Underweight and obesity increase the risk of mortality after lung transplantation: a systematic review and meta-analysis

Impact of Transplant Body Mass Index and Post-Transplant Weight Changes on the Development of Chronic Lung Allograft Dysfunction Phenotypes

INTRODUCTION

Chronic lung allograft dysfunction (CLAD) is a lung transplant complication for which four phenotypes are recognized: Bronchiolitis obliterans syndrome (BOS), Restrictive allograft syndrome (RAS), mixed and undefined phenotypes. Weight gain is common after transplant and may negatively impact lung function. Study objectives were to describe post-transplant weight trajectories of patients who developed (or did not) CLAD phenotypes and examine the associations between BMI at transplant, post-transplant changes in weight and BMI, and the risk of developing these phenotypes.

METHODS

Adults who underwent a bilateral lung transplant between 2000 and 2020 at our institution were categorized as having (or not) one of the four CLAD phenotypes based on the proposed classification system. Demographic, anthropometric, and clinical data were retrospectively collected from medical records and analyzed.

RESULTS

Study population included 579 recipients (412 [71.1%] CLAD-free, 81 [14.0%] BOS, 20 [3.5%] RAS, 59 [10.2%] mixed, and 7 [1.2%] undefined phenotype). Weight gains of greater amplitude were seen in recipients with restrictive phenotypes than CLAD-free and BOS patients within the first five years post-transplant. While the BMI category at transplant was not statistically associated with the risk of developing CLAD phenotypes, an increase in weight (Hazard ratio [HR]: 1.04, 95% CI [1.01-1.08]; P = .008) and BMI (HR: 1.13, 95% CI [1.03-1.23]; P = .008) over the post-transplant period was associated with a greater risk of RAS.

CONCLUSION

Post-LTx gain in weight and BMI modestly increased the risk of RAS, adding to the list of unfavorable outcomes associated with weight gain following transplant.

Obesity, organ failure, and transplantation: a review of the role of metabolic and bariatric surgery in transplant candidates and recipients

Obesity is a risk factor for kidney, liver, heart, and pulmonary diseases, as well as failure. Solid organ transplantation remains the definitive treatment for the end-stage presentation of these diseases. Among many criteria for organ transplant, efficient management of obesity is required for patients to acquire transplant eligibility. End-stage organ failure and obesity are 2 complex pathologies that are often entwined. Metabolic and bariatric surgery before, during, or after organ transplant has been studied to determine the long-term effect of bariatric surgery on transplant outcomes. In this review, a multidisciplinary group of surgeons from the Society of American Gastrointestinal and Endoscopic Surgeons and the American Society for Transplant Surgery presents the current published literature on metabolic and bariatric surgery as a therapeutic option for patients with obesity awaiting solid organ transplantation. This manuscript details the most recent recommendations, pharmacologic considerations, and psychological considerations for this specific cohort of patients. Since level one evidence is not available on many of the topics covered by this review, expert opinion was implemented in several instances. Additional high-quality research in this area will allow for better recommendations and, therefore, treatment strategies for these complex patients.

Obesity, organ failure, and transplantation: A review of the role of metabolic and bariatric surgery in transplant candidates and recipients

Obesity is a risk factor for kidney, liver, heart, and pulmonary diseases, as well as failure. Solid organ transplantation remains the definitive treatment for the end-stage presentation of these diseases. Among many criteria for organ transplant, efficient management of obesity is required for patients to acquire transplant eligibility. End-stage organ failure and obesity are 2 complex pathologies that are often entwined. Metabolic and bariatric surgery before, during, or after organ transplant has been studied to determine the long-term effect of bariatric surgery on transplant outcomes. In this review, a multidisciplinary group of surgeons from the Society of American Gastrointestinal and Endoscopic Surgeons and the American Society for Transplant Surgery presents the current published literature on metabolic and bariatric surgery as a therapeutic option for patients with obesity awaiting solid organ transplantation. This manuscript details the most recent recommendations, pharmacologic considerations, and psychological considerations for this specific cohort of patients. Since level one evidence is not available on many of the topics covered by this review, expert opinion was implemented in several instances. Additional high-quality research in this area will allow for better recommendations and, therefore, treatment strategies for these complex patients.

Utility of the Stanford Integrated Psychosocial Assessment for Transplant in predicting outcomes before and after lung transplantation

BACKGROUND

Optimizing donor use and achieving maximal survival following lung transplantation (LTx) require a pretransplant assessment that identifies clinical, physiological, and psychosocial patient factors associated with both poor and optimal post-LTx survival. We examined the utility of a psychosocial tool, the Stanford Integrated Psychosocial Assessment for Transplant (SIPAT), to identify patient suitability for LTx, as well as its association with clinical outcomes before and after LTx.

METHODS

This was a retrospective single-center study analyzing LTx assessment clinical variables (age, gender, diagnosis, functional capacity, nutrition, renal function), with a particular focus on the utility of the SIPAT score, to predict patient suitability for LTx. The same variables were analyzed against LTx waitlist mortality, as well as post-LTx survival.

RESULTS

Over an 8-year period dating from December 2012, 914 patients (male 54.4%, mean age 55.2 years) underwent LTx assessment. Patients declined for LTx (n = 152, 16.6%) were older and had reduced functional capacity, nutritional markers, and renal function but had a higher SIPAT score. Once listed for LTx, a higher SIPAT score was not associated with waitlist mortality or reduced post-LTx survival.

CONCLUSIONS

The SIPAT tool measures psychosocial suitability for transplantation that can be incorporated into a standardized assessment of LTx suitability. While patients with higher SIPAT score were more likely to be declined for LTx, the SIPAT score did not predict outcome in transplanted patients. A subgroup of patients with high SIPAT scores were successfully transplanted, suggesting that unfavorable psychosocial variables are potentially modifiable with a well-resourced multidisciplinary LTx team.

Nutrition support management of organ transplant recipients in the acute posttransplant phase

Patients who undergo solid organ transplant can have an extensive and challenging postoperative course. The chronicity of the disease state prior to transplant in combination with transplant-specific complications and immunosuppressant medications can lead to distinct challenges that are not observed in other critically ill patients. Although the manifestation of posttransplant complications may be specific to the organ being transplanted, there are common transplant challenges that affect nutrition therapy in these patients. Effects of malnutrition, metabolic aberrations, and posttransplant organ dysfunction should be considered when developing a nutrition care plan for patients in the immediate posttransplant phase. This article addresses the various complications that can arise in the immediate posttransplant phase among patients undergoing solid organ transplant and the appropriate nutrition interventions or considerations for this specialized patient population.

Body mass index percentage and survival in pediatric patients listed for lung transplantation: A modern-era multi-institutional analysis

BACKGROUND

Prior studies suggest that being underweight by body mass index percentiles (BMI%) or thinness grade did not affect post-transplant survival in pediatric lung transplant (LTx) recipients regardless of cystic fibrosis (CF) or non-CF diagnosis. Graft and overall survival from the time of listing was instead evaluated based on listing BMI%, the current standard of practice for BMI definitions in pediatrics, to ascertain the impact of a "severely low" subcategory.

