Waiting time and mortality rate on lung transplant candidates in Japan: a single-center retrospective cohort study

Long-term survival and clinical outcomes of delayed chest closure following lung transplantation

PURPOSES

Delayed chest closure (DCC) is a widely accepted procedure in the context of lung transplantation (LTx); yet there are few reports detailing its long-term survival and clinical outcomes.

METHODS

We reviewed the medical records of recipients who underwent deceased-donor lung transplantation (LTx) at Tohoku University Hospital. Long-term survival, including overall survival, freedom from chronic lung allograft dysfunction (CLAD), and CLAD-free survival and the clinical outcomes of graft function and physical performance and constitution were reviewed in recipients with DCC.

RESULTS

Between 2009 and 2022, 116 patients underwent LTx, 33 of whom (28.4%) required DCC. The intra-and post-operative courses of the recipients who required DCC were more complicated than those of the recipients who underwent primary chest closure (PCC), with frequent volume reduction surgery and longer periods of invasive mechanical ventilation. Pulmonary vascular disease was considered a risk factor for these complications and DCC. Nonetheless, long-term survival and graft functions were comparable between the DCC and PCC groups. The physical performance and constitution of recipients who required DCC continued to improve, and by 2 years after transplantation, exhibited almost no difference from those who underwent PCC.

CONCLUSIONS

In view of the profoundly complicated intra- and post-operative courses, DCC should be performed cautiously and only when clinically indicated, despite which it can result in equivalent long-term survival and acceptable outcomes to PCC.

Effect of revised organ transplant law in Japan on lung transplantation

PURPOSE

To investigate how revision of the organ transplant law in Japan affected lung transplantation in this country.

METHODS

Lung transplant candidates registered between January, 2000 and December, 2009 were designated as the pre-revision group (n = 396) and those registered between January, 2011 and December, 2020, as the post-revision group (n = 1326). Both groups were analyzed retrospectively using data collected by the Japanese Society of Lung and Heart-Lung Transplantation.

RESULTS

The number of patients who underwent brain-dead donor lung transplantation (BDLT) increased significantly after the law amendment (32.2 vs. 13.8%, p < 0.01). The median waiting time for BDLT was significantly reduced (708 days vs. 1163 days, p < 0.01) and the mortality rate while waiting for BDLT improved significantly after the law amendment (33.1 vs. 42.6%, p < 0.01). In the post-revision group, 18 pediatric patients underwent BDLT. The 5-year survival rates after BDLT were comparable between the groups (73.5% in the pre-revision group vs. 73.2% in the post-revision group, p = 0.32).

CONCLUSIONS

The organ transplant law revision shortened the waiting time for BDLT significantly and decreased the mortality rate while waiting for BDLT. The posttransplant outcomes in Japan remained favorable throughout the study period.

The impact of time from ILD diagnosis to referral to the transplant center on the probability of inclusion in the transplant waiting list

BACKGROUND

Lung transplant is a therapeutic option for patients with progressive interstitial lung disease (ILD).

OBJECTIVES

The objective of this study was to determine whether time from ILD diagnosis to referral to a transplant center influences the probability of being included in the transplant waiting list.

METHODS

We performed a retrospective cohort study including all ILD patients evaluated as lung transplantation (LT) candidates at a lung transplant center between 01/01/2017 and 31/12/2022. The primary endpoint was the probability of being included in the lung transplant waiting list according to the time elapsed from diagnosis to referral to the transplant center.

RESULTS

A total of 843 lung transplant requests were received, of which 367 (43.5%) were associated with ILD. Thirteen patients were excluded because they did not attend the first visit, whereas another 11 were excluded because some information was missing. As a result, our final sample was composed of 343 patients. The median time from diagnosis to referral was 29.4 (10.9 - 61.1) months. The overall probability of inclusion in the waiting list was 29.7%. By time from diagnosis to referral, the probability of inclusion in the waiting list was 48.1% for the patients referred 〈 6 months from diagnosis; 27.5% for patients referred 6 to 24 months from diagnosis; and 25.8% for patients referred 〉 24 months from diagnosis (p = 0.007).

CONCLUSIONS

Early referral to a lung transplant center seemed to increase the probability of being included in the lung transplant waiting list. Further research is needed in this topic.

