Airway anastomotic dehiscence associated with use of sirolimus immediately after lung transplantation

Effect of mTOR inhibitors on the mortality and safety of patients with lymphangioleiomyomatosis on the lung transplantation waitlist: A retrospective cohort study

BACKGROUND

Although lung transplantation (LTx) is the last resort for patients with end-stage lymphangioleiomyomatosis (LAM), the high waitlist mortality is a source of concern in Japan. Discontinuation of mechanistic target of rapamycin (mTOR) inhibitors prior to LTx is recommended due to the incidence of severe adverse events. Therefore, we hypothesized that mTOR inhibitors may affect the mortality of patients with LAM on the LTx waitlist.

METHODS

We retrospectively compared the characteristics of consecutive patients with LAM on the LTx waitlist who were and were not receiving mTOR inhibitors.

RESULTS

Twenty-nine consecutive patients with LAM who listed our center between January 2004 and December 2021 were selected from the database and enrolled in the present study. Seventeen patients (58.6%) were receiving a mTOR inhibitor, sirolimus (treatment group). During a median listing period of 1277 days, 12 patients (41.4%) were hospitalized, six patients (20.7%) died from disease before LTx, and 15 patients underwent LTx. Among the deceased patients, four patients (66.6%) had pneumothoraces. The waitlist mortality in the treatment group was significantly lower than that in the non-treatment group (p = 0.03). Among the six patients who discontinued sirolimus in the treatment group, four patients (66.6%) were hospitalized with respiratory complications after the discontinuation of sirolimus. No mTOR inhibitor-related complications arose in the treatment group undergoing LTx (n = 7), including those on a reduced sirolimus dose.

CONCLUSIONS

Administration of an mTOR inhibitor until LTx may decrease waitlist mortality. Due to life-threatening events after discontinuing sirolimus pre-LTx, a reduced dose until LTx is permissible.

Interstitial lung disease as an indication for pediatric lung transplant

Interstitial lung disease can be an indication for lung transplant at any age, but it is a particularly common indication for lung transplant in infants. Nevertheless, not all interstitial lung diseases will lead to lung transplant in childhood. Genetic testing has aided the identification of these diseases in children. In severely affected patients, however, definitive diagnosis is not always necessary to consider referral to a transplant center. At experienced transplant centers, a multidisciplinary team educates patient families and aids in the transplant evaluation of children with interstitial lung disease. Children who have undergone transplant require lifetime immunosuppression and close surveillance, but can enjoy good quality of life for years following surgery.

Wound complications frequency in heart transplant recipients on mammalian target of rapamycin inhibitors: A meta-analysis

A meta-analysis investigation was executed to measurethe wound complications (WCs) frequency in heart transplant (HT) recipients on mammalian target of rapamycin inhibitors (MTRIs). A comprehensive literature investigation till February 2023 was applied and 978 interrelated investigations were reviewed. The 10 chosen investigations enclosed 2173 individuals with HT were in the chosen investigations' starting point, 1164 of them were utilising MTRIs, and 1009 were utilising control. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were utilised to compute the value of the WCs frequency in HT recipients on MTRIs by the dichotomous approaches and a fixed or random model. MTRIs had significantly higher WCs (OR, 1.53; 95% CI, 1.19-1.98, P = .001) compared with those with control in individuals with HT. MTRIs had significantly higher WCs compared with those with control in individuals with HT. However, care must be exercised when dealing with its values because of the low number of the nominated investigations and the low sample size of some of the nominated investigations for the meta-analysis.

Conventional and Novel Approaches to Immunosuppression in Lung Transplantation

Most therapeutic advances in immunosuppression have occurred over the past few decades. Although modern strategies have been effective in reducing acute cellular rejection, excess immunosuppression comes at the price of toxicity, opportunistic infection, and malignancy. As our understanding of the immune system and allograft rejection becomes more nuanced, there is an opportunity to evolve immunosuppression protocols to optimize longer term outcomes while mitigating the deleterious effects of traditional protocols.

Incidence, risk factors, and clinical characteristics of airway complications after lung transplantation

Airway complications may occur after lung transplantation and are associated with considerable morbidity and mortality. We investigated the incidence, risk factors, and clinical characteristics of these complications. We retrospectively reviewed the medical records of 137 patients who underwent lung transplantation between 2008 and 2021. The median follow-up period was 20 months. Of the 137 patients, 30 (21.9%) had postoperative airway complications, of which 2 had two different types of airway complications. The most common airway complication was bronchial stenosis, affecting 23 patients (16.8%). Multivariable Cox analysis revealed that a recipient's body mass index ≥ 25 kg/m² (hazard ratio [HR], 2.663; p = 0.013) was a significant independent risk factor for airway complications, as was postoperative treatment with extracorporeal membrane oxygenation (ECMO; HR, 3.340; p = 0.034). Of the 30 patients who had airway complications, 21 (70.0%) were treated with bronchoscopic intervention. Survival rates did not differ significantly between patients with and without airway complications. Thus, our study revealed that one fifth of patients who underwent lung transplantation experienced airway complications during the follow-up period. Obesity and receiving postoperative ECMO are risk factors for airway complications, and close monitoring is warranted in such cases.

