Unsupervised Exercise Intervention vs. Adherence to a Mediterranean Diet Alone: The Role of Bioelectrical Impedance Vector Analysis and Cardiovascular Performance in Liver-Transplanted Recipients

(1) Background: Cardiovascular disease is one of the leading causes of mortality after liver transplantation. Body composition and cardiovascular performance assessment represent a potential approach for modulating lifestyle correction and proper follow-up in chronic disease patients. This study aimed to verify the additional role of an unsupervised physical activity program in a sample of male liver transplant recipients who follow the Mediterranean diet. (2) Methods: Thirty-three male liver transplant recipients were enrolled. Sixteen subjects followed a moderate-intensity home exercise program in addition to nutritional support, and seventeen received advice on the Mediterranean diet. After six months, bioelectrical vector impedance analysis (BIVA) and cardiopulmonary exercise testing (CPET) were performed. (3) Results: No differences in CPET (VO2 peak: exercise 21.4 ± 4.1 vs. diet 23.5 ± 6.5 mL/kg/min; p = 0.283) and BIVA (Z/H: exercise 288.3 ± 33.9 vs. diet 310.5 ± 34.2 Ω/m; p = 0.071) were found. Furthermore, the BIVA values of resistance correlate with the submaximal performance of the Ve/VCO2 slope (R = 0.509; p < 0.05) and phase angle with the maximal effort of the VO2 peak (R = 0.557; p < 0.05). (4) Conclusions: Unsupervised physical exercise alone for six months does not substantially modify liver transplant recipients' cardiovascular performance and hydration status, despite their adherence to a Mediterranean diet. The body composition analysis is useful to stratify the risk profile, and it is potentially associated with better outcomes in transplanted subjects.

From Listing to Recovery: A Review of Nutritional Status Assessment and Management in Liver Transplant Patients

Liver transplantation (LT) is a complex surgical procedure requiring thorough pre- and post-operative planning and care. The nutritional status of the patient before, during, and after LT is crucial to surgical success and long-term prognosis. This review aims to assess nutritional status assessment and management before, during, and after LT, with a focus on patients who have undergone bariatric surgery. We performed a comprehensive topic search on MEDLINE, Ovid, In-Process, Cochrane Library, EMBASE, and PubMed up to March 2023. It identifies key factors influencing the nutritional status of liver transplant patients, such as pre-existing malnutrition, the type and severity of liver disease, comorbidities, and immunosuppressive medications. The review highlights the importance of pre-operative nutritional assessment and intervention, close nutritional status monitoring, individualised nutrition care plans, and ongoing nutritional support and monitoring after LT. The review concludes by examining the effect of bariatric surgery on the nutritional status of liver transplant recipients. The review offers valuable insights into the challenges and opportunities for optimising nutritional status before, during, and after LT.

Accuracy of surrogate methods to estimate skeletal muscle mass in non-dialysis dependent patients with chronic kidney disease and in kidney transplant recipients

BACKGROUND & AIMS

Bioelectrical impedance analysis (BIA) and anthropometric predictive equations have been proposed to estimate whole-body (SMM) and appendicular skeletal muscle mass (ASM) as surrogate for dual energy X-ray absorptiometry (DXA) in distinct population groups. However, their accuracy in estimating body composition in non-dialysis dependent patients with chronic kidney disease (NDD-CKD) and kidney transplant recipients (KTR) is unknown. The aim of this study was to investigate the accuracy and reproducibility of BIA and anthropometric predictive equations in estimating SMM and ASM compared to DXA, in NDD-CKD patients and KTR.

METHODS

A cross-sectional study including adult NDD-CKD patients and KTR, with body mass index (BMI) ≥18.5 kg/m². ASM and estimated SMM were evaluated by DXA, BIA (Janssen, Kyle and MacDonald equations) and anthropometry (Lee and Baumgartner equations). Low muscle mass (LowMM) was defined according to cutoffs proposed by guidelines for ASM, ASM/height² and ASM/BMI. The best performing equation as surrogate for DXA, considering both groups of studied patients, was defined based in the highest Lin's concordance correlation coefficient (CCC) value, the lowest Bland-Altman bias (<1.5 kg) combined with the narrowest upper and lower limits of agreement (LoA), and the highest Cohen's kappa values for the low muscle mass diagnosis.

