Higher Lung Allocation Score Research Articles

Impact of Acute Exacerbation of Idiopathic Pulmonary Fibrosis on Lung Transplant Outcomes.

Acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF) are acute, significant respiratory deteriorations in patients with IPF and can lead to increased morbidity and mortality. It remains unclear how AE-IPF impacts lung transplant (LTX) outcomes. All adult patients who were listed for LTX between July 2005 and October 2020 at the Loyola University Medical Center with a diagnosis of IPF were included. Pretransplant characteristics and posttransplant outcomes were gathered via retrospective chart review. The primary outcome was short- and long-term survival for patients transplanted during stable IPF versus those with AE-IPF. One hundred fifty-nine patients were included in this study, 17.6% of whom were transplanted during AE-IPF. AE-IPF patients were more likely to have higher oxygen needs pretransplant, have higher lung allocation score, and were more likely to be intubated or be on extracorporeal membrane oxygenation as compared with stable IPF patients. Survival by AE status at transplant did not differ at 90 d or 1 y posttransplantation. There were also no significant differences in rates of severe primary graft dysfunction or acute rejection within 1 y. Patients with AE-IPF were more likely to have higher oxygenation requirements and higher lung allocation score at the time of LTX than those with stable IPF. Despite this, there were no differences in survival at 90 d, 1 y, or 3 y, or differences in incidence of severe primary graft dysfunction or acute cellular rejection. Transplantation of patients with AE-IPF has clinical outcomes comparable with transplantation of patients with stable IPF. This contrasts with previous studies examining LTX in patients with AE-IPF.

Two single lung transplantations from one donor: lung twinning in the LAS era.

The implementation of the Lung Allocation Score (LAS) in the Eurotransplant international collaborative framework decreased waiting list mortality, but organ shortage remains a significant problem. Transplantation of two single lungs from one donor into two recipients (lung twinning) may decrease waiting list mortality. We sought to analyze if this strategy can lead to an acceptable intermediate-term outcome. Since the LAS-implementation we performed 32 paired single-lung transplantations from 16 postmortal donors. Data and outcome were analyzed retrospectively comparing recipients receiving the first lung (first twins) with recipients receiving the second lung (second twins), left versus right transplantation and restrictive versus obstructive disease. Survival at one year was 81% and 54% at five years. Veno-venous ECMO had been successfully used as bridge-to-transplant in three patients with ECMO-explantation immediately after surgery. Bronchial anastomotic complications were not observed in any patient. First twins and second twins exhibited similar survival (p = 0.82) despite higher LAS in first twins (median 45 versus 34, p < 0.001) and longer cold ischemic time in second twins (280 ± 83 vs. 478 ± 125min, p < 0.001). Survival of left and right transplantation was similar (p = 0.45) with similar best post-transplant FEV1 (68 ± 15% versus 62 ± 14%, p = 0.26). Survival was similar in restrictive and obstructive disease (p = 0.28) with better post-transplant FEV1 (70 ± 15% versus 57 ± 11%, p = 0.02) in restrictive disease. Performing two single-lung transplantations from one donor can be performed safely with encouraging intermediate-term outcome and good functional capacity. Lung twinning maximizes the donor pool and may help to overcome severe organ shortage. This research is not a clinical trial. Thus no registration details will be provided.

The Risk of Pretransplant Blood Transfusion for Primary Graft Dysfunction After Lung Transplant

BackgroundPrimary graft dysfunction (PGD) is the leading cause of short- and long-term mortality associated with lung transplantation. The impact of pretransplantation blood transfusions for recipients is not fully elucidated. MethodsThis is a retrospective review of 206 consecutive lung transplantations performed at a single academic center (Northwestern University Feinberg School of Medicine, Chicago, IL) from January 2018 to July 2022. Data on patient characteristics, pretransplantation laboratory values, transfusion requirements, and intraoperative and postoperative outcomes were collected. ResultsPGD grade 3 (PGD 3) occurred in 13.2% of the cohort (n = 28). A total of 33 patients received a blood transfusion within 4 weeks, whereas 21 patients received a blood transfusion a week before their lung transplant. Pretransplantation transfusions were strongly associated with a higher incidence of PGD 3 (48.5% vs 6.9%; P < .001). There was no significant difference in 1-year survival between the pretransplantation transfused group and the nontransfused group (77.7% vs 88.0%; P = .478). The 1year survival was reduced in recipients with PGD 3 compared with recipients without PGD 3 (63.5% vs 89.9%; P = .0012). In univariate analysis, pretransplant and intratransplant predictors of PGD 3 included younger age (P < .01), pretransplant extracorporeal membrane oxygenation (ECMO) use (P < .001), higher lung allocation score (P < .001), coronavirus disease 2019 (COVID-19)–related acute respiratory distress syndrome (P < .01), blood transfusion within 4 weeks (P < .001), longer operative time (P < .001), intratransplant blood transfusion (P < .001), and intratransplant venoarterial ECMO use (P < .001). ConclusionsPretransplantation blood transfusions could be associated with a higher rate of PGD. The findings indicated the potential risks of pretransplantation blood transfusions in lung transplant recipients.

