Thoracic muscle cross-sectional area is associated with hospital length of stay post lung transplantation: a retrospective cohort study

Effect of pretransplant sarcopenia on patient and graft outcomes in solid organ transplant recipients: A systematic review and meta-analysis

The relationship between sarcopenia and prognosis in solid organ transplantation recipients (SOTr) remains unverified. We aimed to quantify the prevalence of pretransplant sarcopenia and its effect on patient and graft survival in SOTr. We used PubMed, EMBASE, Cochrane Library and Web of Science to search relevant studies published in English (from inception to December 31, 2021). Prospective and retrospective cohort studies that reported the prevalence of sarcopenia before transplant or the association between sarcopenia and clinical outcomes in SOTr were included. Primary outcomes were the prevalence of sarcopenia and its impact on patient and graft survival. Secondary outcomes included perioperative complications, acute rejection, length of hospital stay, length of intensive care unit stay (ICU LOS) and early readmission. Thirty-nine studies involving 5792 patients were included. Pooled prevalence of sarcopenia amongst SOTr candidates was 40 % (95 % confidence interval [CI]: 34%-47 % and I2 = 97 %). Sarcopenia was associated with increased risk of death (hazard ratio [HR] = 1.87, 95 % CI: 1.46-2.41 and I2 = 60 %), poor graft survival (HR = 1.71, 95 % CI: 1.16-2.54 and I2 = 57 %) and increased liver graft loss (HR = 1.43, 95 % CI: 1.03-1.99 and I2 = 38 %). Patients with sarcopenia demonstrated increased incidence of perioperative complications (risk ratio [RR] = 1.34, 95 % CI: 1.17-1.53 and I2 = 40 %), long ICU LOS (mean difference = 2.31 days, 95 % CI: 0.58-4.04 and I2 = 97 %) and decreased risk of acute rejection (RR = 0.61, 95 % CI: 0.42-0.89 and I2 = 0 %). In Conclusion, sarcopenia is prevalent in SOTr candidates and associated with death and graft loss. Identifying sarcopenia before transplantation and intervening may improve long-term outcomes.

Impact of changes in skeletal muscle mass and quality during the waiting time on outcomes of lung transplantation

INTRODUCTION

The association of changes in skeletal muscle mass and quality during the waiting time with outcomes of lung transplantation (LT) remains unclear. We aimed to examine the association of changes in skeletal muscle mass and quality during the waiting time, as well as preoperative skeletal muscle mass and quality, with outcomes of LT.

METHODS

This study included individuals who underwent LT from brain-dead donors. Skeletal muscle mass (cm2 /m2 ) and quality (mean Hounsfield units [HU]) of the erector spinae muscle at the 12th thoracic level were evaluated using computed tomography. Preoperative skeletal muscle mass and quality, and their changes during the waiting time were calculated. We evaluated the associations among mechanical ventilation (MV) duration, intensive care unit (ICU) length of stay (LOS), hospital LOS, 6-minute walk distance at discharge, and 5-year survival after LT.

RESULTS

This study included 98 patients. The median waiting time was 594.5 days (interquartile range [IQR], 355.0-913.0). The median changes in skeletal muscle mass and quality were -4.4% (IQR, -13.3-3.1) and -2.9% (IQR, -16.0-4.1), respectively. Severe low skeletal muscle mass at LT was associated with prolonged ICU LOS (B = 8.46, 95% confidence interval [CI]: .51-16.42) and hospital LOS (B = 36.00, 95% CI: 3.23-68.78). Pronounced decrease in skeletal muscle mass during the waiting time was associated with prolonged MV duration (B = 7.85, 95% CI: .89-14.81) and ICU LOS (B = 7.97, 95% CI: .83-15.10).

CONCLUSION

Maintaining or increasing skeletal muscle mass during the waiting time would be beneficial to improve the short-term outcomes of LT.

Cigarette smoking and disproportionate changes of thoracic skeletal muscles in low-dose chest computed tomography

Association between smoking intensity and the quantity and quality of thoracic skeletal muscles (TSMs) remains unexplored. Skeletal muscle index (SMI; skeletal muscle area/height2) and percentage of normal attenuation muscle area (NAMA%) were measured to represent the quantity and quality of the skeletal muscles, respectively, and quantification was performed in pectoralis muscle at aortic arch (AA-PM), TSM at carina (C-TSM), erector spinae muscle at T12 (T12-ESM), and skeletal muscle at L1 (L1-SM). Among the 258 men (median age, 62 years [IQR: 58-69]), 183 were current smokers (median smoking intensity, 40 pack-years [IQR: 30-46]). SMI and NAMA% of AA-PM significantly decreased with pack-year (β =  - 0.028 and - 0.076; P < 0.001 and P = 0.021, respectively). Smoking intensity was inversely associated with NAMA% of C-TSM (β =  - 0.063; P = 0.001), whereas smoking intensity showed a borderline association with SMI of C-TSM (β =  - 0.023; P = 0.057). Smoking intensity was associated with the change in NAMA% of L1-SM (β =  - 0.040; P = 0.027), but was not associated with SMI of L1-SM (P > 0.05). Neither NAMA% nor SMI of T12-ESM was affected by smoking intensity (P > 0.05). In conclusion, smoking intensity was associated with the change of TSMs. Its association varied according to the location of TSMs, with the most associated parts being the upper (AA-PM) and middle TSMs (C-TSM).