METHODS

The UNOS registry was queried for children listed for LTx (aged 2 to <18 years) from January 1986 to March 2020. BMI% at listing and transplant were calculated per CDC guidelines according to age in years, sex, and reported BMI%. Patients were divided by listing BMI%: severely low (<3rd), low (3-<5th), normal (5-<85th), overweight (85-<95th), and obese (≥95th). Kaplan-Meier curves were generated to assess differences in overall survival since listing based on BMI% classes. Cox proportional-hazards models were developed to assess risk factors for overall and graft survival, including listing BMI%, transplant listing era (≥2005), and listing age, by reporting hazard ratios (HR).

RESULTS

Listing BMI% was calculable for 1,876 patients. The proportion of patients with CF differed significantly between BMI% groups (p < 0.001). Patients listed with a non-CF diagnosis comprised 34% of those in the severely low category, and 88% of those listed with an obese BMI%. Compared to patients with a normal listing BMI%, the cohort with severely low BMI% had worse overall survival regardless of LTx (p = 0.009) and graft survival (p = 0.034). Compared to patients with a low BMI%, those with a severely low BMI% had significantly poorer graft survival as well (p = 0.040). Mean graft survival was not significantly different between groups that remained at listing BMI% vs those that improved in category despite an overall small sample size. Independent predictors of poorer survival from the time of listing include severely low vs low-normal BMI% (HR = 1.20) and listing age (HR = 1.02).

CONCLUSION

The proportion of children listed at severely low BMI% has steadily decreased with time, yet pediatric LTx candidates listed with a severely low BMI% had poorer graft and overall survival compared to those of normal BMI%. Severely low listing BMI% was an independent prognostic factor for higher mortality risk from the time of placement on the waitlist. BMI% may be a modifiable target for improving survival regardless of transplantation.

Body mass Index does not impact long-term survival of patients with idiopathic pulmonary fibrosis undergoing lung transplantation

Objective

We investigated the impact of body mass index (BMI) on post-operative outcomes and survival of patients with interstitial pulmonary fibrosis (IPF) undergoing lung transplantation.

Methods

We retrospectively reviewed 222 patients with IPF that underwent lung transplant (LT) at our institution from 2005 to 2019. Recipients were divided in 4 groups: group-1 consisted of underweight patients (BMI ≤18.5 kg/m2), group-2 of normal weight patients (BMI 18.5-25 kg/m2), group-3 of over-weight patients (BMI 25-29.9 kg/m2) and group-4 of obese patients (BMI ≥30 kg/m2).

Results

Group-1 consisted of 13 (6%) patients, group-2 of 67 (30%) patients, group-3 of 79 (36%) patients, group-4 consisted of 63 (28%) patients. Median BMI for group-1 was 17 [interquartile range (IQR): 17, 18], for group-2 was 23 (22, 24), for group-3 was 29 (28, 29.5) and group-4 was 32 (31, 33). Patients in group-1 were significantly younger (p < 0.01). Single LT comprised the majority of operation type in group-2 to group-4 and it was significantly higher than group 1 (p < 0.01). Median follow-up time was 39 months (13-76). A total of 79 (35.5%) patients died by the end of study. Overall, five deaths occurred in group-1, 17 in group-2, 33 in group-3, and 24 in group-4. Kaplan-Meier analysis showed that mortality was not statistically significant between the groups (p = 0.24). Cox-regression analysis was used to assess other possible risk factors that could influence the effect of BMI on mortality, including transplant type (single, double), lung allocation score, and age, diabetes and creatinine levels at surgery. None of these factors were shown to affect patient mortality (p > 0.05). Overall reasons for death included graft failure (24%), infection (23%), respiratory failure (14%), and malignancy (13%).

Conclusions

Body mass index does not impact long-term survival of patients with IPF undergoing lung transplantation.

Lung Transplantation in a New Era in the Field of Cystic Fibrosis

Lung transplantation for people with cystic fibrosis (PwCF) is a critical therapeutic option, in a disease without a cure to this day, and its overall success in this population is evident. The medical advancements in knowledge, treatment, and clinical care in the field of cystic fibrosis (CF) rapidly expanded and improved over the last several decades, starting from early pathology reports of CF organ involvement in 1938, to the identification of the CF gene in 1989. Lung transplantation for CF has been performed since 1983, and CF now accounts for about 17% of pre-transplantation diagnoses in lung transplantation recipients. Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have been the latest new therapeutic modality addressing the underlying CF protein defect with the first modulator, ivacaftor, approved in 2012. Fast forward to today, and we now have a growing CF population. More than half of PwCF are now adults, and younger patients face a better life expectancy than they ever did before. Unfortunately, CFTR modulator therapy is not effective in all patients, and efficacy varies among patients; it is not a cure, and CF remains a progressive disease that leads predominantly to respiratory failure. Lung transplantation remains a lifesaving treatment for this disease. Here, we reviewed the current knowledge of lung transplantation in PwCF, the challenges associated with its implementation, and the ongoing changes to the field as we enter a new era in the care of PwCF. Improved life expectancy in PwCF will surely influence the role of transplantation in patient care and may even lead to a change in the demographics of which people benefit most from transplantation.

Lung transplantation outcomes in underweight recipients: A single center experience

Background

Current guidelines recommend a body mass index (BMI) of 16 kg/m² as the minimum threshold for lung transplantation, despite mixed evidence on outcomes in underweight patients. The current study aimed to describe survival outcomes of underweight patients who underwent lung transplantation at a single center.

Methods

This retrospective observational study included adult lung transplant recipients who underwent transplantation for the first time between March 2010 and March 2022 at King Faisal Specialist Hospital and Research Center and excluded patients with obesity. We defined an underweight status as a BMI <17 kg/m².

Results

Forty-eight of the 202 lung transplant recipients were underweight at the time of surgery. The underweight patients had similar lengths of hospital (p = 0.53) and intensive care unit (p = 0.81) stays compared to other patients. Thirty-three percent of underweight patients had died within 5-year follow-up, compared to 34% of patients who were not underweight. There was no significant difference in mortality risk between underweight patients and patients with normal BMIs in our multivariable Cox regression model (adjusted HR 1.57, 95%CI: 0.77-3.20, p = 0.21). Exploratory analyses revealed that a pre-transplant BMI <13 kg/m² was associated with a trend towards increased 5-year mortality (adjusted HR 4.00, 95%CI: 0.87-18.35, p = 0.07).

Conclusions

Our findings suggest that patients with BMIs of 13-17 kg/m² may be candidates for lung transplantation. Large multi-center cohort studies are needed to confirm the lower BMI limit for safely transplanting patients.

Computed tomography body composition and clinical outcomes following lung transplantation in cystic fibrosis

BACKGROUND

Low muscle mass is common in patients approaching lung transplantation and may be linked to worse post-transplant outcomes. Existing studies assessing muscle mass and post-transplant outcomes include few patients with cystic fibrosis (CF).

METHODS

Between May 1993 and December 2018, 152 adults with CF received lung transplants at our institution. Of these, 83 met inclusion criteria and had usable computed tomography (CT) scans. Using Cox proportional hazards regression, we evaluated the association between pre-transplant thoracic skeletal muscle index (SMI) and our primary outcome of death after lung transplantation. Secondary outcomes, including days to post-transplant extubation and post-transplant hospital and intensive care unit (ICU) length of stay, were assessed using linear regression. We also examined associations between thoracic SMI and pre-transplant pulmonary function and 6-min walk distance.