Outcomes after lung transplantation from selected donors older than 70 years in a single centre: time to close the debate?

The aim of this study was to compare the outcomes of lung transplantations using grafts from donors aged over 70 years against those performed using younger donors. This retrospective single-centre analysis includes lung transplants conducted at our institution from January 2014 to June 2022. Lung recipients were classified into 2 groups based on donor age (group A <70 years; group B ≥70 years). Variables regarding demographics, peri and postoperative outcomes and survival were included. The statistical analysis approach included univariable analysis, propensity score matching to address imbalances in donor variables (smoking status), recipient characteristics (sex, age, diagnosis and lung allocation score) and calendar period and survival analysis. A total of 353 lung transplants were performed in this period, 47 (13.3%) using grafts from donors aged over 70 years. Donors in group B were more frequently women (70.2% vs 51.6%, P = 0.017), with less smoking history (22% vs 43%, P = 0.002) and longer mechanical ventilation time (3 vs 2 days, P = 0.025). Recipients in group B had a higher lung allocation score (37.5 vs 35, P = 0.035). Postoperative variables were comparable between both groups, except for pulmonary function tests. Group B demonstrated lower forced expiratory volume 1 s levels (2070 vs 2580 ml, P = 0.001). The propensity score matching showed a lower chance of chronic lung allograft dysfunction by 12% for group B. One-, three- and five-year survival was equal between the groups. The use of selected expanded-criteria donors aged over 70 years did not result in increased postoperative morbidity, early mortality or survival in this study.

Lung transplantation in HIV seropositive recipients: An analysis of the UNOS registry.

Experience with lung transplantation (LT) in patients with human immunodeficiency virus (HIV) is limited. Many studies have demonstrated the success of kidney and liver transplantation in HIV-seropositive (HIV+) patients. Our objective was to conduct a national registry analysis comparing LT outcomes in HIV+ to HIV-seronegative (HIV-) recipients. The United Network for Organ Sharing database was queried to identify LTs performed in adult HIV+ patients between 2016 and 2023. Patients with unknown HIV status, multiorgan transplants, and redo transplants were excluded. The primary endpoints were mortality and graft rejection. Survival time was analyzed using Kaplan-Meier analysis. The study included 17487 patients, 67 of whom were HIV+. HIV+ recipients were younger (59 vs. 62years, p=.02), had higher pulmonary arterial pressure (28 vs. 25mm Hg, p=.04), and higher lung allocation scores (47 vs. 41, p=.01) relative to HIV- recipients. There were no differences in graft/recipient survival time between groups.HIV+ recipients had higher rates of post-transplant dialysis (18% vs. 8.4%, p=.01), but otherwise had similar post-transplant outcomes to HIV-recipients. This national registry analysis suggests LT outcomes in HIV+ patients are not inferior to outcomes in HIV- patients and that well-selected HIV+ recipients can achieve comparable patient and graft survival rates relative to HIV- recipients.

Race-Specific Interpretation of Spirometry: Impact on the Lung Allocation Score.

