Cardiovascular implantable electronic device infection

Background

• Ranges from local pocket infection to bacteremia to endocarditis

Definitions

• Isolated pocket erosion: device or lead exposed through the skin, with or without signs of infection
• Isolated generator pocket infection: localized erythema, swelling, pain, tenderness, warmth, or drainage, with negative blood cultures
• Lead infection: lead vegetation with positive blood cultures

Microbiology

• Gram-positive bacteria (80%)1
  • Staphylococcus species (75%)
    • Staphylococcus aureus (30%), often with acute onset
    • Coagulase-negative staphylococci (40%), most common cause of device pocket infections
  • Others (5%): Enterococcus species, viridans group streptococci, Streptococcus pneumoniae
• Gram-negative bacteria (10%): Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, Strenotrophomonas maltophilia, Acinetobacter xylosoxidans, Acinetobacter baumannii, Citrobacter koseri, Morganella morganii, Haemophilus influenzae, Moraxella catarrhalis
• Fungi (2%): Candida albicans, Aspergillus fumigatus
• Polymicrobial (5%)
• Culture-negative (5%)

Epidemiology

• Occurs in about 2 per 1000 device-years

Risk Factors

• Patient-related: age, CKD, hemodialysis, diabetes mellitus, heart failure, COPD, preprocedure fever, malignancy, skin disorder, immunosuppression, prior CIED infection, anticoagulation
• Procedure-related: pocket intervention (including generator change, upgrade, or lead or pocket revision), pocket hematoma, longer procedure, inexperienced operator, ICD (compared to pacemaker), no prophylactic antibiotics
• Organism-related: highly virulent bacteria such as staphylococci

Clinical Manifestations

• Frequently infected at time of implantation, replacement, or surgical manipulation
• Often starts with generator pocket infection, then infection tracts back up the leads to intravascular and intracardiac parts
  • Local signs of infection followed by fevers, chills, malaise, fatigue, or anorexia
• Can be early (within 6 months) or late (more than 6 months)
  • Early is more likely to present with pocket infection
  • Late more often has bacteremia and endocarditis

Investigations

• Blood cultures, ideally before antibiotics
• Transesophageal echocardiogram in most cases (in strong preference to transthoracic echocardiogram)
• Pacemaker pocket swab at time of removal

Management

• Management depends on blood culture findings
  • If positive, get TEE
  • If negative but high clinical suspicion, get TEE
• If bacteremia or prior antibiotics
  • Valve vegetation ± bacteremia: remove CIED and treat as endocarditis
  • Lead vegetation ± bacteremia: remove CIED and treat for 2 weeks, or 4 weeks for Staphylococcus aureus
  • Negative TEE: consider CIED removal depending on microbiology and treat for 2 weeks
• If no bacteremia but TEE positive, treat as above
• If no bacteremia and no TEE or TEE negative
  • Pocket site infection or erosion: remove CIED and treat for 2 weeks
  • No pocket site infection: monitor
• CIED can be reimplanted when blood cultures are negative for at least 72 hours

Further Reading

• 2017 HRS expert consensus statement on cardiovascular implantable electronic device lead management and extraction. Heart Rhythm. 2017;14(12):e503-e551. doi: 10.1016/j.hrthm.2017.09.001