The Diagnosis and Treatment of Pacemaker-Associated Infection

Abstract

Background: Approximately 105 000 cardiac electronic devices are newly implanted in Germany each year. Germany has the highest implantation rate with respect to population of any European country. Infections in cardiac implants are serious complications, with an associated in-hospital mortality of 5-15%. It is thus very important to optimize the diagnostic and therapeutic strategies by which such infections can be detected early and treated effectively.

Methods: This review is based on pertinent publications retrieved by a search in PubMed, with special attention to the current recommendations of international medical specialty societies.

Results: According to the international literature, the incidence of device-associated infection is 1.7% (in six months) for implanted defibrillators and 9.5% (in two years) for resynchronization devices. No absolute figures on infection rates are available for Germany. Infection can involve either the site where the impulse generator is implanted or the intravascular portion of the electrodes. The most important elements of the diagnostic evaluation are: assessment of the local findings; pathogen identification by culture of peripheral blood, swabs of the infected site, or material recovered at surgery; and transesophageal echocardiography to detect endocarditic deposits on the electrodes or cardiac valves. The treatment consists of appropriate antibiotic administration and the complete removal of all foreign material. These special extractions are generally performed via the transvenous route. With the aid of various sheath systems, the procedure can be carried out safely and effectively, with a success rate above 95% and a complication rate below 3%. The indications for the implantation of a new device after eradication of the infection should be critically reassessed.

Conclusion: Untreated infection carries a high mortality. Evaluation and treatment according to a standardized clinical algorithm facilitate correct and timely diagnosis and the choice of an appropriate therapeutic strategy.

Figure 1

Various findings in device-associated infection Infection of the device pocket (a) is generally associated with typical clinical signs such as swelling, redness, and warmth. Perforation of the device through the skin (b) equates to an infection as a result of subsequent colonization with skin bacteria. Device-associated endocarditis is characterized by the detection of vegetation on transesophageal echocardiography (c) and pathogen detection in blood cultures (→ lead in right atrium; * endocarditis vegetation). In the case of device-associated infection without clear laboratory, clinical, or echocardiographic findings, 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG-PET-CT) can contribute to establishing the diagnosis—evidence here of increased uptake (→) in the region of the left infraclavicular implantation site consistent with infection (d).

Figure 2

Recommendations on the diagnosis and appropriate treatment of device-associated infection (modified from [10, 26, 28, 40]) 18-FDG-PET-CT, 18-fluorodeoxyglucose positron emission tomography/computed tomography; CRP, C-reactive protein; ICD, implantable cardiac defibrillator; PCT, procalcitonin *¹ Generally as interventional transvenous lead extraction. An open surgical procedure can be considered in the case of vegetation > 2 cm on electrodes and is urgently indicated if surgery is already indicated due to valve endocarditis. *² System explantation is indicated in the case of occult bacteremia with gram-positive pathogens. Likewise, in the case of recurrent bacteremia with gram-negative bacteria and no clear alternative focus of infection, system explantation needs to be considered. *³ Antibiotic therapy according to the European Society for Cardiology’s endocarditis guidelines (28). *⁴ Antibiotic therapy for 4 weeks if Staphylococcus aureus is identified, 2 weeks for all other pathogens. *⁵ Antibiotic therapy for 10 days in the case of dry pocket perforation, 14 days in the case of pocket infection. Empirical antibiotic therapy prior to pathogen detection should consist of vancomycin. *⁶ Following a critical evaluation of the indication, re-implantation is required in only 67%–86% of patients.

eFigure

Various tools used for lead extraction a) A locking stylet (*),inserted in a right atrial lead, is used to stabilize and lengthen the leads. A right ventricular lead (+) and an occluder in the left atrial auricle (‡) are visualized as secondary findings. b) Mechanical polypropylene extraction sheaths, which are available in a variety of sizes, are advanced to the tip of the ICD lead to be extracted (*) in order to disrupt adhesions. A temporary catheter (+) in the right ventricular apex ensures stimulation in pacemaker-dependent patients. c) A mechanically controlled rotating extraction sheath with a rotating blade a the tip (*) is used to extract a right arterial lead d) Snares are used to extract leads via a femoral or jugular approach. An ICD lead (*) trapped in the right ventricle is extracted via a right jugular approach (+) Lead in the right atrium, (‡) Seldinger wire in the left subclavian vein to secure the vessel lumen