299.3 🏥 內科專科考前版

299.3.1 Mechanistic Deep Dive

299.3.1.1 Biofilm on Prosthetic Material

  • Adherence of organisms within minutes of implantation
  • Polysaccharide intercellular adhesin (PIA), embp, accumulation-associated protein (Aap)
  • Resistant to immune clearance + antibiotic penetration
  • Surgery often necessary

299.3.1.2 Why Rifampin in Staph PVE

  • Rifampin penetrates biofilm
  • Concentrates in macrophages
  • Adds significant efficacy when combined with cell wall agent
  • Avoid monotherapy (rapid resistance)
  • Wait until day 3-5 of effective therapy to start (avoid resistance development)

299.3.2 Recent Trials & Updates

299.3.2.1 POET Sub-Analysis (Stable PVE)

  • Some applicability to stable PVE patients
  • Practical for low-resource settings

299.3.2.2 PADIT (2019) — TYRX Envelope

  • Polymeric envelope releases antibiotics
  • ↓ Major infection in high-risk CIED
  • Approved for re-do, high-risk implants

299.3.2.3 2023 ESC IE Guidelines PVE Update

  • Earlier imaging
  • More PET-CT use
  • Closer surgical evaluation
  • Endocarditis team mandatory

299.3.2.4 Subcutaneous ICD (S-ICD) Outcomes

  • Better infection profile
  • Long-term durability emerging
  • Selected indications (no pacing required, no anti-tachy pacing needs)

299.3.2.5 Micra Leadless Pacemaker

  • Lower infection rate
  • Right-sided only
  • Limited indications (VVI)

299.3.2.6 TAVR Endocarditis Specifics

  • Risk factors identified
  • IE within 1 year: 0.5-1%
  • Outcomes similar to surgical PVE

299.3.3 High-Yield Specialist Points

299.3.3.1 Surgical Approach to PVE

  • Re-do sternotomy (carry higher morbidity)
  • Root replacement if abscess
  • Pulmonic autograft (Ross) in young selected
  • Bioprosthetic preferred if AC contraindication
  • Complete debridement of abscess
  • Pericardial patch reconstruction

299.3.3.2 Mechanical vs Bioprosthetic for PVE Re-Replacement

  • Patient + lesion considerations
  • AC requirements
  • Re-do risk
  • Life expectancy

299.3.3.3 Annular Abscess Management

  • Common with PVE
  • Often requires root replacement
  • High morbidity but life-saving
  • Bentall procedure for aortic root abscess

299.3.3.4 Heart Block + PVE

  • Annular abscess invading conduction
  • Temporary pacing
  • Permanent pacing post-surgery often
  • Sub-Q ICD or epicardial leads if recurrent

299.3.3.5 LVAD Infection Comprehensive Management

  • Driveline site care daily
  • Daptomycin or vanc for empiric S. aureus suspicion
  • Pseudomonas: anti-pseudomonal coverage
  • Suppressive long-term antibiotics often used
  • Pump exchange in severe pump pocket / pump
  • Heart transplant if eligible

299.3.3.6 Fungal IE Specific

  • Candida most common
  • Aspergillus rare but severe
  • Echinocandin first-line
    • Amphotericin B in severe
  • Long-term suppression with fluconazole
  • Almost always need surgical valve replacement
  • High mortality

299.3.3.7 Healthcare-Associated IE

  • Catheter-related bloodstream infection
  • Dialysis access
  • IV drug use in hospital
  • Mortality similar or higher than community-acquired

299.3.3.8 Anticoagulation in PVE

  • Continue warfarin if on mechanical valve
  • Risk of bleeding vs thrombosis weighed
  • Hold briefly for surgery
  • Bridge with heparin

299.3.3.9 Outcomes + Multidisciplinary Approach

  • IE team: Class I (2023 ESC)
  • Reduces mortality 30-40%
  • Standardized care pathways

299.3.3.10 Future Therapies

  • Bacteriophage therapy for resistant organisms (trials)
  • CRISPR-based anti-biofilm
  • New antibiotics: oritavancin, dalbavancin (long-acting glycopeptides), tedizolid
  • Antimicrobial-coated implants: improving

299.3.4 Pearls

  • Early PVE (< 12 mo): nosocomial (CoNS, S. aureus, fungi, GNR)
  • Late PVE (> 12 mo): similar to NVE
  • Staph PVE: nafcillin/vanc + gent + rifampin (biofilm penetration)
  • Surgery indications more liberal for PVE than NVE
  • FDG-PET-CT > 3 months post-implant
  • CIED infection: complete extraction + IV antibiotics + re-implant contralateral
  • TYRX envelope for high-risk CIED implants
  • LVAD infection: long-term + multidisciplinary
  • Subcutaneous ICD + leadless pacemaker for high infection risk