Deep learning-based pectoralis muscle volume segmentation method from chest computed tomography image using sagittal range detection and axial slice-based segmentation

The pectoralis muscle is an important indicator of respiratory muscle function and has been linked to various parenchymal biomarkers, such as airflow limitation severity and diffusing capacity for carbon monoxide, which are widely used in diagnosing parenchymal diseases, including asthma and chronic obstructive pulmonary disease. Pectoralis muscle segmentation is a method for measuring muscle volume and mass for various applications. The segmentation method is based on deep-learning techniques that combine a muscle area detection model and a segmentation model. The training dataset for the detection model comprised multichannel images of patients, whereas the segmentation model was trained on 7,796 cases of the computed tomography (CT) image dataset of 1,841 patients. The dataset was expanded incrementally through an active learning process. The performance of the model was evaluated by comparing the segmentation results with manual annotations by radiologists and the volumetric differences between the CT image datasets of the same patients. The results indicated that the machine learning model is promising in segmenting the pectoralis major muscle, with good agreement between the automatic segmentation and manual annotations by radiologists. The training accuracy and loss values of the validation set were 0.9954 and 0.0725, respectively, and for segmentation, the loss value was 0.0579. This study shows the potential clinical usefulness of the machine learning model for pectoralis major muscle segmentation as a quantitative biomarker for various parenchymal and muscular diseases.

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.

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.

Reference values of skeletal muscle area for diagnosis of sarcopenia using chest computed tomography in Asian general population

BACKGROUND

Diagnostic cutoff points for sarcopenia in chest computed tomography (CT) have not been established although CT is widely used for investigating skeletal muscles. This study aimed to determine reference values for sarcopenia of thoracic skeletal muscles acquired from chest CT scans and to analyse variables related to sarcopenia using the cutoff values determined in a general Asian population.

METHODS

We retrospectively reviewed chest CT scans of 4470 participants (mean age 54.8 ± 9.9 years, 65.8% male) performed at a check-up centre in South Korea (January 2016-August 2017). To determine cutoffs, 335 participants aged 19-39 years (mean age 35.2 ± 3.6 years, 75.2% male) were selected as the healthy and younger reference group, and 4135 participants aged ≥40 years (mean age 56.4 ± 8.4 years, 65.1% male) were selected as the study group. We measured the following: cross-sectional area (CSA) of the pectoralis, intercostalis, paraspinal, serratus, and latissimus muscles at the 4^th vertebral region (T4_CSA ); T4_CSA divided by height² (T4MI); pectoralis muscle area (PM_CSA ); and PM_CSA divided by height² (PMI) at the 4^th vertebral region. Sarcopenia cutoff was defined as sex-specific values of less than -2 SD below the mean from the reference group.

RESULTS

In the reference group, T4_CSA , T4MI, PM_CSA , and PMI cutoffs for sarcopenia were 100.06cm² , 33.69cm² /m² , 29.00cm² , and 10.17cm² /m² in male, and 66.93cm² , 26.01cm² /m² , 18.29cm² , and 7.31cm² /m² in female, respectively. The prevalence of sarcopenia in the study group measured with T4_CSA , T4MI, PM_CSA and PMI cutoffs were 11.4%, 8.7%, 8.5%, and 10.1%, respectively. Correlations were observed between appendicular skeletal mass divided by height² measured by bioelectrical impedance analysis (BIA) and T4_CSA (r = 0.82; P < 0.001)/T4MI (r = 0.68; P < 0.001), and ASM/height² measured by BIA and PM_CSA (r = 0.72; P < 0.001)/PMI (r = 0.63; P < 0.001). In the multivariate logistic regression models, sarcopenia defined by T4_CSA /T4MI were related to age [odds ratio (95% confidence interval), P-values: 1.09 (1.07-1.11), <0.001/1.05 (1.04-1.07), <0.001] and diabetes [1.60 (1.14-2.25), 0.007/1.47 (1.01-2.14), 0.043]. Sarcopenia defined by PM_CSA /PMI were related to age [1.09 (1.08-1.10), <0.001/1.05 (1.03-1.06), <0.001], male sex [0.23 (0.18-0.30), <0.001/0.47 (0.32-0.71), <0.001], diabetes [2.30 (1.73-3.05), <0.001/1.63 (1.15-2.32), 0.007], history of cancer [2.51 (1.78-3.55), <0.001/1.61 (1.04-2.48), 0.033], and sufficient physical activity [0.67 (0.50-0.89), 0.007/0.74 (0.56-0.99), 0.042].

CONCLUSIONS

The reference cutoff values of a general population reported here will enable sex-specific standardization of thoracic muscle mass quantification and sarcopenia assessment.

Validation for measurements of skeletal muscle areas using low-dose chest computed tomography

Various methods were suggested to measure skeletal muscle areas (SMAs) using chest low-dose computed tomography (chest LDCT) as a substitute for SMA at 3rd lumbar vertebra level (L3-SMA). In this study, four SMAs (L1-SMA, T12-erector spinae muscle areas, chest wall muscle area at carina level, pectoralis muscle area at aortic arch level) were segmented semi-automatically in 780 individuals taking concurrent chest and abdomen LDCT for healthcare screening. Four SMAs were compared to L3-SMA and annual changes were calculated from individuals with multiple examinations (n = 101). Skeletal muscle index (SMI; SMA/height²) cut-off for sarcopenia was determined by lower 5th percentile of young individuals (age ≤ 40 years). L1-SMA showed the greatest correlation to L3-SMA (men, R² = 0.7920; women, R² = 0.7396), and the smallest annual changes (0.3300 ± 4.7365%) among four SMAs. L1-SMI cut-offs for determining sarcopenia were 39.2cm²/m² in men, and 27.5cm²/m² in women. Forty-six men (9.5%) and ten women (3.4%) were found to have sarcopenia using L1-SMI cut-offs. In conclusion, L1-SMA could be a reasonable substitute for L3-SMA in chest LDCT. Suggested L1-SMI cut-offs for sarcopenia were 39.2cm²/m² for men and 27.5cm²/m² for women in Asian.

