Progression of native lung fibrosis in lung transplant recipients with idiopathic pulmonary fibrosis

Summary 

Background

Single lung transplant recipients with idiopathic pulmonary fibrosis provide an opportunity to study fibrosis in the native lung over time in the setting of pronounced immunosuppression. Lung transplant patients are treated with a regimen of steroids, an antiproliferative agent and a calcineurin inhibitor. This represents a much greater immunosuppression regime than the typical treatment for IPF. To determine whether this regimen of high dose immunosuppression would arrest the progression of fibrosis, the high-resolution chest CT scans (HRCTs) of these patients were reviewed.

Methods

HRCTs of 21 patients who underwent single lung transplant for IPF between 1/96 and 1/06 were reviewed. Scans were evaluated by two readers at 6 months intervals, beginning within 1–2 months after transplant. Two calculations were made on the native lung: total volume and percentage of lung affected by fibrosis. Baseline pulmonary function test data was correlated with the immediate post-transplant CT. Patients were followed for an average of 35 months after transplant.

Results

The mean total volume of the native lung just after transplant was 1120cc. This decreased to 875cc by 2 years and 691cc by 4 years after transplant, representing an average decline of 10.8%/year. Initially, 52% of the native lung was affected by fibrosis compared to 92% at 4 years. Excluding scans with 100% of the lung affected by fibrosis, percentage fibrosis increased 11% per year.

Conclusion

Fibrotic disease within the native lung progresses rapidly in single lung transplant recipients with IPF despite prolonged high dose immunosuppression.

Keywords: Interstitial lung disease, Idiopathic pulmonary fibrosis, Lung transplant