Rationale: Interpretation of spirometry using race-specific reference equations may contribute to health disparities via underestimation of the degree of lung function impairment in Black patients. The use of race-specific equations may differentially affect patients with severe respiratory disease via the use of percentage predicted forced vital capacity (FVCpp) when included in the lung allocation score (LAS), the primary determinant of priority for lung transplantation. Objectives: To determine the impact of a race-specific versus a race-neutral approach to spirometry interpretation on the LAS among adults listed for lung transplantation in the United States. Methods: We developed a cohort from the United Network for Organ Sharing database including all White and Black adults listed for lung transplantation between January 7, 2009, and February 18, 2015. The LAS at listing was calculated for each patient under race-specific and race-neutral approaches, using the FVCpp generated from the Global Lung Function Initiative equation corresponding to each patient's race (race-specific) or from the Global Lung Function Initiative "other" (race-neutral) equation. Differences in LAS between approaches were compared by race, with positive values indicating a higher LAS under the race-neutral approach. Results: In this cohort of 8,982 patients, 90.3% were White and 9.7% were Black. The mean FVCpp was 4.4% higher versus 3.8% lower among White versus Black patients (P < 0.001) under a race-neutral compared with a race-specific approach. Compared with White patients, Black patients had a higher mean LAS under both a race-specific (41.9 vs. 43.9; P < 0.001) and a race-neutral (41.3 vs. 44.3; P < 0.001) approach. However, the mean difference in LAS under a race-neutral approach was -0.6 versus +0.6 for White versus Black patients (P < 0.001). Differences in LAS under a race-neutral approach were most pronounced for those in group B (pulmonary vascular disease) (-0.71 vs. +0.70; P < 0.001) and group D (restrictive lung disease) (-0.78 vs. +0.68; P < 0.001). Conclusions: A race-specific approach to spirometry interpretation has potential to adversely affect the care of Black patients with advanced respiratory disease. Compared with a race-neutral approach, a race-specific approach resulted in lower LASs for Black patients and higher LASs for White patients, which may have contributed to racially biased allocation of lung transplantation. The future use of race-specific equations must be carefully considered.

Uptake and 1-year outcomes of lung transplantation for COVID-19

ObjectiveEnd-stage lung disease from severe COVID-19 infection is an increasingly common indication for lung transplantation (LT), but there are limited data on outcomes. We evaluated 1-year COVID-19 LT outcomes. MethodsWe identified all adult US LT recipients January 2020 to October 2022 in the Scientific Registry for Transplant Recipients, using diagnosis codes to identify recipients transplanted for COVID-19. We used multivariable regression to compare in-hospital acute rejection, prolonged ventilator support, tracheostomy, dialysis, and 1-year mortality between COVID-19 and non-COVID-19 recipients, adjusting for donor, recipient, and transplant characteristics. ResultsLT for COVID-19 increased from 0.8% to 10.7% of total LT volume during 2020 to 2021. The number of centers performing LT for COVID-19 increased from 12 to 50. Recipients transplanted for COVID-19 were younger; were more likely to be male and Hispanic; were more likely to be on a ventilator, extracorporeal membrane oxygenation support, and dialysis pre-LT; were more likely to receive bilateral LT; and had higher lung allocation score and shorter waitlist time than other recipients (all P values < .001). COVID-19 LT had higher risk of prolonged ventilator support (adjusted odds ratio, 2.28; P < .001), tracheostomy (adjusted odds ratio 5.3; P < .001), and longer length of stay (median, 27 vs 19 days; P < .001). Risk of in-hospital acute rejection (adjusted odds ratio, 0.99; P = .95) and 1-year mortality (adjusted hazard ratio, 0.73; P = .12) were similar for COVID-19 LTs and LTs for other indications, even accounting for center-level differences. ConclusionsCOVID-19 LT is associated with higher risk of immediate postoperative complications but similar risk of 1-year mortality despite more severe pre-LT illness. These encouraging results support the ongoing use of LT for COVID-19–related lung disease.

The Effect of Prone Positioning After Lung Transplantation

BackgroundProne positioning has become a standard therapy in acute respiratory distress syndrome to improve oxygenation and decrease mortality. However, little is known about prone positioning in lung transplant recipients. This large, singe-center analysis investigated whether prone positioning improves gas exchange after lung transplantation. MethodsClinical data of 583 patients were analyzed. Prone position was considered in case of impaired gas exchange Pao2/fraction of oxygen in inhaled air (<250), signs of edema after lung transplantation, and/or evidence of reperfusion injury. Patients with hemodynamic instability or active bleeding were not proned. Impact of prone positioning (n = 165) on gas exchange, early outcome and survival were determined and compared with patients in supine positioning (n = 418). ResultsPatients in prone position were younger, more likely to have interstitial lung disease, and had a higher lung allocation score. Patients were proned for a median of 19 hours (interquartile range,15-26) hours). They had significantly lower Pao2/fraction of oxygen in inhaled air (227 ± 96 vs 303 ± 127 mm Hg, P = .004), and lower lung compliance (24.8 ± 9.1 mL/mbar vs 29.8 ± 9.7 mL/mbar, P < .001) immediately after lung transplantation. Both values significantly improved after prone positioning for 24 hours (Pao2/fraction of oxygen ratio: 331 ± 91 mm Hg; lung compliance: 31.7 ± 20.2 mL/mbar). Survival at 90 days was similar between the 2 groups (93% vs 96%, P = .105). ConclusionsProne positioning led to a significant improvement in lung compliance and oxygenation after lung transplantation. Prospective studies are needed to confirm the benefit of prone positioning in lung transplantation.