RESULTS

Median thoracic SMI was 26.95 cm²/m² (IQR 23.97, 31.32) for men and 22.83 cm²/m² (IQR 21.27, 26.92) for women. There was no association between pre-transplant thoracic SMI and death after transplant (HR 1.03; 95% CI 0.95, 1.11), days to post-transplant extubation, or post-transplant hospital or ICU length of stay. There was an association between pre-transplant thoracic SMI and pre-transplant FEV1% predicted (b = 0.39; 95% CI 0.14, 0.63), with higher SMI associated with higher FEV1% predicted.

CONCLUSIONS

Skeletal muscle index was low for men and women. We did not identify a significant relationship between pre-transplant thoracic SMI and post-transplant outcomes. There was an association between thoracic SMI and pre-transplant pulmonary function, confirming the potential value of sarcopenia as a marker of disease severity.

Listing Dilemmas: Age, Frailty, Weight, Preexisting Cancers, and Systemic Diseases

Selection of lung transplant candidates is an evolving field that pushes the boundaries of what is considered the norm. Given the continually changing demographics of the typical lung transplant recipient as well as the growing list of risk factors that predispose patients to poor posttransplant outcomes, we explore the dilemmas in lung transplant candidate selections pertaining to older age, frailty, low and high body mass index, preexisting cancers, and systemic autoimmune rheumatic diseases.

Independent risk factors for an increased incidence of thromboembolism after lung transplantation

BACKGROUND

Thromboembolism (TE) after lung transplantation (LTX) is associated with increased morbidity and mortality. The aim of this study is to analyze the incidence and outcome of venous and arterial thromboembolic complications and to identify independent risk factors.

PATIENTS AND METHODS

We retrospectively analyzed the medical records of 221 patients who underwent LTX at our institution between 2002 and 2021. Statistical analysis was performed using SPSS and GraphPad software.

RESULTS

74 LTX recipients (33%) developed TE. The 30-days incidence and 12-months incidence were 12% and 23%, respectively. Nearly half of the patients (48%) developed pulmonary embolism, 10% ischemic stroke. Arterial hypertension (p = 0.006), a body mass index (BMI) > 30 (p = 0.006) and diabetes mellitus (p = 0.041) were independent predictors for TE. Moreover, a BMI of > 25 at the time of transplantation was associated with an increased risk for TE (43% vs. 32%, p = 0.035). At the time of LTX, 65% of the patients were older than 55 years. An age > 55 years also correlated with the incidence of TE (p = 0.037) and these patients had reduced overall post-transplant survival when the event occurred within the first postoperative year (59% vs. 72%, p = 0.028).

CONCLUSIONS

The incidence of TE after LTX is high, especially in lung transplant recipients with a BMI > 25 and an age > 55 years as well as cardiovascular risk factors closely associated with the metabolic syndrome. As these patients comprise a growing recipient fraction, intensified research should focus on the risks and benefits of regular screening or a prolonged TE prophylaxis in these patients. Trial registration number DKRS: 00021501.

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.

Indications for Lung Transplantation and Patient Selection

Globally, thousands of patients undergo lung transplantation owing to end-stage lung disease each year. As lung transplantation evolves, recommendations and indications are constantly being updated. In 2021, the International Society for Heart and Lung Transplantation published a new consensus document for selecting candidates for lung transplantation. However, it is still difficult to determine appropriate candidates for lung transplantation among patients with complex medical conditions and various diseases. Therefore, it is necessary to analyze each patient’s overall situation and medical condition from various perspectives, and ongoing efforts to optimize the analysis will be necessary. The purpose of this study is to review the extant literature and discuss recent updates.

New-onset Obesity After Lung Transplantation: Incidence, Risk Factors, and Clinical Outcomes

BACKGROUND

Lung transplant (LTx) recipients who gain weight after transplantation may experience an upward shift in body mass index (BMI) that places them in the obese category. The incidence, risk factors, and impact on metabolic health and mortality of new-onset obesity have not been documented in the LTx setting.

METHODS

This single-center retrospective study included 564 LTx recipients. Individuals were stratified according to their BMI trajectories from pretransplant evaluation up to 10 y posttransplant. New-onset obesity was defined as a pretransplant BMI <30 kg/m2 and posttransplant BMI >30 kg/m2. The incidence, risk factors, and posttransplant diabetes mellitus, metabolic syndrome, and mortality of recipients with new-onset obesity were compared with those of nonobese (BMI <30 kg/m2, pre/post-LTx), consistently obese (BMI >30 kg/m2, pre/post-LTx), and obese recipients with weight loss (BMI >30 kg/m2 pre-LTx, BMI <30 kg/m2 post-LTx).

RESULTS

We found that 14% of recipients developed obesity after transplantation. Overweight individuals (odds ratio [OR]: 9.01; 95% confidence interval [CI] [4.86-16.69]; P < 0.001) and candidates with chronic obstructive pulmonary disease (OR: 6.93; 95% CI [2.30-20.85]; P = 0.001) and other diagnoses (OR: 4.28; 95% CI [1.22-14.98]; P = 0.023) were at greater risk. Multivariable regression analysis showed that new-onset obesity was associated with a greater risk of metabolic syndrome (hazard ratio: 1.70; 95% CI [1.17-2.46]; P = 0.005), but not of posttransplant diabetes mellitus, than nonobesity. Recipients with new-onset obesity had a survival comparable to that of consistently obese individuals.

CONCLUSIONS

A greater understanding of the multifaceted nature of post-LTx obesity may lead to interventions that are better tailored to the characteristics of these individuals.

Low body mass index as a barrier to lung transplant in cystic fibrosis

RATIONALE

Low body mass index (BMI) may influence lung transplant decisions for patients with advanced cystic fibrosis (CF) lung disease.

OBJECTIVE

Determine whether patients with advanced CF lung disease and BMI ≤17 kg/m2 are less likely to be listed for lung transplant or have a higher risk of death without listing compared to those with higher BMI.

METHODS

Using merged United Network for Organ Sharing and CF Foundation Patient Registries, we identified adults with onset of advanced lung disease (FEV1 ≤ 40% predicted) between May-2005 and December-2016. We analyzed survival using competing risks regression with cause-specific risks of listing for lung transplant and death without listing. BMI ≤ 17 kg/m2 was our predictor.

MEASUREMENTS AND MAIN RESULTS

Among 5,121 CF patients with advanced lung disease, 23% were listed for lung transplant (n = 1,201), 23% died without listing (n = 1,190), and 44% were alive without listing (n = 2,730) as of December-2016. Patients with BMI ≤ 17 kg/m2 were less likely to be listed for transplant (HR 0.69; 95% CI 0.57, 0.83) and more likely to die without listing (HR 1.63; 95% CI 1.41, 1.88). We identified important regional variations in the likelihood of referral and listing, based on BMI.

CONCLUSIONS

Patients with advanced CF lung disease and BMI ≤ 17 kg/m2 are less likely to be listed for lung transplant and have a higher risk of dying without listing, compared to those with higher BMI. Regional differences suggest access to transplant for malnourished CF patients may be limited by location.

Management of long-term cardiovascular risk factors post organ transplant

PURPOSE OF REVIEW

Cardiovascular disease is one of the leading causes of death in solid organ transplant (SOT) recipients. Early identification of cardiovascular risk factors and their adequate management in this population is key for prevention and improved outcomes.

RECENT FINDINGS

Approximately 80% of SOT present one or more cardiovascular risk factors, with increasing prevalence with time posttransplantation. They are due to the interplay of pretransplant conditions and metabolic consequences of immunosuppressive agents, mainly corticosteroids and calcineurin inhibitors. Among the pharmacological management strategies, statins have shown an important protective effect in SOT.

