Transplant size mismatch in restrictive lung disease

Area of Science:

• Thoracic surgery
• Transplantation immunology
• Pulmonary medicine

Background:

• Lung transplantation is a life-saving procedure for end-stage lung diseases.
• Optimizing lung transplant outcomes requires careful consideration of donor-recipient factors, including organ size.
• Restrictive lung disease (RLD) presents unique challenges in lung transplantation due to altered chest wall mechanics and lung volumes.

Purpose of the Study:

• To investigate the impact of donor-recipient lung size mismatch on survival after lung transplantation in patients with RLD.
• To identify specific size mismatch thresholds associated with adverse survival outcomes in single and bilateral lung transplants for RLD.

Main Methods:

• Analysis of lung transplant data from the United Network for Organ Sharing (UNOS) Database (1987-2011).
• Inclusion of all single and bilateral lung transplants for RLD.
• Quantification of size mismatch using the donor predicted total lung capacity to recipient predicted total lung capacity ratio (pTLCr).
• Statistical analysis using Cox proportional hazards models and restricted cubic splines to assess the association between pTLCr and mortality.

Main Results:

• A total of 6656 RLD lung transplants were analyzed.
• Undersized single lungs (pTLCr <0.8) were associated with significantly increased mortality (HR 1.711, P=0.01).
• Moderately oversized bilateral lungs (pTLCr =1.1-1.2) also showed a harmful survival effect (HR 1.717, P=0.02).
• Spline analysis indicated critical pTLCr ranges for altered SOLT mortality between 0.8-0.9 and 1.1-1.2.

Conclusions:

• Single lung transplants for RLD are particularly susceptible to the negative effects of lung undersizing.
• Bilateral lung transplants for RLD have an increased mortality risk when the lung size ratio is between 1.1 and 1.2.
• Optimizing donor-recipient lung size matching is essential for improving survival in RLD lung transplant recipients.