Center volume effect on acute cellular rejection and outcomes in pediatric lung transplant recipients

Acute cellular rejection (ACR) is common after lung transplant (LTx). We sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. The United Network for Organ Sharing (UNOS) Registry was queried for patients <18-years-of-age who underwent LTx 1987-2020. Cohorts were children who survived the first-year post transplant and were treated for ACR within that first year (ACR group) and those not treated for ACR (non-ACR). LTx center volume was defined as: high volume center (HVC) (>5LTxs/year), medium volume center (MVC) (>1≤5 LTxs/year), and low volume center (LVC) (≤1LTxs/year). 1320 patients were enrolled into the study; 269 (20.4%) did not experience ACR. The ACR cohort was older (median 14 [11-16] vs 13 [7-16] years, p < 0.001), female (65.3% vs 57.3%, p=0.016), had cystic fibrosis (62.3% vs 45.5%, p < 0.001), and had a higher lung allocation score (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). The ACR cohort trended (p=0.06) towards lower survival at 5-year (37% vs 47%) and 10-year (25% vs 34%) post-LTx. Among children at HVCs, ACR occurred in 17% of recipients (n=98/574), compared to 18.5% (n=73/395) at MVCs and 27% (n=100/369) at LVCs. Children treated for ACR at HVCs had higher survival than LVCs at 5-years (52% vs 29%) and 10-years (36% vs 15%) (p < 0.001) but similar survival to MVCs at 5-years (52% vs 43%) and 10-years (36% vs 24%) (p=0.081). No survival differences were detected in MVCs vs LVCs (p=0.14). ACR treated within the first post-LTx year influence survival of children. ACR incidence was lowest at higher volume centers whereas post-ACR treatment survival outcomes were also superior.

Donor's long-term quality of life following living-donor lobar lung transplantation.

Living-donor lobar lung transplantation is an alternative procedure to deceased donation lung transplantation. It involves graft donation from healthy donors; however, only a few reports have discussed its long-term prognosis in living lung donors and their associated health-related quality of life. This study aimed to examine living lung donors' health-related quality of life. In our cross-sectional survey of living lung donors, we assessed health-related quality of life-based on three key aspects (physical, mental, and social health) using the 36-Item Short Form Health Survey. We also evaluated chronic postoperative pain and postoperative breathlessness using the numeric rating scale and the modified Medical Research Council Dyspnea scale, respectively. We obtained consent from 117 of 174 living lung donors. The average scores of the living lung donors on the 36-Item Short Form Health Survey were higher than the national average. However, some donors had poorer physical, mental, and social health, with lower summary scores than the national averages. Low mental component summary predictors included donor age (<40 years; odds ratio=10.2; p<.001) and recipient age (<18 years; odds ratio=2.73; p<.032). Low role-social component summary predictors included high lung allocation score (≥50; odds ratio=3.94, p<.002) and recipient death (odds ratio=3.64; p=.005). There were no predictors for a physical component summary. Additionally, many donors did not complain of pain or dyspnea. Living lung donors maintained an acceptable long-term health-related quality of life after surgery. Potential donors should be informed of relevant risk factors, and high-risk donors should receive appropriate support.

1-Year Outcomes of Lung Transplantation for Coronavirus Disease 2019-Associated End-Stage Lung Disease in the United States.