Thoracic skeletal muscle quantification using computed tomography and prognosis of elderly ICU patients

In elderly ICU patients, the prevalence of skeletal muscle loss is high. Longitudinal effect of thoracic muscles, especially in elderly ICU patients, are unclear although skeletal muscle loss is related with the short- and long-term outcomes. This study aimed to evaluate whether pectoralis muscle mass loss could be a predictor of prognosis in elderly ICU patients. We retrospectively evaluated 190 elderly (age > 70 years) patients admitted to the ICU. We measured the cross-sectional area (CSA) of the pectoralis muscle (PM_CSA) at the fourth vertebral region. CT scans within two days before ICU admission were used for analysis. Mortality, prolonged mechanical ventilation, and longitudinal changes in Sequential Organ Failure Assessment (SOFA) scores were examined. PM_CSA below median was significantly related with prolonged ventilation (odds ratio 2.92) and a higher SOFA scores during the ICU stay (estimated mean = 0.94). PM_CSA below median was a significant risk for hospital mortality (hazards ratio 2.06). In elderly ICU patients, a low ICU admission PM_CSA was associated with prolonged ventilation, higher SOFA score during the ICU stay, and higher mortality. Adding thoracic skeletal muscle CSA at the time of ICU admission into consideration in deciding the therapeutic intensity in elderly ICU patients may help in making medical decisions.

Association of Thoracic Computed Tomographic Measurements and Outcomes in Patients with Hematologic Malignancies Requiring Mechanical Ventilation

Rationale: Patients with hematologic malignancies requiring mechanical ventilation have historically experienced poor outcomes.Objectives: We aimed to determine whether body composition characteristics derived from thoracic computed tomographic (CT) imaging were associated with time to liberation from mechanical ventilation.Methods: We evaluated mechanically ventilated patients with hematological malignancies admitted between 2014 and 2018. We included patients with thoracic CT imaging completed between 1 month before and 48 hours after intensive care unit (ICU) admission. We assessed the association of carinal skeletal muscle cross-sectional area (CSA), subcutaneous fat CSA, and fat index (fat/skeletal muscle ratio) with time to liberation from mechanical ventilation within 28 days. We accounted for the competing event of death within 28 days of mechanical ventilation.Results: One hundred fifty-six patients were included; the mean age was 57 years (standard deviation 14) and 39% were female. Thirty-seven percent had received a hematopoietic stem cell transplant, and the median ratio of arterial oxygen tension/pressure to fraction of inspired oxygen was 134 mm Hg (interquartile range [IQR], 92-205). Median skeletal muscle CSA was 68 cm² (IQR, 54-88) and subcutaneous fat CSA was 38 cm² (IQR, 27-52). Forty-two percent of patients were liberated from mechanical ventilation within 28 days and 56% died in the ICU. Subcutaneous fat CSA (subdistribution hazard ratio [sHR], 0.81; 95% confidence interval [95% CI], -0.68 to 0.97) and fat index (sHR, 0.81; 95% CI, -0.68 to 0.97) were significantly associated with longer time to liberation from mechanical ventilation. Skeletal muscle CSA was not associated with time to liberation from ventilation (sHR, 1.08; 95% CI, -0.94 to 1.23).Conclusions: Body composition measurements based on thoracic CT scans were associated with time to liberation from ventilation. These could represent novel surrogate markers of physical frailty in patients with hematologic malignancies receiving mechanical ventilation.

Feasibility of assessment of skeletal muscle mass on a single cross-sectional image at the level of the fourth thoracic vertebra

BACKGROUND

Skeletal muscle mass (SMM) determined on computed tomography (CT) is emerging as a novel imaging biomarker. Cross-sectional area (CSA) of SMM at the level of the third lumbar vertebra (L3) on abdominal imaging is considered the clinical reference standard for measuring SMM. In certain patient groups, such as those with oncological or non-oncological lung disease like COVID-19, a chest CT may be available while an abdominal CT is not. The purpose of this study was to investigate whether determining SMM on a chest CT is a feasible alternative to abdominal CT.

RESEARCH QUESTION

What is the correlation between SMM measurements at the level of L3 and the level of the fourth thoracic vertebra (Th4)?

STUDY DESIGN AND METHODS

In this study we retrospectively analyzed abdominal and thoracic series of whole-body CT-scans of trauma patients (N = 47) and head and neck cancer patients (N = 194). All abdominal muscles were delineated on a single axial slice at the level of L3. The erector spinae, levator scapulae, rhomboideus minor and major and pectoralis minor and major muscles were delineated on a single axial slice at the level of Th4. CSA of the muscles at Th4 and the L3 level were compared using linear regression, and a multivariate linear regression model was established.

RESULTS

Muscle CSA at level Th4 strongly correlates with L3 muscle CSA (r = 0.791, p < 0.05). A multivariate model incorporating the patient characteristics arm positioning, age, sex, and weight achieved a stronger correlation (r = 0.856, p < 0.05).

INTERPRETATION

Skeletal muscle CSA measured at the level of Th4 is a feasible alternative to measurements at L3. This allows diagnosing low SMM using clinically available thoracic CT-scans. SMM measurements at the level of Th4 may become a prognostic or triage tool when faced with mechanical ventilator shortage.

Frailty and aging-associated syndromes in lung transplant candidates and recipients

Many lung transplant candidates and recipients are older and frailer compared to previous eras. Older patients are at increased risk for pre- and posttransplant mortality, but this risk is not explained by numerical age alone. This manuscript represents the product of the American Society of Transplantation (AST) conference on frailty. Experts in the field reviewed the latest published research on assessment of elderly and frail lung transplant candidates. Physical frailty, often defined as slowness, weakness, low physical activity, shrinking, and exhaustion, and frailty evaluation is an important tool for evaluation of age-associated dysfunction. Another approach is assessment by cumulative deficits, and both types of frailty are common in lung transplant candidates. Frailty is associated with death or delisting before transplant, and may be associated with posttransplant mortality. Sarcopenia, cognitive dysfunction, depression, and nutrition are other important components for patient evaluation. Aging-associated inflammation, telomere dysfunction, and adaptive immune system senescence may also contribute to frailty. Developing tools for frailty assessment and interventions holds promise for improving patient outcomes before and after lung transplantation.