Lung transplantation for lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease, associated with respiratory symptoms of dyspnea and spontaneous pneumothorax, along with various extra-thoracic manifestations. Often a progressive disease, albeit slowly, patients can develop chronic and severe respiratory failure and require supplemental oxygen. Lung transplantation (LTX) can offer improved duration and quality of life for patients with end-stage lung disease due to LAM. There are several unique considerations for LTX in LAM patients, and disease-specific complications of LAM prior to LTX can affect management decisions. Furthermore, there are several possible post-transplant issues specific to LAM. In this review, we discuss evaluation and management, disease-specific complications (both pre- and post-transplant), and outcomes for LAM patients undergoing lung transplantation.

ECMO support as a bridge to lung transplantation is an independent risk factor for bronchial anastomotic dehiscence

BACKGROUND

Airway complications are frequent after lung transplantation (LT), as they affect up to 23% of recipients. The implication of perioperative extracorporeal membrane oxygenation (ECMO) support and haemodynamic instability has never been specifically assessed. The first aim of this study was to explore the impact of perioperative ECMO support on bronchial anastomotic dehiscence (BAD) at Day 90 after LT.

METHODS

This prospective observational monocentric study analysed BAD in all consecutive patients who underwent LT in the Bichat Claude Bernard Hospital, Paris, France, between January 2016 and May 2019. BAD visible on bronchial endoscopy and/or tomodensitometry was recorded. A univariate analysis was performed (Fisher's exacts and Mann-Whitney tests), followed by a multivariate analysis to assess independent risk factors for BAD during the first 90 days after LT (p < 0.05 as significant). The Paris North Hospitals Institutional Review Board approved the study.

RESULTS

A total of 156 patients were analysed. BAD was observed in the first 90 days in 42 (27%) patients and was the main cause of death in 22 (14%) patients. BAD occurred during the first month after surgery in 34/42 (81%) patients. ECMO support was used as a bridge to LT, during and after surgery in 9 (6%), 117 (75%) and 40 (27%) patients, respectively. On multivariate analysis, ECMO as a bridge to LT (p = 0.04) and septic shock (p = 0.01) were independent risk factors for BAD.

CONCLUSION

ECMO as a bridge to LT is an independent risk factor for BAD during the first 90 days after surgery. Close monitoring of bronchial conditions must be performed in these high-risk recipients.

Perioperative management of thoracic surgery in patients with lymphangioleiomyomatosis

Background

General surgery for patients with lymphangioleiomyomatosis (LAM) is infrequent, however, general surgeons also occasionally experience it. Only a few reports have described the specific perioperative management appropriate for patients with LAM. Hence, in this case series, we aimed to investigate the surgical outcomes of LAM patients and their characteristics.

Case presentation

Medical records of 4482 patients who underwent thoracic surgery between 2009 and 2017 at our institution were assessed. Twelve patients were diagnosed with LAM. Details of the postoperative courses and surgical outcomes of LAM patients were retrospectively examined.

All LAM patients were female (age 41.3 ± 10.6 years). Surgeries were performed for patients undergoing biopsy (n = 4) and those with pneumothorax (n = 3), lung cancer (n = 2), and other conditions (n = 3). The mortality rate was 0% and the length of hospital stay was 27.4 ± 8.9 days. Ten postoperative complications occurred in six patients (50%): hypoxemia (n = 5), chylothorax (n = 2), and prolonged air leakage (n = 3).

Conclusions

Thoracic surgery may pose a risk of postoperative complications and long hospitalization for patients with LAM, although it lowers the risk of fatality. Management of perioperative air and chyle leakages and lymphatic stasis in the lungs is important for preventing morbidities.

Translation suppression underlies the restrained COVID-19 mRNA vaccine response in the high-risk immunocompromised group

Background

Immunocompromised (IC) patients show diminished immune response to COVID-19 mRNA vaccines (Co-mV). To date, there is no ‘empirical’ evidence to link the perturbation of translation, a rate-limiting step for mRNA vaccine efficiency (VE), to the dampened response of Co-mV.

Materials and methods

Impact of immunosuppressants (ISs), tacrolimus (T), mycophenolate (M), rapamycin/sirolimus (S), and their combinations on Pfizer Co-mV translation were determined by the Spike (Sp) protein expression following Co-mV transfection in HEK293 cells. In vivo impact of ISs on SARS-CoV-2 spike specific antigen (SpAg) and associated antibody levels (IgGSp) in serum were assessed in Balb/c mice after two doses (2D) of the Pfizer vaccine. Spike Ag and IgGSp levels were assessed in 259 IC patients and 50 healthy controls (HC) who received 2D of Pfizer or Moderna Co-mV as well as in 67 immunosuppressed solid organ transplant (SOT) patients and 843 non-transplanted (NT) subjects following three doses (3D) of Co-mV. Higher Co-mV concentrations and transient drug holidays were evaluated.

Results

We observed significantly lower IgGSP response in IC patients (p&lt;0.0001) compared to their matched controls in 2D and 3D Co-mV groups. IC patients on M or S showed a profound dampening of IgGSP response relative to those that were not on these drugs. M and S, when used individually or in combination, significantly attenuated the Co-mV-induced Sp expression, whereas T did not exert significant influence. Sirolimus combo pretreatment in vivo significantly attenuated the Co-mV induced IgMSp and IgGSp production, which correlated with a decreasing trend in the early levels (after day 1) of Co-mV induced Sp immunogen levels. Neither higher Co-mV concentrations (6μg) nor withholding S for 1-day could overcome the inhibition of Sp protein levels. Interestingly, 3-days S holiday or using T alone rescued Sp levels in vitro.