RESULTS

Studied groups comprised NDD-CKD patients (n = 321: males = 55.1%; 65.4 ± 13.1 years; eGFR = 28.8 ± 12.7 ml/min) and KTR (n = 200: males = 57.7%; 47.5 ± 11.3 years; eGFR = 54.7 ± 20.7 ml/min). In both groups, the predictive equations presenting the best accuracy compared to DXA were SMM-BIA-Janssen (NDD-CKD patients: CCC = 0.88, 95%CI = 0.83-0.92; bias = 0.0 kg; KTR: CCC = 0.89, 95%CI = 0.86-0.92, bias = -1.2 kg) and ASM-BIA-Kyle (NDD-CKD patients: CCC = 0.87, 95%CI = 0.82-0.90, bias = 0.7 kg; KTR: CCC = 0.89, 95%CI = 0.86-0.92, bias = -0.8 kg). In NDD-CKD patients and KTR, LowMM frequency was similar according to ASM-BIA-Kyle versus ASM-DXA. The reproducibility and inter-agreement to diagnose LowMM using ASM/height² and ASM/BMI estimated by BIA-Kyle equation versus DXA was moderate (kappa: 0.41-0.60), in both groups. Whereas female patients showed higher inter-agreement (AUC>80%) when ASM/BMI index was used, male patients presented higher AUC (70-74%; slightly <80%) for ASM/height² index.

CONCLUSIONS

The predictive equations with best performance to assess muscle mass in both NDD-CKD patients and KTR was SMM-BIA by Janssen and ASM-BIA by Kyle. The reproducibility to diagnose low muscle mass, comparing BIA with DXA, was high using ASM/BMI in females and ASM/height² in males in both groups.

Skeletal muscle size, function, and adiposity with lifelong aerobic exercise

We examined the influence of lifelong aerobic exercise on skeletal muscle size, function, and adiposity. Young exercisers [YE; n = 20, 10 women (W), 25 ± 1 yr], lifelong exercisers (LLE; n = 28, 7 W, 74 ± 2 yr), and old healthy nonexercisers (OH; n = 20, 10 W, 75 ± 1 yr) were studied. On average, LLE exercised 5 days/wk for 7 h/wk over the past 52 ± 1 yr. The LLE men were subdivided by exercise intensity [Performance (LLE-P), n = 14; Fitness (LLE-F), n = 7]. Upper and lower leg muscle size and adiposity [intermuscular adipose tissue (IMAT)] were determined via MRI, and quadriceps isotonic and isometric function was assessed. For the quadriceps, aging decreased muscle size, isotonic and isometric strength, contraction velocity (men only), and power (P < 0.05). In women, LLE did not influence muscle size or function. In men, LLE attenuated the decline in muscle size and isometric strength by ~50% (P < 0.05). LLE did not influence other aspects of muscle function, nor did training intensity influence muscle size or function. For the triceps surae, aging decreased muscle size only in the women, whereas LLE (both sexes) and training intensity (LLE men) did not influence muscle size. In both sexes, aging increased thigh and calf IMAT by ~130% (P < 0.05), whereas LLE attenuated the thigh increase by ~50% (P < 0.05). In the LLE men, higher training intensity decreased thigh and calf IMAT by ~30% (P < 0.05). In summary, aging and lifelong aerobic exercise influenced muscle size, function, and adipose tissue infiltration in a sex- and muscle-specific fashion. Higher training intensity throughout the life span provided greater protection against adipose tissue infiltration into muscle.NEW & NOTEWORTHY This is the first study to examine skeletal muscle size, function, and adiposity in women and men in their eighth decade of life that have engaged in lifelong aerobic exercise. The findings reveal sex and upper and lower leg muscle group-specific benefits related to skeletal muscle size, function, and adiposity and that exercise intensity influences intermuscular adiposity. This emerging cohort will further our understanding of the health implications of maintaining exercise throughout the life span.