Proposed Clinical Algorithm for Pleuroparenchymal Fibroelastosis (PPFE)

Pleuroparenchymal fibroelastosis (PPFE) is characterized by fibrosis involving the pleura and subpleural lung parenchyma, predominantly in the upper lobes. As PPFE appears to occur in patients with heterogeneous etiologies, the disease course is thus also heterogenous, with some patients showing rapid progression while others have slow progression. Therefore, it is very difficult to predict prognosis with PPFE. Needless to say, this problematic matter has influenced the treatment strategy of PPFE patients. In fact, until now no evidence has been shown for use in creating an appropriate management algorithm for PPFE. We speculate that "uncoordinated breathing" is the most important reason for dyspnea in PPFE patients. Because monitoring of physique and not just pulmonary function and radiological evaluation is also very important, particularly in PPFE patients, this review focused on the characteristics of PPFE through an overview of previous studies in this field, and we proposed an algorithm as precision medicine based on the current evidence. Multiple views by the pulmonologist are needed to standardize a clinical algorithm that is necessary to correctly assess PPFE patients under the premise of maintenance of physique by providing appropriate nutritional care and pulmonary rehabilitation.

Japanese guidelines for the treatment of idiopathic pulmonary fibrosis 2023:Revised edition

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with a poor prognosis and an unknown cause that generally progresses to pulmonary fibrosis and leads to irreversible tissue alteration. The "Guidelines for the treatment of idiopathic pulmonary fibrosis 2017," specializing in the treatment of IPF for the first time in Japan and presenting evidence-based standard treatment methods suited to the state of affairs in Japan, was published in 2017, in line with the 2014 version of "Formulation procedure for Minds Clinical Practice Guidelines." Because new evidence had accumulated, we formulated the "Guidelines for the treatment of Idiopathic Pulmonary Fibrosis 2023 (revised 2nd edition)." While keeping the revision consistent with the ATS/ERS/JRS/ALAT IPF treatment guidelines, new clinical questions (CQs) on pulmonary hypertension were added to the chronic stage, in addition to acute exacerbation and comorbid lung cancer, which greatly affect the prognosis but are not described in the ATS/ERS/JRS/ALAT IPF guidelines. Regarding the advanced stages, we additionally created expert consensus-based advice for palliative care and lung transplantation. The number of CQs increased from 17 in the first edition to 24. It is important that these guidelines be used not only by respiratory specialists but also by general practitioners, patients, and their families; therefore, we plan to revise them appropriately in line with ever-advancing medical progress.

Patient selection, surgery and perioperative management in lung transplantation in Japan

Lung transplantation (LT) is the final treatment option for end-stage respiratory diseases. The current prognosis of LT recipients in Japan is good, however, the reason for the good prognosis is unclear. In Japan, the waiting time for cadaveric LT is long, which is approximately 900 days on average. A long waiting time affects several aspects of LT. The diseases progress while they await LT in most patients are waiting for LT. Along with the disease progression of the disease, secondary pulmonary hypertension can newly emerge. Some patients suffer from refractory secondary pneumothorax and may receive pleurodesis. Transplant operations can become more difficult, and postoperative management becomes more complicated owing to the disease progression. Thoracic surgeons in Japan have managed the tough difficult situation of LT patients with LT. Possible explanations for how we to maintain a better prognosis in such a situation include sophisticated surgical techniques and ideas, and vigorous postoperative management by thoracic surgeons. Thoracic surgeons are vigorously involved both in operations and in postoperative management in the intensive care unit with or without intensivists in Japan. On the other hand, the long waiting time in Japan and allocation rules with age restriction without considering the severity of patients may have resulted in the selection of recipients to include relatively young recipients, fewer patients with interstitial lung disease and fewer recipients with extracorporeal membrane oxygenation (ECMO) as a bridge to LT. These recipients' characteristics possibly may have affected the prognosis of LT patients with LT in Japan. There is a chance that a future increase in the number of cadaveric donors in Japan may result in a prognosis close that is similar to the international average if the current waiting time in Japan decreases. We review patient selection, surgery and perioperative management in LT in Japan to address the question of why the current prognosis of LT recipients in Japan is good.

Native-lung complications following single-lung transplantation for interstitial lung disease: an in-depth analysis

BACKGROUND

Interstitial lung disease (ILD) represents a heterogeneous group of lung disorders characterized by fibrotic lung tissue changes. In regions with severe donor shortages, single-lung transplantation (SLTx) is often preferred over bilateral lung transplantation for advanced ILD. However, temporal changes and complications in the retained native lung remain poorly understood.

METHODS

A retrospective analysis of 149 recipients who had undergone SLTx was conducted, including 34 ILD SLTx recipients. Native-lung volume, radiological alterations, and perfusion were assessed at distinct post-SLTx time points. Statistical analyses compared ILD and non-ILD SLTx groups.

RESULTS

Our study revealed a progressive reduction in native-lung volume over time, accompanied by radiographic deterioration and declining perfusion. Complications in the retained native lung were observed, such as pneumothorax (29.4%), pulmonary aspergillosis (11.8%), and acute exacerbation (8.9%). Long-term survival rates were similar between ILD and non-ILD SLTx recipients.

CONCLUSIONS

This study illuminates the unique challenges and complications with respect to the native lung following SLTx for ILD. Ongoing monitoring and tailored management are essential. Despite limitations, this research contributes to our understanding of the temporal progression of native-lung complications post-SLTx for ILD, underscoring the need for further investigation.