Lung transplantation can provide quality of life and survival benefits for patients with coronavirus disease 2019 (COVID-19)-associated end-stage lung disease. Characteristics and outcomes of these lung transplant recipients are limited to mostly single-center experiences or provide a short-term follow-up. Characteristics of deceased donors and adult lung transplant recipients for COVID-19-associated end-stage lung disease between August-2020 and June-2022 were analyzed using deidentified United Network for Organ Sharing database. Post-transplant patient survival of COVID-19 recipients was analyzed and compared with non-COVID-19 recipients. Secondary outcomes were length of hospitalization, post-transplant complications, and rates of organ rejection. During the study period, 400 lung transplants for COVID-associated end-stage lung disease comprised 8.7% of all lung transplants performed in United States. In the COVID-19 group, Hispanic males received lung transplants at significantly higher rates. The COVID-19 group was younger and had greater need for intensive care unit stay, mechanical ventilation, hemodialysis, extracorporeal membrane oxygenation support, and receipt of antibiotics pre-lung transplant. They had higher lung allocation score, with a shorter wait-list time and received more double lung transplants compared with non-COVID-19 recipients. Post-transplant, the COVID-19 cohort had longer hospital stays, with similar 1-year patient survival (COVID, 86.6% vs non-COVID, 86.3%). Post-transplant, COVID-19-associated deaths were 9.2% of all deaths among lung transplant recipients. Lung transplantation offers a effective option for carefully selected patients with end-stage lung disease from prior COVID-19, with short-term and long-term outcomes similar to those for lung transplant recipients of non-COVID-19 etiology.

Development and validation of the lung donor (LUNDON) acceptability score for pulmonary transplantation

There is a chronic shortage of donor lungs for pulmonary transplantation due, in part, to low lung utilization rates in the United States. We performed a retrospective cohort study using data from the Scientific Registry of Transplant Recipients database (2006-2019) and developed the lung donor (LUNDON) acceptability score. A total of 83 219 brain-dead donors were included and were randomly divided into derivation (n = 58 314, 70%) and validation (n = 24 905, 30%) cohorts. The overall lung acceptance was 27.3% (n = 22 767). Donor factors associated with the lung acceptance were age, maximum creatinine, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen, mechanism of death by asphyxiation or drowning, history of cigarette use (≥20 pack-years), history of myocardial infarction, chest x-ray appearance, bloodstream infection, and the occurrence of cardiac arrest after brain death. The prediction model had high discriminatory power (C statistic, 0.891; 95% confidence interval, 0.886-0.895) in the validation cohort. We developed a web-based, user-friendly tool (available at https://sites.wustl.edu/lundon) that provides the predicted probability of donor lung acceptance. LUNDON score was also associated with recipient survival in patients with high lung allocation scores. In conclusion, the multivariable LUNDON score uses readily available donor characteristics to reliably predict lung acceptability. Widespread adoption of this model may standardize lung donor evaluation and improve lung utilization rates.

Lung transplant waitlist outcomes among ABO blood groups vary based on disease severity

Blood group O candidates have lower lung transplantation rates despite having the most common blood group. We postulated that waitlist outcomes among these candidates and those with other blood types vary with disease severity and lung allocation score (LAS). We performed a retrospective cohort study of 32,772 waitlist candidates using the United Network of Organ Sharing registry from May 2005 to 2020. After identifying an interaction between blood group and LAS, we evaluated the association between blood group and waitlist outcomes within LAS quartiles using unadjusted and adjusted competing risk models. In the lowest LAS quartile, blood group O had a 20% reduced transplantation rate (SHR: 0.80, 95%CI: 0.75-0.85) and higher waitlist death/removal (1.33, 95%CI: 1.15-1.55) compared with group A. Blood group AB had a 52% higher transplantation rate (SHR: 1.52, 95%CI: 1.34-1.73) in the lowest LAS quartile compared with group A. In the highest LAS quartile, there was no difference in transplantation rates between groups O and A. In contrast, group B had a 19% reduced transplantation rate (SHR, 0.81 95%CI: 0.73-0.89) and AB had a 28% reduced transplantation rate (SHR: 0.72, 95%CI: 0.61-0.86) in the highest LAS quartile. Additionally, groups B and AB had increased risk of waitlist death/removal in the highest LAS quartile compared with A (SHR: 1.27, 95%CI: 1.08-1.48; SHR: 1.31, 95%CI: 1.00-1.72). Waitlist outcomes among ABO blood groups vary depending on illness severity, which is represented by LAS. Blood group O has lower transplantation rates at low LAS while groups B and AB have lower transplantation rates at high LAS.