Conclusions

This is the first study to demonstrate that ISs, sirolimus and mycophenolate inhibited Co-mV-induced Sp protein synthesis via translation repression. Selective use of tacrolimus or drug holiday of sirolimus can be a potential means to rescue translation-dependent Sp protein production. These findings lay a strong foundation for guiding future studies aimed at improving Co-mV responses in high-risk IC patients.

Outpatient Pharmacologic Management of Lung Transplant Candidates on the Waiting List

The medical care of patients awaiting lung transplantation is complex and requires the treatment of active medical conditions, including lung disease, while at the same time maintaining candidacy for transplantation. Some medications that would otherwise be considered routine may create undesirable challenges or complications in the perioperative setting. Therefore, a comprehensive assessment of the risks and benefits of these medications must take into account both their potential utility in managing a patient's current disease state, as well as the risks of compromising postlung transplant outcomes. In this review, we summarize the available data regarding several medications that are commonly used to treat patients with a variety of lung diseases, but that may impact a patient's course on the waiting list or in the posttransplant period.

Immunosuppression in Lung Transplantation

Immunosuppression in lung transplantation is an area devoid of robust clinical data. This chapter will review the history of immunosuppression in lung transplantation. Additionally, it will evaluate the three classes of induction, maintenance, and rescue immunosuppression in detail. Induction immunosuppression in lung transplantation aims to decrease incidence of lung allograft rejection, however infectious risk must be considered when determining if induction is appropriate and which agent is most favorable. Similar to other solid organ transplant patient populations, a multi-drug approach is commonly prescribed for maintenance immunosuppression to minimize single agent drug toxicities. Emphasis of this review is placed on key medication considerations including dosing, adverse effects, and drug interactions. Clinical considerations will be reviewed per drug class given available literature. Finally, acute cellular, antibody mediated, and chronic rejection are reviewed.

Tuberous sclerosis complex for the pulmonologist

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disorder affecting almost all organs with no sex predominance. TSC has an autosomal-dominant inheritance and is caused by a heterozygous mutation in either the TSC1 or TSC2 gene leading to hyperactivation of the mammalian target of rapamycin (mTOR). TSC is associated with several pulmonary manifestations including lymphangioleiomyomatosis (LAM), multifocal micronodular pneumocyte hyperplasia (MMPH) and chylous effusions. LAM is a multisystem disorder characterised by cystic destruction of lung parenchyma, and may occur in either the setting of TSC (TSC-LAM) or sporadically (S-LAM). LAM occurs in 30–40% of adult females with TSC at childbearing age and is considered a nonmalignant metastatic neoplasm of unknown origin. TSC-LAM is generally milder and, unlike S-LAM, may occur in males. It manifests as multiple, bilateral, diffuse and thin-walled cysts with normal intervening lung parenchyma on chest computed tomography. LAM is complicated by spontaneous pneumothoraces in up to 70% of patients, with a high recurrence rate. mTOR inhibitors are the treatment of choice for LAM with moderately impaired lung function or chylous effusion. MMPH, manifesting as multiple solid and ground-glass nodules on high-resolution computed tomography, is usually harmless with no need for treatment.

Tuberous sclerosis complex is associated with diverse pulmonary manifestations including LAM, multiple micronodular pneumocyte hyperplasia and chylous effusions. LAM occurs in 30–40% of adult females with tuberous sclerosis complex.https://bit.ly/3iLqZ08

A Retrospective Study of Lung Transplantation in Patients With Lymphangioleiomyomatosis: Challenges and Outcomes

Background: Lymphangioleiomyomatosis (LAM) is a rare systemic disease that generally leads to a progressive decline in pulmonary function. Experience, especially from the Asian population, including combined drug therapy before and after lung transplantation (LT) in LAM, is still limited. This study aimed to summarize the clinical data from patients with pulmonary LAM who underwent LT at centers in China. Methods: A retrospective review of all patients with LAM undergoing LT at the two largest centers in China between 2010 and 2018 was conducted. Pre- and posttransplant data were assessed and analyzed. Results: Overall, 25 patients with LAM underwent bilateral LT. The mean age was 35.0 ± 8.6 years at diagnosis and 36.8 ± 9.3 years at the time of transplant. Before LT, only six patients could complete pulmonary function test; the reachable mean forced expiratory volume in one second (FEV₁) before LT was 15.9 ± 6.9%. Twenty-one patients (84%) had a recurrent pneumothorax, four (16.0%) of which required pleurodesis. Eight patients (32%) were treated with sirolimus pretransplant for 3.9 years (1-9 years). The average intra-surgery bleeding volume was 1,280 ± 730 ml in need of a transfusion of 1,316 ± 874 ml due to moderate-to-severe adhesion and pretransplant pleurodesis. The causes of death of four patients (16%) included primary graft dysfunction, bronchial dehiscence with long-term use of sirolimus, and uncontrollable infections. The median follow-up time from LT was 41.1 ± 25.0 months. Conclusions: LT for LAM patients from the Asian population has been reinforced from the data that we presented. Peri-transplantation use of sirolimus and LAM-related complications should be further defined and under constant surveillance.

