Lung transplant complications

Background

Lobes of the lung with related anatomy.

• Can transplant single lung, bilateral lungs, or heart-lungs
• Indications: cystic fibrosis, COPD, idiopathic pulmonary fibrosis > alpha-1 antitrypsin deficiency, primary pulmonary hypertension, bronchiectasis, sarcoidosis, COVID-19
• Lung is denervated
  • regulation of breathing is not lost, as it is through chest wall efferents
  • cough response lost below anastomosis
  • should have normal ABG (unless patient reliant on hypoxic respiratory drive), exercise response, and bronchomotor tone

Immunosuppressant Medications

• Balance between immune suppression, rejection and susceptibility to infection
• Typical regimen includes: calcineurin inhibitor + antimetabolite + steroid
  • Calcineurin inhibitor
    • Cyclosporine
    • Tacrolimus
  • Steroids
    • Prednisone/Prednisolone
  • +/- Antimetabolite
    • Azathioprine
    • Mycophenolate mofetil (MMF)

Clinical Features/Differential Diagnosis

Infection

• Bronchitis, Pneumonia (common)
  • usually bacterial early in course
  • MRSA and pseudomonas common
  • Fungi, protozoa, CMV more common >6 weeks post-op
• Extra-pulmonary infections (may be severe or opportunistic due to immunosuppression)

Medication adverse effects

• Prednisone
  • Hyperglycemia, psychiatric symptoms, poor wound healing, edema, hypertension
• Tacrolimus, cyclosporine
  • Neurotoxicity, tremor, hyperkalemia, nephrotoxicity, hypertension, hyperglycemia, gout
• Mycophenolate
  • Cytopenias, GI distress
• Azathioprine
  • Cytopenias, pancreatitis, hepatitis

Airway complications

• Anastomotic bronchial necrosis, dehiscence, or stenosis
  • bronchial vasculature is disrupted during procedure, ergo:
    • donor bronchus reliant on retrograde pulmonary circulation for perfusion
    • anastomoses vulnerable to ischemia
  • mild cases may be asymptomatic
  • may lead to worsening respiratory symptoms, pneumothorax, pneumomediastinum, focal infections/abscess
• Occlusive granulation tissue
  • Asymptomatic, or worsening cough, wheezing, post-obstructive pneumonia
• bronchial/tracheal stenosis, tracheobronchomalacia
  • cough, dyspnea, difficulty clearing respiratory secretions, recurrent infections, wheezing, stridor
• bronchopleural, bronchomediastinal, or bronchovascular fisulae
  • can cause pneumothorax, hypotension, mediastinitis, pneumomediastinum, respiratory distress
• Pulmonary vasculature problems
  • Pulmonary artery stricture→ hypoxia
  • Pulmonary venous anastomoses: vulnerable to kinking, pulmonary embolism, and thromboses→ pulmonary edema
• Rejection
  • Acute/cellular rejection: clinically silent or nonspecific respiratory symptoms
  • Chronic rejection (bronchiolitis obliterans): leads to airflow limitation

Evaluation

• CBC, BMP, tacrolimus/cyclosporine levels
• Infectious workup (including sputum and testing for opportunistic/atypical infections if indicated)
• CXR, CT Chest
• Advanced/inpatient workup may include:
  • Bronchoscopy
  • Biopsy
  • Angiography or dopplers of pulmonary vasculature

Management

• See Immunocompromised antibiotics, pneumonia, sepsis
• See Pneumothorax, mediastinitis, pneumomediastinum
• Bronchoscopic debridement of necrotic, infected, or overly granulated anastomotic tissue may be needed
• Severe/symptomatic tracheobronchial stenosis may require stenting or resection

Disposition

• Depends on complication, usually admit.

See Also

• Transplant complications
• Neutropenic fever
• Immunocompromised antibiotics
• Pneumonia, pneumothorax, mediastinitis, pneumomediastinum