Lung Transplantation for COVID-19-related Lung Disease: Clinical Experience and Call for a Global Registry.

Lung Transplantation for COVID-19-related Lung Disease: Clinical Experience and Call for a Global Registry.

High Volume Centers Have Lower Incidence of Acute Cellular Rejection in Pediatric Lung Transplant Recipients and Better Survival After Treatment

Purpose Acute cellular rejection (ACR) is a common form of allograft rejection in pediatric recipients after lung transplant (LTx). ACR most commonly occurs during the 1st post-transplant year. This study sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. Methods The United Network for Organ Sharing (UNOS) Registry was queried for patients <18 years who underwent LTx in 1987-2020. Cohorts were patients who were treated for ACR during the 1st post-LTx year (ACR group) and who did not experience ACR (non-ACR). Survival of patients who had ACR was compared by LTx center volume defined as average of LTx/year: >5LTx/year (high), >1-≤5LTx/year (medium) and 1LTx/year (low). Results 1338 patients were included in our analysis with 271 (20.3%) identified as having ACR. Compared to non-ACR, the ACR cohort were older (median 14 [11-16] vs 13 [7-16] years, p<0.001), more commonly female (65.3% vs 57.3%, p=0.016), more commonly diagnosed with cystic fibrosis (62.3% vs 45.5%, p<0.001), and had a higher lung allocation score at LTx (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). Kaplan-Meier survival of ACR vs non-ACR cohorts trended towards lower survival at 5-yr (37% vs 47%) & 10-yr (25% vs 34%) post-LTx, p=0.06. ACR occurred in 17% of patients at high (n=98/574), 18.5% (n=73/395) at medium, and 27% (n=100/369) at low volume centers. Patients treated for ACR at high volume centers had better post-transplant survival than low volume centers (p<0.001) but similar survival to those at medium volume centers (p=0.081; Figure). No significant difference in survival was observed in medium vs low volume centers (p=0.14). Conclusion ACR treated within the 1st post-LTx year influences survival of pediatric LTx recipients. ACR incidence was lowest at higher volume centers where post-ACR treatment survival outcomes were also superior. More analysis is needed to determine factors affecting differences in center outcomes regarding ACR. Acute cellular rejection (ACR) is a common form of allograft rejection in pediatric recipients after lung transplant (LTx). ACR most commonly occurs during the 1st post-transplant year. This study sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. The United Network for Organ Sharing (UNOS) Registry was queried for patients <18 years who underwent LTx in 1987-2020. Cohorts were patients who were treated for ACR during the 1st post-LTx year (ACR group) and who did not experience ACR (non-ACR). Survival of patients who had ACR was compared by LTx center volume defined as average of LTx/year: >5LTx/year (high), >1-≤5LTx/year (medium) and 1LTx/year (low). 1338 patients were included in our analysis with 271 (20.3%) identified as having ACR. Compared to non-ACR, the ACR cohort were older (median 14 [11-16] vs 13 [7-16] years, p<0.001), more commonly female (65.3% vs 57.3%, p=0.016), more commonly diagnosed with cystic fibrosis (62.3% vs 45.5%, p<0.001), and had a higher lung allocation score at LTx (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). Kaplan-Meier survival of ACR vs non-ACR cohorts trended towards lower survival at 5-yr (37% vs 47%) & 10-yr (25% vs 34%) post-LTx, p=0.06. ACR occurred in 17% of patients at high (n=98/574), 18.5% (n=73/395) at medium, and 27% (n=100/369) at low volume centers. Patients treated for ACR at high volume centers had better post-transplant survival than low volume centers (p<0.001) but similar survival to those at medium volume centers (p=0.081; Figure). No significant difference in survival was observed in medium vs low volume centers (p=0.14). ACR treated within the 1st post-LTx year influences survival of pediatric LTx recipients. ACR incidence was lowest at higher volume centers where post-ACR treatment survival outcomes were also superior. More analysis is needed to determine factors affecting differences in center outcomes regarding ACR.