Lymphatic vessels in solid organ transplantation and immunobiology

With the recent advances in our understanding of the function and biology of the lymphatic vascular system, it is clear that the lymphatic system plays an integral role in physiology, and in pathological settings, may contribute to either enhance or repress inflammation and disease progression. Inflammation is central to both acute and chronic rejection in the context of solid organ transplantation, and emerging evidence suggests the lymphatic system plays a key role in shaping outcomes. The goals of this review are to highlight and contextualize the roles of lymphatic vessels and lymphangiogenesis in immunobiology, the impact immunosuppressive therapies have on the lymphatic system and emerging evidence of organ-specific heterogeneity of lymphatic vessels in the context of solid organ transplantation.

Long-Term Results of Bilateral Lung Transplantation in Patients With End-Stage Pulmonary Lymphangioleiomyomatosis

INTRODUCTION

Lymphangioleiomyomatosis (LAM) is a rare disease in women, leading to progressive deterioration of lung function and respiratory failure. We describe the outcome of patients with end-stage LAM who underwent lung transplantation at our center.

MATERIALS AND METHODS

The records of patients with LAM transplanted at our institution between February 1997 and May 2015 were reviewed retrospectively. Morbidity and mortality were analyzed, and actuarial survival was calculated using Kaplan-Meier methods. The cumulative survival of transplant patients with LAM at our center was compared with survival after transplantation due to different diseases at our center and the results of the International Society for Heart and Lung Transplantation. Quality of life was assessed by a patient self-report at the end of the first postoperative year.

RESULTS

During the study period, 25 patients underwent lung transplantation for LAM. All patients were women with a mean age of 50 (9) years. Thirteen patients (52%) had undergone previous thoracotomy. All patients (100%) received bilateral lung transplantation. One (4%) case of in-hospital mortality occurred and 9 (36%) late deaths. Two (8%) cases of late death were due to chronic lung allograft dysfunction. The 1-, 3-, and 5-year survival rates were 92%, 84%, and 76%, respectively. Quality-of-life ratings were above the normal in all eight 36-Item Short Form Health Survey subscales 1 year after transplantation.

CONCLUSIONS

Lung transplantation offers a valuable therapy for patients with end-stage pulmonary LAM.

Immunosuppressive strategies in lung transplantation

Lung transplantation is a viable option for those with end-stage lung disease which is evidenced by the continued increase in the number of lung transplantations worldwide. However, patients and clinicians are constantly faced with acute and chronic rejection, infectious complications, drug toxicities, and malignancies throughout the lifetime of the lung transplant recipient. Conventional maintenance immunosuppression therapy consisting of a calcineurin inhibitor (CNI), anti-metabolite, and corticosteroids have become the standard regimen but newer agents and modalities continue to be developed. Here we will review induction agents, maintenance immunosuppressives, adjunctive therapies and other strategies to improve long-term outcomes.

Favorable survival even with high disease-specific complication rates in lymphangioleiomyomatosis after lung transplantation-long-term follow-up of a Japanese center

BACKGROUND

Lung transplantation (LT) is a reliable therapeutic option for end-stage pulmonary lymphangioleiomyomatosis (LAM). Long-term outcome of LAM recipients after LT remains unknown. The aim of this study was to describe the outcomes of LT for LAM with a long-term follow-up, comparing those for other diseases in the same period.

METHODS

We retrospectively reviewed consecutive 145 LT recipients between 1998 and 2015 at Okayama University Hospital with minimum 3-year follow-up.

RESULTS

Twelve LAM recipients including nine sporadic-LAM and three tuberous sclerosis complex -LAM were identified. Nine of 12 underwent bilateral LT including four living-donor lobar LT. There was no significant difference in overall survival between the two groups. (P = 0.15). Chronic lung allograft dysfunction free survival rate in LAM compared with other diseases tended to be better (P = 0.058). However, the rate of requiring hemodialysis was significantly higher in LAM recipients than in the recipients of other diseases (P = 0.047). Notably, 8 of 12 (67%) LAM patients encountered LAM-related complication including chylothorax and pneumothorax, seven (58%) had proliferative diseases consisting of renal angiomyolipoma and recurrent LAM. Nine patients required mTOR inhibitors for LAM-related problems, contributing to improved control of LAM-related problems. While all nine recipients of bilateral LT have still survived, two patients died of diseases in their native lungs and one required re-LT among three recipients of single LT.

CONCLUSION

Although the rates of LAM-related complications were unexpectedly high in the long term, LT is a feasible therapeutic option for patients with advanced pulmonary LAM.

Survival Associated With Sirolimus Plus Tacrolimus Maintenance Without Induction Therapy Compared With Standard Immunosuppression After Lung Transplant

Importance

Median survival after lung transplant is less than 6 years. Standard maintenance therapy typically includes tacrolimus and an antimetabolite (mycophenolate mofetil or azathioprine). Replacing the antimetabolite with sirolimus after postoperative wound healing may improve long-term survival due to antifibrotic, antiproliferative, and antiaging effects of sirolimus.

Objectives

To compare survival between patients receiving sirolimus plus tacrolimus vs mycophenolate mofetil plus tacrolimus (the most common maintenance therapy) and to identify the combination of induction and maintenance therapy associated with the highest survival.

