Clinical Overview: Cardiovascular Implantable Electronic Devices

Cardiovascular implantable electronic devices (CIED), such as pacemakers and implantable cardioverter-defibrillators, have become increasingly important in the management of cardiac disease.^1-3 Infections with these devices can be life-threatening.

CIED infections are an increasing problem, potentially due to the increased implantation rate and dwell time of these devices, and implantations in higher-risk patients. CIED infections may be limited to the pocket, involve the leads, or lead to endocarditis. Hematogenous seeding to CIED is also a concern.¹ There are many challenges of CIED infections, with prevention being of vital importance.^1,2

Risk factors for CIED infections include younger age, male gender, heart conditions such as hypertension and congestive heart failure, diabetes mellitus, end-stage renal disease (ESRD), prior device infection, and fever prior to procedure.^1,2 Postoperative hematomas are another risk factor for infections.

Pharmacists need to ensure anticoagulants are held appropriately before and after surgery to prevent this complication. Patients with systemic embolization, tricuspid regurgitation, abnormal right ventricular function, and abnormal renal function are at an increased risk of mortality.

Of the reported cases, staphylococcal species account for the majority of cases with coagulase-negative staphylococci and methicillin-sensitive staphylococcus aureus having the highest prevalence.¹ Polymicrobial infections may be a concern depending on time since surgery.

Before implantation, a patient needs to be evaluated to ensure they do not have any clinical signs of infection.^1,3,4 Proper preoperative antibiotic choices and doses are also imperative.

A first-generation cephalosporin, such as cefazolin, is preferred for prophylaxis in most patients. Alternative agents, such as vancomycin, may be warranted to ensure proper coverage in institutions in which methicillin-resistance staphylococcus aureus (MRSA) rates are high, patients with risk factors for MRSA such as a positive MRSA nasal swab, or in severe beta-lactam allergies.

Prepping the surgical site with preoperative antiseptic and ensuring sterile technique throughout the procedure are other important steps in prevention.¹ Appropriate weight-based dosing of preoperative antibiotics is becoming more of a concern in many institutions.

Standard preoperative doses include cefazolin 2 to 3 g depending on the patient’s weight, and vancomycin 15 mg/kg.⁵ Currently, there are no data to support the need for postoperative antibiotics.¹

Diagnosis for CIED infections can be difficult because patients present with non-specific symptoms.^3,4 In many cases, some patients will present with local inflammatory changes or percutaneous exposure where their device is located.

These local changes are generally accompanied by pain or discomfort. Patients can present with malaise, fatigue or anorexia, and systemic symptoms, such as fever can be absent.^1,3,4

Treatment for suspected CIED infection starts with obtaining at least 2 sets of blood cultures prior to starting broad antimicrobial therapy.^1,3,4 If the device is explanted, generator-pocket tissue gram stain and culture and lead-tip culture should be performed.

All patients with suspected CIED infection should undergo a transesophageal echocardiogram (TEE) to evaluate for infection on the heart valves or any leads on the cardiac device. If there is no involvement of the device and the infection is superficial or incisional at the pocket site, device removal is likely not required.¹

Patients with established CIED infection may need complete removal of all hardware.³ Antimicrobial therapy is considered adjunctive therapy for CIED infections and, therefore, complete device removal should be performed as soon as possible.

Agents should have good coverage against staphylococcal species, with vancomycin being the preferred empiric antibiotic until microbiological identification.¹ After pathogen identification, patients can be de-escalated to narrower agents based on pathogen sensitivity.

Treatment duration depends on the presence of bacteremia and whether the valve or leads are infected.1 For patients with superficial infections and negative blood cultures, it is reasonable to treat for 7-14 days.

If the valves are infected, treatment with 4-6 weeks of antibiotics is necessary. If the TEE is negative, treatment duration is 2-4 weeks with longer durations needed for staph aureus infection.

Biofilm formation is another concern due to the nature of hardware presence with this type of infection. For patients with deep CIED infections who are unable to have their device removed, it is important to consider long-term suppressive antibiotic therapy once definitive treatment is complete.¹

After the infection is treated, there is the question of when a new CIED can be placed. For most cases, it is reasonable to implant a new CIED after blood cultures remain negative for 72 hours. If the patient has valve vegetation, a longer duration of at least 14 days from the first negative blood culture is necessary.¹

Cardiac implantable electronic device infections can be difficult to diagnose and treat, and pharmacists should be aware these problematic infections. Pharmacists can impact patients by ensuring appropriate preoperative antibiotics are chosen. Pharmacists can also help guide antimicrobial therapy if a cardiac device becomes infected.

References

1. Baddour LM, EPstein AE, Erickson CC, et al. Update on cardiovascular implantable electronic device infections and their management. Circulation. 2010;121:458-477. DOI: 10.1161/CIRCULATIONAHA.109.192665.
2. Baman TS, Gupta SK, Valle JA and Yamada E. Risk factors for mortality in patients with cardiac device-related infection. Circulation: Arrhythmia and Electrophysiology. 2009;2:129-134. DOI: 10.1161/CIRCEP.108.816868.
3. Kirkfeldt RE, Johansen JB, and Nielsen JC. Management of cardiac electronic device infections: challenges and outcomes. Arrhythm Electrophysiol Rev. 2016;5(3):183-187. DOI: 10.15420/aer.2016:21:2.
4. Chung EH. European consensus document on cardiac implantable electronic device infections. Eur Heart J. 2020;[Epub ahead of print].
5. Crader MF, Varacallo M. Preoperative antibiotic prophylaxis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022. Available from: Preoperative Antibiotic Prophylaxis - StatPearls - NCBI Bookshelf (nih.gov)