Postoperative pulmonary function and complications in living-donor lobectomy

Postoperative Complications in Living Donors for Lung Transplantation

Background

Living donor lobar lung transplantation is a life-saving procedure for critically ill patients. This requires 2 healthy donors exposed to risks and without medical benefit. Therefore, the donor's safety and minimal postoperative complications are crucial. This study aimed to investigate the short-term outcomes and identify the risk factors affecting these outcomes.

Methods

The data of 175 living donors enrolled between 1998 and 2022 were analyzed. Donors were divided into era 1 (1998-2009) and era 2 (2010-2022).

Results

The overall incidence of postoperative complications was 39%, of which 7% were major complications. Donors who underwent surgery on the right side had a higher incidence of delayed pulmonary fistulae (P = 0.01) and elevated liver enzyme levels (P = 0.028). Living donor surgery on the right side (P = 0.01), era 2 (P = 0.01), and the need for plasty (P = 0.04) were predictors of postoperative complications.

Conclusions

Updated data on complications and their correlation with postoperative quality of life from this study could aid in the selection of potential donors and facilitate informed consent.

Living-donor lobar lung transplantation

Living-donor lobar lung transplantation (LDLLT) is indicated for critically ill patients who would not survive the waiting period in the case of severe brain-dead donor shortage. It is essential to confirm that potential donors are willing to donate without applying psychological pressure from others. In standard LDLLT, the right and left lower lobes donated by 2 healthy donors are implanted into the recipient under cardiopulmonary support. LDLLT can be applied to various lung diseases including restrictive, obstructive, infectious, and vascular lung diseases in both adult and pediatric patients if size matching is acceptable. Functional size matching by measuring donor pulmonary function and anatomical size matching by 3-dimensional computed tomography volumetry are very useful. When 2 donors with ideal size matching are not available, various transplant procedures, such as single lobe, segmental, recipient lobe-sparing, and inverted lobar transplants are valuable options. There seems to be immunological advantages in LDLLT as compared to cadaveric lung transplantation (CLT). Unilateral chronic allograft dysfunction is a unique manifestation after bilateral LDLLT, which may contribute to better prognosis. The growth of adult lung graft implanted into growing pediatric recipients is suggested by radiologic evaluation. Although only 2 lobes are implanted, postoperative pulmonary function is equivalent between LDLLT and CLT. The long-term outcome after LDLLT is similar to or better than that after CLT. The author has performed 164 LDLLTs resulting in 71.6% survival rate at 10 years. All living-donors returned to their previous life styles. Because of possible serious morbidity in donors, LDLLT should be applied only for critically ill patients.

Depicting and predicting changes of lung after lobectomy for cancer by using CT images

Lobectomy is an effective and well-established therapy for localized lung cancer. This study aimed to assess the lung and lobe change after lobectomy and predict the postoperative lung volume. The study included 135 lung cancer patients from two hospitals who underwent lobectomy (32, right upper lobectomy (RUL); 31, right middle lobectomy (RML); 24, right lower lobectomy (RLL); 26, left upper lobectomy (LUL); 22, left lower lobectomy (LLL)). We initially employ a convolutional neural network model (nnU-Net) for automatically segmenting pulmonary lobes. Subsequently, we assess the volume, effective lung volume (ELV), and attenuation distribution for each lobe as well as the entire lung, before and after lobectomy. Ultimately, we formulate a machine learning model, incorporating linear regression (LR) and multi-layer perceptron (MLP) methods, to predict the postoperative lung volume. Due to the physiological compensation, the decreased TLV is about 10.73%, 8.12%, 13.46%, 11.47%, and 12.03% for the RUL, RML, RLL, LUL, and LLL, respectively. The attenuation distribution in each lobe changed little for all types of lobectomy. LR and MLP models achieved a mean absolute percentage error of 9.8% and 14.2%, respectively. Radiological findings and a predictive model of postoperative lung volume might help plan the lobectomy and improve the prognosis.

