and Treatment of Chronic and Acute Cardiac Device Infection

Potentially lethal complications include arterial-venous fistula and/or dissecting hematoma, tears into the thoracic cavity, and tears of the superior vena cava (SVC) and/or heart wall.These potentially lethal complications all result from vascular tissue disruption during lead extraction. Disruptions are caused by tears, cutting, perforations, or separation of a vascular wall. Tearing or cutting of the SVC or atrial wall has been found to be the most common complication resulting in cardiac tamponade. Indications are difficult to describe because of the complexities associated with device-related complications and procedure-related risk. Various reasons for lead extraction can be due to a patient s device-related infection, formation of a channel, or superfluous leads. In order to proceed with an extraction, physicians should estimate if the risks of not proceeding with the extraction would be greater than the potential risks of the lead extraction itself. Specifically, the presence of infection in a lead mandates extraction, while the creation of a conduit or channel is a necessary (though not mandatory) indication. Importantly, superfluous leads are noted only as a discretionary indication. Research on lead extraction can be found in literature. For example, Ellenbogen et al write that the risk of S. aureus device infection without extraction was supported by a series of 33 patients from Duke Medical Center, in which 10 (47.6%) of 21 patients died without lead extraction, and 2 (16.7%) of 12 died despite lead extraction, and none from lead extraction. The safety and efficacy of complete lead extraction, with debridement and delayed re-implantation at a remote anatomic site, were demonstrated in 123 patients at the Cleveland Clinic Foundation with device infection. Despite infections from a wide range of bacterial organisms (mostly coagulate-negative staphylococci and S. aureus), extraction was associated with no major complications. Infection reoccurred only in those four patients who had incomplete extraction or re-implantation concurrent with the extraction.¹ Staphylococci are the cause of 88% of all device-related infections.¹ Staphylococci are defined as gram-positive bacteria, pyrogenic (pus producing), slime producers, and clinically separated into coagulate-positive and coagulate-negative types.¹ Although some of these bacteria are capable of producing exotoxins (powerful soluble toxin produced by a bacterium), neurotoxins and endotoxins (toxin produced within a certain bacteria that is released only when the bacteria disintegrate), they usually are not associated with device infections. In addition, when categorizing staphylococci, it is important to note whether or not there is slime production, because the pathogenic organisms may be the slime producers. Slime production definitely enhances their effectiveness as a pathogen in device infections. The ability to adhere to smooth surfaces, such as an implanted device and encapsulating fibrous tissue, is a major factor enhancing the infectivity of these bacteria.¹ Slime helps protect the bacteria from the body s defense mechanisms and from antibiotics. It is important to also mention that staphylococci are naturally separated in the identification phase into the pathogenic coagulate-positive species (S. aureus) and the relatively nonpathogenic coagulate-negative species (S. epidermidis).¹ Septicemia is caused by drainage of bacteria and/or their toxins into the bloodstream through the vein entry site along the lead, through breaks in the lead insulation, through a venous branch draining in the pocket, or, theoretically, through the lymphatics.¹ Treatment can consist of intravenous antibiotic therapy for 6-8 weeks, removal of implanted devices (pulse generator and leads) and vegetative material, debridement of all inflammatory tissue, abandonment of the pocket, and re-implantation (using epicardial leads or at a remote site). Removal of foreign material is often ignored because of perceived risk associated with lead extraction.¹ Acute infections occurring after an initial implantation in normal tissue are rare and usually result from some breach in surgical technique that contaminates the pocket with a virulent bacterium. An acute infection is characterized by cellulitis, a pus-producing effusion within the pocket (abscess), and in some cases, decompression into the blood, causing septicemia or discharge through the skin or both. If septicemia is present, the infection is life-threatening and demands immediate treatment.¹ Infections can be caused by contamination at the time of pulse generator or lead re-implantation, or by metastatic infections. Some chronic pacemaker pockets cannot tolerate minimal levels of contamination without developing an infection. If other material is present in the pocket, such as granulation tissue or clot, the material should be debrided, drained with a closed system (e.g., Jackson-Pratt), excluded, and abandoned. Another cause of pocket infection is seeding of the pocket by bacteria from a remote infection or from a procedure such as teeth cleaning or colon polyp biopsy or resection.¹ The question of coverage with prophylactic antibiotics in these situations is still mostly unanswered in the literature. The same logic used for prophylactic therapy in chronic implants also applies to acute implants. In fact, likelihood of metastatic spread is similar in both chronic and acute implants. Furthermore, phlebitis and lymphadenitis caused by an infected intravenous fluid administration site has the potential of infecting a new device implant pocket and probably a chronic pocket.¹ Therefore, one may deduce that intravenous fluids should not be administered on the same side as the implanted device. Every attempt should also be made to find out how an infection started. It is thought to be counterproductive to treat a device infection, implant a new device, and have it become re-infected because the infection was the result of metastatic spread from some remote infection.¹ Infections caused by a transient bacteremia due to teeth cleaning or by a biopsy or removal of a colon polyp may be prevented by use of prophylactic antibiotics. Antibiotics are essential to the management of device infections. They should be used in conjunction with the corrective surgical procedures. All device infections should be treated with intravenous antibiotics before the corrective surgical procedures are performed. Because the infecting bacterium and its susceptibilities usually are not known when therapy is instituted, it is suggested to administer 1 gram of vancomycin and 60 mg of gentamicin to all patients before the surgical procedure. All other antibiotics should be stopped at this point, unless culture susceptibilities show them to be effective.¹ In particular, the antibiotic vancomycin is often used since most infections are caused by staphylococci, and almost all staphylococci are susceptible to vancomycin.¹ In addition, allergic reactions to vancomycin are rare. The patient may experience itching and have a flushed appearance, but this is caused by rapid infusion of the drug and are not signs of an allergy. Gentamicin has been suggested for administration for general gram-negative coverage, and prophylactic doses should be given.¹ Ciprofloxacin and levofloxacin are the more frequently prescribed oral antibiotics for treatment before and after discharge from the hospital. The duration of antibiotic therapy before the procedure should be determined by the magnitude of the infection. Antibiotic therapy is found not to be curative and should not be used alone as a curative approach. Antibiotics can cause remission of the clinical signs and symptoms. The remission with virulent bacteria such as S. aureus is short term, and the signs and symptoms usually reappear as soon as the antibiotic therapy is stopped. The length of remission is usually related to the condition of the pocket. For example, in pockets subjected to concealed infection, with a thick layer of encapsulating fibrous tissue, infection is found to usually recur within one or two weeks after the antibiotics are stopped. More normal pockets have longer remissions due to the ability of the body s defense systems to engage the bacteria.¹ Another persuasive reason for avoiding long-term treatment with antibiotics is the development of resistance to the drugs. Current intravascular extraction techniques are effective for extraction of pacemaker leads. However, there are still complications to be taken into account with small but significant risk. Lead extraction as primary treatment, including antibiotic therapy, even for localized infections, will result in the best opportunity to cure the infection and prevent systematic complications.