Progressive loss of muscle mass could be an adverse prognostic factor of 28-day mortality in septic shock patients

A decrease in skeletal muscle mass has been shown to increase hospital mortality. Nevertheless, little is known about the association between progressive muscle loss over time and clinical outcomes. We aimed to evaluate whether progressive loss of muscle mass in septic shock patients was associated with mortality. We reviewed prospectively enrolled registry of septic shock which had 817 consecutive patients. Of these, 175 patients who had computed tomography (CT) at a time of admission as well as 3-6 months prior to admission were included. Between these two CTs, the change in total abdominal muscle area index (TAMAI) was evaluated for progressive muscle loss. The change in TAMAI was higher in the non-survivors (-7.6 cm²/m², 19.0% decrease) than the survivors (-4.0 cm²/m², 10.5% decrease) with statistical significance (p = 0.002). Multiple logistic regression showed that the patients who had more than a 6.4 cm²/m² (16.7%) reduction of TAMAI had a 4.42-fold higher risk for mortality at 28 days (OR, 4.42; 95% CI, 1.41-13.81, p = 0.011). Our study suggested that progressive loss of muscle mass might be a useful prognostic factor for septic shock patients. This implication will need to be further explored in future prospective studies.

Muscle Mass and Mortality After Cardiac Transplantation

BACKGROUND

Frailty assessment is recommended to evaluate the candidacy of adults referred for orthotopic heart transplantation (OHT). Psoas muscle area (PMA) is an easily measured biomarker for frailty. There has yet to be a study examining the prognostic impact of PMA in OHT patients.

METHODS

In this retrospective study, preoperative and postoperative computed tomography (CT) scans were retrieved for adults transplanted between 2000 and 2015 at a tertiary care hospital. Psoas muscle area was measured on a single axial image. Outcomes of interest were all-cause mortality over 6 years and a composite of in-hospital mortality or major morbidity (prolonged ventilation, stroke, dialysis, mediastinitis, or reoperation).

RESULTS

Of 161 adult patients transplanted, 82 had at least 1 abdominal CT scan. At baseline, mean PMA was 25.7 ± 5.8 cm in men and 16.0 ± 3.6 cm in women, and decreased by 8% from the first to the last available CT scan. Adjusting for age, sex, body mass index, and cardiomyopathy etiology, every 1-cm increase in PMA was found to be associated with a 9% reduction in long-term mortality (hazard ratio, 0.91; 95% confidence interval [CI], 0.83-0.99; P = 0.031) and a 17% reduction in in-hospital mortality or major morbidity (odds ratio, 0.83; 95% CI, 0.72-0.96; P = 0.014). When PMA was smaller than the sex-specific median, the risk of mortality or major morbidity increased fourfold (odds ratio, 4.29; 95% CI, 1.19-15.46; P = 0.026).

CONCLUSIONS

Muscle mass is an independent predictor of mortality and major morbidity after OHT. Further research is needed to determine whether frail OHT patients with low PMA may benefit from muscle-building interventions to improve outcomes.

SARCOPENIA, OBESITY AND SARCOPENIC OBESITY IN LIVER TRANSPLANTATION: A BODY COMPOSITION PROSPECTIVE STUDY

BACKGROUND

Sarcopenia is prevalent before liver transplantation, and it is considered to be a risk factor for morbidity/mortality. After liver transplantation, some authors suggest that sarcopenia remains, and as patients gain weight as fat, they reach sarcopenic obesity status.

AIM

Prospectively to assess changes in body composition, prevalence and associated factors with respect to sarcopenia, obesity and sarcopenic obesity after transplantation.

METHODS

Patients were evaluated at two different times for body composition, 4.0±3.2y and 7.6±3.1y after transplantation. Body composition data were obtained using bioelectrical impedance. The fat-free mass index and fat mass index were calculated, and the patients were classified into the following categories: sarcopenic; obesity; sarcopenic obesity.

RESULTS

A total of 100 patients were evaluated (52.6±13.3years; 57.0% male). The fat-free mass index decreased (17.9±2.5 to 17.5±3.5 kg/m2), fat mass index increased (8.5±3.5 to 9.0±4.0; p<0.05), prevalence of sarcopenia (19.0 to 22.0%), obesity (32.0 to 37.0%) and sarcopenic obesity (0 to 2.0%) also increased, although not significantly. The female gender was associated with sarcopenia.

CONCLUSION

The fat increased over the years after surgery and the lean mass decreased, although not significantly. Sarcopenia and obesity were present after transplantation; however, sarcopenic obesity was not a reality observed in these patients.