Design, Setting, and Participants

This cohort study of US recipients of lung transplants from January 1, 2003, through August 31, 2016, analyzed United Network for Organ Sharing (UNOS) data from January 1 through September 13, 2018. Because initiation of sirolimus therapy is usually delayed 3 to 12 months after lung transplant, primary analyses were based on patients alive and free of chronic rejection and malignant disease at 1 year in all groups, whereas sensitivity analyses used appropriate methods to include all patients from transplant time. Regression models adjusted for available potential confounders, including transplant center performance.

Exposures

Cell cycle inhibitor maintenance therapies, including sirolimus (n = 219), mycophenolate mofetil (n = 5782), mycophenolate sodium (n = 408), azathioprine (n = 2556), and concurrent sirolimus plus mycophenolate mofetil (n = 54), were compared within a tacrolimus-based regimen. Combinations of each induction (basiliximab, daclizumab, antithymocyte globulin, alemtuzumab, or none) and maintenance (tacrolimus plus sirolimus, mycophenolate mofetil, or azathioprine) therapy were also compared.

Main Outcomes and Measures

Survival was the primary outcome; chronic rejection incidence and subsequent mortality were secondary outcomes.

Results

Among this population of 9019 patients (median age, 57 years [interquartile range {IQR}, 46-63 years]; 5194 men [57.6%]), sirolimus plus tacrolimus was associated with better survival than mycophenolate mofetil plus tacrolimus (median, 8.9 years [IQR, 4.4-12.7 years] vs 7.1 years [IQR, 3.6-12.1 years]; adjusted hazard ratio [aHR], 0.71; 95% CI, 0.56-0.89; P = .003). Chronic rejection incidence (aHR, 0.75; 95% CI, 0.61-0.92) and mortality after chronic rejection (aHR, 0.52; 95% CI, 0.31-0.81) were lower with sirolimus plus tacrolimus. Compared with mycophenolate mofetil plus tacrolimus, survival differences for sirolimus plus mycophenolate mofetil plus tacrolimus (aHR, 1.14; 95% CI, 0.79-1.65), mycophenolate sodium plus tacrolimus (aHR, 0.95; 95% CI, 0.77-1.17), and azathioprine plus tacrolimus (aHR, 0.93; 95% CI, 0.84-1.02) were not significant. The induction-maintenance combination with the highest survival was sirolimus plus tacrolimus without induction therapy (median survival, 10.7 years [IQR, 7.3-12.7 years]; aHR, 0.48; 95% CI, 0.31-0.76; P = .002) compared with mycophenolate mofetil plus tacrolimus with induction therapy (median survival, 7.4 years [IQR, 3.9-12.6 years]).

Conclusions and Relevance

Sirolimus plus tacrolimus was associated with improved patient survival after lung transplant compared with mycophenolate mofetil plus tacrolimus; no antibody induction therapy with sirolimus plus tacrolimus was associated with maximal survival.

Early Sirolimus-Based Immunosuppression is Safe for Lung Transplantation Patients: Retrospective, Single Arm, Exploratory Study

Background

Sirolimus, a mechanistic target of sirolimus inhibitor, is an immunosuppression medication for patients undergoing heart and abdominal transplantation. Sirolimus-based immunosuppression administered de novo post-lung transplantation is associated with bronchial anastomosis healing-related complications. We hypothesized that sirolimus administration within the first postoperative month in selected lung transplant recipients is safe and may be associated with favorable short-term and long-term outcomes due to its anti-proliferative properties and minimal adverse side effects.

Material/Methods

Thirteen patients (13.3%; mean age, 46.8±11.9 years) received early sirolimus-based immunosuppression along with cyclosporine and prednisone; 10 patients received single-lung transplantation, 3 received double-lung transplantation, and all received induction immunosuppressants. Patients received early sirolimus-based immunosuppression after an uncomplicated postoperative course and detailed bronchoscopic assessment.

Results

Sirolimus was begun on a mean of 20.6±4.7 days postoperatively (range, 14–32 days). The in-hospital and 30-day mortality rate was 0%. At long-term follow-up, 5 patients died (due to bacterial infection in 4 patients and pneumocystis jiroveci pneumonia in 1 patient). The mean overall survival was 4.4±2.53 (range, 0.8–10.0) years, 1-year survival was 92%, and 5-year survival was 62%. In 4 patients (30.8%), sirolimus was stopped due to infection in 3 patients and re-transplantation in 1 patient. Only one of the 13 patients developed bronchiolitis obliterans syndrome. In patients still taking sirolimus, renal function, systolic blood pressure, and lipid profile were within normal ranges; however, these patients required statin therapy.

Conclusions

In selected lung transplant recipients, early sirolimus-based immunosuppression is safe and associated with beneficial short-term and long-term outcomes.

Immunosuppression for Lung Transplantation: Current and Future

Purpose of the review

The number of lung transplantations performed worldwide continues to increase. There is a growing need in these patients for more effective immunosuppressive medications with less toxicity.

Recent findings

This review article summarizes the recent studies and developments in lung transplant immunosuppression. Novel immunosuppressive medications and strategies used in other solid organ transplantations are being trialed in lung transplantation. This includes the use of co-stimulation blockers like belatacept and mTOR inhibitors like everolimus. Calcineurin sparing regimens have been described in an attempt to minimize nephrotoxicity. Assays to measure the bioactivity of immunosuppressive medications to determine the global immune competence, such as Immuknow assay and Gamma interferon response are gaining traction.

