Clinical overview: electronic devices for cardiovascular transplantation

Implantable cardiovascular electronic devices (CIED), such as pacemakers, implantable defibrillators, and defibrillators, are becoming increasingly important in the management of heart disease.^1-3 Infection with these devices can be life threatening.

CIED infection is an increasing problem, possibly due to the increased implantation rate and survival time of these devices, and implantation in patients at higher risk. CIED infection may be confined to the sinus, involve sutures, or lead to endocarditis. Hematogenous seeding for CIED is also a concern.¹ There are many challenges of CIED infection, with prevention being so important.^1,2

Risk factors for CIED infection include young age, male gender, heart disease such as high blood pressure and congestive heart failure, diabetes mellitus, end-stage kidney disease (ESRD), previous organ infection, and fever before the procedure.^1,2 Hematomas after surgery are another risk factor for infection.

Pharmacists need to ensure that anticoagulants are taken appropriately before and after surgery to prevent these complications from occurring. Patients with systemic embolism, tricuspid regurgitation, abnormal right ventricular function, and abnormal renal function are at increased risk of death.

Among the reported cases, staphylococcal species account for the majority of coagulase-negative cases staphylococcus; and an allergy to methicillin staphylococcus; aureus; which has the highest prevalence.¹ Polymicrobial infection may be a concern depending on the time since surgery.

Prior to transplantation, the patient should be evaluated to ensure that there are no clinical signs of infection.^1,3,4 Proper antibiotic choices and doses before surgery are also essential.

First generation cephalosporins, such as Cefazolin, are preferred for prophylaxis in most patients. Alternative agents, such as vancomycin, may be warranted to ensure adequate coverage in institutions where methicillin resistance is present. Staphylococcus aureus MRSA rates are high, and patients with risk factors for MRSA infection such as a positive MRSA nasal swab, or severe beta-lactam allergy.

Preparing the surgical site with antiseptic prior to surgery and ensuring sterile technique throughout the procedure are other important steps in prevention.¹ Appropriate weight-based dosing of antibiotics before surgery has become a greater 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 antibiotics after surgery.¹

Diagnosing a CIED infection can be difficult because patients present with non-specific symptoms.^3,4 In many cases, some patients have local inflammatory changes or percutaneous exposure where their organ is located.

These positional changes are usually accompanied by pain or discomfort. Patients can become malaise, fatigue, or anorexia, and systemic symptoms such as fever can be absent.^1,3,4

Treatment for suspected CIED infection begins with obtaining at least two sets of blood cultures prior to initiating broad-spectrum antimicrobial therapy.^1,3,4 If the device is implantable, a Gram stain should be performed on the generator sinus tissue, culture it, and lead tip culture.

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

Patients with confirmed CIED infection may require complete removal of all organs.³ Antimicrobial therapy is an adjunctive treatment for CIED infection, and therefore, complete removal of the device should be performed as soon as possible.

Agents must have good coverage against staphylococcus; With vancomycin being the experimental antibiotic of choice until microbiological determination.¹ After pathogen identification, patients can be mitigated into narrower factors based on pathogen susceptibility.

The duration of treatment depends on the presence of bacteremia and whether the valve or sutures are infected.

If the valves are infected, treatment with antibiotics is required for 4-6 weeks. If the TEE is negative, the duration of treatment is 2-4 weeks with longer periods required for S. aureus infections.

Thin biofilm formation is another concern due to the nature of devices with this type of infection. For patients with deep CIED infections who cannot remove their organs, it is important to consider long-term antibiotic therapy once definitive treatment is complete.¹

After the infection has been treated, there is a question about when a new CIED may be developed. For most cases, it is reasonable to implant a new CIED after blood cultures have remained negative for 72 hours. If the patient has valvular vegetation, it is necessary that there be at least 14 days longer than the first negative blood culture.¹

Infections of electronic devices implanted in the heart can be difficult to diagnose and treat, and pharmacists need to be aware of these problematic infections. Pharmacists can influence patients by ensuring appropriate antibiotic selection prior to surgery. Pharmacists can also help direct antimicrobial treatment if the heart device becomes infected.

References

1. Baddour LM, EPstein AE, Erickson CC, et al. An update on implantable cardiovascular electronic device infections and their management. Rotation. 2010; 121:458-477. DOI: 10.1161/CIRCULATIONAHA.109.192665.
2. Baman TS, Gupta SK, Valle JA, Yamada E. Risk factors for death in patients with infection associated with cardiac devices. Circulatory system: arrhythmias and electrophysiology. 2009; 2: 129-134. DOI: 10.1161/CIRCEP.108.816868.
3. Kerfield R, Johansen JB, and Nielsen JC. Management of cardiac electronic device infections: challenges and outcomes. Electrophysiological Arrhythmias Rev. 2016; 5 (3): 183-187. DOI: 10.15420/aer.2016:21:2.
4. Chung eh. European consensus document on infection of the electronic heart implanted device. Your Heart J 2020;[Epub ahead of print].
5. Crader MF, Varacallo M. Preoperative antibiotic prophylaxis. In: StatPearls.com [Internet]. Treasure Island (Florida): StatPearls Publishing; 2022. Available from: Preoperative Antibiotic Prophylaxis – StatPearls – NCBI Bookshelf (nih.gov)