Computed tomography-derived skeletal muscle index: A novel predictor of frailty and hospital length of stay after transcatheter aortic valve replacement

Sarcopenia and frailty in patients undergoing transcatheter aortic valve replacement

BACKGROUND

Skeletal muscle mass (SMM) plays a crucial role in risk assessment in transcatheter aortic valve replacement (TAVR) candidates, yet it remains underutilized. Traditional methods focus on weakness or performance but omit SMM. This study compared traditional and novel markers of sarcopenia and frailty in terms of their ability to predict adverse outcomes post-TAVR.

METHODS

Three risk models were evaluated for the composite outcome of perioperative complications, 1-year rehospitalization, or 1-year mortality: (1) sarcopenia by combining low muscle mass (LMM) and weakness/performance assessed by hand grip strength or gait speed; (2) frailty by an Adapted Green score; and (3) frailty by the Green-SMI score incorporating LMM by multilevel opportunistic pre-TAVR thoracic CT segmentation.

RESULTS

In this study we included 184 eligible patients from January to December of 2018, (96.7%) of which were balloon expandable valves. The three risk models identified 22.8% patients as sarcopenic, 63.6% as frail by the Adapted Green score, and 53.8% as frail by the Green-SMI score. There were higher rates of the composite outcome in patients with sarcopenia (54.8%) and frailty (41.9% with the Adapted Green and 50.5% with the Green-SMI score) compared to their nonsarcopenic (30.3%) and nonfrail counterparts (25.4% with the Adapted Green and 18.8% with the Green-SMI score). Sarcopenia and frailty by Green-SMI, but not by the Adapted Green, were associated with higher risks of the composite outcome on multivariable adjustment (HR 2.2 [95% CI: 1.25-4.02], P = .007 and HR 3.4 [95% CI: 1.75-6.65], P < .001, respectively).

CONCLUSIONS

The integration of preoperative CT-based SMM to a frailty score significantly improves the prediction of adverse outcomes in patients undergoing TAVR.

Sarcopenia and adipose tissue evaluation by artificial intelligence predicts the overall survival after TAVI

Sarcopenia is a serious systemic disease that reduces overall survival. TAVI is selectively performed in patients with severe aortic stenosis who are not indicated for open cardiac surgery due to severe polymorbidity. Artificial intelligence-assisted body composition assessment from available CT scans appears to be a simple tool to stratify these patients into low and high risk based on future estimates of all-cause mortality. Within our study, the segmentation of preprocedural CT scans at the level of the lumbar third vertebra in patients undergoing TAVI was performed using a neural network (AutoMATiCA). The obtained parameters (area and density of skeletal muscles and intramuscular, visceral, and subcutaneous adipose tissue) were analyzed using Cox univariate and multivariable models for continuous and categorical variables to assess the relation of selected variables with all-cause mortality. 866 patients were included (median(interquartile range)): age 79.7 (74.9-83.3) years; BMI 28.9 (25.9-32.6) kg/m2. Survival analysis was performed on all automatically obtained parameters of muscle and fat density and area. Skeletal muscle index (SMI in cm2/m2), visceral (VAT in HU) and subcutaneous adipose tissue (SAT in HU) density predicted the all-cause mortality in patients after TAVI expressed as hazard ratio (HR) with 95% confidence interval (CI): SMI HR 0.986, 95% CI (0.975-0.996); VAT 1.015 (1.002-1.028) and SAT 1.014 (1.004-1.023), all p < 0.05. Automatic body composition assessment can estimate higher all-cause mortality risk in patients after TAVI, which may be useful in preoperative clinical reasoning and stratification of patients.

Prognostic value of sarcopenia in older adults with transcatheter aortic valve implantation: A systematic review and meta-analysis

OBJECTIVE

We conducted this systematic review and meta-analysis to summarize the prevalence of sarcopenia and its impact on mortality in patients undergoing TAVI.

METHOD

Medline, EMBASE, and PubMed were searched from inception to October 14, 2022 to retrieve eligible studies that assessed sarcopenia in patients undergoing TAVI. Pooled sarcopenia prevalence was calculated with 95% confidence interval (CI), and heterogeneity was estimated using the I2 test. Associations of sarcopenia with mortality of post-TAVI were expressed as hazard ratio (HR) or odds ratios (OR) and 95% CI.