Impact of Spousal Donation on Postoperative Outcomes of Living-donor Lobar Lung Transplantation

BACKGROUND

The effect of human leukocyte antigen mismatches between donors and recipients on postoperative outcomes of lung transplantation remains controversial. We retrospectively reviewed adult recipients receiving living-donor lobar lung transplantation (LDLLT) to examine the difference in de novo donor-specific antibody (dnDSA) development and clinically diagnosed unilateral chronic lung allograft dysfunction per graft (unilateral CLAD) between lung grafts donated by spouses (nonblood relatives) and nonspouses (relatives within the third degree). We also investigated the difference in prognoses between recipients undergoing LDLLTs including spouse donors (spousal LDLLTs) and not including spouse donors (nonspousal LDLLTs).

METHODS

In this study, 63 adult recipients undergoing LDLLTs (61 bilateral and 2 unilateral LDLLTs from 124 living donors) between 2008 and 2020 were enrolled. The cumulative incidence of dnDSAs per lung graft was calculated, and prognoses were compared between recipients undergoing spousal and nonspousal LDLLTs.

RESULTS

The cumulative incidence of both dnDSAs and unilateral CLAD in grafts donated by spouses was significantly higher than that in grafts donated by nonspouses (5-y incidence of dnDSAs: 18.7% versus 6.4%, P = 0.038; 5-y incidence of unilateral CLAD: 45.6% versus 19.4%, P = 0.011). However, there were no significant differences in the overall survival or chronic lung allograft dysfunction-free survival between recipients undergoing spousal and nonspousal LDLLTs ( P > 0.99 and P = 0.434, respectively).

CONCLUSIONS

Although there were no significant differences in prognoses between spousal and nonspousal LDLLTs, more attention should be paid to spousal LDLLTs because of the higher development rate of dnDSAs and unilateral CLAD.

Outcome and growth of lobar graft after pediatric living-donor lobar lung transplantation

BACKGROUND

Living-donor lobar lung transplantation (LDLLT) remains a life-saving option for pediatric patients with respiratory failure. However, the long-term survival and post-transplant quality of adult lobar grafts transplanted into children are unknown. Therefore, this study aimed to evaluate the outcomes of pediatric LDLLT and post-transplant graft growth.

METHODS

We retrospectively reviewed the prospectively collected clinical data of 25 living-donor lung transplantations performed in 24 pediatric recipients aged ≤17 years. The annual pulmonary function test data and computed tomography scans of 12 recipients, followed up for >5 years without significant complications, were used to evaluate growth in height, graft function, and radiological changes. The Kaplan-Meier method and simple linear regression were performed for analysis.

RESULTS

Bilateral lower lobe transplantation was performed in 12 patients, unilateral lower lobe transplantation in 12, and bilateral middle lobe transplantation in 1. The median volumetric size matching at transplantation was 142% (range, 54%-457%). The 5- and 10-year overall survival rates were 87.7% and 75.1༅, respectively. Chronic lung allograft dysfunction occurred in 2 patients. During a median follow-up of 6 years, the median increases in height and vital capacity were 14.4% (range, 0.80%-43.5%) and 58.5% (range, 6.7%-322%), respectively. Graft weight was positively correlated with graft volume (r²=0.622, p<0.001) after the graft volume exceeded the original lobar volume in the donor.

CONCLUSIONS

This study shows that pediatric LDLLT offers satisfactory long-term survival, with the growth of mature adult lobes transplanted into growing children.

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.

Comparison of de novo donor-specific antibodies between living and cadaveric lung transplantation

BACKGROUND

Despite growing interest in donor-specific antibodies (DSAs) and antibody-mediated rejection (AMR) in lung transplantation (LTx), no study evaluating the outcomes in recipients with de novo DSAs (dnDSAs) in living-donor lobar LTx (LDLLT) exists. We compared various characteristics of DSAs in LDLLT with those in cadaveric LTx (CLT) based on prospectively collected data.

METHODS

Between October 2009 and September 2019, 211 recipients underwent LTx (128 CLTs and 83 LDLLTs). We reviewed 108 CLTs and 74 LDLLTs to determine the characteristics and clinical impact of dnDSAs. Eighteen data-deficient cases, 7 cases with preformed DSAs, and 4 re-transplants were excluded.

RESULTS

There were significant differences between CLT and LDLLT patients in age, primary disease, ischemic time, and number of human leukocyte antigen mismatches per donor. The dnDSA incidence in LDLLT (6.8%) was significantly lower than that in CLT (19.4%, p = 0.02). The dnDSAs appeared later in LDLLT (mean 1,256 days) than in CLT (mean 196 days, p = 0.003). According to Cox models analyzed using dnDSA as a time-dependent covariate, dnDSA positivity was significantly associated with a poor overall survival (OS; hazard ratio [HR] 3.46, 95% confidence interval [CI] 1.59-7.57, p = 0.002) and poor CLAD-free survival in case of CLT (HR: 2.23, 95% CI: 1.08-4.63, p = 0.003). However, no such significant associations were noted in case of LDLLT.