Long-Term Weaning of Mechanical Ventilation After Lung Transplantation: Patient Characteristics and Impact on Survival

<h3>Purpose</h3> Following lung transplantation (LTx), some recipients may require a prolonged postoperative course including long-term weaning of mechanical ventilation, raising concerns regarding transplant benefit. The aim of this study was to characterize this subgroup of patients, identify risk factors of prolonged mechanical ventilation (PMV), and determine impact on survival. <h3>Methods</h3> We retrospectively reviewed all adult LTx procedures performed at our center between January 2008 and January 2019 (n=1138). Logistic regression analysis of baseline characteristics and peri-operative variables was utilized to identify risk factors for PMV. The subgroup with PMV > 60 days was then compared to a random sample of patients of equal size with short MV (< 48 hr). <h3>Results</h3> Fifty-eight patients (5%) underwent PMV > 60 days (median 99.5, IQR 71-152 days). Independent risk factors for PMV > 60 days were bridging on MV, double (versus single) LTx, concomitant cardiac procedure, re-exploration for bleeding, and primary graft dysfunction higher grades. At time of LTx listing, the group with PMV > 60 days had higher lung allocation score (72 [44-89] vs 40 [35-48], p < .01), greater chest wall soft tissue to pectoralis muscle thickness ratio (3 ± 1 vs 2 ± 1, p = .02), lower 6-minute walk test distance (873 [680-1058] vs 1003 [821-1183], p = .03), increased bridging on MV (72% vs 53%, p = .03) or ECMO (29% vs 0%, p < .01), compared to patients with short MV (< 48 hr). The group with PMV > 60 days underwent more double LTx (93% vs 48%, p < .01), cardiopulmonary bypass utilization (93% vs 45%, p < .01), concomitant cardiac procedures (29% vs 5%, p < .01), re-exploration for bleeding (36% vs 3%, p < .01), delayed chest closure (52% vs 2%, p < .01), post-LTx ECMO (24% vs 0%, p < .01), and had higher primary graft dysfunction grade 3 (48% vs 2%, p < .01). Additionally, patients with PMV > 60 days had higher hospital mortality (15% vs 3%, p = 0.02) and lower 1-year survival (59% vs 86%, p < .01); however, there was no difference in 3- or 5-year survival. <h3>Conclusion</h3> LTx recipients who undergo long-term weaning of MV have unique baseline characteristics prior to listing that influence the likelihood of a prolonged perioperative course and worse short-, but not long-, term survival. Understanding the specific predictors of PMV, and which are potentially modifiable, would contribute to optimal recipient selection.

Safety of Single Lung Transplantation Post Donation Service Area-Specific Organ Distribution

<h3>Purpose</h3> The organ allocation change in 2017 removed donation service area (DSA) and was aimed at prioritizing donor lungs for patients with a higher lung allocation score (LAS). Given that patients who are listed for singe lung transplantation alone have, on average, a lower LAS, we hypothesized that this allocation change would negatively impact those listed for a single lung transplant. <h3>Methods</h3> A UNOS database analysis was performed for patients listed for an isolated single lung transplant. Data was queried 2.5 years prior to and after the allocation change with recipients from 1/2015-6/2017 deemed as pre-allocation and recipients from 1/2018-6/2020 as post-allocation. The primary outcome was waitlist time and post-transplant survival. <h3>Results</h3> 1,435 patients were identified: 753 pre-allocation patients and 682 post-allocation patients. In the post-allocation era, patients were less likely to be listed for single lung transplant alone (15% vs 12%, P<0.001). Post-allocation recipients were older (P<0.001), more likely to be hospitalized (P=0.033), and had a nominally higher LAS score at transplant (P=0.002). While donor distance was greater (P<0.001) in the post-allocation era, demographics were similar and PaO2/FiO2 was higher in post-allocation era donors (P<0.001). The change in allocation did not impact waitlist times (42 (16-114) vs 45 (13-122), P=0.898). Survival (87% vs 87%, P=0.889) and freedom from graft failure (P=0.964) at 1 year was similar in both groups. Patients in the post-allocation group were less likely to have severe primary graft dysfunction at 72h (24% vs 31%, P=0.043). <h3>Conclusion</h3> After removal of the DSA, there was a lower prevalence of listing for only single lung transplantation. However, waitlist times, available donor lungs, and post-transplant outcomes were similar, or potentially improved, after the allocation change. Given this, single lung transplantation appears to be a reasonable strategy for appropriate patients requiring lung transplantation.

