EFFECT OF SIZE (MIS)MATCHING IN CLINICAL DOUBLE-LUNG TRANSPLANTATION

Current United Network for Organ Sharing policy requires listing lung transplant recipients with an acceptable donor weight range, but lung size is a function of height, age, sex, and race. Frequently, lung tra nsplant recipients are underweight, which results in a large discrepan cy between donor and recipient weights, We reviewed our experience wit h size discrepancy between donors (D) and recipients (R) of 49 double- lung transplant (DLTX) procedures since July 1990. Pneumoreduction pro cedures were performed in 11 recipients of lungs judged to be too larg e at the time of DLTX (right middle lobectomy, 2; lingulectomy, 2; bot h, 6; right middle lobectomy and bilateral apical resections, 1), Pred icted forced vital capacity (FVC) and total lung capacity (TLC) of don ors and recipients were calculated. Donors were larger than recipients in general (D:R height = 1.02; D:R weight = 1.46), and, as a result, recipient-predicted lung volumes were smaller than donor-predicted lun g volumes (D:R FVC = 1.1; D:R TLC = 1.1), Recipients undergoing pneumo reduction procedures had a significantly greater size discrepancy betw een donors and recipients; thus, both the ratio of D:R and the differe nce between D and R predicted FVC and TLC were significantly greater a mong recipients who underwent pneumoreduction, compared with nonreduce d recipients, For recipients in the pneumoreduction group, predicted F VC and TLC were recalculated, with a proportionate amount subtracted b ased on the number of pulmonary segments removed, When the ''corrected '' FVC and TLC of the donors were compared with recipient-predicted FV C and TLC, there was no longer any significant difference between redu ced and nonreduced groups, which implies that visual estimate of size mismatch at surgery is an accurate measure of size discrepancy. Post-D LTX spirometry showed identical improvement in FVC in patients who had pneumoreduction and those who did not, and survival at 6 months was i dentical in both groups. We conclude that pneumoreduction had no adver se effect on survival or post-DLTX spirometry, allowing safe use of la rger donors in small recipients. Also, because lung size is more a fun ction of height than weight, this study challenges the United Network for Organ Sharing practice of listing recipients with an acceptable do nor weight range.