Low Thoracic Skeletal Muscle Area Is Not Associated With Negative Outcomes in Patients With COVID-19

OBJECTIVE

Sarcopenia has been related to negative outcomes in different clinical scenarios from critical illness to chronic conditions. The aim of this study was to verify whether there was an association between low skeletal muscle index and in-hospital mortality, intensive care unit admission, and invasive mechanical ventilation need in hospitalized patients with COVID-19.

DESIGN

This was a retrospective cohort study of a referral center for COVID-19. We included all consecutive patients admitted to the hospital between February 26 and May 15, 2020, with a confirmed diagnosis of COVID-19. Skeletal muscle index was assessed from a transverse computed tomography image at the level of twelfth thoracic vertebra with National Institutes of Health ImageJ software, and statistical analysis was performed to find an association between skeletal muscle index and in-hospital mortality, need of invasive mechanical ventilation, and intensive care unit admission.

RESULTS

We included 519 patients, the median age was 51 (42-61) yrs, and 115 patients (22%) had low skeletal muscle index. On multivariable analysis, skeletal muscle index was not associated with mortality, intensive care unit admission, or invasive mechanical ventilation need nor in a subanalysis of patients 65 yrs or older.

CONCLUSIONS

Skeletal muscle index determined by computed tomography at the level of twelfth thoracic vertebra was not associated with negative outcomes in hospitalized patients with COVID-19.

The use of alternate vertebral levels to L3 in computed tomography scans for skeletal muscle mass evaluation and sarcopenia assessment in patients with cancer: a systematic review

Body composition measurement using diagnostic computed tomography (CT) scans has emerged as a method to assess sarcopenia (low muscle mass) in oncology patients. Assessment of skeletal muscle mass (SMM) using the cross-sectional area of a single vertebral slice (at lumbar L3) in a CT scan is correlated with whole-body skeletal muscle volume. This method is used to assess CT-defined sarcopenia in patients with cancer, with low SMM effecting outcomes. However, as diagnostic scans are based on tumour location, not all include L3. We evaluated the evidence for the use of alternate vertebral CT slices for SMM evaluation when L3 is not available. Five electronic databases were searched from January 1996 to April 2020 for studies using CT scan vertebral slices above L3 for SM measurement in adults with cancer (solid tumours). Validation with whole-body SMM, rationale for the chosen slice and sarcopenia cut-off values were investigated. Thirty-two studies were included, all retrospective and cross-sectional in design. Cervical, thoracic and lumbar slices were used (from C3 to L1), with no validation of whole-body SMM using CT scans. Alternate slices were used in lung, and head and neck cancer patients. Sarcopenia cut-off values were reported in 75 % of studies, with differing methods, with or without sex-specific values, and a lack of consensus. Current evidence is inadequate to provide definitive recommendations for alternate vertebral slice use for SMM evaluation in cancer patients. Variation in sarcopenia cut-offs warrants more robust investigation, in order for risk stratification to be applied to all patients with cancer.

Recovery of physical function in lung transplant recipients with sarcopenia

Background

Lung transplant (LTX) can provide a survival benefit and improve physical function for selected patients with advanced pulmonary disease. Sarcopenia is a systemic muscle-failure that can be found in a variety of life stages and disabilities. In this study, we follow the evolution of each variable defined in sarcopenia and the outcomes in LTX recipients with post-transplant sarcopenia.

Methods

Patients who underwent LTX at Tohoku University Hospital between 2013 and 2018 were consecutively included in the retrospective cohort study, with follow-up to 2019. Sarcopenia was defined by low muscle mass (the cross-sectional area (CSA) of erector spinae muscle (ESM) in thoracic CT with a threshold < 17.24 cm²/m²) and either low muscle strength (hand-grip with a threshold of < 26 kg in males and of < 18 kg in females) or physical performance (6-min walk distance with a threshold < 46.5% of predicted distance).

Results

Fifty-five recipients were included into the study, of whom 19 patients were defined as sarcopenic and 36 as non-sarcopenic. The muscle mass improved after transplant in both sarcopenic and non-sarcopenic individuals: the median ESM-CSA enlarged from 17.25 cm²/m² in 2 months post-LTX to 18.55 cm²/m² in 12 months (p < 0.001) and 17.63 cm²/m² in 36 months (p < 0.001) in non-sarcopenic individuals, while in sarcopenic patients it improved from 13.36 cm²/m² in 2 months to 16.31 cm²/m² in 12 months (p < 0.005) and 18.01 cm²/m² in 36 months (p < 0.001). The muscle mass in sarcopenia substantially recovered to close to non-sarcopenic conditions within 36-months (p < 0.001 in 2 months and p = 0.951 in 36 months). Accordingly, muscle strength and physical performance in both groups improved over time. No difference in survival was seen in both groups (Log-rank p = 0.096), and sarcopenia was not associated with an overall hazard of death (p = 0.147). There was no difference in the cumulative incidence of chronic lung allograft dysfunction between patients with or without sarcopenia (Log-rank p = 0.529).

Conclusions

Even patients with post-transplant sarcopenia have a chance to recover physical function to levels close to those without sarcopenia several years post LTX.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01442-5.

CLINICAL IMPLICATIONS OF BODY COMPOSITION AND EXERCISE CAPACITY FOLLOWING PULMONARY ENDARTERECTOMY

BACKGROUND

Pulmonary endarterectomy (PEA) is a curative procedure for patients with chronic thromboembolic pulmonary hypertension. Body composition and exercise capacity have been associated with adverse outcomes in patients undergoing cardiothoracic surgeries, but their significance with PEA is unclear. We evaluated the association of body composition and 6-minute walk distance (6MWD) with disease severity, hospital length of stay, discharge disposition and post-operative functional recovery.

