What are key considerations when evaluating a patient for a lung transplant?

Key Considerations When Evaluating a Patient for Lung Transplantation

Pre-Transplant Assessment Questions

Disease-Specific Severity Criteria

For COPD patients, evaluate whether they meet transplant listing criteria: FEV₁ <20% predicted plus either DLCO <20% or homogeneous emphysema on imaging, evidence of secondary pulmonary hypertension despite adequate oxygenation, or history of hospitalization with acute hypercapnic respiratory failure with PaCO₂ >50 mmHg. 1

• BODE score ≥7 has been proposed as an indicator for transplant listing, though its applicability remains unclear and requires validation studies. 1
• For COPD, also consider listing when FEV₁ <15-20% predicted or three or more severe exacerbations in the preceding year. 2

For pulmonary fibrosis patients, assess diffusion capacity decline, progressive disease despite optimal medical management, severe functional impairment with oxygen dependency, and deteriorating physiologic course. 2

Single vs. Bilateral Transplantation Decision

Bilateral lung transplantation is mandatory for patients with diffuse bilateral bronchiectasis or cystic fibrosis to prevent cross-contamination of the transplanted lung from the diseased contralateral native lung. 2

• For COPD patients younger than 60 years, bilateral transplantation provides better long-term outcomes and should be preferred. 1, 2
• For IPF, no definitive survival advantage exists between single and bilateral transplantation (HR 0.47; 95% CI 0.19-1.17), so the decision should be guided by organ availability and surgical factors. 2
• For bronchiectasis specifically, bilateral transplantation shows superior 1-year survival (73%) compared to single (57%). 2

Age and Timing Considerations

Patients above 65 years have an unfavorable risk-benefit mortality ratio and should only be considered exceptionally. 1

• List patients early enough to avoid extreme disability or pre-transplant death, but not so early that they undergo unnecessary risk. 2
• Actuarial 5-year survival following lung transplantation is approximately 50% overall. 2

Functional Status Assessment

Patients should reach NYHA functional class III or IV with hypoxemia at rest, severe impairment in lung function, and exercise capacity (VO₂ max <50% predicted) before listing. 1

• The 6-minute walk test is a critical prognostic indicator—as walking distance increases, risk for death or re-transplantation significantly decreases. 3
• Double-lung transplantation shows a hazard ratio of 0.514 (p=0.001) versus single-lung transplantation for survival. 3

Post-Transplant Monitoring Questions

Surveillance for Bronchiolitis Obliterans Syndrome (BOS)

BOS is suspected when FEV₁ is ≤90% of baseline (BOS Grade 0-p) and/or FEF₂₅₋₇₅% is ≤75% of baseline in both bilateral and single lung transplant recipients. 1

• Home spirometry should be performed daily at a fixed time each morning, with patients instructed to contact the hospital if FVC or FEV₁ shows a persistent (≥2 days) decrease of 10% compared with the average of the last 7 days. 4
• During rejection episodes, FVC and FEV₁ decrease significantly (mean 14% and 21% respectively, range +8% to -53%). 4
• Recipients with higher FEV₁ or 6-minute walk test values have better survival chances. 3

Risk Factors for BOS Development

The following risk factors are associated with BOS development and should be monitored: 1

• Primary graft dysfunction (PGD)
• Acute cellular rejection including minimal Grade A1 and higher grades
• Lymphocytic bronchiolitis (Grade B rejection)
• Antibody-mediated rejection (AMR)
• Gastro-esophageal reflux (acid and non-acid)
• CMV pneumonitis
• Symptomatic community-acquired respiratory virus infection
• Pseudomonas aeruginosa colonization and infection
• Aspergillus colonization or fungal pneumonitis
• Autoimmune sensitization to collagen V
• Increased BAL neutrophils

Diagnostic Workup for Allograft Dysfunction

When lung function declines, prompt clinical evaluation should identify the likely cause through surveillance bronchoscopy, though bronchoscopy has poor sensitivity for diagnosing obliterative bronchiolitis. 1, 5

• Routine chest radiographs are neither sensitive nor specific for diagnosing BOS. 1
• HRCT findings of air trapping with expiratory views and/or mosaic attenuation patterns support BOS presence but lack sensitivity and specificity. 1
• BAL neutrophilia suggests obliterative bronchiolitis may be occurring and indicates increased risk for BOS progression, though infection is a confounder. 1
• Donor-specific antibody (DSA) presence suggests antibody-mediated rejection when detected with delayed allograft functional decline. 1

Optimal Sensitivity of Functional Tests

Indices of ventilation distribution, FEF₂₅₋₇₅%, and TLC have the best optimal sensitivity (66-68%) for diagnosing infection and rejection after transplantation. 6

• Positive predictive value of pulmonary function tests ranges from 72-88%, indicating that diagnostic procedures should be performed whenever functional tests deteriorate. 6
• Negative predictive value is only 27-52%, meaning stable pulmonary function does not rule out allograft dysfunction. 6

Special Populations and Comorbidities

Renal Disease Considerations

For patients with CKD (GFR <60 mL/min/1.73m²), minimize contrast exposure during diagnostic workup and use isosmolar contrast agents when necessary. 7

• CKD patients have 10-30 times higher cardiovascular death rates than the general population. 7
• Adjust doses of renally cleared medications appropriately based on creatinine clearance. 7
• Monitor closely for increased bleeding complications due to platelet dysfunction in CKD. 7

Contraindications Assessment

Candidates must be free of single major contraindications or multiple minor contraindications before listing. 1

• For TSC-LAM patients, TSC alone should not preclude transplantation, though TSC-related medical or cognitive problems require careful pre-transplant evaluation. 1
• Detection of renal angiomyolipoma in LAM is important preoperatively due to bleeding risk; 35-38% of LAM patients have angiomyolipomas. 1

Common Pitfalls to Avoid

Do not delay referral to transplant centers—early referral is essential given organ scarcity and prolonged waiting times. 2

• Do not use BODE score as the sole criterion for listing without considering other validated prognostic indices. 1
• Do not assume stable pulmonary function rules out allograft dysfunction—the negative predictive value is only 27-52%. 6
• Do not ignore the ethical consideration that bilateral transplantation uses organs that could potentially benefit two patients with single-lung transplants. 2