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

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.

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.

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.

High visceral adipose tissue area is independently associated with early allograft dysfunction in liver transplantation recipients: a propensity score analysis

OBJECTIVES

To evaluate the association between adipose tissue distribution and early allograft dysfunction (EAD) in liver transplantation (LT) recipients.

METHODS

A total of 175 patients who received LT from April 2015 to September 2020 were enrolled in this retrospective study. The areas of abdominal adipose tissue and skeletal muscle of all patients were measured based on the preoperative CT images. The appropriate statistical methods including the propensity score-matched (PSM) analysis were performed to identify the association between adipose tissue distribution and EAD.

RESULTS

Of 175 LT recipients, 55 patients (31.4%) finally developed EAD. The multivariate logistic analysis revealed that preoperative serum albumin (odds ratio (OR) 0.34, 95% confidence interval (CI) 0.17-0.70), platelet-lymphocyte ratio (OR 2.35, 95% CI 1.18-4.79), and visceral adipose tissue (VAT) area (OR 3.17, 95% CI 1.56-6.43) were independent associated with EAD. After PSM analysis, VAT area was still significantly associated with EAD (OR 3.95, 95% CI 1.16-13.51). In survival analysis, no significant difference was identified in one-year graft failure (log-rank: p = 0.487), and conversely result was identified in overall survival (OS) (log-rank: p = 0.012; hazard ratio (HR) 4.10, 95% CI 1.27-13.16).

CONCLUSIONS

LT recipients with high VAT area have higher risk for the occurrence of EAD, and high VAT area might have certain clinical value for predicting the poor OS of patients. For LT candidates with large amount of VAT, the clinicians can take clinical interventions by suggesting physical and nutritional treatments to improve outcomes after LT.

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.

Mortality risk factors in patients on waiting list for lung transplantation between 2005 and 2018: A single institutional experience

BACKGROUND

Lung transplantation is a therapeutic option for patients with end-stage lung disease. However, the increase in organ demand has surpassed the number of donors, with many patients unable to outlive the long waiting period. This study aimed to assess mortality and its risk factors in patients on the waiting list for lung transplantation in a single medical centre.

METHODS

All evaluated clinical and laboratory data of the patients with end-stage lung disease assessed for lung transplantation between February 2005 and November 2018 in National Taiwan University Hospital were recorded in the waiting list database. The patients in this study were divided into two groups: survival and death groups.

RESULTS

Between February 2005 and November 2018, 169 patients were enrolled in the waiting list. Thirty-one patients were alive and waiting for the chance of lung transplantation, 56 underwent lung transplantation, and 82 died while waiting. The mean age of all patients was 43.7 years, and 91 were women. The mean body mass index (BMI) was 20.3. The most common blood type was type O. All patients were in New York Heart Association (NYHA) class III or IV. After analysis of the two groups, lower BMI presented as a mortality factor.

CONCLUSION

This is the first Taiwanese study to describe the mortality factors in patients waiting for lung transplantation. The main factors influencing the survival of these patients were lower BMI, NYHA class IV, and diseases which cause end-stage lung diseases (infection and pulmonary fibrosis).

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.

Anesthetic considerations in lung transplantation: past, present and future

Lung transplantation is a very complex surgical procedure with many implications for the anesthetic care of these patients. Comprehensive preoperative evaluation is an important component of the transplant evaluation as it informs many of the decisions made perioperatively to manage these complex patients effectively and appropriately. These decisions may involve pre-emptive actions like pre-habilitation and nutrition optimization of these patients before they arrive for their transplant procedure. Appropriate airway and ventilation management of these patients needs to be performed in a manner that provides an optimal operating conditions and protection from ventilatory injury of these fragile post-transplant lungs. Pain management can be challenging and should be managed in a multi-modal fashion with or without the use of an epidural catheter while recognizing the risk of neuraxial technique in patients who will possibly be systemically anticoagulated. Complex monitoring is required for these patients involving both invasive and non-invasive including the use of transesophageal echocardiography (TEE) and continuous cardiac output monitoring. Management of the patient's hemodynamics can be challenging and involves managing the systemic and pulmonary vascular systems. Some patients may require extra-corporeal lung support as a planned part of the procedure or as a rescue technique and centers need to be proficient in instituting and managing this sophisticated method of hemodynamic support.

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.

Factors that Influence Treatment Delay for Patients with Breast Cancer

INTRODUCTION

The diagnosis or treatment of breast cancer is sometimes delayed. A lengthy delay may have a negative psychological impact on patients. The aim of our study was to evaluate the sociodemographic, clinical and pathological factors associated with delay in the provision of surgical treatment for localised breast cancer, in a prospective cohort of patients.

METHODS

This observational, prospective, multicentre study was conducted in ten hospitals belonging to the Spanish national public health system, located in four Autonomous Communities (regions). The study included 1236 patients, diagnosed through a screening programme or found to be symptomatic, between April 2013 and May 2015. The study variables analysed included each patient's personal history, care situation, tumour history and data on the surgical intervention, pathological anatomy, hospital admission and follow-up. Treatment delay was defined as more than 30 days elapsed between biopsy and surgery.

