Relative Lung Perfusion on Ventilation-Perfusion Scans After Double Lung Transplant

Area of Science:

• Pulmonary medicine
• Transplant surgery
• Radiology

Background:

• Pulmonary blood flow is assessed using ventilation-perfusion (VQ) scans.
• A normal right-to-left differential in lung perfusion is typically 55% to 45% (10%).
• Wide perfusion differentials post-lung transplant may indicate adverse outcomes.

Purpose of the Study:

• To investigate the association between a wide perfusion differential on VQ scans at 3 months post-lung transplant and outcomes.
• To determine if perfusion differential predicts death, retransplantation, chronic lung allograft dysfunction (CLAD), or baseline lung allograft dysfunction.

Main Methods:

• Retrospective cohort study of double-lung transplant recipients (2005-2016).
• Identified patients with a perfusion differential >10% on 3-month VQ scans.
• Used survival analysis (Kaplan-Meier, proportional hazards) and regression models to assess outcomes.

Main Results:

• 49% of patients (169/340) exhibited a perfusion differential ≥10% at 3 months.
• Increased perfusion differential was significantly associated with higher risks of death/retransplantation (P=0.011) and CLAD onset (P=0.012).
• Wider perfusion differentials correlated with reduced lung function at the time of the scan.

Conclusions:

• A wide lung perfusion differential is a frequent finding post-lung transplant.
• This abnormality is associated with increased mortality, reduced lung function, and higher rates of CLAD.
• Further investigation is warranted to understand the clinical significance and predictive utility of perfusion differentials.