Summary

Immunosuppression in lung transplant is evolving with the development of newer drugs and promising strategies to optimize immunosuppression. Further studies with multicenter randomized trials are required to increase the strength of the evidence.

Single lung transplantation for lymphangioleiomyomatosis: a single-center experience in Japan

PURPOSE

Lung transplantation is accepted as an effective modality for patients with end-stage pulmonary lymphangioleiomyomatosis (LAM). Generally, bilateral lung transplantation is preferred to single lung transplantation (SLT) for LAM because of native lung-related complications, such as pneumothorax and chylothorax. It remains controversial whether SLT is a suitable surgical option for LAM. The objective of this study was to evaluate the morbidity, mortality and outcome after SLT for LAM in a lung transplant center in Japan.

METHODS

We reviewed the records of 29 patients who underwent SLT for LAM in our hospital between March, 2000 and November, 2017. The data collected included the pre-transplant demographics of recipients, surgical characteristics, complications, morbidity, mortality and survival after SLT for LAM.

RESULTS

The most common complication after SLT for LAM was contralateral pneumothorax (n = 7; 24.1%). Six of these recipients were treated successfully with chest-tube placement and none required surgery for the pneumothorax. The second-most common complication was chylous pleural effusion (n = 6; 20.7%) and these recipients were all successfully treated by pleurodesis. The 5-year survival rate after SLT for LAM was 79.5%.

CONCLUSION

LAM-related complications after SLT for this disease can be managed. SLT is a treatment option and may improve access to lung transplantation for patients with end-stage LAM.

New frontiers in immunosuppression

Immunosuppressive therapy is arguably the most important component of medical care after lung transplantation. The goal of immunosuppression is to prevent acute and chronic rejection while maximizing patient survival and long-term allograft function. However, the benefits of immunosuppressive therapy must be balanced against the side effects and major toxicities of these medications. Immunosuppressive agents can be classified as induction agents, maintenance therapies, treatments for acute rejection and chronic rejection and antibody directed therapies. Although induction therapy remains an area of controversy in lung transplantation, it is still used in the majority of transplant centers. On the other hand, maintenance immunosuppression is less contentious; but, unfortunately, since the creation of three-drug combination therapy, including a glucocorticoid, calcineurin inhibitor and anti-metabolite, there have been relatively modest improvements in chronic maintenance immunosuppressive regimens. The presence of HLA antibodies in transplant candidates and development of de novo antibodies after transplantation remain a major therapeutic challenge before and after lung transplantation. In this chapter we review the medications used for induction and maintenance immunosuppression along with their efficacy and side effect profiles. We also review strategies and evidence for HLA desensitization prior to lung transplantation and management of de novo antibody formation after transplant. Finally, we review immune tolerance and the future of lung transplantation to limit the toxicities of conventional immunosuppressive therapy.

ISHLT Consensus Statement on adult and pediatric airway complications after lung transplantation: Definitions, grading system, and therapeutics

Airway complications remain a major cause of morbidity and mortality after cardiothoracic transplantation. The reported incidence of airway ischemic complications varies widely, contributed to by the lack of a universally accepted grading system and standardized definitions. Furthermore, the majority of the existing classification systems fail to integrate the wide range of possible bronchial complications that may develop after lung transplant. Hence, a Working Group was created by the International Society for Heart and Lung Transplantation with the aim of elaborating a universal definition of adult and pediatric airway complications and grading system. One such area of focus is to understand the problem in the context of a more standardized consensus of classifying airway ischemia. This consensus definition will have major clinical, therapeutics, and research implications.

Prevention of chronic rejection after lung transplantation

Long-term survival after lung transplantation (LTx) is limited by chronic rejection (CR). Therapeutic strategies for CR have been largely unsuccessful, making prevention of CR an important and challenging therapeutic approach. In the current review, we will discuss current clinical evidence regarding prevention of CR after LTx.

Experience of Lung Transplantation in Patients with Lymphangioleiomyomatosis at a Brazilian Reference Centre

INTRODUCTION

Lung transplantation (LT) is the standard of care for patients with advanced lung diseases, including lymphangioleiomyomatosis (LAM). LAM accounts for only 1% of all LTs performed in the international registry. As a result, the global experience, including the use of mechanistic target of rapamycin (mTOR) inhibitors before and after LT in LAM, is still limited.

METHODS

We conducted a retrospective review of all LAM patients who underwent LT at our centre between 2003 and 2016. Pre- and post-transplant data were assessed.

RESULTS

Eleven women with LAM underwent LT, representing 3.3% of all procedures. Ten (91%) patients underwent double-LT. The mean age at diagnosis was 39 ± 6 years and the mean FEV₁ before LT was 28 ± 14%. Only one patient underwent pleurodesis for recurrent pneumothorax. Pulmonary hypertension was confirmed in 3 (27%) patients. Four (36%) patients received sirolimus preoperatively; three of them received it until the day of LT, and there was no occurrence of bronchial anastomotic dehiscence after the procedure. Four patients (36%) received mTOR inhibitors post-transplant. The median follow-up from LT was 44 months. There were 3 deaths (27%) during the study and survival probabilities at 1, 3, and 5 years after LT were, 90, 90, and 77%, respectively.

