title: Lung size mismatch in bilateral lung transplantation is associated with allograft function and bronchiolitis obliterans syndrome.
abstract: BACKGROUND
  Size mismatch between donor lungs and a recipient thorax could affect the major determinants of maximal expiratory airflow: airway resistance, propensity of airways to collapse, and lung elastic recoil.
  
  
  METHODS
  A retrospective review of 159 adults who received bilateral lung transplants was performed. The predicted total lung capacity (pTLC) for donors and recipients was calculated based on sex and height. Size matching was represented using the following formula: pTLC ratio = donor pTLC / recipient pTLC. Patients were grouped according to those with a pTLC ratio > 1.0 (oversized) or those with a pTLC ratio ≤ 1.0 (undersized). Allograft function was analyzed in relation to the pTLC ratio and to recipient and donor predicted function.
  
  
  RESULTS
  The 96 patients in the oversized cohort had a mean pTLC ratio of 1.16 ± 0.13 vs 0.89 ± 0.09 in the 63 patients of the undersized group. At 1 to 6 months posttransplant, the patients in the oversized cohort had higher FEV(1)/FVC ratios (0.895 ± 0.13 vs 0.821 ± 0.13, P < .01) and lower time constant estimates of lung emptying (0.38 ± 0.2 vs 0.64 ± 0.4, P < .01) than patients in the undersized cohort. Although the FVCs expressed as % predicted for the recipient were not different between cohorts, the FVCs expressed as % predicted for the donor organ were lower in the oversized cohort compared with the undersized cohort (at 1-6 months, 52.4% ± 17.1% vs 65.3% ± 18.3%, P < .001). Kaplan-Meier estimates for the occurrence of bronchiolitis obliterans syndrome (BOS) showed that patients in the oversized cohort had a lower probability of BOS (P < .001).
  
  
  CONCLUSIONS
  A pTLC ratio > 1.0, suggestive of an oversized allograft, is associated with higher expiratory airflow capacity and a less frequent occurrence of BOS.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD; Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD. Electronic address: michael-eberlein@uiowa.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Eberlein
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD.
authors.forename: Solbert
authors.initials: S
authors.lastname: Permutt
authors.affiliation: Division of Hospital Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD.
authors.forename: Mayy F
authors.initials: MF
authors.lastname: Chahla
authors.affiliation: Department of Thoracic Surgery, Horst-Schmidt-Klinik, Wiesbaden, Germany.
authors.forename: Servet
authors.initials: S
authors.lastname: Bolukbas
authors.affiliation: Advanced Lung Disease Program, Inova Fairfax Hospital, Falls Church, VA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Nathan
authors.affiliation: Advanced Lung Disease Program, Inova Fairfax Hospital, Falls Church, VA.
authors.forename: Oksana A
authors.initials: OA
authors.lastname: Shlobin
authors.affiliation: Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD.
authors.forename: James H
authors.initials: JH
authors.lastname: Shelhamer
authors.affiliation: Division of Pulmonary and Critical Care Medicine, School of Medicine, University of Maryland, Baltimore, MD.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Reed
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD.
authors.forename: David B
authors.initials: DB
authors.lastname: Pearse
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Orens
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, MD.
authors.forename: Roy G
authors.initials: RG
authors.lastname: Brower
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001989:Bronchiolitis Obliterans / Q000209:etiology*; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008168:Lung / Q000033:anatomy & histology*; D016040:Lung Transplantation; D008297:Male; D009929:Organ Size; D011183:Postoperative Complications / Q000209:etiology*; D016016:Proportional Hazards Models; D012129:Respiratory Function Tests; D012189:Retrospective Studies