Living-donor lobar lung transplantation with sparing of bilateral native upper lobes: A novel strategy

Living-donor Segmental Lung Transplantation for Pediatric Patients

OBJECTIVE

The preset study evaluated the outcome of living-donor segmental lung transplantation for pediatric patients.

METHODS

Between August 2009 and May 2021, we performed living-donor segmental lung transplantation in 6 critically ill pediatric patients, including 1 patient on a ventilator alone and another patient on a ventilator and extracorporeal membrane oxygenation (ECMO). There were 4 male and 2 female patients, with a median age of 7 years (range, 4-15 years) and a median height of 112.7 cm (range, 95-125.2 cm). The diagnoses included complications of allogeneic hematopoietic stem cell transplantation (n = 4) and pulmonary fibrosis (n = 2). All patients received bilateral lung transplantation under cardiopulmonary bypass. A basal segment and a lower lobe were implanted in 3 patients, and a basal segment and an S6 segment were implanted in the other 3 patients. In 2 patients, the right S6 segmental graft was horizontally rotated 180° and implanted as the left lung.

RESULTS

Among the 9 segmental grafts implanted, 7 functioned well after reperfusion. Two rotated S6 segmental grafts became congestive, with 1 requiring graft extraction and the other venous repair, which was successful. There was 1 hospital death (14 days) due to sepsis and 1 late death (9 years) due to leukoencephalopathy. The remaining 4 patients are currently alive at 9 months, 10 months, 1.3 years, and 1.9 years.

CONCLUSIONS

Living-donor segmental lung transplantation was a technically difficult but feasible procedure with acceptable outcomes for small pediatric patients with chest cavities that were too small for adult lower lobe implantation.

Living-donor lobar lung transplantation

Living-donor lobar lung transplantation (LDLLT) has become an important life-saving option for patients with severe respiratory disorders, since it was developed by a group in the University of Southern California in 1993 and introduced in Japan in 1998 in order to address the current severe shortage of brain-dead donor organs. Although LDLLT candidates were basically limited to critically ill patients who would require hospitalization, the long-term use of steroids, and/or mechanical respiratory support prior to transplantation, LDLLT provided good post-transplant outcomes, comparable to brain-dead donor lung transplantation in the early and late phases. In Kyoto University, the 5- and 10-year survival rates after LDLLT were reported to be 79.0% and 64.6%, respectively. LDLLT should be performed under appropriate circumstances, considering the inherent risk to the living donor. In our transplant program, all living donors returned to their previous social lives without any major complications, and living-donor surgery was associated with a morbidity rate of <15%. Both functional and anatomical size matching were preoperatively performed between the living-donor lobar grafts and recipients. Precise size matching before surgery could provide a favorable pulmonary function and exercise capacity after LDLLT. Various transplant procedures have recently been developed in LDLLT in order to deal with the issue of graft size mismatching in recipients, and favorable post-transplant outcomes have been observed. Native upper lobe-sparing and/or right-to-left inverted transplantation have been performed for undersized grafts, while single-lobe transplantation has been employed with or without contralateral pneumonectomy and/or delayed chest closure for oversized grafts.

Current trends in thoracic surgery

Thoracic surgery has evolved drastically in recent years. Although thoracic surgeons mainly deal with tumorous lesion in the lungs, mediastinum, and pleura, they also perform lung transplantation surgery in patients with end-stage lung disease. Herein, we introduce various major current topics in thoracic surgery. Minimally invasive surgical procedures include robot-assisted thoracic surgery and uniportal video-assisted thoracic surgery. Novel techniques for sublobar resection include virtual-assisted lung mapping, image-guided video-assisted thoracic surgery, and segmentectomy using indocyanine green. Three-dimensional (3D) computed tomography (CT) simulation consists of surgeon-friendly 3D-CT image analysis systems and new-generation, dynamic 3D-CT imaging systems. Updates in cadaveric lung transplantation include use of marginal donors, including donation after circulatory death, and ex vivo lung perfusion for such donors. Topics in living donor lobar lung transplantation include size matching, donor issues, and new surgical techniques. During routine clinical practice, thoracic surgeons encounter various pivotal topics related to thoracic surgery, which are described in this report.

Native upper lobe-sparing living-donor lobar lung transplantation maximizes respiratory function of the donor graft

BACKGROUND

We have developed a novel method for native upper lobe-sparing living-donor lobar lung transplantation (LDLLT) to overcome a small-for-size graft in standard LDLLT with acceptable results. We hypothesized that grafts implanted with this procedure might work more efficiently than those in standard lobe transplantation.

METHODS

Bilateral LDLLT was performed in 31 patients with a functional graft matching of less than 60% at our institution between August 2008 and December 2015. Of these, 22 patients were available for evaluation of pulmonary function more than 1 year later: 15 undergoing standard LDLLT with less than 60% functional matching and 7 undergoing native upper lobe-sparing LDLLT.