SUMMARY

Strict surveillance of cardiovascular risk factors is recommended in SOT due to their high prevalence and prognostic implications. Further studies on the best managements strategies in this population are needed.

Association of obesity with mortality and clinical outcomes in children and adolescents with transplantation: A systematic review and meta-analysis

Obesity might be associated with mortality and clinical outcomes following transplantation; however, the direction of this relationship has not been well-recognized in youth. The aim of this systematic review and meta-analysis was to investigate the association of obesity with post-transplant mortality and clinical outcomes in children and adolescents. Following a systematic search of observational studies published by December 2018 in PubMed, Scopus, Embase, and Cochrane library, 15 articles with total sample size of 50,498 patients were included in the meta-analysis. The main outcome was mortality and secondary outcomes included acute graft versus host disease (GVHD), acute rejection, and overall graft loss. The pooled data analyses showed significantly higher odds of long term mortality (OR 1.30, 95% CI 1.15-1.48, P < 0.001, I² = 50.3%), short term mortality (OR 1.79, 95% CI 1.19-2.70, P = 0.005, I² = 59.6%), and acute GVHD (OR 2.13, 95% CI 1.5-3.02, P < 0.001, I² = 1.7%) in children with obesity. There were no significant differences between patients with and without obesity in terms of acute rejection (OR 1.07, 95% CI 0.98-1.16, P = 0.132, I² = 7.5%) or overall graft loss (OR 1.04, 95% CI 0.84-1.28, P = 0.740, I² = 51.6%). This systematic review and meta-analysis has stated higher post-transplant risk of short and long term mortality and higher risk of acute GVHD in children with obesity compared to those without obesity. Future clinical trials are required to investigate the effect of pre-transplant weight management on post-transplant outcomes to provide insights into the clinical application of these findings. This may in turn lead to establish guidelines for the management of childhood obesity in transplantations.

Both Underweight and Obesity Are Associated With an Increased Risk of Coronavirus Disease 2019 (COVID-19) Severity

Introduction: As coronavirus Disease 2019 (COVID-19) has evolved into a global pandemic, increasing numbers of reports have linked obesity to more severe COVID-19 illness and death. However, almost all the studies focused on an increased risk of mortality or intensive care unit (ICU) admission among hospitalized obese patients with COVID-19. Is obesity also associated with the incidence of acute lung injury (ALI) in the patients with COVID-19? How about underweight patients? The answer is lacking. Therefore, our following research will answer the above two questions. Methods: We collected and analyzed epidemiologic, demographic, clinical, and laboratory data from 193 confirmed cases of COVID-19 at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology in Wuhan, China, between January 1, 2020, and March 13, 2020. They were followed up until April 15, 2020. Underweight was defined by body mass index (BMI) lower than 18.5 kg/m², normal weight by 18.5-23.9 kg/m², overweight by 24.0-27.9 kg/m², and obesity as ≥28 kg/m². Results: Among these patients, 5.70% were underweight, 58.03% were normal weight, 27.98% were overweight, and 8.29% were obese. Underweight patients were more likely to have a headache (P = 0.029). Obese patients were more likely than other groups to experience a decline in lymphocyte counts (P = 0.038), an increase in C-reactive protein (CRP; P = 0.023), bilateral multiple mottling, and ground glass opacity in the lungs (P = 0.007). Besides, the proportion of patients receiving human immunoglobulin + systematic corticosteroids treatment is the highest among the obese group compared with other BMI groups. After adjusting for potential confounders, underweight patients had a 6.483-fold higher (P = 0.012), and obese patients showed a 5.965-fold higher odds for developing ALI than normal-weight patients (P = 0.022). In addition, underweight patients were 3.255 times more likely than normal-weight patients to develop secondary infections (P = 0.041). Conclusions: Our study showed that both underweight and obese patients with COVID-19 tend to develop ALI compared with normal-weight patients. Underweight patients were more likely to develop a secondary infection than other patients.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Incidence and risk factors for respiratory tract bacterial colonization and infection in lung transplant recipients

To evaluate incidence of and risk factors for respiratory bacterial colonization and infections within 30 days from lung transplantation (LT). We retrospectively analyzed microbiological and clinical data from 94 patients transplanted for indications other than cystic fibrosis, focusing on the occurrence of bacterial respiratory colonization or infection during 1 month of follow-up after LT. Thirty-three percent of patients developed lower respiratory bacterial colonization. Bilateral LT and chronic heart diseases were independently associated to a higher risk of overall bacterial colonization. Peptic diseases conferred a higher risk of multi-drug resistant (MDR) colonization, while longer duration of aerosol prophylaxis was associated with a lower risk. Overall, 35% of lung recipients developed bacterial pneumonia. COPD (when compared to idiopathic pulmonary fibrosis, IPF) and higher BMI were associated to a lower risk of bacterial infection. A higher risk of MDR infection was observed in IPF and in patients with pre-transplant colonization and infections. The risk of post-LT respiratory infections could be stratified by considering several factors (indication for LT, type of LT, presence of certain comorbidities, and microbiologic assessment before LT). A wider use of early nebulized therapies could be useful to prevent MDR colonization, thus potentially lowering infectious risk.

Spectrum of findings on ventilation‒perfusion lung scintigraphy after lung transplantation and association with outcomes

BACKGROUND

Air trapping (AT) is one of the hallmarks of allograft dysfunction after lung transplantation (LT). Inert gas‒based ventilation‒perfusion (VQ) lung scintigraphy has excellent sensitivity in the detection of AT.

METHODS

We reviewed the charts of patients who underwent single or double LT between January 2012 and December 2014 (N = 193). Patients without a VQ scintigraphy at the first annual visit (n = 16) and those who did not survive till 1 year (n = 26) were excluded (final n = 151, mean age = 55.8 [SD =14] years, male = 85, female = 66). VQ scintigraphy was independently reviewed and reconciled for the presence and severity of AT by 2 investigators blinded to the clinical data (D.F.P. and D.M.). A 3-year post-transplant survival was the primary end-point.

RESULTS

AT was common (n = 73, 48.3%). Patients with obstructive lung diseases as the underlying diagnosis (adjusted odds ratio [OR], 4.36, 95% CI: 1.64‒11.6; p = 0.003) and those with lower body mass index (BMI) (BMI < 25 kg/m² and 25‒30 kg/m²; p < 0.001) had an increased risk of developing AT in the allograft. The presence of AT (adjusted OR, 2.33, 95% CI: 1.01‒5.36; p = 0.04) and peak forced expiratory volume in 1 sec (FEV₁) <60% predicted during the first year after LT were independently associated with 3-year mortality. The association of AT with post-transplant mortality was the strongest among patients with BMI <30 kg/m² and peak FEV₁ <60% predicted.

CONCLUSIONS

The finding of AT on VQ scintigraphy at the first annual visit after LT is independently associated with worse post-transplant mortality. The sub-group of patients who fail to achieve a peak FEV₁ of 60% predicted during the first year after LT appears to be the key driver of this association.