METHODS

Retrospective, single-center cohort study of patients who underwent PEA (Jan/2014-Dec/2017). Body composition (skeletal muscle mass and adiposity cross sectional area, body mass index) was quantified using thoracic computed tomography with Slice-O-Matic software. Association of body composition measures and 6MWD with clinical outcomes was evaluated using multivariable regression models.

RESULTS

127 patients (58±14 years; 42% males, Body Mass Index: 31±7 kg/m², 6MWD: 361±165 m) were included. Muscle and 6MWD were associated with disease severity measures. Of those surviving hospitalization (n=125), a greater 6MWD was associated with a shorter hospital stay (1.9 median days per 100m, p<0.001) and higher likelihood of being discharged directly home from hospital (OR: 2.1 per 100m, p= 0.004), independent of age, sex and body mass index. Those with a lower pre-operative 6MWD (per 100m) had a greater increase in their post-operative 6MWD (52m, p< 0.0001), independent of age, sex, and body mass index. Body composition measures were not associated with hospital outcomes or exercise capacity in the first-year post-operatively.

CONCLUSIONS

Exercise capacity was a more prognositc marker of PEA outcomes compared to body composition. Future research is needed to explore pre-PEA rehabilitation strategies.

Cumulative Deficits Frailty Index Predicts Outcomes for Solid Organ Transplant Candidates

Supplemental Digital Content is available in the text.

Despite comprehensive multidisciplinary candidacy assessments to determine appropriateness for solid organ transplantation, limitations persist in identifying candidates at risk of adverse outcomes. Frailty measures may help inform candidacy evaluation. Our main objective was to create a solid organ transplant frailty index (FI), using the cumulative deficits model, from data routinely collected during candidacy assessments. Secondary objectives included creating a social vulnerability index (SVI) from assessment data and evaluating associations between the FI and assessment, waitlist, and posttransplant outcomes.

Chest computed tomography is a valid measure of body composition in individuals with advanced lung disease

There is growing interest in evaluating body composition using routine clinical computed tomography (CT) scans; however, the validity of this technique in lung transplant patients has not been described. The study objectives were to determine the reliability of measuring fat compartments from thoracic CT and evaluate the validity of muscle and fat cross-sectional area (CSA) from thoracic CT by comparing to bioelectrical impedance analysis (BIA). Thoracic CT scans from lung transplant assessments were obtained for analysis. Total thoracic muscle CSA, pectoral muscle CSA, subcutaneous adipose tissue (SAT), and mediastinal adipose tissue (MAT) were manually segmented by two independent raters. Reliability was analysed using intra-class correlation coefficient (ICC). Correlations were determined between CT measures with fat-free mass index (FFMI), body fat mass index (BFMI) and per cent body fat (%BF) from BIA; and anthropometrics [body mass index (BMI) and waist circumference (WC)]. High inter- and intra-rater reliability were found for SAT and MAT (ICCs = 0.99). Pectoral and total muscle CSA were correlated with FFMI (r = .41, p = .003 and r = .57, p < .001, respectively). SAT was associated with whole-body fat from BIA and with BMI and WC (r = .61 to .80, p < .001). MAT was associated with BMI (r = .58, p < .001) and WC (r = .61, p < .001). This study supports the reliability and validity of using thoracic CT to measure muscle and fat. Future studies are needed to investigate whether these CT-based measures are predictive of clinical and post-transplant outcomes in advanced lung disease.

Quantity and quality of antigravity muscles in patients undergoing living-donor lobar lung transplantation: 1-year longitudinal analysis using chest computed tomography images

Background

Skeletal muscle dysfunction is a common feature in patients with severe lung diseases. Although lung transplantation aims to save these patients, the surgical procedure and disuse may cause additional deterioration and prolonged functional disability. We investigated the postoperative course of antigravity muscle condition in terms of quantity and quality using chest computed tomography.

Methods

35 consecutive patients were investigated for 12 months after living-donor lobar lung transplantation (LDLLT). The erector spinae muscles (ESMs), which are antigravity muscles, were evaluated, and the cross-sectional area (ESM_CSA) and mean attenuation (ESM_CT) were analysed to determine the quantity and quality of ESMs. Functional capacity was evaluated by the 6-min walk distance (6MWD). Age-matched living donors with lower lobectomy were evaluated as controls.

Results

Recipient and donor ESM_CSA values temporarily decreased at 3 months and recovered by 12 months post-operatively. The ESM_CSA of recipients, but not that of donors, surpassed baseline values by 12 months post-operatively. Increased ESM_CSA (ratio to baseline ≥1) may occur at 12 months in patients with a high baseline ESM_CT. Although the recipient ESM_CT may continuously decrease for 12 months, the ESM_CT is a major determinant, in addition to lung function, of the postoperative 6MWD at both 3 and 12 months.

Conclusion

The quantity of ESMs may increase within 12 months after LDLLT in recipients with better muscle quality at baseline. The quality of ESMs is also important for physical performance; therefore, further approaches to prevent deterioration in muscle quality are required.

The quantity of antigravity muscles in patients undergoing lung transplantation (LTx) will increase within 1 year after LTx. The quality of muscles is important for increase of muscle quantity as well as physical performance.https://bit.ly/3bItfB9

Pectoralis muscle area is associated with bone mineral density and lung function in lung transplant candidates

Loss of bone mineral density and skeletal muscle area are linked in lung transplant patients. This loss is greater in patients with restrictive compared with obstructive lung diseases.

INTRODUCTION

Sarcopenia and osteoporosis are associated with aging and chronic illnesses and may be linked in patients with advanced lung disease. Pectoralis muscle index (PMI) quantitated on computed tomography (CT) of the chest can be used to measure skeletal muscle mass. This study aimed to determine the relationship of PMI to clinical parameters including bone mineral density (BMD) in candidates for lung transplantation.

