Peripheral Lung Volume Reduction Improved Early Graft Function in Severe Size Mismatched Living Donor Lobar Lung Transplantation

Graft reduction surgery is associated with poorer outcome after lung transplantation: a single-centre propensity score-matched analysis

OBJECTIVES

Implanted lung volume-reduction surgery due to donor/recipient size mismatch could affect both lung function and survival. We examined the outcomes of lung volume-reduction procedures post-lung transplant.

METHODS

We retrospectively reviewed 366 consecutive adult lung transplants carried out between January 2014 and December 2018 at one single centre. Patients were divided into either a non-reduced-size lung transplant or a reduced-size lung transplant (RT) group. To adjust for covariates, a propensity score analysis was performed. Survival was estimated using the Kaplan-Meier method. Differences were considered significant with P-values <0.05.

RESULTS

In the RT group, 45 patients (12.3%) had some type of graft reduction surgery: 31 (68.9%) patients had pulmonary lobectomies and 14 (31.1%) wedge resections. Of the total cohort, 30 patients (8.2%) were prioritized, 23% of whom required graft reduction surgery. The propensity score analysis matched 41 patients in each group. In the RT group, there was an increased need for cardiopulmonary bypass (P = 0.017) during surgery and extracorporeal membrane oxygenation (P = 0.025) after lung transplant. Furthermore, the median length of mechanical ventilation was higher (P = 0.008), and lung function at discharge, 3 and 6 months post-lung transplant was significantly lower in the RT group (P < 0.05). Survival analysis demonstrated a significantly poorer overall outcome at 1, 3 and 5 years post-lung transplantation in patients with a reduced graft (P = 0.007), while the 1-year conditional survival was also worse in this group (P = 0.025).

CONCLUSIONS

Graft reduction surgery in lung transplant recipients is associated with lower pulmonary function and poorer overall survival. However, it does allow transplantation in prioritized recipients for whom it might otherwise be impossible to find an organ of suitable size.

Lobar lung transplantation--is it comparable with standard lung transplantation?

Lobar lung transplantation is used mainly for urgent small recipients who are less likely to obtain size matched lungs in due time. Only limited numbers have been published, and we herewith report the largest series of lobar-LuTX. We analyzed our LuTX database from 1/2001 to 12/2012 and compared the outcome of lobar-LuTX recipients with those receiving standard LuTX. Seven hundred and seventy-eighty LuTX (group 1) were performed either in standard technique by implanting the whole lungs (n = 539) or with downsizing by wedge resection of the right middle lobe and/or the left lingula (n = 239). One hundred and thirty-eight LuTX were performed in lobar technique (group 2) to overcome more pronounced size discrepancies. Patients in group 1 had a different spectrum of diagnoses and were less frequently bridged to LuTX (P < 0.001). Intubation time, ICU stay, and hospital stay were shorter in group 1 (P < 0.001). One-year survival was 84.8% vs. 65.1%, and 5-years survival 69.9% vs. 54.9% (P < 0.001). In multivariate analyzes, procedure, diagnosis, and pre-operative bridging were shown to be significant prognostic factors in survival. Early postoperative outcome in Lobar LuTX was significantly inferior to standard LuTX recipients. However, survival rates of successfully dismissed patients were comparable with standard LuTX (P = 0.168); thereby, Lobar-LuTX remains an important option in the management of urgent small recipients.

First brain dead donor bilateral lobar lung transplant in Turkey

A 57-year-old woman with severe bilateral bronchiectasis was evaluated for lung transplant. She was 148 cm tall and weighed 46 kg. Her FEV(1) was 0.63 liters (32% of predicted). Her PAO(2) was 64.6 mm Hg, and her Pa(CO2) was 44 mm Hg. All of her cardiac functions were within normal ranges. Her mean pulmonary arterial pressure was 32 mm Hg. She had no infections and no other systemic diseases. She was psychologically well and eager to undergo the lung transplant. She underwent a bilateral brain dead donor lobar lung transplant. After the recipient pneumo-nectomies had been performed, bilateral lower lobes were implanted sequentially. She was given extracorporeal membrane support during the operation. Her postoperative course was uneventful. Chest drains were removed after 8 days. She went to the general ward on the fifth postoperative day, and was discharged on the 15th day. As of this writing, she has had no problems through the ninth month follow-up. To the best of our knowledge, she is the first case of successful bilateral brain dead donor lung transplant in our country.