A Single-Center Analysis of How HLA Mismatch and Donor-Specific Antibodies Affect Short-Term Outcome After Lung Transplantation: A Pilot Study Before a Country-Wide Histocompatibility Study in Japan

BACKGROUND

Analyzing HLA polymorphism in lung transplantation (LTx) is important, given its impact on LTx recipient survival and graft function. Accordingly, we conducted a retrospective study to examine the influence of HLA mismatch and donor-specific antibodies (DSA) on short-term outcomes and early-phase post-LTx complications.

METHOD

HLA antigen or eplet mismatch in LTx patients at Tohoku University Hospital from 2018 to 2023 was determined, and DSA was measured on admission for surgery to identify preformed DSA and at weeks 4 to 12 post-LTx for de novo DSA, respectively.

RESULTS

The participants were 45 LTx recipients, HLA-A/B/DR antigen mismatch (5-6 of 6) being identified in 57%, HLA-A/B/Cw/DR/DQ mismatch (8-10 of 10) in 57%, and HLA eplet mismatch (>61) in 46%. The prevalence of preformed DSA was 24%, and persistence (uncleared) was 16%. The incidence of de novo DSA was 16% after LTx. During the study,16 recipients experienced grade 3 primary graft dysfunction (PGD), 8 developed acute rejection, and 5 died. No HLA-related variables were significantly associated with post-LTx mortality and were not risk factors for high-grade PGD or acute rejection.

CONCLUSION

Despite limitations in sample size, resulting in tentative findings, the study serves as a crucial pilot study for an ongoing multicenter prospective trial in Japan.

Roles of respirologists in lung transplantation in Japan: narrative review

Background and Objective

Lung transplantation (LTx) in Japan has taken steps toward increasing the number of donors and recipients and is at the maturity stage of development, at which point pulmonologists (hereinafter referred to as "respirologists") become involved in transplant practice. Because of severe donor shortage and limited number of LTx surgeries, most of transplant process from candidacy evaluation to post-operative management has been handled only by thoracic surgeons, which takes away opportunities from respirologists to manage LTx recipients. Given the growth of both LTx and the number of patients with complex problems, cooperation with respirologists in transplant practice is urgently needed to achieve transplant success in Japan.

Methods

Authors summarized current transplant circumstance in Japan from the transplant physician's standpoint. A systematic search through PubMed database and Google Scholar was performed by terms of "respirologists", "pulmonologist", "lung transplant" or "Japan" from 2000 and 2022. Thoracic surgeons working at each transplant center were asked to complete a questionnaire on physicians' intervention to LTx.

Key Content and Findings

The roles of respirologists in LTx differ with facility size and function, depending on whether they are working at a non-transplant center with other respirologists or at a transplant center with transplant physicians. LTx centers are currently devoted to educating respirologists who work at non-transplant or low-volume transplant centers in order for them to deal with patients before and after transplantation.

Conclusions

Joint efforts and training of outstanding personnel who can take care of recipients are required, this being the greatest issue for the success of transplantation in Japan.

Prognosis of patients with systemic sclerosis-related interstitial lung disease on the lung transplant waiting list: a retrospective study

Advanced systemic sclerosis-associated interstitial lung disease (SSc-ILD) can be treated with lung transplantation. There is limited data on lung transplantation outcomes in patients with SSc-ILD, in non-Western populations.We assessed survival data of patients with SSc-ILD, on the lung transplant (LT) waiting list, and evaluated post-transplant outcomes in patients from an Asian LT center. In this single-center retrospective study, 29 patients with SSc-ILD, registered for deceased LT at Kyoto University Hospital, between 2010 and 2022, were identified. We investigated post-transplant outcomes in recipients who underwent LT for SSc-ILD, between February 2002 and April 2022. Ten patients received deceased-donor LT (34%), two received living-donor LT (7%), seven died waiting for LT (24%), and ten survived on the waiting list (34%). Median duration from registration to deceased-donor LT was 28.9 months and that from registration to living-donor LT or death was 6.5 months. Analysis of 15 recipients showed improved forced vital capacity with a median of 55.1% at baseline, 65.8% at 6 months, and 80.3% at 12 months post-transplant. The 5-year survival rate for post-transplant patients with SSc-ILD was 86.2%. The higher post-transplant survival rate at our institute than previously reported suggests that lung transplantation is acceptable in Asian patients with SSc-ILD.

Cellular and humoral immune responses after a third dose of SARS-CoV-2 mRNA vaccine in lung transplant recipients in Japan

BACKGROUND

Lung transplant (LTx) recipients are at higher risk of infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). There is an increasing demand for additional analysis regarding the efficacy and safety of after the initial series of mRNA SARS-CoV-2 vaccines in Japanese transplant recipients.