METHODS

A retrospective review of transplant candidates at a single center was performed. Demographic, anthropomorphic, and clinical data were recorded. Pectoralis muscle area (PMA) was determined on an axial slice from a chest CT. PMI was calculated as the PMA divided by height squared. BMD was obtained from routine dual-energy X-ray absorptiometry (DXA) scan.

RESULTS

In 226 included patients, mean PMI was 8.2 ± 3.0 cm²/m² in males and 6.1 ± 2.1 cm²/m² in females. Osteopenia was present in 44.4%, and 23.2% of patients had osteoporosis. Patients with obstructive lung disease had lower body mass index (22.0 ± 4.9 versus 27.9 ± 4.9 kg/m², p < 0.001), PMI (6.0 ± 2.3 versus 8.2 ± 2.8 cm²/m², p < 0.001), and BMD (- 2.3 ± 1.1 versus - 1.3 ± 1.1, p < 0.001) compared with patients with restrictive lung disease. PMI was a significant predictor of BMD (β = 0.16, p < 0.001).

CONCLUSION

The association between muscle area and BMD in lung transplant candidates suggests that similar mechanisms may underlie the development of both. Differences in PMI and BMD in patients with obstructive versus restrictive lung disease may result from differences in respiratory physiology or disease processes.

Low thoracic muscle radiation attenuation is associated with postoperative pneumonia following partial hepatectomy for colorectal metastasis

BACKGROUND

Low skeletal muscle radiation attenuation (SM-RA) is indicative of myosteatosis and diminished muscle function. It is predictive of poor outcome following oncological surgery in several cancer types. Postoperative pneumonia is a known risk factor for increased postoperative mortality. We hypothesized that low SM-RA of the respiratory muscles at the 4th thoracic-vertebra (T4) is associated with postoperative pneumonia following liver surgery.

METHODS

Postoperative pneumonia was identified using prospective infection control data. Computed tomography body composition analysis was performed at the L3-and T4 level to determine SM-RA. Body composition variables were corrected for confounders and related to postoperative pneumonia and admission time by multivariable logistic regression.

RESULTS

Body composition analysis of 180 patients was performed. Twenty-one patients developed postoperative pneumonia (11.6%). Multivariable analysis showed that low T4 SM-RA as well as low L3 SM-RA were significantly associated with postoperative pneumonia (OR 3.65, 95% CI 1.41-9.49, p < 0.01) and (OR 3.22, 95% CI 1.20-8.61, p = 0.02, respectively).

CONCLUSION

Low SM-RA at either the L3-or T4-level is associated with a higher risk of postoperative pneumonia following CLRM resection.

An interdisciplinary approach to the older transplant patient: strategies for improving clinical outcomes

PURPOSE OF REVIEW

To describe the latest investigations into the role of frailty and assessment of other aging-related issues in the solid organ transplant candidate and recipient. This information is relevant for all involved in the care of transplant patients, but is especially relevant in infectious diseases, given the increased burden of infection seen in older and frailer patients.

RECENT FINDINGS

The Fried Frailty Phenotype (FFP) and Short Performance Physical Battery (SPPB) are well validated tools for measuring frailty in older adults. Recently, these frailty tools have also been used to predict a range of clinical outcomes in adults with endstage organ disease undergoing advanced therapies including mechanical circulatory device (MCSD) or transplantation including death on the waiting list, length of hospital stay, need for readmission, infection, and death. Frailty may also be estimated by chart review and comorbidity assessment. Other aging-related evaluations of interest are cognitive function, sarcopenia, and nutritional status. The strength of association for each tool varies by the type of end organ disease, although there are many findings in common across organ types.

SUMMARY

As trends in the aging of the population continue to impact transplant and MCSD candidates and recipients, it is increasingly important for providers to be cognizant of the methods for assessment of aging-associated dysfunction including frailty and sarcopenia.

A Comparison of Frailty Measures at Listing to Predict Outcomes After Lung Transplantation

BACKGROUND

Sarcopenia may be an important predictive factor of outcomes after lung transplantation (LTx). Serum albumin and the 6-minute walk distance (6MWD) have been shown to be a marker of LTx outcomes. We measured sarcopenia, albumin, and 6MWD in a cohort of LTx patients and analyzed the utility of these as markers of outcomes for LTx patients.

METHODS

We retrospectively identified LTx recipients from 2013-2018 at our institution who underwent computed tomographic imaging during their listing evaluation. From that image, we measured skeletal muscle cross-sectional surface area at the third lumbar vertebral level, and sarcopenia was diagnosed by established cutoffs. Associations between sarcopenia, albumin, 6MWD, and survival, and hospital length of stay, complications, readmissions, and discharge destination were evaluated.

RESULTS

Sarcopenia was found in 72% (95 of 132) of patients, 18% (24 of 131) of patients were hypoalbuminemic, and 41% had a low 6MWD. Survival was not associated with presence of sarcopenia (hazard ratio [HR], 1.06; 95% confidence interval [CI], 0.46-2.42) or low 6MWD (HR, 0.86; 95% CI, 0.410-1.83). Hospital length of stay, complications, readmissions, and discharge destination were not influenced by sarcopenia or 6MWD. In contrast, hypoalbuminemia was independently associated with decreased survival (HR, 2.25; 95% CI, 1.04-4.85) and a higher grade of postoperative complications (P = .04).

CONCLUSIONS

Sarcopenia is prevalent in LTx patients. Neither sarcopenia nor 6MWD predicted mortality or short-term outcomes after LTx. This is in contrast to albumin levels, which were inversely associated with survival and complications. Albumin shows promise as an important predictor of mortality and short-term outcomes after LTx.