CONCLUSIONS

The dnDSA occurrence was significantly lower and later in LDLLT than in CLT. Furthermore, dnDSA-positivity was significantly associated with worse OS and CLAD-free survival after CLT but not after LDLLT.

Prognostic Factors in Lung Transplantation After Hematopoietic Stem Cell Transplantation

BACKGROUND

Lung transplantation is the final lifesaving option for patients with pulmonary complications after hematopoietic stem cell transplantation (HSCT). Patients undergoing HSCT for hematologic diseases are thought to be high-risk candidates for lung transplantation; therefore, few lung transplants are performed for these patients, and few studies have been reported. This study aimed to describe the characteristics and outcomes of lung transplantation in patients with pulmonary complications after HSCT.

METHODS

We retrospectively investigated 62 patients who underwent lung transplantation after HSCT. All data were collected from 6 lung transplant centers in Japan.

RESULTS

Seventeen patients underwent cadaveric lung transplantation, whereas 45 underwent living-donor lobar lung transplantation (LDLLT). In the LDLLT group, 18 patients underwent LDLLT after HSCT in which one of the donors had also served as a donor for HSCT. Seven patients underwent single LDLLT for which the donor was the same as the patient from whom stem cells were obtained for HSCT. Preoperative hypercapnia was observed in 52 patients (84%). Thirteen patients (21%) required mechanical ventilation preoperatively. Fifty-five patients underwent HSCT for hematologic malignancies, and 4 (7%) relapsed after lung transplantation. The 5-year survival rate was 64.2%. In a multivariable analysis, patients younger than 45 years and those with the same donor for both procedures exhibited significantly better survival (P = 0.012 and 0.041, respectively).

CONCLUSIONS

Lung transplantation for pulmonary complications after HSCT was performed safely and yielded better survival, especially in younger recipients for whom both lung transplantation and HSCT involved the same donor.

Radiologic and Functional Analysis of Compensatory Lung Growth After Living-Donor Lobectomy

BACKGROUND

Whether compensatory lung growth occurs in adult humans is controversial. The aim of this study was to confirm compensatory lung growth by analyzing ipsilateral residual lung after lower lobectomy in living lung transplant donors with quantitative and qualitative computed tomography assessments.

METHODS

Chest computed tomography and pulmonary function tests were performed in 31 eligible donors before and 1 year after donor lobectomy. Ipsilateral residual lung volume was measured with three-dimensional computed tomography volumetry. The computed tomography-estimated volumes of low, middle, and high attenuations in the lung were calculated. Assessment of the D value, a coefficient of the cumulative size distribution of low-density area clusters, was performed to evaluate the structural quality of the residual lung.

RESULTS

Postoperative pulmonary function test values were significantly larger than preoperative estimated values. Although postoperative total volume, low attenuation volume, middle attenuation volume, and high attenuation volume of the ipsilateral residual lung were significantly larger than the preoperative volumes, with 50.2%, 50.0%, 41.5%, and 43.1% increase in the median values, respectively (all p < 0.0001), the differences in D values before and after donor lobectomy were not significant (p = 0.848). The total volume of ipsilateral residual lung was increased by more than 600 mL (50%).

CONCLUSIONS

The volume of ipsilateral residual lung increased, but its structural quality did not change before and after donor lobectomy. The existence of compensatory lung growth in adult humans was suggested by quantitative and qualitative computed tomography assessments.

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.

Pulmonary Function and Exercise Capacity in Patients With Flat Chests After Lung Transplantation

BACKGROUND

Severe chest wall deformation is generally a contraindication for lung transplantation; however, it is not known whether patients with flat chests have reduced postoperative exercise capacity and pulmonary function. This study's purpose was to investigate the relationship between preoperative thoracic shape and postoperative exercise capacity and pulmonary function in patients undergoing lung transplantation.