METHOD

In this open-label, nonrandomized prospective study carried out at Tohoku University Hospital, Sendai, Japan, LTx recipients and controls received third doses of either the BNT162b2 or the mRNA-1273 vaccine, and the cellular and humoral immune responses were analyzed.

RESULTS

A cohort of 39 LTx recipients and 38 controls participated in the study. The third dose of SARS-CoV-2 vaccine promoted much greater humoral responses at 53.9 % of LTx recipients than after the initial series at 28.2 % of patients without increasing the risk of adverse events. However, still fewer LTx recipients responded to the SARS-CoV-2 spike protein with the median IgG titer of 129.8 AU/mL and with the median IFN-γ level of 0.01 IU/mL when compared to controls with those of 7394 AU/mL and 0.70 IU/mL, respectively.

CONCLUSION

Although the third dose of mRNA vaccine in LTx recipients was effective and safe, impaired cellular and humoral responses to SARS-CoV-2 spike protein were noted. Given lower antibody production and establishing vaccine safety, repeating the administration of mRNA vaccine will lead to robust protection in such a high-risk population (jRCT1021210009).

Outcomes of Patients on the Lung Transplantation Waitlist in Korea: A Korean Network for Organ Sharing Data Analysis

BACKGROUND

The demand for lung transplants continues to increase in Korea, and donor shortages and waitlist mortality are critical issues. This study aimed to evaluate the factors that affect waitlist outcomes from the time of registration for lung transplantation in Korea.

METHODS

Data were obtained from the Korean Network for Organ Sharing for lung-only registrations between September 7, 2009, and December 31, 2020. Post-registration outcomes were evaluated according to the lung disease category, blood group, and age.

RESULTS

Among the 1,671 registered patients, 49.1% had idiopathic pulmonary fibrosis (group C), 37.0% had acute respiratory distress syndrome and other interstitial lung diseases (group D), 7.2% had chronic obstructive pulmonary disease (group A), and 6.6% had primary pulmonary hypertension (group B). Approximately half of the patients (46.1%) were transplanted within 1 year of registration, while 31.8% died without receiving a lung transplant within 1 year of registration. Data from 1,611 patients were used to analyze 1-year post-registration outcomes, which were classified as transplanted (46.1%, n = 743), still awaiting (21.1%, n = 340), removed (0.9%, n = 15), and death on waitlist (31.8%, n = 513). No significant difference was found in the transplantation rate according to the year of registration. However, significant differences occurred between the waitlist mortality rates (P = 0.008) and the still awaiting rates (P = 0.009). The chance of transplantation after listing varies depending on the disease category, blood type, age, and urgency status. Waitlist mortality within 1 year was significantly associated with non-group A disease (hazard ratio [HR], 2.76, P < 0.001), age ≥ 65 years (HR, 1.48, P < 0.001), and status 0 at registration (HR, 2.10, P < 0.001).

CONCLUSION

Waitlist mortality is still higher in Korea than in other countries. Future revisions to the lung allocation system should take into consideration the high waitlist mortality and donor shortages.

Efficacy and safety of mRNA SARS-CoV-2 vaccines in lung transplant recipients

BACKGROUND

To date, reports addressing the antibody response following mRNA SARS-CoV-2 vaccination in lung transplant (LTX) recipients are limited. Thus, the aim of this clinical study was to investigate the efficacy and safety of the vaccines in LTX recipients compared to controls.

METHODS

An open-label, nonrandomized prospective study was conducted at Tohoku University Hospital. LTX recipients and controls who received either the BNT162b2 vaccine or the mRNA-1273 vaccine were recruited, and SARS-CoV-2 IgG was measured before and after vaccination. The adverse events were reviewed. Predictors of negative serology after vaccination were evaluated with logistic regression.

RESULTS

Forty-one LTX recipients and 24 controls were analyzed. Although all controls had a positive antibody response to a SARS-CoV-2 mRNA vaccine, antibody response was found in 24.4% of LTX recipients (p < .0001). The amount of SARS-CoV-2 IgG following the 2nd dose significantly climbed to 6557 AU/mL in controls, whereas the increase in IgG in LTX recipients was 8.3 AU/mL (p < .0001). Fewer LTX recipients developed systemic fever than controls (p < .0001) despite equivalent overall adverse event percentages in both groups. A higher plasma concentration of mycophenolate was a significant predictor of negative serology (p = .032).

CONCLUSIONS

An impaired antibody response to mRNA vaccines was significantly found in LTX recipients compared to controls and was associated with the plasma concentration of mycophenolate. While repeating mRNA vaccination may be one of the strategies to improve antibody response given the safety of the vaccines, emerging data on humoral immune responses based on immunosuppression regimens in LTX recipients should be studied (jRCT1021210009).