CONCLUSIONS

This data reinforces the role of LT for LAM patients with end-stage disease. The use of sirolimus seems to be safe before LT and the occurrence of complications after LT, including those LAM-related, should be continuously monitored.

Aberrant SYK Kinase Signaling Is Essential for Tumorigenesis Induced by TSC2 Inactivation

Somatic or germline mutations in the tuberous sclerosis complex (TSC) tumor suppressor genes are associated closely with the pathogenesis of lymphangioleiomyomatosis, a rare and progressive neoplastic disease that predominantly affects women in their childbearing years. Serum levels of the lymphangiogenic growth factor VEGF-D are elevated significantly in lymphangioleiomyomatosis. However, there are gaps in knowledge regarding VEGF-D dysregulation and its cellular origin in lymphangioleiomyomatosis. Here, we show that increased expression and activation of the tyrosine kinase Syk in TSC2-deficient cells and pulmonary nodules from lymphangioleiomyomatosis patients contributes to tumor growth. Syk kinase inhibitors blocked Syk signaling and exhibited potent antiproliferative activities in TSC2-deficient cells and an immunodeficient mouse xenograft model of lymphangioleiomyomatosis. In TSC2-deficient cells, Syk signaling increased the expression of monocyte chemoattractant protein MCP-1, which in peripheral blood mononuclear cells (PBMC) stimulated the production of VEGF-D. In clinical isolates of PBMCs from lymphangioleiomyomatosis patients, VEGF-D expression was elevated. Furthermore, levels of VEGF-D and MCP-1 in patient sera correlated positively with each other. Our results illuminate the basis for lymphangioleiomyomatosis growth and demonstrate the therapeutic potential of targeting Syk in this and other settings driven by TSC genetic mutation. Cancer Res; 77(6); 1492-502. ©2017 AACR.

Therapeutic Drug Monitoring of Everolimus: A Consensus Report

In 2014, the Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology called a meeting of international experts to provide recommendations to guide therapeutic drug monitoring (TDM) of everolimus (EVR) and its optimal use in clinical practice. EVR is a potent inhibitor of the mammalian target of rapamycin, approved for the prevention of organ transplant rejection and for the treatment of various types of cancer and tuberous sclerosis complex. EVR fulfills the prerequisites for TDM, having a narrow therapeutic range, high interindividual pharmacokinetic variability, and established drug exposure-response relationships. EVR trough concentrations (C0) demonstrate a good relationship with overall exposure, providing a simple and reliable index for TDM. Whole-blood samples should be used for measurement of EVR C0, and sampling times should be standardized to occur within 1 hour before the next dose, which should be taken at the same time everyday and preferably without food. In transplantation settings, EVR should be generally targeted to a C0 of 3-8 ng/mL when used in combination with other immunosuppressive drugs (calcineurin inhibitors and glucocorticoids); in calcineurin inhibitor-free regimens, the EVR target C0 range should be 6-10 ng/mL. Further studies are required to determine the clinical utility of TDM in nontransplantation settings. The choice of analytical method and differences between methods should be carefully considered when determining EVR concentrations, and when comparing and interpreting clinical trial outcomes. At present, a fully validated liquid chromatography tandem mass spectrometry assay is the preferred method for determination of EVR C0, with a lower limit of quantification close to 1 ng/mL. Use of certified commercially available whole-blood calibrators to avoid calibration bias and participation in external proficiency-testing programs to allow continuous cross-validation and proof of analytical quality are highly recommended. Development of alternative assays to facilitate on-site measurement of EVR C0 is encouraged.

A Case of Successful Therapy by Intrapleural Injection of Fibrin Glue for Chylothorax after Lung Transplantation for Lymphangioleiomyomatosis

A 37-year-old woman underwent bilateral lung transplantation for lymphangioleiomyomatosis. Dense pleural adhesions due to past pleurodesis for chylothorax were observed and dissected in both thoracic cavities. The patient developed chylothorax after transplant. Chylothorax in the right thoracic cavity was successfully treated by conventional pleurodesis; however, pleural effusion from the left thoracic cavity was not reduced. According to fluoroscopic images obtained by injecting a contrast medium through the chest tube, the remaining pleural space in the left thoracic cavity was small and localized in the lower region adjacent to the mediastinum. We opted to fill this space with fibrin glue; we injected fibrinogen and thrombin solution into the space through the chest tube. We performed fibrin glue treatment three times and pleural effusion was dramatically decreased. We removed the chest tube on day 107 post-transplant. No recurrent chylothorax has been recorded for 10 years after lung transplantation.

New Antiproliferative Immunosuppressive Agents

Since the early 1980s, the combination of cyclosporine, azathioprine, and prednisone has been the mainstay tripledrug immunosuppressive regimen used in transplantation. However, advances in drug research, design, and development have allowed for the introduction of new agents that have greatly increased the number of immunosuppressive agents available for use in transplant recipients. Particularly, the newer antiproliferative immunosuppressive drugs (agents that directly inhibit the proliferation of T and B lymphocytes) have had an important impact on patient outcomes posttransplant. These agents are mycophenolate mofetil and sirolimus.

Lung Transplantation for Lymphangioleiomyomatosis in Japan

Background

Lung transplantation has been established as the definitive treatment option for patients with advanced lymphangioleiomyomatosis (LAM). However, the prognosis after registration and the circumstances of lung transplantation with sirolimus therapy have never been reported.