Patient and Caregiver Attitudes and Practices of Exercise in Candidates Listed for Liver Transplantation

BACKGROUND

Impaired physical capacity increases peri-liver transplant complications. Patient perceptions regarding exercise prior to transplantation are not known.

AIMS

This study aimed to assess patient and caregiver activity levels, perceptions of willingness to exercise, and of provider advice.

METHODS

Consecutive patients listed for liver transplant and caregivers presenting for routine outpatient visits were evaluated over a 3-month interval. Anonymous surveys adapted to patients and caregivers addressed the importance and safety of exercise, type and duration of exercise performed, barriers, willingness to wear a monitoring device, and perceived provider recommendations. Responses were logged on a Likert scale from 1 to 5.

RESULTS

Three hundred and sixty-eight responses were received. Most participants perceived exercise as important. Patients exercised three times per week for 30 min. Eighty percent endorsed walking (median response: 2-agree; IQR 1-2). Most did not jog, swim, cycle, or strength train. Fatigue, reported by 70%, was the major barrier (2, IQR 1-3). Over 90% of caregivers endorsed exercise as important (1-strongly agree, IQR 1-2) and encouraged exercise (median response 2, IQR 1-2). Over 60% of patients (median response 2, IQR 1-3) and caregivers (median response 2, IQR 2-3) felt providers encouraged exercise.

CONCLUSIONS

Patients and caregivers are willing to exercise to optimize physical fitness prior to liver transplantation.

Nutrition, dietary intake, and eating behavior after liver transplantation

PURPOSE OF REVIEW

Nutritional status of patients after liver transplantation is affected by dietary intake and this, in turn, is affected by eating behavior. The present review will highlight recent studies on these topics after liver transplantation.

RECENT FINDINGS

Malnutrition drops significantly after liver transplantation. Recovery of weight lost during liver disease occurs within 1 year. Liver transplantation recipients gain weight up to the second or third year, often becoming overweight and obese. Muscle mass may not recover completely, and sarcopenia could increase within 1 year after liver transplantation. Some studies, but not all, demonstrated modifications of food intake before and after liver transplantation. A positive energy balance was found in the first year, and a greater energy intake along time after liver transplantation, although some authors mentioned potential underreporting of the true consumption, mainly among people overweight/obese. Dietary survey methods are unable to detect eating behavior, resulting in a lack of data. Weight gain and obesity were related to higher scores for patterns of eating behaviors after liver transplantation. Food deprivation in the pretransplantation period and psychological factors could affect eating behavior and consequently food intake and nutritional status of liver transplantation patients.

SUMMARY

Understanding eating behavior after liver transplantation could be key knowledge regarding dietary intake and its impact on nutritional modifications occurring after liver transplantation.

Severe Sarcopenia and Increased Fat Stores in Pediatric Patients With Liver, Kidney, or Intestine Failure

OBJECTIVES

Malnutrition and wasting predict clinical outcomes in children with severe chronic illness. Objectively calculated malnutrition in children with end-stage organ failure has not been well studied. This analysis compares children with kidney, liver or intestine failure to healthy controls to quantitate the disparity in muscle and fat stores.

METHODS

Children younger than 19 years with end-stage liver, kidney, or intestine failure and with pretransplant computed tomography (CT) imaging were selected from the transplant database. Age- and sex-matched healthy controls were selected from the trauma database. Measures of nutrition status included a scaled scoring of core muscle mass, and visceral and subcutaneous fat stores. Analysis was conducted using the pooled and individually matched subject-control differences.

RESULTS

There were 81 subjects included in the final analysis (liver [n = 35], kidney [n = 20], and intestine [n = 26]). Children with end-stage liver disease had a 23% reduction in muscle mass, a 69% increase in visceral fat, and a 29% increase in subcutaneous fat. End-stage renal disease patients had a 19% reduction in muscle mass and a 258% increase in subcutaneous fat. Intestine failure patients had a 24% reduction in muscle mass, a 30% increase in visceral fat, and a 46% increase in subcutaneous fat.

CONCLUSIONS

These results demonstrate significant sarcopenia and increased fat stores in end-stage organ failure patients, which supports the idea of an active physiologic mechanism to store fat while losing muscle mass. Sarcopenia may be related to total protein loss from a catabolic state, or from decreased synthesis (liver), wasting (kidney), or malabsorption (intestine).