Lung Transplantation for Pleuroparenchymal Fibroelastosis

Pleuroparenchymal fibroelastosis (PPFE), a new disease entity associated with interstitial pneumonia, is characterized by fibrosis and elastosis involving the pleura and subpleural lung parenchyma, predominantly in the upper lobe. As the awareness of this disease entity has increased, many studies have revealed the prevalence and incidence, clinical and pathological characteristics, and disease course of PPFE. Patients with PPFE reportedly have several unique clinical characteristics—including an extremely low body mass index with a slender body and chest wall deformity, known as “flat chest”. As this disease progresses, shrinking of the lungs often causes life-threatening complications, such as pneumothorax, and associated air leak syndrome. Lung transplantation is considered the only effective treatment for patients with advanced PPFE; however, little is known about the influences of the characteristics of PPFE on the outcome of lung transplantation. This review focuses on the unique clinicopathologic characteristics of PPFE and associated outcomes of lung transplantation for these patients.

Outcomes of lung transplantation for idiopathic pleuroparenchymal fibroelastosis

PURPOSE

This study was performed to compare the outcome of lung transplantation (LT) for idiopathic pleuroparenchymal fibroelastosis (IPPFE) with that of LT for idiopathic pulmonary fibrosis (IPF).

METHODS

We reviewed, retrospectively, all adult patients who underwent LT for IPPFE or IPF in Japan between 1998 and 2018.

RESULTS

There were 100 patients eligible for this study (31 with IPPFE and 69 with IPF). Patients with IPPFE tended to have a significantly lower body mass index (BMI) than those with IPF (median, 16.7 vs. 22.6 kg/m², respectively; P < 0.01). However, Kaplan-Meier survival curves showed no significant difference in overall survival between the groups. The BMI did not increase in patients with IPPFE, even 1 year after LT (pretransplant, 16.5 ± 3.2 kg/m² vs. 1 year post-transplant, 15.6 ± 2.5 kg/m²; P = 0.08). The percent predicted forced vital capacity (%FVC) 1 year after LT was significantly lower in the IPPFE group than in the IPF group (48.4% ± 19.5% vs. 68.6% ± 15.5%, respectively; P < 0.01).

CONCLUSIONS

Despite extrapulmonary problems such as a flat chest, low BMI, and associated restrictive impairment persisting in patients with IPPFE, patient survival after LT for IPPFE or IPF was equivalent.

The Association Between BMI and Mortality in Surgical Patients

BACKGROUND

While obesity is commonly associated with increased morbidity and mortality, in patients with chronic diseases, it has have been associated with a better prognosis, a phenomenon known as the 'obesity paradox'.

OBJECTIVE

We investigated the relationship between mortality, length of hospital stay (LOHS), and body mass index (BMI) in patients hospitalized to general surgical wards.

METHODS

We extracted data of patients admitted to the hospital between January 2011 and December 2017. BMI was classified according to the following categories: underweight (< 18.5), normal weight (18.5-24.9), overweight (25-29.9), obesity (30-34.9) and severe obesity (≥ 35). Main outcomes were mortality at 30-day mortality and at the end-of-follow-up mortality), as well as LOHS.

RESULTS

A total of 27,639 patients (mean age 55 ± 20 years; 48% males; 19% had diabetes) were included in the study. Median LOHS was longer in patients with diabetes vs. those without diabetes (4.0 vs 3.0 days, respectively), with longest LOHS among underweight patients. A 30-day mortality was 2% of those without (371/22,297) and 3% of those with diabetes (173/5,342). In patients with diabetes, 30-day mortality risk showed a step-wise decrease with increased BMI: 10% for underweight, 6% for normal weight, 3% for overweight, 2% for obese and only 1% for severely obese patients. In patients without diabetes, 30-day mortality was found to be 6% for underweight, 3% for normal weight and 1% across the overweight and obese categories. Mortality rate at the end-of-follow-up was 9% of patients without diabetes and 18% of those with diabetes (adjusted OR = 1.3, 95% CI, 1.2-1.5). In patients with diabetes, mortality risk showed an inverse association with respect to BMI: 52% for underweight, 29% for normal weight, 17% for overweight, 14% for obesity and 7% for severely obese patients, with similar trend in patients without diabetes.

CONCLUSIONS

The results support the 'obesity paradox' in the general surgical patients as those with and without diabetes admitted to surgical wards, BMI had an inverse association with short- and long-term mortality.

The Transplant Evaluation Rating Scale Predicts Clinical Outcomes 1 Year After Lung Transplantation: A Prospective Longitudinal Study

Objectives: It has been recommended that all candidates for lung transplantation undergo pre-transplant psychosocial evaluation for risk assessment. However, psychosocial issues are only important if they correlate with outcomes after transplantation. Methods: In this prospective study patients who were referred for lung transplantation from 2016 to 2018 (n = 352) at Hannover Medical School were evaluated using the Transplant Evaluation Rating Scale (TERS). Clinical outcomes included listing, and post-transplant outcomes including mortality, medical aspects such as lung allograft dysfunction, hospitalizations, and renal function, behavioral aspects such as BMI and adherence, and mental issues such as levels of depression, anxiety, and quality of life. TERS scores were divided into tertiles and, in addition, the impact of the two subscale scores-"defiance" and "emotional sensitivity"-was investigated. Results: Of the patients who were transplanted (n = 271) and were still alive (n = 251), 240 had already reached their 1-year assessment at the end of 2020 and were evaluated 1 year after the operation. A subgroup of 143 received an extended mental assessment. BMI, adherence scores, levels of anxiety, depression, and quality of life 1 year post-transplantation differed significantly between TERS tertiles with higher TERS scores predicting less favorable outcomes. The TERS subscale "defiance" was predictive of BMI and adherence whereas the TERS subscale "emotional sensitivity" was predictive of symptoms of anxiety and depression, and quality of life 1 year after transplantation. Patients in the lowest TERS tertile were more likely to having been listed and-as a trend-to having survived the first year after transplantation Conclusions: Our findings show that psychosocial factors as measured by TERS score are predictors of behavioral and mental outcomes 1 year after lung transplantation. The TERS allows us to focus on psychosocial risk factors that can be treated or minimized before or after transplantation.

Weight loss for critical care patient to improve lung transplantation candidacy: A case report

A 47-year-old male with morbid obesity and progressive pulmonary fibrosis was admitted to the intensive care unit (ICU) with worsening hypoxia and nocturnal ventilator dependence. Due to a significant oxygen requirement, the patient could only safely remain in an acute care setting. Unfortunately, he was not eligible for lung transplantation due to having obesity, a relative contraindication to lung transplantation due to potential for post transplantation complications and increased mortality. Therefore, we treated the patient with a modified very low calorie diet (MVLCD) to achieve weight loss. He had successful, sustained weight loss over a period of seven weeks and reached a target weight that made him eligible for transplantation. He subsequently underwent successful bilateral lung transplantation. The patient had improved metabolic parameters and no side effects attributable to the reduced calorie diet. This report shows that in patients with end stage lung disease and a poor prognosis without transplantation, inpatient weight loss is safe and may allow for potentially lifesaving lung transplantation.

Obesity, transplantation, and bariatric surgery: An evolving solution for a growing epidemic

The increasing obesity epidemic has major implications in the realm of transplantation. Patients with obesity face barriers in access to transplant and unique challenges in perioperative and postoperative outcomes. Because of comorbidities associated with obesity, along with the underlying end-stage organ disease leading to transplant candidacy, these patients may not even be referred for transplant evaluation, much less be waitlisted or actually undergo transplant. However, the use of bariatric surgery in this population can help optimize the transplant candidacy of patients with obesity and end-stage organ disease and improve perioperative and postoperative outcomes. We review the impact of obesity on kidney, liver, and cardiothoracic transplant candidates and recipients and explore potential interventions to address obesity in these populations.