Methods

In this national survey, we analyzed data from 98 LAM patients registered for lung transplantation in the Japan Organ Transplantation Network.

Results

Transplantation was performed in 57 patients as of March 2014. Survival rate was 86.7% at 1 year, 82.5% at 3 years, 73.7% at 5 years, and 73.7% at 10 years. Of the 98 patients, 21 had an inactive status and received sirolimus more frequently than those with an active history (67% vs. 5%, p<0.001). Nine of twelve patients who remained inactive as of March 2014 initiated sirolimus before or while on a waiting list, and remained on sirolimus thereafter. Although the statistical analysis showed no statistically significant difference, the survival rate after registration tended to be better for lung transplant recipients than for those who awaited transplantation (p = 0.053).

Conclusions

Lung transplantation is a satisfactory therapeutic option for advanced LAM, but the circumstances for pre-transplantation LAM patients are likely to alter with the use of sirolimus.

Lung Transplantation

The therapeutic options for patients with advanced pulmonary parenchymal or vascular disorders are currently limited. Lung transplantation remains one of the few viable interventions, but on account of the insufficient donor pool only a minority of these patients actually undergo the procedure each year. Following transplantation there are a number of early and late allograft complications such as primary graft dysfunction, allograft rejection, infection, post-transplant lymphoproliferative disorder and late injury that is now classified as chronic lung allograft dysfunction. The pathologist plays an essential role in the diagnosis and classification of these myriad complications. Although the transplant procedures are performed in selected centers patients typically return to their local centers. When complications arise it is often the responsibility of the local pathologist to evaluate specimens. Therefore familiarity with the pathology of lung transplantation is important.

Mayo clinic experience of lung transplantation in pulmonary lymphangioleiomyomatosis

OBJECTIVES

Lymphangioleiomyomatosis (LAM) is a rare, cystic lung disease that generally results in progressive decline in lung function. Despite advancement of pharmacological therapy for LAM, lung transplantation remains an important option for women with end-stage LAM.

METHODS

Patients with LAM undergoing lung transplantation at the Mayo Clinic campuses in Rochester, Minnesota and Jacksonville, Florida since 1995 were retrospectively reviewed.

RESULTS

Overall, 12 women underwent lung transplantation. Nine of 12 (75%) underwent double lung transplant. The mean age was 42 ± 8 years at the time of transplant. One patient (8%) had a chylothorax and 7 (58%) had recurrent pneumothoraces, 4 (33%) of which required pleurodesis. All had diffuse, cystic lung disease on chest CT consistent with LAM which was confirmed in the explant of all patients. The average length of ICU and hospital stays were 5 ± 4 and 19 ± 19 days, respectively. Mild to moderate anastomotic ischemia was evident in all patients but resolved with time. No patient was treated with sirolimus pre-transplant. Seven patients received sirolimus post-transplant; however, clinical benefit was documented in only 2 patients, 1 of which was treated for large retroperitoneal cysts with ureteral obstruction and another with persistent chylothorax and retroperitoneal lymphangioleimyomas. Five patients are deceased. The median survival by Kaplan-Meier analysis was 119 months with a median follow-up of 68 months (range 2-225 months).

CONCLUSIONS

Lung transplant remains a viable treatment for patients with end-stage LAM. The role of sirolimus peri-transplantation remains ill-defined.

Risk Factors for Urinary Tract Infections in Cardiac Surgical Patients

BACKGROUND

Risk factors for catheter-associated urinary tract infections (CAUTIs) in patients undergoing non-cardiac surgical procedures have been well documented. However, the variables associated with CAUTIs in the cardiac surgical population have not been clearly defined. Therefore, the purpose of this study was to investigate risk factors associated with CAUTIs in patients undergoing cardiac procedures.

METHODS

All patients undergoing cardiac surgery at a single institution from 2006 through 2012 (4,883 patients) were reviewed. Patients with U.S. Centers for Disease Control (CDC) criteria for CAUTI were identified from the hospital's Quality Assessment database. Pre-operative, operative, and post-operative patient factors were evaluated. Univariate and multivariable analyses were used to identify significant correlations between perioperative characteristics and CAUTIs.

RESULTS

There were 55 (1.1%) documented CAUTIs in the study population. On univariate analysis, older age, female gender, diabetes mellitus, cardiogenic shock, urgent or emergent operation, packed red blood cell (PRBC) units transfused, and intensive care unit length of stay (ICU LOS) were all significantly associated with CAUTI [p<0.05]. On multivariable logistic regression, older age, female gender, diabetes mellitus, and ICU LOS remained significantly associated with CAUTI. Additionally, there was a significant association between CAUTI and 30-d mortality on univariate analysis. However, when controlling for common predictors of operative mortality on multivariable analysis, CAUTI was no longer associated with mortality.

CONCLUSIONS

There are several identifiable risk factors for CAUTI in patients undergoing cardiac procedures. CAUTI is not independently associated with increased mortality, but it does serve as a marker of sicker patients more likely to die from other comorbidities or complications. Therefore, awareness of the high-risk nature of these patients should lead to increased diligence and may help to improve peri-operative outcomes. Recognizing patients at high risk for CAUTI may lead to improved measures to decrease CAUTI rates within this population.