The effect of lung size mismatch on complications and resource utilization after bilateral lung transplantation

Background: Oversizing the lung allograft, as estimated by a donor-to-recipient predicted total lung capacity (pTLC) ratio > 1.0, was associated with improved long-term survival after lung transplantation (LTx) but could be associated with increased post-operative complications and higher resource utilization. Methods: The prospectively maintained LTx database at The Johns Hopkins Hospital was retrospectively reviewed for bilateral LTx patients in the post-Lung Allocation Score (LAS) era. Patients were grouped by pTLC ratio ≤ 1.0 (undersized) or > 1.0 (oversized). Post-operative complications and hospital charges were analyzed. Results: The pTLC ratio was available for 70 patients: 31 were undersized and 39 oversized. Undersized patients had a higher LAS (40.4 vs 35.8, p = 0.009), were more often in the intensive care unit (ICU) pre-LTx (35% vs 10%, p = 0.01), and had a higher occurrence of primary graft dysfunction (PGD; 25% vs 5%, p = 0.013) and tracheostomy (32% vs 10%, p = 0.02), longer index hospitalizations (20 [interquartile range (IQR), 10-46] vs 16 [IQR, 12-25] days, p = 0.048), and higher index hospitalization charges ($176,247 [IQR, $137,646-$284,012] vs $158,492 [IQR, $136,250-$191,301], p = 0.04). After adjusting for LAS and pre-LTx ICU stay, a lower pTLC ratio remained associated with higher hospital charges (p = 0.049). Airway complications were more frequent and severe in undersized patients. Conclusion: Oversized allografts were not associated with an increase in post-LTx complications. However, LTx recipients of undersized allografts were more likely to experience PGD, tracheostomy, and had higher resource utilization. Higher acuity in the undersized group might explain these findings; however, multivariate models suggest an independent association between undersizing, PGD, and resource utilization.