Lung size mismatch and survival after single and bilateral lung transplantation

BACKGROUND

A higher predicted total lung capacity (pTLC)-ratio (=pTLC donor/pTLC recipient), suggestive of oversized allografts, is associated with improved survival after lung transplantation. It is unknown whether the pTLC-ratio has a different association with survival in bilateral (BLT) versus single lung transplantation (SLT).

METHODS

The pTLC-ratio was calculated for all adult patients in the United Network of Organ Sharing lung transplant (LTx) registry who underwent first-time LTx in the post lung allocation score era, between May 2005 and April 2010. The LTx recipients were stratified according to procedure (BLT vs SLT). Risk of death at 1 year after LTx was analyzed using Kaplan-Meier survival and Cox proportional hazards models.

RESULTS

In the 4,520 BLT patients, each 0.1 increase in pTLC-ratio conferred a 7% decrease in the hazard for death at 1 year (p < 0.001) in univariate analysis. This association remained significant after controlling for diagnosis, comorbidities, acuity, donor, and transplant factors (hazard ratio [HR] 0.93, 95% confidence interval [CI] 0.88 to 0.98, p = 0.01). Additional adjustment by a propensity score to account for biases to oversizing showed similar results (HR 0.94, 95% CI 0.90 to 0.99, p = 0.018). In the 2,477 SLT patients, each 0.1 increase in pTLC-ratio conveyed a 6% decrease in the hazard for death at 1 year (p = 0.002) in univariate analysis, which did not persist in the multivariate model (HR 1.00, p = 0.8).

CONCLUSIONS

A higher pTLC-ratio, suggestive of an oversized allograft, is associated with improved survival after lung transplantation. This association is primarily evident in BLT patients.

Long-term outcomes of bilateral lobar lung transplantation

OBJECTIVES

Lobar lung transplantation is an option that provides the possibility of transplanting an urgent listed recipient of small size with a size-mismatched donor lung by surgically reducing the size of the donor lung. We report our short- and long-term results with bilateral lobar lung transplantation (BLLT) and compare it with the long-term outcomes of our cohort.

METHODS

Retrospective analyses of 75 lung transplant recipients who received downsized lungs with a special focus on 23 recipients with BLLT performed since January 2000. Postoperative surgical complications, lung function tests, late complications and survival were analyzed. The decision to perform lobar transplantation was considered during allocation and finally decided prior to implantation.

RESULTS

Cystic fibrosis was the most common indication (43.5%) followed by pulmonary fibrosis (35%). Median age at transplantation was 41 (range 13-66) years. Fifteen were females. Nineteen of the transplantations (83%) were done with extracorporeal membrane oxygenation (ECMO) support; 3 of them were already on ECMO prior to transplantation. There was no 30-day or in-hospital mortality. No bronchial complications occurred. The most common early complication was haematothorax (39%), which required surgical intervention. The rate of postoperative atrial arrhythmias was 30%. Forced expiratory volumes in 1 s (% predicted) at 1 and 2 years were 76 ± 23 and 76 ± 22, respectively (mean ± standard deviation). By 2-year follow-up, bronchiolitis obliterans syndrome was documented in 3 patients with a median follow-up of 1457 days. Overall survivals at 1 and 5 years were 82 ± 8 and 64 ± 11%, respectively and were comparable with those of 219 other recipients who received bilateral lung transplantation during the same period (log rank test, P = 0.56).

CONCLUSIONS

This study demonstrates that BLLT has short- and long-term outcomes comparable with those of standard bilateral lung transplantation. The limitation of lung transplantation due to size-mismatch, particularly in smaller recipients, could be overcome by utilizing lobar lung transplantation.