Association of Chest CT-Based Quantitative Measures of Muscle and Fat with Post-Lung Transplant Survival and Morbidity: A Single Institutional Retrospective Cohort Study in Korean Population

OBJECTIVE

Abnormal body composition is an important modifiable risk factor in lung transplantation. Therefore, precise quantification of different body components, including muscle and fat, may play an important role in optimizing outcomes in lung transplant patients. The purpose of the study was to investigate the prognostic significance of muscle and subcutaneous fat mass measured on chest CT with regard to lung transplantation survival and other post-transplant outcomes.

MATERIALS AND METHODS

The study population included 45 consecutive adult lung transplant recipients (mean age of 47.9 ± 12.1 years; 31 males and 14 females) between 2011 and 2017. Preoperative cross-sectional areas of muscle and subcutaneous fat were semi-automatically measured on axial CT images at the level of the 12th thoracic vertebra (T12). Additional normalized indexed parameters, adjusted for either height or weight, were obtained. Associations of quantitative parameters with survival and various other post-transplant outcomes were evaluated.

RESULTS

Of the 45 patients included in the present study, 10 mortalities were observed during the follow-up period. Patients with relative sarcopenia (RS) classified based on height-adjusted muscle area with a cut-off value of 28.07 cm²/m² demonstrated worse postoperative survival (log-rank test, p = 0.007; hazard ratio [HR], 6.39:1) despite being adjusted for age, sex, and body mass index (HR, 8.58:1; p = 0.022). Weight-adjusted parameters of muscle area were negatively correlated with duration of ventilator support (R = -0.54, p < 0.001) and intensive care unit (ICU) stay (R = -0.33, p = 0.021).

CONCLUSION

Patients with RS demonstrate worse survival after lung transplantation that those without RS. Additionally, quantitative parameters of muscles measured at the T12 level on chest CT were associated with the duration of post-lung transplant ventilator support and duration of stay in the ICU.

Nutrition-related factors associated with waiting list mortality in patients with interstitial lung disease: A retrospective cohort study

Japanese patients with interstitial lung disease (ILD) sometimes die waiting for lung transplantation (LTx) because it takes about 2 years to receive it in Japan. We evaluated nutrition-related factors associated with waiting list mortality. Seventy-six ILD patients were hospitalized in Kyoto University Hospital at registration for LTx from 2013 to 2015. Among them, 40 patients were included and analyzed. Patient background was as follows: female, 30%; age, 50.3 ± 6.9 years; body mass index, 21.1 ± 4.0 kg/m² ; 6-minute walk distance (6MWD), 356 ± 172 m; serum albumin, 3.8 ± 0.4 g/dL; serum transthyretin (TTR), 25.3 ± 7.5 mg/dL; and C-reactive protein, 0.5 ± 0.5 mg/dL. Median observational period was 497 (range 97-1015) days, and median survival time was 550 (95% CI 414-686) days. Survival rate was 47.5%, and mortality rate was 38.7/100 person-years. Cox analyses showed that TTR (HR 0.791, 95% CI 0.633-0.988) and 6MWD (HR 0.795, 95% CI 0.674-0.938) were independently correlated with mortality and were influenced by body fat mass and leg skeletal muscle mass, respectively. It is suggested that nutritional markers and exercise capacity are important prognostic markers in waitlisted patients, but further study is needed to determine whether nutritional intervention or exercise can change outcomes.

Frailty assessment: from clinical to radiological tools

Frailty is a syndrome of cumulative decline across multiple physiological systems, which predisposes vulnerable adults to adverse events. Assessing vulnerable patients can potentially lead to interventions that improve surgical outcomes. Anaesthesiologists who care for older patients can identify frailty to improve preoperative risk stratification and subsequent perioperative planning. Numerous clinical tools to diagnose frailty exist, but none has emerged as the standard tool to be used in clinical practice. Radiological modalities, such as computed tomography and ultrasonography, are widely performed before surgery, and are therefore available to be used opportunistically to objectively evaluate surrogate markers of frailty. This review presents the importance of frailty assessment by anaesthesiologists; lists common clinical tools that have been applied; and proposes that utilising radiological imaging as an objective surrogate measure of frailty is a novel, expanding approach for which anaesthesiologists can significantly contribute to broad implementation.

Report from the American Society of Transplantation on frailty in solid organ transplantation

A consensus conference on frailty in kidney, liver, heart, and lung transplantation sponsored by the American Society of Transplantation (AST) and endorsed by the American Society of Nephrology (ASN), the American Society of Transplant Surgeons (ASTS), and the Canadian Society of Transplantation (CST) took place on February 11, 2018 in Phoenix, Arizona. Input from the transplant community through scheduled conference calls enabled wide discussion of current concepts in frailty, exploration of best practices for frailty risk assessment of transplant candidates and for management after transplant, and development of ideas for future research. A current understanding of frailty was compiled by each of the solid organ groups and is presented in this paper. Frailty is a common entity in patients with end-stage organ disease who are awaiting organ transplantation, and affects mortality on the waitlist and in the posttransplant period. The optimal methods by which frailty should be measured in each organ group are yet to be determined, but studies are underway. Interventions to reverse frailty vary among organ groups and appear promising. This conference achieved its intent to highlight the importance of frailty in organ transplantation and to plant the seeds for further discussion and research in this field.

Thoracic skeletal muscle quantification: low muscle mass is related with worse prognosis in idiopathic pulmonary fibrosis patients

BACKGROUND

Sarcopenia can contribute to negative outcomes in patients with various lung diseases. However, whether sarcopenia affects prognosis in patients with idiopathic pulmonary fibrosis (IPF) has not been reported. Simple measures of muscle mass, derived from chest computed tomography (CT), are increasingly being used to identify patients with sarcopenia. We hypothesized that skeletal muscle mass could be a predictor of prognosis in IPF patients.

