Association Between Early Posttransplant Graft Perfusion and CLAD-Free Survival After Single Lung Transplantation.

BACKGROUND

The physiological relevance of postoperative perfusion distribution after single lung transplantation (SLT) remains poorly defined, as asymmetric blood flow toward the graft is often regarded as an inherent consequence of the remaining native lung. This study aimed to determine whether the graft-directed perfusion ratio assessed by quantitative lung perfusion scintigraphy (QLPS) in the early postoperative period serves as an early physiological marker after SLT.

METHODS

We retrospectively analyzed SLT recipients who underwent surgery at Okayama University Hospital between 1998 and 2021 and completed QLPS approximately 3 months posttransplant. The graft perfusion ratio (graft flow/total pulmonary flow × 100%) was quantified, and recipients were classified into high (≥ 80%) and low (< 80%) perfusion groups. CLAD-free survival, overall survival, and longitudinal perfusion changes were compared using Kaplan-Meier analysis and repeated-measures ANOVA.

RESULTS

Recipients with higher graft perfusion demonstrated significantly better CLAD-free survival (p = 0.027). Overall survival was higher in the high-perfusion group, although the difference did not reach statistical significance (p = 0.075). Repeated-measures ANOVA revealed a significant group-by-time interaction (p = 0.019): recipients who developed CLAD had lower graft perfusion as early as 3 months after transplantation, followed by a progressive decline, whereas those who did not develop CLAD maintained stable perfusion. In the multivariable Cox analysis, higher graft perfusion was associated with a lower hazard of reaching the composite CLAD-free survival endpoint.

CONCLUSIONS

Early postoperative graft perfusion assessed by QLPS may serve as a noninvasive physiological marker after SLT. Higher graft-directed perfusion was associated with a lower hazard of reaching the composite CLAD-free survival endpoint and may aid early risk stratification and posttransplant surveillance.