RESULTS

Over half of the study population experienced surgical treatment delay. This delay was greater for patients with no formal education and among widows, persons not requiring assistance for usual activities, those experiencing anxiety or depression, those who had a high BMI or an above-average number of comorbidities, those who were symptomatic, who did not receive NMR spectroscopy, who presented a histology other than infiltrating ductal carcinoma or who had poorly differentiated carcinomas.

CONCLUSIONS

Certain sociodemographic and clinical variables are associated with surgical treatment delay. This study identifies factors that influence surgical delays, highlighting the importance of preventing these factors and of raising awareness among the population at risk and among health personnel.

Influence of Body Mass Index on Perioperative Outcomes Following Pancreaticoduodenectomy

Background: Overweight and obesity are increasing year by year all over the world, and there is a correlation between overweight and obesity and the risk of pancreatic cancer. However, the relationship between overweight and obesity and perioperative outcomes of pancreaticoduodenectomy (PD) was controversial. The purpose of this study was to investigate the effect of body mass index (BMI) on the perioperative outcome of PD. Methods: This study retrospectively evaluated 227 patients who underwent PD from 2015 to 2019. The patients were divided into three groups: underweight group (BMI <18.5 kg/m²), normal weight group (18.5 ≤ BMI <25 kg kg/m²), and overweight group (BMII ≥25 kg/m²). The association between different BMI groups and different perioperative results was discussed. Finally, the independent risk factors of clinically relevant-postoperative pancreatic fistula (CR-POPF) were analyzed by multivariate logistic regression. Results: The level of preoperative albumin was higher in patients of overweight group (P = .03). The incidence of hypertension increased gradually in the three BMI groups (P = . 039). The preoperative median CA19-9 level was significantly higher in the underweight group than that in the control groups (P = .001). The median operation time in the high BMI group was significantly longer than that in the other two groups. High BMI was an independent risk factor influencing CR-POPF after PD (P = .022, odds ratio 2.253, 95% confidence interval 1.123-4.518). Conclusions: Operation time of PD was increased in patients with high BMI. High BMI was an independent risk factor for the incidence of CR-POPF after PD. However, PD surgery is safe and feasible for patients with different BMI, and overweight and obese patients should not refuse PD surgery because of their BMI.

Trends, Determinants, and Impact on Survival of Post-Lung Transplant Weight Changes: A Single-center Longitudinal Retrospective Study

BACKGROUND

Weight gain is commonly seen in lung transplant (LTx) recipients. Although previous studies have focused on weight changes at fixed time periods and relatively early after transplant, trends over time and long-term weight evolution have not been described in this population. The study objectives were to document weight changes up to 15 years post-LTx and assess the predictors of post-LTx weight changes and their associations with mortality.

METHODS

Retrospective cohort study of LTx recipients between January 1, 2000, and November 30, 2016 (n = 502). Absolute weight changes from transplant were calculated at fixed time periods (6 mo, 1, 2, 5, 10, and 15 y), and continuous trends over time were generated. Predictors of weight changes and their association with mortality were assessed using linear and Cox regression analysis.

RESULTS

LTx recipients experienced a gradual increase in weight, resulting from the combination of multiple weight trajectories. Interstitial lung disease diagnosis negatively predicted post-LTx weight changes at all time points, whereas transplant body mass index categories were significant predictors at earlier time points. Patients with a weight gain of >10% at 5 years had a better survival (hazard ratio [HR], 0.36; 95% confidence interval [CI], 0.20-0.66), whereas a 10% weight loss at earlier time points was associated with worse survival (1 y: HR, 2.04; 95% CI, 1.22-3.41 and 2 y: HR, 2.37; 95% CI, 1.22-4.58).

CONCLUSIONS

Post-LTx weight changes display various trajectories, are predicted to some extent by individual and LTx-related factors, and have a negative or positive impact on survival depending on the time post-LTx. These results may lead to a better individualization of weight management after transplant.

Noteworthy Literature Published in 2018 for Thoracic Organ Transplantation

Publications of note from 2018 are reviewed for the cardiothoracic transplant anesthesiologist. Strategies to expand the availability of donor organs were highlighted, including improved donor management, accumulating experience with increased-risk donors, ex vivo perfusion techniques, and donation after cardiac death. A number of reports examined posttransplant outcomes, including outcomes other than mortality, with new data-driven risk models. Use of extracorporeal support in cardiothoracic transplantation was a prominent theme. Major changes in adult heart allocation criteria were implemented, aiming to improve objectivity and transparency in the listing process. Frailty and prehabilitation emerged as targets of comprehensive perioperative risk mitigation programs.

Bariatric surgery in patients with interstitial lung disease

BACKGROUND

Perioperative pulmonary complications are frequent in patients with interstitial lung diseases (ILD). Limited literature exists regarding the safety of bariatric procedures in patients with ILD. This study aims to assess the safety, feasibility, and outcomes of patients with ILD who underwent bariatric surgery at our institution.