Review 1: Lung transplant-from donor selection to graft preparation

For various end-stage lung diseases, lung transplantation remains one of the only viable treatment options. While the demand for lung transplantation has steadily risen over the last few decades, the availability of donor grafts is limited, which have resulted in progressively longer waiting lists. In the early years of lung transplantation, only the 'ideal' donor grafts are considered for transplantation. Due to the donor shortages, there is ongoing discussion about the safe use of 'suboptimal' grafts to expand the donor pool. In this review, we will discuss the considerations around donor selection, donor-recipient matching, graft preparation and graft optimisation.

Developments in lung transplantation over the past decade

With an improved median survival of 6.2 years, lung transplantation has become an increasingly acceptable treatment option for end-stage lung disease. Besides survival benefit, improvement of quality of life is achieved in the vast majority of patients. Many developments have taken place in the field of lung transplantation over the past decade. Broadened indication criteria and bridging techniques for patients awaiting lung transplantation have led to increased waiting lists and changes in allocation schemes worldwide. Moreover, the use of previously unacceptable donor lungs for lung transplantation has increased, with donations from donors after cardiac death, donors with increasing age and donors with positive smoking status extending the donor pool substantially. Use of ex vivo lung perfusion further increased the number of lungs suitable for lung transplantation. Nonetheless, the use of these previously unacceptable lungs did not have detrimental effects on survival and long-term graft outcomes, and has decreased waiting list mortality. To further improve long-term outcomes, strategies have been proposed to modify chronic lung allograft dysfunction progression and minimise toxic immunosuppressive effects. This review summarises the developments in clinical lung transplantation over the past decade.

Many developments have taken place in lung transplantation over the last decade: indications have broadened, donor criteria expanded, allocations systems changed, and novel therapeutic interventions implemented, leading to improved long-term survivalhttp://bit.ly/2vnpwc1

Anti-aging properties of Dendrobium nobile Lindl.: From molecular mechanisms to potential treatments

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium Nobile Lindl. (DNL) is one of the central herbs in traditional Chinese medicine which mainly distributes in Guizhou, Yunnan, Guangxi and other sub-tropical areas south of the Yangtze River. In the past decades, it has been used to treat tumors, hyperglycemia, hyperlipidemia, and diseases of the nervous system that may be caused by aging.

AIM OF THE REVIEW

The purpose of this review is to summarize the anti-aging information of DNL from the molecular mechanism level, including classic theories related to aging, main chemical components, pharmacological research and anti-aging theory based on traditional Chinese medicine theory, for exploring the future development and clinical treatment.

MATERIALS AND METHODS

The information in this paper has been collected from the scientific literature databases including PubMed, Google Scholar, Web of Science, Science Direct, Springer, China National Knowledge Infrastructure, published books, Ph.D. and M.S. dissertations systematically.

RESULTS

In this paper, we have reviewed the several mechanisms underlying the potential effects of DNL on the prevention of aging, including the scavenging of free radicals for oxidation, delaying of DNA impairment, inhibition of apoptosis, and alteration of DNA methylation. Together with the theory of telomeres, this review also has summarized recent research progress in the use of DNL and its traditional efficacy.

CONCLUSIONS

We conclude that "strengthening Yin and benefiting the spirit", "thickening the intestine and stomach", "lightning the body and prolonging the life-span", and delaying aging, are key effects of DNL that can be used to combat age-related diseases (ARDs) such as Alzheimer's disease, hyperlipidemia, and diabetes. This review provides a reference for future study of ARDs and the clinical application of DNL.

Evaluation of Malnutrition Risk in Lung Transplant Candidates Using the Nutritional Risk Index

BACKGROUND

Malnutrition in lung transplant (LTx) candidates is an important risk factor for adverse outcomes. We sought to evaluate the Nutritional Risk Index (NRI) in LTx candidates, a validated measure of malnutrition risk in chronic disease. We aimed to characterize malnutrition risk using NRI, evaluate change in body weight between nutritional risk groups, and assess association of malnutrition risk with pretransplant and posttransplant outcomes.

METHODS

Retrospective, single-center cohort study of LTx candidates (2014-2015) evaluated by a dietitian before listing. Nutritional parameters, weight change pretransplant and posttransplant, and clinical outcomes were abstracted up to 1-year posttransplant. NRI was calculated as follows: (1.519 × albumin) + (41.7 × current weight/ideal weight) with high malnutrition risk defined as the lowest quartile of NRI for cystic fibrosis (CF) and non-CF patients.

RESULTS

The cohort comprises 247 LTx candidates (57% male; median age 59 y; non-CF 88%). Non-CF candidates had a greater mean NRI compared with CF patients (109 ± 11 versus 95 ± 12; P < 0.0001). 86% with high malnutrition risk maintained/gained weight (≥5%) pretransplant. In 196 LTx recipients, malnutrition risk was not associated with hospital stay, discharge disposition, or 1-year mortality. The median percent weight gain for LTx recipients in the first year was 10.5% (4.0-20.1), with high malnutrition risk recipients having comparable or greater weight gain to the low-risk group (mean difference for non CF: 6.8%; P = 0.02 and CF: -3.8%; P = 0.65).

CONCLUSIONS

Malnutrition risk assessed with NRI was not prognostic of posttransplant outcomes in this retrospective cohort. LTx candidates with high malnutrition risk were able to maintain their weight pretransplant and demonstrated considerable weight gain in the first-year posttransplant.

Body Weight Parameters are Related to Morbidity and Mortality After Liver Transplantation: A Systematic Review and Meta-analysis

BACKGROUND

Weight gain and obesity are well-known clinical issues in liver transplantation (LTx). However, their impacts on patient outcomes remain unclear, as only the impact of pre-LTx body mass index (BMI) on survival has been meta-analyzed. We summarized and synthesized the evidence on pre- and post-LTx body weight parameters' relations with post-LTx outcomes such as survival, metabolic and cardiovascular comorbidities, and healthcare utilization.

METHODS

We followed the Cochrane Handbook for Systematic Reviews of Interventions' recommendations. Quality was assessed via a 19-item instrument. Odds ratios and 95% confidence intervals were calculated for outcomes investigated in ≥5 studies.

RESULTS

Our meta-analysis included 37 studies. Patients with pre-LTx BMI ≥ 30 kg/m and BMI ≥ 35 kg/m had lower overall survival rates than those with pre-LTx normal weight (72.6% and 69.8% versus 84.2%; P = 0.02 and P = 0.03, respectively). Those with pre-LTx BMI ≥ 30 kg/m had worse overall graft survival than normal weight patients (75.8% and 85.4%; P = 0.003). Pre-LTx BMI and pre-LTx overweight were associated with new-onset diabetes (P < 0.001 and P = 0.015, respectively), but post-LTx BMI showed no relationship. No associations were evident with healthcare utilization.

CONCLUSIONS

Patients with BMI values ≥30 kg/m had worse patient and graft survival than those with normal weight. Few of the reviewed studies examined post-LTx body weight parameters or other relevant outcomes such as cardiovascular comorbidities. High heterogeneity as well as diverse definitions and operationalizations of measurement and outcomes severely impeded comparability.