Lung transplantation for chronic obstructive pulmonary disease: A call to modify the lung allocation score to decrease waitlist mortality

ObjectiveApproximately 40% of lung transplants for chronic obstructive pulmonary disease (COPD) in the lung allocation score era are single lung transplantations (SLTs). We hypothesized that double lung transplantation (DLT) results in superior survival, but that mortality on the waitlist may compel clinicians to perform SLT. We investigated both waitlist mortality in COPD patients with restricted versus unrestricted listing preferences and posttransplant survival in SLT versus DLT to identify key predictors of mortality. MethodsA retrospective analysis of waitlist mortality and posttransplant survival in patients with COPD was conducted using post-lung allocation score data from the United Network for Organ Sharing database between 2005 and 2018. ResultsOf 6740 patients with COPD on the waitlist, 328 (4.87%) died and 320 (4.75%) were removed due to clinical deterioration. Median survival on the waitlist was significantly worse in patients listed as restricted for DLT (4.39 vs 6.09 years; P = .002) compared with patients listed as unrestricted (hazard ratio, 1.34; 95% CI, 1.13-1.57). Factors that increase waitlist mortality include female sex, increased pulmonary artery pressure, and increased wait time. Median posttransplant survival was 5.3 years in SLT versus 6.5 years in DLT (P < .001). DLT recipients are younger, male patients with a higher lung allocation score. The survival advantage of DLT persisted in adjusted analysis (hazard ratio, 0.819; 95% CI, 0.741-0.905). ConclusionsRestricted listing preference is associated with increased waitlist mortality, but DLT recipients have superior posttransplant survival. Because the lung allocation score does not prioritize COPD, concern for increased waitlist mortality with restricted listing preference may drive continued use of SLT despite better posttransplant survival in DLT.

Effects of broader geographic distribution of donor lungs on travel mode and estimated costs of organ procurement

On November 24, 2017, US lung transplant policy replaced donor service area with 250-nautical-mile radius as the first unit of allocation. Understanding this policy's economic impact is important, because the United States is poised to adopt the broadest feasible geographic organ distribution. All lung transplant recipients from January 1, 2015, to December 31, 2018, in the Scientific Registry of Transplant Recipients, were included. Recipients before and after November 24, 2017 were in the donor service area-first and 250-nautical-mile donor service area-free periods, respectively. Travel time was estimated using a Google application; mode was assigned as flying when driving time was longer than 60min. Travel costs were estimated by mode and distance. Travel distance and time for organ procurement increased under the policy change. The estimated proportion of organs traveling by air increased from 61% to 76%. Estimated average costs increased by $14051 if travel mode changed to flying, resulting in an average increase of $1264 for all transplants. Travel costs were highest for candidates <18years and adults with high lung allocation scores. Broader geographic distribution increased estimated organ procurement costs for a small percentage of lung transplants. Further analysis should elucidate the broad economic impact of such policies.

Evolution of Recipient Characteristics Over 3 Decades and Impact on Survival After Lung Transplantation

Lung transplantation (LTx) is a definitive treatment for end-stage lung disease. Herein, we reviewed our center experience over 3 decades to examine the evolution of recipient characteristics and contemporary predictors of survival for LTx. We retrospectively reviewed the data of LTx procedures performed at our institution from January 1990 to January 2019 (n = 1819). The cohort is divided into 3 eras; I: 1990-1998 (n = 152), II: 1999-2008 (n = 521), and III: 2009-2018 (n = 1146). Univariate and multivariate analyses of survival in era III were performed. Pulmonary fibrosis has become the leading indication for LTx (13% in era I, 57% in era III). Median recipient age increased (era I: 46 y-era III: 61 y) as well as intraoperative mechanical circulatory support (era I: 0%-era III: 6%). Higher lung allocation score was associated with primary graft dysfunction (P < 0.0001), postoperative extracorporeal mechanical support (P < 0.0001), and in-hospital mortality (P = 0.002). In era III, hypoalbuminemia, thrombocytopenia, and high primary graft dysfunction grade were multivariate predictors of early mortality. The 5-y survival in eras II (55%) and III (55%) were superior to era I (40%, P < 0.001). Risk factors for late mortality in era III included recipient age, chronic allograft dysfunction, renal dysfunction, high model for end-stage liver disease score, and single LTx. In this longitudinal single-center study, recipient characteristics have evolved to include sicker patients with greater complexity of procedures and risk for postoperative complications but without significant impact on hospital mortality or long-term survival. With advancing surgical techniques and perioperative management, there is room for further progress in the field.