Association of lung perfusion disparity and mortality in patients with cystic fibrosis awaiting lung transplantation

Background: The risk of death for patients with end-stage cystic fibrosis awaiting lung transplantation remains high and most patients succumb to respiratory failure. This study was conducted to evaluate the usefulness of ventilation-perfusion scintillation scans, obtained during the pre-transplant period, to identify patterns that predict prognosis while on the waiting list. These patterns were compared with other pulmonary physiologic markers of ventilation and perfusion obtained from pulmonary function and cardiopulmonary exercise tests. Methods: From November 1990 to January 1999, 46 patients with cystic fibrosis were listed for bilateral lung transplantation. Fourteen (30.4%) died while waiting for a transplant (Group 1), whereas 32 were transplanted successfully or remain alive and waiting (Group 2). Mean arterial blood gas values, Brasfield radiograph scores, cardiopulmonary exercise data and the degree of scintillation scan abnormalities between lungs were compared for each group. Results: Mean survival for Group 1 was 10.2 +/- 1.7 months, and for Group 2 was 23.5 +/- 3.0 months (p < 0.001). The right upper lung zone was the most severely affected segment. The Cox proportional hazards model revealed an increased perfusion disparity and resting hypercapnia as the main predictors of death while on the transplant list. The Kaplan-Meier analysis indicated greater survival for the groups with <30% disparity between lungs on the pre-transplant scintillation scans. Conclusions: The results suggest that severe, unilateral perfusion abnormalities seen on scintillation scans in patients with cystic fibrosis are associated with an increased risk of dying while on the lung transplant waiting list and may be helpful in identifying patients who should be considered for early or living-donor transplantation.