Perioperative assessment of oversized lobar graft downsizing in living-donor lobar lung transplantation using three-dimensional computed tomographic volumetry

A 15-year-old boy with bronchiolitis obliterans after bone marrow transplantation successfully underwent bilateral living-donor lobar lung transplantation (LDLLT) with segmentectomy of the superior segment of an oversized right lower lobe graft. As the recipient was small for his age, the predicted value of his functional vital capacity of the recipient was difficult to determine preoperatively. Three-dimensional computed tomography (CT) volumetry revealed that the ratio of donor graft volume to recipient hemithorax volume was 159% on the right side and 82% on the left side. The patient is alive and well 7 months after transplantation, and three-dimensional CT volumetry revealed that the right and left donor lungs were still compressed to 73% and 84% of the original size, respectively. In LDLLT, segmentectomy of the superior segment of the lower lobe is a useful option for downsizing an oversized graft and three-dimensional CT volumetry can provide meaningful data for size matching.

Size reduction of donor organs in pediatric lung transplantation

Lobar transplantation and peripheral segmental resection allow downsizing of larger lungs for use in smaller recipients, particularly with regard to pediatric patients on the high urgency waiting list. We studied the safety and outcome of these techniques in children. All pediatric patients who underwent reduced size LTx between January 2000 and March 2009 were retrospectively reviewed and compared with pediatric patients who underwent full size LTx during the same period. Patient characteristics, intra-operative variables, and post-operative morbidity and mortality were compared. Among 28 primary LTxs, 16 (57%) were performed in reduced size technique. Preoperatively, there was a trend toward a higher rate of mechanical ventilation and a higher capillary pCO(2) in the reduced size group. Surgical procedures tended to be longer in that group. Post-operative complications, survival and functional parameters were comparable between both groups. Our study demonstrates that reduced size LTx in children is a reliable therapeutic option that provides results comparable to full size LTx. This technique might help to reduce waiting list mortality by expanding the donor pool in pediatric LTx.

Matching donor to recipient in lung transplantation: How much does size matter?

OBJECTIVE

The impact of size matching between donor and recipient is unclear in lung transplantation. Therefore, we determined the relation of donor lung size to 1) posttransplant survival and 2) pulmonary function as measured by forced expiratory volume in 1 second.

METHODS

From 1990 to 2006, 469 adults underwent lung transplantation with lungs from donors aged 7 to 70 years. Donor and recipient total lung capacities were calculated using established formulae (predicted total lung capacity), and actual recipient lung size was measured in the pulmonary function laboratory. Disparity between donor and recipient lung size was expressed as a ratio of donor predicted total lung capacity to recipient predicted total lung capacity-the predicted total lung capacity ratio-and predicted donor total lung capacity to actual recipient total lung capacity-the actual total lung capacity ratio. Survival was measured by multiphase hazard methodology and repeated measures of National Health and Nutrition Examination Survey-normalized forced expiratory volume in 1 second analyzed by temporal decomposition.

RESULTS

Predicted total lung capacity ratio and actual total lung capacity ratio ranged widely, from 0.55 to 1.59 and 0.52 to 4.20, respectively. Overall survival was unaffected by predicted total lung capacity ratio (P = .3) or actual total lung capacity ratio (P = .5). Patients with emphysema and an actual total lung capacity ratio of 0.67 or less or 1.03 or greater had higher predicted mortality (P = .01). During the first posttransplant year, forced expiratory volume in 1 second increased and then gradually declined. Predicted total lung capacity ratio and actual total lung capacity ratio had a small impact on forced expiratory volume in 1 second, primarily in the late phase after transplant in a disease-specific manner.

CONCLUSION

Size matching between donor and recipient using predicted total lung capacity ratio and actual total lung capacity ratio is an effective technique. Wide discrepancies in lung sizing do not affect overall posttransplant survival or pulmonary function. Therefore, a greater degree of lung size mismatch can likely be accepted, thereby improving patients' odds of undergoing transplantation.