Underweight Patients With Cystic Fibrosis Have Acceptable Survival Following Lung Transplantation: A United Network for Organ Sharing Registry Study

BACKGROUND

Reduced BMI is an absolute contraindication for lung transplantation (LTx) at most centers in the United States. The objective of this study was to quantify post-LTx survival of moderate to severely underweight patients with cystic fibrosis (CF) (BMI < 17 kg/m²) in the United States relative to normal-weight recipients with CF and other frequently transplanted patient cohorts.

METHODS

Using United Network for Organ Sharing Registry data (undergoing transplant from June 2005-November 2015), Kaplan-Meier estimates of median posttransplant survival were calculated for all patients with CF, COPD, and idiopathic pulmonary fibrosis (IPF), as well as low and normal weight CF subgroups. Cox regression modeling stratified according to transplant center assessed risk of posttransplant mortality in recipients with CF and a BMI < 17 kg/m² compared with recipients with COPD (reference).

RESULTS

Median posttransplant survival (95% CI) for CF, COPD, and IPF was 7.9 (7.2-8.6), 5.9 (5.6-6.2), and 5.5 (5.2-5.8) years, respectively. Although an absolute decrease was noted in posttransplant survival for recipients with CF and a BMI < 17 kg/m², compared with those with CF and a BMI ≥ 17 kg/m² (7.0 years [4.5-7.9] vs 8.2 years [7.3-9.0]), Cox modeling found no increased mortality risk (adjusted hazard ratio, 1.09; 95% CI, 0.90-1.32; P = .38). There was no difference in posttransplant mortality between patients with CF and a BMI < 17 kg/m² and recipients with COPD and all BMIs (adjusted hazard ratio, 1.04; 95% CI, 0.86-1.25; P = .71).

CONCLUSIONS

Transplant recipients with CF and a BMI < 17 kg/m² had posttransplant survival rates comparable to those of other groups frequently undergoing transplantation. BMI < 17 kg/m² as a single risk factor in the CF population should not be treated as an absolute contraindication to LTx.

Need for tracheostomy after lung transplant predicts decreased mid- and long-term survival

BACKGROUND

Tracheostomy is an important adjunct for lung transplant patients requiring prolonged ventilation. We explored the effects of post-transplant tracheostomy on survival and bronchiolitis obliterans syndrome after lung transplant.

METHODS

A retrospective, single center analysis was performed on all lung transplant recipients during the Lung Allocation Score (LAS) era. Risk factors for post-transplant tracheostomy or death within 30 days were assessed. Kaplan-Meier estimates and Cox proportional hazards models were used to examine the association between tracheostomy within 30 days after transplant and survival at 1 and 3 years. A total of 403 patients underwent single or bilateral lung transplant between May 2005 and February 2016 with complete data for 352 cases, and 35 patients (9.9%) underwent tracheostomy or died (N = 10, 2.8%) within 30 days.

RESULTS

In adjusted analyses, primary graft dysfunction grade 3 (PGD3) was associated with a composite end point of tracheostomy or death within 30 days (HR 3.11 (1.69, 5.71), P-value < .001). Tracheostomy within 30 days was associated with decreased survival at 1(HR 4.25 [1.75, 10.35] P-value = .001) and 3 years (HR 2.74 [1.30, 5.76], P-value = .008), as well as decreased bronchiolitis obliterans (BOS)-free survival at 1 (HR 1.87 [1.02, 3.41] P-value = .042) and 3 years (HR 2.15 [1.33, 3.5], P-value = .002).

CONCLUSION

Post-transplant tracheostomy is a marker for advanced lung allograft dysfunction with significant reduction in long-term overall and BOS-free survival.

Incidence of Massive Transfusion and Overall Transfusion Requirements During Lung Transplantation Over a 25-Year Period

OBJECTIVE

To establish the incidence of massive transfusion and overall transfusion requirements during lung transplantation, changes over time, and association with outcome in relation to patient complexity.

DESIGN

Retrospective cohort study.

SETTING

University hospital.

PARTICIPANTS

All 514 adult patients who underwent transplantation from 1990 until 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient records and transfusion data, divided into 5-year intervals, were analyzed. The incidence of massive transfusion (>10 units of red blood cells [RBCs] in 24 h) was 27% and did not change over time, whereas the median (interquartile range) transfusion requirement in the whole cohort decreased from 8 (5-12) to 3 (0-10) RBCs (p < 0.001). In patients transplanted from the intensive care unit, the incidence of massive transfusion increased over time from 25% to 54% (p = 0.04) and median transfusion requirements from 4.5 (3-8.5) units to 14.5 (5-26) units of RBCs (p = 0.03). Multivariable analysis showed that circulatory support, pulmonary hypertension, re-transplantation, cystic fibrosis, Eisenmenger syndrome, bilateral transplantation, and low body mass index were associated with massive transfusion. Patients with massive transfusion had more primary graft dysfunction grade III at 0, 24, 48, and 72 hours (p < 0.001), higher 30-day mortality (13% v 4%; p < 0.001), and lower 5-year survival (hazard ratio 3.67 [95% confidence interval 1.72-7.85]; p < 0.001).

CONCLUSION

The incidence of massive transfusion did not change over time, whereas transfusion requirements in the whole cohort decreased. In patients transplanted from the intensive care unit, massive transfusion and transfusion requirements increased. Massive transfusion was associated with poor outcome.

The Impact of Waiting List BMI Changes on the Short-term Outcomes of Lung Transplantation

BACKGROUND

Obesity and underweight are associated with a higher postlung transplantation (LTx) mortality. This study aims to assess the impact of the changes in body mass index (BMI) during the waiting period for LTx on early postoperative outcomes.

METHODS

Medical records of 502 consecutive cases of LTx performed at our institution between 1999 and 2015 were reviewed. Patients were stratified per change in BMI category between pre-LTx assessment (candidate BMI) and transplant BMI as follows: A-candidate BMI, less than 18.5 or 18.5 to 29.9 and transplant BMI, less than 18.5; B-candidate BMI, less than 18.5 and transplant BMI, 18.5 to 29.9; C-candidate BMI, 18.5 to 29.9 and transplant BMI, 18.5 to 29.9; D-candidate BMI, 30 or greater and transplant BMI, 18.5 to 29.9; and E-candidate BMI, 30 or greater or 18.5 to 29.9 and transplant BMI, 30 or greater. Our primary outcome was in-hospital mortality and secondary outcomes were length of mechanical ventilation, intensive care unit length of stay (LOS), hospital LOS and postoperative complications.

RESULTS

BMI variation during the waiting time was common, as 1/3 of patients experienced a change in BMI category. Length of mechanical ventilation (21 days vs 9 days; P = 0.018), intensive care unit LOS (26 days vs 15 days; P = 0.035), and rates of surgical complications (76% vs 44%; P = 0.018) were significantly worse in patients of group E versus group D. Obese candidates who failed to decrease BMI less than 30 by transplant exhibited an increased risk of postoperative mortality (odds ratio, 2.62; 95% confidence interval, 1.01-6.48) compared with patients in group C. Pre-LTx BMI evolution had no impact on postoperative morbidity and mortality in underweight patients.

CONCLUSIONS

Our results suggest that obese candidates with an unfavorable pretransplant BMI evolution are at greater risk of worse post-LTx outcomes.

Analytic Morphomics Predict Outcomes After Lung Transplantation

BACKGROUND

The purpose of this study was to identify morphomic factors on standard, pretransplantation computed tomography (CT) scans associated with outcomes after lung transplantation.