METHODS

After IRB approval, all patients with preoperative diagnosis of ILD who had bariatric surgery at an academic center between 2004 and 2014 were retrospectively reviewed.

RESULTS

A total of 25 patients with ILD underwent bariatric surgery: Roux-en-Y gastric bypass (n = 17, 68%), sleeve gastrectomy (n = 7, 28%), and adjustable gastric banding (n = 1, 4%). Twenty-one patients (84%) were females. The median age and preoperative body mass index (BMI) were 53 (IQR 42-58) years and 39 (IQR 37-44) kg/m², respectively. The median operative time and length of stay was 137 (IQR 110-187) min and 3 (IQR 2-5) days, respectively. The 30-day complications were reported in four patients (16%) but there was no pulmonary complication or unplanned admission to the intensive care unit. At 1-year follow-up (85%), the median BMI and excess weight loss were 30 (IQR 25-36) kg/m² and 67% (IQR 45-100), respectively. Compared to preoperative values, there was significant improvement in the pulmonary function test (PFT) variables at 1 year with respect to forced vital capacity (62% vs 74%; n = 13, p = 0.003), and diffusing capacity of the lungs for carbon monoxide (53% vs 66%; n = 10, p = 0.003). Six out of the seven potential lung transplant candidates became eligible for transplantation after weight loss, and one of them had successful lung transplant at 88 months after bariatric surgery.

CONCLUSION

In our experience, bariatric patients with ILD achieved significant weight loss and improvement in PFT. Bariatric surgery in these higher risk ILD patients appears relatively safe with acceptable perioperative morbidity and improved candidacy for lung transplantation.

Nutritional Requirements of Lung Transplant Recipients: Challenges and Considerations

An optimal nutritional status is associated with better post-transplant outcomes and survival. Post-lung transplant nutrition management is however particularly challenging as lung recipients represent a very heterogeneous group of patients in terms of age, underlying diseases, weight status and presence of comorbidities. Furthermore, the post-transplant period encompasses several stages characterized by physiological and pathophysiological changes that affect nutritional status of patients and necessitate tailored nutrition management. We provide an overview of the current state of knowledge regarding nutritional requirements in the post-lung transplant period from the immediate post-operative phase to long-term follow-up. In the immediate post-transplantation phase, the high doses of immunosuppressants and corticosteroids, the goal of maintaining hemodynamic stability, the presence of a catabolic state, and the wound healing process increase nutritional demands and lead to metabolic perturbations that necessitate nutritional interventions. As time from transplantation increases, complications such as obesity, osteoporosis, cancer, diabetes, and kidney disease, may develop and require adjustments to nutrition management. Until specific nutritional guidelines for lung recipients are elaborated, recommendations regarding nutrient requirements are formulated to provide guidance for clinicians caring for these patients. Finally, the management of recipients with special considerations is also briefly addressed.

Association Between BMI and Obesity With Survival in Pulmonary Arterial Hypertension

BACKGROUND

An obesity paradox, wherein patients who are obese have lower mortality, has been described in cardiopulmonary diseases, including pulmonary arterial hypertension (PAH). Our objective was to determine whether obesity and BMI are associated with mortality in patients with PAH.

METHODS

We assessed incident patients with idiopathic, drug-induced, and heritable PAH from the French Pulmonary Hypertension Network registry. Cox regression and Kaplan-Meier analysis were used to assess the association between BMI and obesity with all-cause mortality.

RESULTS

Of 1,255 patients included, 30% were obese. A higher proportion of women (65.1% vs 53.4%, P < .01), drug-induced PAH (28.9% vs 9.2%, P < .01), systemic hypertension, diabetes, and hypothyroidism were present in the obese group. More obese patients were in New York Heart Association class III (66.4% vs 57.1%), fewer were class IV (11.8% vs 16.9%, P < .01), and 6-min walk distance was lower (276 ± 121 vs 324 ± 146, P < .01). Right atrial pressure, pulmonary wedge pressure, and cardiac index were higher, whereas pulmonary vascular resistance was lower in patients who were obese. Neither BMI (hazard ratio [HR], 0.99; 95% CI, 0.97-1.01; P = .41) nor obesity (HR, 1.0; 95% CI, 0.99-1.01; P = .46) were associated with mortality in multivariable analyses. There was a significant interaction between age and obesity such that mortality increased among patients < 65 years of age who were morbidly obese (HR, 3.01; 95% CI, 1.56-5.79; P = .001).

CONCLUSIONS

Obesity was not associated with mortality in the overall population, but there was an age-obesity interaction with increased mortality among young patients who were morbidly obese. These results have implications for active weight management in younger patients who are morbidly obese who are otherwise candidates for lung transplantation.

Noteworthy Literature Published in 2017 for Thoracic Transplantation Anesthesiologists

Thoracic organ transplantation constitutes a significant proportion of all transplant procedures. Thoracic solid organ transplantation continues to be a burgeoning field of research. This article presents a review of remarkable literature published in 2017 regarding perioperative issues pertinent to the thoracic transplant anesthesiologists.