Pre-sarcopenia and bone mineral density in adults submitted to hematopoietic stem cell transplantation

BACKGROUND

The aim of this study was to evaluate the prevalence of pre-sarcopenia and bone mineral density after hematopoietic stem cell transplantation.

METHODS

The study group consisted of over 18-year-old patients who had been submitted to allogeneic transplantation at least one year previously. Patients and healthy controls were matched by sex, ethnic background, age, and body mass index. Body composition and bone mineral density were measured by dual-energy X-ray absorptiometry. A 24-h food recall and food frequency survey were performed. The biochemical evaluation included calcium, parathormone and vitamin D. Eighty-seven patients (52 men; age: 37.2±12.7 years; body mass index: 25±4.5kg/m2) were compared to 68 controls [31 men; age 35.4±15.5 years (p=0.467); body mass index 25.05±3.7kg/m2 (p=0.927)].

RESULTS

There was no significant difference in the dietary intake between patients and controls. The mean levels of vitamin D were 23.5±10.3ng/mL; 29 patients (41.0%) had insufficient and 26 (37.14%) deficient levels. A higher prevalence of reduced bone mineral density was observed in 24 patients (25%) compared to 12 controls (19.1% - p<0.001). Pre-sarcopenia was diagnosed in 14 (14.4%) patients and none of the controls (p=0.05). There was a higher prevalence of pre-sarcopenia (66%) in patients with grades III and IV compared to those with grades 0-II graft-versus-host disease (10.9%) (p=0.004).

CONCLUSION

patients submitted to transplantation had a higher prevalence of pre-sarcopenia and greater changes in bone mineral density compared to controls; the severity of graft-versus-host disease had an impact on the prevalence of pre-sarcopenia.

A comparative study of software programmes for cross-sectional skeletal muscle and adipose tissue measurements on abdominal computed tomography scans of rectal cancer patients

BACKGROUND

The association between body composition (e.g. sarcopenia or visceral obesity) and treatment outcomes, such as survival, using single-slice computed tomography (CT)-based measurements has recently been studied in various patient groups. These studies have been conducted with different software programmes, each with their specific characteristics, of which the inter-observer, intra-observer, and inter-software correlation are unknown. Therefore, a comparative study was performed.

METHODS

Fifty abdominal CT scans were randomly selected from 50 different patients and independently assessed by two observers. Cross-sectional muscle area (CSMA, i.e. rectus abdominis, oblique and transverse abdominal muscles, paraspinal muscles, and the psoas muscle), visceral adipose tissue area (VAT), and subcutaneous adipose tissue area (SAT) were segmented by using standard Hounsfield unit ranges and computed for regions of interest. The inter-software, intra-observer, and inter-observer agreement for CSMA, VAT, and SAT measurements using FatSeg, OsiriX, ImageJ, and sliceOmatic were calculated using intra-class correlation coefficients (ICCs) and Bland-Altman analyses. Cohen's κ was calculated for the agreement of sarcopenia and visceral obesity assessment. The Jaccard similarity coefficient was used to compare the similarity and diversity of measurements.

RESULTS

Bland-Altman analyses and ICC indicated that the CSMA, VAT, and SAT measurements between the different software programmes were highly comparable (ICC 0.979-1.000, P < 0.001). All programmes adequately distinguished between the presence or absence of sarcopenia (κ = 0.88-0.96 for one observer and all κ = 1.00 for all comparisons of the other observer) and visceral obesity (all κ = 1.00). Furthermore, excellent intra-observer (ICC 0.999-1.000, P < 0.001) and inter-observer (ICC 0.998-0.999, P < 0.001) agreement for all software programmes were found. Accordingly, excellent Jaccard similarity coefficients were found for all comparisons (mean ≥ 0.964).

CONCLUSIONS

FatSeg, OsiriX, ImageJ, and sliceOmatic showed an excellent agreement for CSMA, VAT, and SAT measurements on abdominal CT scans. Furthermore, excellent inter-observer and intra-observer agreement were achieved. Therefore, results of studies using these different software programmes can reliably be compared.