METHODS

Twenty recipients who underwent successful bilateral living-donor lobar lung transplantation were evaluated. To analyze postoperative graft function in relation to preoperative thoracic shape, 40 donor grafts implanted into 20 recipients were divided into two groups: flat chest group and normal chest group. Flat chest is diagnosed when the thoracic anteroposterior diameter to transverse diameter ratio is 1:3 or less.

RESULTS

The ratio of the postoperative forced vital capacity to the preoperatively estimated forced vital capacity was significantly lower in the flat chest group than in the normal chest group 1 year after lung transplantation (p = 0.002). However, there were no significant differences in postoperative 6-minute walk distances between the two groups. Furthermore, the thoracic anteroposterior diameter to transverse diameter ratio in the flat chest group significantly increased after lung transplantation (p = 0.02).

CONCLUSIONS

Although postoperative pulmonary function was significantly poorer for patients with flat chests than for patients with normal chests, their postoperative exercise capacity was equivalent. We also found that flat chest severity significantly improved after lung transplantation. Our study, the first investigating postoperative functional status in patients with flat chests, clearly shows that it is possible to perform lung transplantation in such patients with acceptable outcomes.

Living-related lung transplantation

Living-donor lobar lung transplantation (LDLLT) was developed to deal with the severe shortage of brain dead door for patients who would not survive the long waiting period. In standard LDLLT, right and left lower lobes removed from two healthy donors are implanted into a recipient after right and left pneumonectomies using cardiopulmonary bypass (CPB). The number of LDLLT has decreased in the USA due to the recent change in allocation system for cadaveric donor lungs. For the past several years, most of the reports on LDLLT have been from Japan, where the average waiting time for a cadaveric lung is exceeding 800 days. LDLLT has been performed both for adult and pediatric patients suffering from various end-stage lung diseases including restrictive, obstructive, vascular and infectious lung diseases. Since only two lobes are implanted, size matching is a very important issue. Functional size matching by measuring donor pulmonary function and anatomical size matching by three-dimensional computed tomography (3D-CT) volumetry are very useful. For oversize graft, we have employed several techniques, including single lobe transplantation, delayed chest closure, downsizing the graft, and middle lobe transplantation. In cases of undersize mismatch, native upper lobe sparing transplant or right-left inverted transplant was performed. The 5-, 10- and 15-year survivals were 80.8%, 72.6% and 61.7%, respectively. There was no difference in survival between standard LDLLT and non-standard LDLLT such as single, sparing and inverted transplant. All donors have been discharged without any restrictions. LDLLT is a viable option for very ill patients who would not survive a long waiting time for cadaveric lungs. We have successfully developed various surgical techniques to overcome size mismatching with favorable outcome.

Update on three-dimensional image reconstruction for preoperative simulation in thoracic surgery

BACKGROUND

Three-dimensional computed tomography (3D-CT) technologies have been developed and refined over time. Recently, high-speed and high-quality 3D-CT technologies have also been introduced to the field of thoracic surgery. The purpose of this manuscript is to demonstrate several examples of these 3D-CT technologies in various scenarios in thoracic surgery.

METHODS

A newly-developed high-speed and high-quality 3D image analysis software system was used in Kyoto University Hospital. Simulation and/or navigation were performed using this 3D-CT technology in various thoracic surgeries.

RESULTS

Preoperative 3D-CT simulation was performed in most patients undergoing video-assisted thoracoscopic surgery (VATS). Anatomical variation was frequently detected preoperatively, which was useful in performing VATS procedures when using only a monitor for vision. In sublobar resection, 3D-CT simulation was more helpful. In small lung lesions, which were supposedly neither visible nor palpable, preoperative marking of the lesions was performed using 3D-CT simulation, and wedge resection or segmentectomy was successfully performed with confidence. This technique also enabled virtual-reality endobronchial ultrasonography (EBUS), which made the procedure more safe and reliable. Furthermore, in living-donor lobar lung transplantation (LDLLT), surgical procedures for donor lobectomy were simulated preoperatively by 3D-CT angiography, which also affected surgical procedures for recipient surgery. New surgical techniques such as right and left inverted LDLLT were also established using 3D models created with this technique.

CONCLUSIONS

After the introduction of 3D-CT technology to the field of thoracic surgery, preoperative simulation has been developed for various thoracic procedures. In the near future, this technique will become more common in thoracic surgery, and frequent use by thoracic surgeons will be seen in worldwide daily practice.