METHODS

A retrospective review of 200 patients undergoing lung transplantation at a single institution from 2003 to 2014 was performed. CT scans obtained within 1 year before transplantation underwent morphomic analysis. Morphomic characteristics included lung, dorsal muscle group, bone, and subcutaneous and visceral fat area and density. Patient data were gathered from institutional and United Network for Organ Sharing databases. Outcomes, including initial ventilator support greater than 48 hours, length of stay, and survival, were evaluated using univariate and multivariable analyses.

RESULTS

On multivariable Cox regression, subcutaneous fat/total body area (hazard ratio [HR] 0.60, p = 0.001), lung density 3 volume (HR 0.67, p = 0.013), and creatinine (HR 4.37, p = 0.010) were independent predictors of survival. Initial ventilator support more than 48 hours was associated with decreased vertebral body to linea alba distance (odds ratio [OR] 0.49, p = 0.002) and Zubrod score 4 (OR 14.0, p < 0.001). Increased bone mineral density (p < 0.001) and increased cross-sectional body area (p < 0.001) were associated with decreased length of stay, whereas supplemental oxygen (p < 0.001), bilateral transplantation (p = 0.002), cardiopulmonary bypass (p < 0.001), and Zubrod score 3 (p < 0.001) or 4 (p = 0.040) were associated with increased length of stay.

CONCLUSIONS

Morphomic factors associated with lower metabolic reserve and frailty, including decreased subcutaneous fat, bone density, and body dimensions were independent predictors of survival, prolonged ventilation, and increased length of stay. Analytic morphomics using pretransplantation CT scans may improve recipient selection and risk stratification.

Association of body mass index with lung transplantation survival in the United States following implementation of the lung allocation score

BACKGROUND

The association of body mass index (BMI) with survival after lung transplantation remains controversial, owing to conflicting evidence in the literature. Previous reports have used traditional BMI categories, included patients who underwent transplantation before implementation of the lung allocation score (LAS), or were limited by single-center experiences. Here we evaluated the association of individual BMI units with short-term and long-term mortality in a large national database following implementation of the LAS.

METHODS

The Scientific Registry of Transplant Recipients database was used to collect data for 17,233 adult lung transplantations performed between May 2005 and June 2016. The primary outcome was all-cause mortality at 90 days and 1 year posttransplantation. Logistic regression modeling was used to independently predict mortality per BMI unit, adjusting for donor and recipient factors.

RESULTS

BMI was an independent predictor of mortality at both 90 days and 1 year. At 90 days, a BMI of 25 was associated with the lowest predicted probability of death (0.053; 95% confidence interval [CI], 0.047-0.049), with increased odds of mortality at BMI ≤20 and ≥28. At 1 year, a BMI of 26 was associated with the lowest predicted probability of death (0.12; 95% CI, 0.11-0.13), with increased odds of mortality at BMI ≤24 and ≥28.

CONCLUSIONS

Each individual BMI unit has a quantifiable effect on posttransplantation survival, and the patterns of effect do not fit into the predefined BMI categories. The mortality risk associated with BMI should be considered by transplant centers when making listing decisions and by regulatory bodies for estimating expected outcomes.

Noteworthy Literature Published in 2016 for Thoracic Organ Transplantation Anesthesiologists

This article is first in the series to review the published literature on perioperative issues in patients undergoing thoracic solid organ transplantations. We present recent literature from 2016 on preoperative considerations, organ preservation, intraoperative anesthesia management, surgical techniques, postoperative complications, and the impact of perioperative management on short- and long-term outcomes that are pertinent to thoracic transplantation anesthesiologists.

Evolution of body weight parameters up to 3 years after solid organ transplantation: The prospective Swiss Transplant Cohort Study

Obesity and weight gain are serious concerns after solid organ transplantation (Tx); however, no unbiased comparison regarding body weight parameter evolution across organ groups has yet been performed. Using data from the prospective nationwide Swiss Transplant Cohort Study, we compared the evolution of weight parameters up to 3 years post-Tx in 1359 adult kidney (58.3%), liver (21.7%), lung (11.6%), and heart (8.4%) recipients transplanted between May 2008 and May 2012. Changes in mean weight and body mass index (BMI) category were compared to reference values from 6 months post-Tx. At 3 years post-Tx, compared to other organ groups, liver Tx recipients showed the greatest weight gain (mean 4.8±10.4 kg), 57.4% gained >5% body weight, and they had the highest incidence of obesity (38.1%). After 3 years, based on their BMI categories at 6 months, normal weight and obese liver Tx patients, as well as underweight kidney, lung and heart Tx patients had the highest weight gains. Judged against international Tx patient data, the majority of our Swiss Tx recipients' experienced lower post-Tx weight gain. However, our findings show weight gain pattern differences, both within and across organ Tx groups that call for preventive measures.

Primary graft dysfunction: pathophysiology to guide new preventive therapies

INTRODUCTION

Primary graft dysfunction (PGD) is a common complication of lung transplantation characterized by acute pulmonary edema associated with bilateral pulmonary infiltrates and hypoxemia in the first 3 post-operative days. Development of PGD is a predictor of poor short- and long-term outcomes after lung transplantation, but there are currently limited tools to prevent its occurrence. Areas covered: Several potentially modifiable donor, recipient, and operative risk factors for PGD have been identified. In addition, basic and translational studies in animals and ex vivo lung perfusion systems have identified several biomarkers and mechanisms of injury in PGD. In this review, we outline the clinical and genetic risk factors for PGD and summarize experimental data exploring PGD mechanisms, with a focus on strategies to reduce PGD risk and on potential novel molecular targets for PGD prevention. Expert commentary: Because of the clinical importance of PGD, development of new therapies for prevention and treatment is critically important. Improved understanding of the pathophysiology of clinical PGD provides a framework to explore novel agents to prevent or reverse PGD. Ex vivo lung perfusion provides a new opportunity for rapid development of therapeutics that target this devastating complication of lung transplantation.

Metabolic consequences of modern immunosuppressive agents in solid organ transplantation

Among other factors, sophistication of immunosuppressive (IS) regimen accounts for the remarkable success attained in the short- and medium-term solid organ transplant (SOT) survival. The use of steroids, mycophenolate mofetil and calcineurin inhibitors (CNI) have led to annual renal graft survival rates exceeding 90% in the last six decades. On the other hand, attrition rates of the allograft beyond the first year have remained unchanged. In addition, there is a persistent high cardiovascular (CV) mortality rate among transplant recipients with functioning grafts. These shortcomings are in part due to the metabolic effects of steroids, CNI and sirolimus (SRL), all of which are implicated in hypertension, new onset diabetes after transplant (NODAT), and dyslipidemia. In a bid to reduce the required amount of harmful maintenance agents, T-cell-depleting antibodies are increasingly used for induction therapy. The downsides to their use are greater incidence of opportunistic viral infections and malignancy. On the other hand, inadequate immunosuppression causes recurrent rejection episodes and therefore early-onset chronic allograft dysfunction. In addition to the adverse metabolic effects of the steroid rescue needed in these settings, the generated proinflammatory milieu may promote accelerated atherosclerotic disorders, thus setting up a vicious cycle. The recent availability of newer agent, belatacept holds a promise in reducing the incidence of metabolic disorders and hopefully its long-term CV consequences. Although therapeutic drug monitoring as applied to CNI may be helpful, pharmacodynamic tools are needed to promote a customized selection of IS agents that offer the most benefit to an individual without jeopardizing the allograft survival.