Age-related deficits in skeletal muscle recovery following disuse are associated with neuromuscular junction instability and ER stress, not impaired protein synthesis

Age-related loss of muscle mass and strength can be accelerated by impaired recovery of muscle mass following a transient atrophic stimulus. The aim of this study was to identify the mechanisms underlying the attenuated recovery of muscle mass and strength in old rats following disuse-induced atrophy. Adult (9 month) and old (29 month) male F344BN rats underwent hindlimb unloading (HU) followed by reloading. HU induced significant atrophy of the hindlimb muscles in both adult (17-38%) and old (8-29%) rats, but only the adult rats exhibited full recovery of muscle mass and strength upon reloading. Upon reloading, total RNA and protein synthesis increased to a similar extent in adult and old muscles. At baseline and upon reloading, however, proteasome-mediated degradation was suppressed leading to an accumulation of ubiquitin-tagged proteins and p62. Further, ER stress, as measured by CHOP expression, was elevated at baseline and upon reloading in old rats. Analysis of mRNA expression revealed increases in HDAC4, Runx1, myogenin, Gadd45a, and the AChRs in old rats, suggesting neuromuscular junction instability/denervation. Collectively, our data suggests that with aging, impaired neuromuscular transmission and deficits in the proteostasis network contribute to defects in muscle fiber remodeling and functional recovery of muscle mass and strength.

Body composition assessed by dual-energy X-ray absorptiometry predicts early infectious complications after liver transplantation

BACKGROUND

It is challenging to identify malnutrition, which is a risk factor for poor outcome in patients with liver cirrhosis. In the present study, we aimed to investigate the prevalence of malnutrition among patients listed for liver transplantation, as assessed by different methods, and also to relate dual-energy X-ray absorptiometry (DXA) to short-term post-transplant outcomes.

METHODS

In this retrospective cohort study, we reviewed the medical records of 106 patients who underwent liver transplantation in 2009-2012. Body composition was assessed by the fat-free mass index (FFMI) and fat mass index (FMI) obtained using DXA. Severe infections within 1 month, length of stay in intensive care unit and length of hospital stay were endpoints of primary interest.

RESULTS

The prevalence of malnutrition was 2-20% depending on sex and the assessment method. Thirty-nine (37%) patients developed severe infections within 1 month after liver transplantation. In multivariate analysis with logistic regression, body composition was significantly associated with post-operative infection when measured with FFMI (P = 0.043) but not with FMI (P = 0.087). Post-operative dialysis (P = 0.004) and post-operative infections (P < 0.001) were significantly associated with length of stay in hospital. Post-operative bleeding (P = 0.015), duration of mechanical ventilation (P < 0.001) and the need for dialysis (P < 0.001), but not body composition, were significant predictors of the length of stay in the intensive care unit.

CONCLUSIONS

The prevalence of malnutrition depends on assessment method. FFMI is an independent predictor for early post-transplant infections. Body composition measured by DXA during the pretransplant evaluation provides valuable information about nutritional status in patients with liver cirrhosis.

Systematic Review and Meta-Analysis of the Impact of Computed Tomography-Assessed Skeletal Muscle Mass on Outcome in Patients Awaiting or Undergoing Liver Transplantation

Liver transplant outcome has improved considerably as a direct result of optimized surgical and anesthesiological techniques and organ allocation programs. Because there remains a shortage of human organs, strict selection of transplant candidates remains of paramount importance. Recently, computed tomography (CT)-assessed low skeletal muscle mass (i.e. sarcopenia) was identified as a novel prognostic parameter to predict outcome in liver transplant candidates. A systematic review and meta-analysis on the impact of CT-assessed skeletal muscle mass on outcome in liver transplant candidates were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Nineteen studies, including 3803 patients in partly overlapping cohorts, fulfilled the inclusion criteria. The prevalence of sarcopenia ranged from 22.2% to 70%. An independent association between low muscle mass and posttransplantation and waiting list mortality was described in 4 of the 6 and 6 of the 11 studies, respectively. The pooled hazard ratios of sarcopenia were 1.84 (95% confidence interval 1.11-3.05, p = 0.02) and 1.72 (95% confidence interval 0.99-3.00, p = 0.05) for posttransplantation and waiting list mortality, respectively, independent of Model for End-stage Liver Disease score. Less-consistent evidence suggested a higher complication rate, particularly infections, in sarcopenic patients. In conclusion, sarcopenia is an independent predictor for outcome in liver transplantation patients and could be used for risk assessment.