METHODS

We retrospectively evaluated 180 patients diagnosed with IPF between January 2010 and December 2015 at a tertiary care hospital in South Korea. We measured thoracic muscle volume by using the cross-sectional area (CSA) of the pectoralis, paraspinal, serratus, and latissimus muscles at the 4th vertebral region (T4_CSA) and the erector spinae muscle (ESM_CSA) at the 12th vertebral region. CT scans at the time of diagnosis were used for analysis and respective CSA were divided by height squared to normalize for stature. Survival times were estimated with the Kaplan-Meier method and compared with the log-rank test. Multivariate Cox proportional hazards models were performed to investigate relationships between clinical parameters and mortality.

RESULTS

Male patients in the lowest quartile of T4_CSA divided by height squared (m²) (T4MI) and in the lowest quartile of ESM_CSA divided by height squared (m²) (T12MI) were more likely to have higher Gender-Age-Physiology Index scores (T4MI, 3.3 ± 1.3 vs 4.0 ± 1.6, P = 0.012; T12MI, 3.2 ± 1.3 vs 4.1 ± 1.6, P = 0.002). Male patients in the lowest quartile of T4MI exhibited a significantly lower survival rate (P = 0.035). After multivariate Cox proportional hazards analysis, T4MI was a significant risk factor for all-cause mortality (HR, 0.955; 95% CI, 0.913-0.998; P = 0.041), whereas T12MI was not (HR, 0.980; 95% CI, 0.856-1.121; P = 0.766).

CONCLUSIONS

Low skeletal mass normalized for stature at the level of 4th vertebrae which can be acquired by quantifying thoracic skeletal muscle on single-slice axial chest CT, may be a strong risk factor for all-cause mortality in patients with IPF.

TRIAL REGISTRATION

The research protocol was approved by the Institutional Review Board of Severance Hospital, South Korea (IRB No.4-2018-0454).

Frailty and clinical benefits with lung transplantation

BACKGROUND

The Fried frailty phenotype is associated with morbidity and mortality in lung transplant (LTx) candidates, but its clinical application and association with post-transplant outcomes are not well defined. We assessed 2 alternate frailty indices in LTx candidates and evaluated associations of frailty with early post-transplant outcomes and 1-year mortality.

METHODS

Frailty was prospectively evaluated in 50 LTx candidates using the Fried and 2 alternate phenotypic indices, one using variables readily available to clinicians and one using variables from an existing data set. Agreement between indices and associations with related measures were assessed to establish validity. The data set index was then applied retrospectively to 221 LTx patients. Post-transplant outcomes were compared between frail and non-frail patients using t-tests and multivariable regression analysis.

RESULTS

Frailty prevalence among the 3 indices was 26% to 30%, and the κ agreement was 0.38 to 0.41. All indices had moderate correlations with London Chest Activity of Daily Living (r = 0.48-0.62) and Short-Physical Performance Battery (r = -0.43 to -0.52). In the retrospective cohort, frail LTx candidates had a worse St. George's Respiratory Questionnaire total score (73 ± 12vs 62 ± 12, p < 0.001). Frail candidates had a larger improvement with transplant in the St. George's Respiratory Questionnaire (-52 ± 19vs -43 ± 18, p = 0.002) and 6-minute walk distance (191 ± 119vs 129 ± 94m, p = 0.001). Frailty was not associated with hospital length of stay or 1-year mortality.

CONCLUSIONS

There was good construct validity and acceptable agreement among the frailty indices. Despite significant disability pre-transplant, frail LTx candidates derived significant benefit with transplantation.

The sarcopenia index: A novel measure of muscle mass in lung transplant candidates

BACKGROUND

Frailty, including low muscle mass, is an emerging risk factor for poor outcomes after lung transplant. The sarcopenia index (SI)-(serum creatinine value/cystatin C value) × 100-is a novel blood test to approximate muscle mass. We sought to validate SI among lung transplant patients.

METHODS

We retrospectively identified adult lung transplant recipients from 2000 through 2012 at our institution who underwent computed tomography within 1 year before transplant and had preserved blood samples. Creatinine and cystatin C values were measured using the samples and used to calculate SI. Muscle mass was estimated by computed tomographic measurement of skeletal muscle cross-sectional surface area (SA) at the L1 to L3 vertebral levels. Correlation between SI and SA was evaluated.

RESULTS

Of 28 patients meeting eligibility criteria, most were white (96%) and men (54%). Median (interquartile range) body mass index, SI, and SA were 25.9 (22-30) kg/m² , 106 (91-119), and 157 (113-195) cm2, respectively. The Pearson correlation coefficient between SI and SA was significant at L2 (0.43; P = .02) and L3 (0.41; P = .03).

CONCLUSION

Sarcopenia index is a potentially objective measure for estimating muscle mass that is noninvasive and less expensive. Sarcopenia index could be considered in lung transplant candidate selection following prospective validation in larger cohorts.

Timing and Amount of Physical Therapy Treatment are Associated with Length of Stay in the Cardiothoracic ICU

Significant variability exists in physical therapy early mobilization practice. The frequency of physical therapy or early mobilization of patients in the cardiothoracic intensive care unit and its effect on length of stay has not been investigated. The goal of our research was to examine variables that influence physical therapy evaluation and treatment in the intensive care unit using a retrospective chart review. Patients (n = 2568) were categorized and compared based on the most common diagnoses or surgical procedures. Multivariate semi-logarithmic regression analyses were used to determine correlations. Differences among patient subgroups for all independent variables other than age and for length of stay were found. The regression model determined that time to first physical therapy evaluation, Charlson Comorbidity Index score, mean days of physical therapy treatment and mechanical ventilation were associated with increased hospital length of stay. Time to first physical therapy evaluation in the intensive care unit and the hospital, and mean days of physical therapy treatment associated with hospital length of stay. Further prospective study is required to determine whether shortening time to physical therapy evaluation and treatment in a cardiothoracic intensive care unit could influence length of stay.