RESULTS

Overall survival at 2 years was 87.5% in the lobe-sparing LDLLT patients and 79.0% in the standard LDLLT patients (p = 0.401). The median forced vital capacity size-matching levels were 50.7% ± 1.6% in the standard LDLLT and 45.2% ± 2.3% in the sparing LDLLT group (p = 0.074). The 1-year and 2-year post-operative volume ratios of inspiration to expiration were significantly different between the 2 groups, at 1.76 and 1.45 after standard LDLLT (p = 0.019) vs 2.41 and 2.23 after lobe-sparing LDLLT (p = 0.015).

CONCLUSIONS

The grafts in lobe-sparing LDLLT functioned more effectively than those in standard LDLLT. This advantage was associated with the improvement of pulmonary functions.

Three-dimensional image in lung transplantation

Three-dimensional computed tomography (3D-CT) technologies have been developed and, recently, high-speed and high-quality 3D-CT technologies have been introduced to the field of thoracic surgery. The purpose of this manuscript is to demonstrate the clinical application of 3D-CT technologies in lung transplantation. In Japan, because of the severe donor shortage, living-donor lobar lung transplantation (LDLLT) is essential, in addition to cadaveric lung transplantation. In LDLLT, size matching is a grave issue, since ideal size matching between donor and recipient is usually difficult because of the limited population of potential donor. Size matching using pulmonary function test results has been widely used as a gold standard, but anatomical size matching using 3D-CT volumetry data has also been utilized in LDLLT. In donor lobectomy, 3D-CT images provided a variety of information regarding anatomical variation of pulmonary vessels and bronchial trees preoperatively. These images ensure surgical quality and safety, and they also affect surgical procedures for the recipient. 3D-CT images are also utilized in various aspects of postoperative care, such as detection of chronic lung allograft dysfunction and clarification of its subtypes. Furthermore, preoperative 3D-CT simulation is useful in developing and performing a special surgical procedure, such as right-to-left inverted LDLLT. In conclusion, following the introduction of 3D-CT to the field of thoracic surgery, various 3D-CT images and their application to preoperative simulations have been introduced in lung transplantation. In the near future, this technique will become more prevalent, and frequent use by thoracic surgeons will be seen worldwide in daily practice.

Sparing Native Upper Lobes in Living-Donor Lobar Lung Transplantation: Five Cases From a Single Center

Living-donor lobar lung transplantation (LDLLT) is indicated for rapidly deteriorating patients, and the total volume of two lower lobe grafts must be sufficient for the recipient. To rescue patients with small lobar grafts, we performed five LDLLTs sparing native upper lobes. This strategy was used when upper lobes or segments were preoperatively less impaired. There were no hospital deaths. Extracorporeal circulation time and operative time were similar to those of conventional LDLLTs. The length of intensive care unit stay was also similar. Late complications attributed to the spared lungs were airway infection in one recipient and pneumothorax in two but they were successfully managed. All recipients were discharged without supplemental oxygen. The spared lung volumes measured by volumetry did not change after LDLLT. Lung perfusion scintigraphy performed at 1 year showed remaining perfusion in the spared lungs, although much less than in the grafts. These results suggested that the spared lobes kept adequate space in the thoracic cavity and kept functioning to a limited extent. The new lobar-sparing strategy appears feasible and effective in LDLLT using small grafts for selected patients when the upper lobes or segments are less impaired.

Right and left inverted lobar lung transplantation

Adult recipients frequently withdraw from living-donor lobar lung transplantation because of the small size of donor grafts. The right lower lobe is 120% larger than the left lower lobe. We developed a novel surgical technique in which an inverted right lower lobe graft can be transplanted into the left thorax. The first patient was a 43-year-old woman with end-stage idiopathic interstitial pneumonia. Her husband was the only eligible donor for living-donor lobar lung transplantation. His right lower lobe was estimated to provide 45% of the recipient's predicted forced vital capacity, which would provide the borderline function required for living-donor lobar lung transplantation. Since lung perfusion scintigraphy of the recipient showed a right-to-left ratio of 64:36, transplanting the right lower lobe graft into the left thorax and sparing the native right lung was considered the only treatment option. We simulated this procedure using three-dimensional models produced by a three-dimensional printer. In living-donor lobar lung transplantation, all anastomoses were performed smoothly as planned preoperatively. Because of the initial success, this procedure was performed successfully in two additional patients. This procedure enables larger grafts to be transplanted, potentially solving critical size matching problems in living-donor lobar lung transplantation.

Pulmonary function of individual lung lobes after complex living-donor lobar lung transplantation using inspiratory and expiratory three-dimensional computed tomographic volumetry

A combination of inspiratory and expiratory three-dimensional computed tomographic volumetry provides useful information on pulmonary function and lung volume. We previously reported an early outcome of a patient undergoing living-donor lobar lung transplantation with sparing of the bilateral native upper lobes. Long-term follow-up on such patients had not been reported, and therefore we herein, for the first time, reported the 2-year follow-up of the previously reported case. According to the inspiratory and expiratory three-dimensional computed tomographic volumetric data, we demonstrated that transplanted lower lobe grafts had been working efficiently and spared bilateral native upper lobes had not provided any adverse effects.