Pre-transplant wasting (as measured by muscle index) is a novel prognostic indicator in lung transplantation

BACKGROUND

Frailty in non-transplant populations increases morbidity and mortality. Muscle wasting is an important frailty characteristic. Low body mass index is used to measure wasting, but can over- or underestimate muscle mass. Computed tomography (CT) software can directly measure muscle mass. It is unknown if muscle wasting is important in lung transplantation.

AIM AND METHODS

The aim of this single-center, retrospective cohort study was to determine whether pre-transplant low muscle mass (as measured by CT using Slice-O-matic software at L2-L3 interspace) was associated with post-transplantation mortality, hospital and intensive care unit length of stay (LOS), duration of mechanical ventilation, or primary graft dysfunction. Lung transplant recipients from 2000 to 2012 with a CT scan less than six months prior to transplant were included. Univariate, multivariate, and Kaplan-Meier analyses were conducted.

RESULTS

Thirty-six patients were included. Those with low muscle index (lower 25th percentile) had a worse survival (hazard ratio = 3.83; 95% confidence interval 1.42-10.3; p = 0.007) and longer hospital LOS by an estimated 7.2 d (p = 0.01) when adjusted for age and sex as compared to those with higher muscle index.

CONCLUSION

Low muscle index at lung transplantation is associated with worse survival and increased hospital LOS.

Short-term prospective study of prescribed physical activity in kidney transplant recipients

Regular physical exercise plays a role in improving cardiovascular and muscular fitness in many metabolic diseases. This study aims to verify any possible benefits, including the eventual influence on any associated risk factors, in a group of kidney transplant recipients after a short period of personalized training programs with mixed exercises. In January 2013, at the Sports Medicine Center of the University of Florence, Italy, we began studying a group of 20 kidney transplant recipients. After 6 months of exercise, they underwent Cardiopulmonary Test (CPET), ECG, skin fold, bioimpedance analysis and stress test for the lower and upper limbs. EF increased significantly from 63.38 ± 4 to 67.30 ± 5.9 with p < 0.05; the anaerobic threshold improved from 14.48 ± 6.3 to 20.24 ± 3.7 (p < 0.05) with good stress tolerance, estimated by CR10 scale; weight decreased significantly (70.06-65.03 kg) as did skin folds at pectoral level (p < 0.002). Upper limb muscular strength increased significantly (p < 0.005). Regular mixed exercise is a proposed program in post-transplant syndrome with the expectation of improving cardiovascular performance and enhancing exercise tolerance. Muscle strength improves with physical fitness with consequent reduction of risk factors linked to visceral fat. Proof of an eventual positive impact on other complex aspects associated with post-transplant metabolic syndrome will require a longer follow-up.

Sarcopenia in lung transplantation: a systematic review

Lung transplant candidates and recipients have significant impairments in skeletal muscle mass, strength and function--individual measures of sarcopenia. Skeletal muscle dysfunction has been observed in the pre-transplant and post-transplant period and could have an important effect on transplant outcomes. A systematic review was performed to characterize the techniques used to study sarcopenia and assess the level of impairment throughout the transplant process. Electronic databases were searched (inception to July 2013) for prospective studies measuring at least 1 element of sarcopenia (muscle mass, strength, or function) in lung transplant patients. Eighteen studies were included, and study quality was assessed using the Downs and Black scale. A variety of measurements were used to evaluate sarcopenia in 694 lung transplant patients. Muscle mass in 7 studies was assessed using bioelectrical impedance (n = 4), computed tomography or magnetic resonance imaging (n = 2), or skin folds (n = 1), and was significantly reduced. Quadriceps strength was examined in 14 studies with computerized dynamometer (n = 10) and hand-held dynamometer (n = 4). Quadriceps strength was reduced in the pre-transplant period (mean range, 49%-86% predicted; n = 455 patients), further reduced immediately after transplant (51%-72%, n = 126), and improved beyond 3 months after transplant (58%-101%, n = 164). Only 2 studies measured lower extremity function (sit-to-stand test). A multitude of measurement techniques have been used to assess individual measures of sarcopenia, with reduced muscle mass and quadriceps strength observed in the pre-transplant and post-transplant period. Further standardization of measurement techniques is needed to assess the clinical effect of sarcopenia in lung transplantation.