RESULTS

13 studies involving 5248 patients (mean age from 78.1 to 84.9 years) undergoing TAVI were included. There were eleven studies defined sarcopenia based on loss of skeletal muscle mass index (SMI), while only two studies used low muscle mass plus low muscle strength and/or low physical performance. Overall, the pooled prevalence of sarcopenia in patients undergoing TAVI was 49% (95% CI 41%-58%). Sarcopenia was associated with an increased risk of long-term (≥1 year) mortality in patients after TAVI (HR 1.57, 95% CI 1.33-1.85, P < 0.001), with similar findings in the subgroups stratified by follow-up time, definition of sarcopenia, study location, and study design. Furthermore, the 1-, 2-, and 3-year cumulative probabilities of survival in patients with sarcopenia were significantly lower than non-sarcopenia (74.0% vs 91.0%, 68.3% vs 78.0%, and 72.6% vs 79.8%, all P < 0.05).

CONCLUSIONS

Although there are substantial differences in diagnostic criteria, sarcopenia is highly prevalent in patients undergoing TAVI and its linked to increased long-term mortality after TAVI.

The association between skeletal muscle mass index (SMI) and survival after gastrectomy: A systematic review and meta-analysis of cohort studies

OBJECTIVE

Low skeletal muscle mass index (SMI) is frequently identified in gastric cancer patients but its association with patient survival rate is not clear. This systematic review and meta-analysis aimed to clarify the association between SMI and overall survival in gastric cancer patients after gastrectomy.

METHODS

PubMed, Scopus, and Web of Science were searched from database inception until July 2021. Studies were eligible if they included gastric cancer patients, measured the SMI level, reported SMI before gastrectomy, defined sarcopenia according to SMI, and had a cohort or case-control design. Primary outcome was cancer survival rate. The risk of bias of individual studies was assessed using the Newcastle - Ottawa Scale.

RESULTS

Overall, 22 cohort studies including 7,203 participants were included. The quality of the included studies was moderate to high. A higher overall survival rate was associated with a higher SMI (RR = 1.62, 95% CI: 1.42-1.85). Subgroup analysis suggested a stronger association in overweight or obese patients (RR = 2.39, 95% CI: 1.13-5.09; I2 = 77%; heterogeneity P < 0.01). But no significant differences in the association based on the surgery type (curative surgery vs radical surgery) or the type of gastrectomy (total gastrectomy vs sub-total gastrectomy) were observed.

CONCLUSIONS

It is suggested that SMI can be a prognostic indicator for overall survival in gastric cancer patients, especially in overweight and obese patients.

Critically ill patients with acute kidney injury: clinical determinants and post-mortem histology

Background

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) in the intensive care unit (ICU) portends a poor prognosis. We aimed to better characterize predictors of survival and the mechanism of kidney failure in these patients.

Methods

This was a retrospective observational study using clinical and radiological electronic health records, analysed by univariable and multivariable binary logistic regression. Histopathological examination of post-mortem renal tissue was performed.

Results

Among 157 patients with AKI requiring RRT, higher serum creatinine at RRT initiation associated with increased ICU survival [odds ratio (OR) 0.33, 95% confidence interval (CI) 0.17-0.62, P = .001]; however, muscle mass (a marker of frailty) interacted with creatinine (P = .02) and superseded creatinine as a predictor of survival (OR 0.26, 95% CI 0.08-0.82; P = .02). Achieving lower cumulative fluid balance (mL/kg) predicted ICU survival (OR 1.01, 95% CI 1.00-1.01, P < .001), as supported by sensitivity analyses showing improved ICU survival with the use of furosemide (OR 0.40, 95% CI 0.18-0.87, P = .02) and increasing net ultrafiltration (OR 0.97, 95% CI 0.95-0.99, P = .02). A urine output of >500 mL/24 h strongly predicted successful liberation from RRT (OR 0.125, 95% CI 0.05-0.35, P < .001). Post-mortem reports were available for 32 patients; clinically unrecognized renal findings were described in 6 patients, 1 of whom had interstitial nephritis. Experimental staining of renal tissue from patients with sepsis-associated AKI (S-AKI) showed glomerular loss of synaptopodin (P = .02).

Conclusions

Confounding of creatinine by muscle mass undermines its use as a marker of AKI severity in clinical studies. Volume management and urine output are key determinants of outcome. Loss of synaptopodin implicates glomerular injury in the pathogenesis of S-AKI.

CT-derived psoas muscle area and density are associated with length of stay and discharge disposition after liver transplantation

BACKGROUND & AIMS

Prolonged length of stay (LOS) and discharge disposition following liver transplantation are associated with postoperative complications and increased healthcare utilization. This study evaluated the relationship between CT-derived psoas muscle measurements and hospital LOS, intensive care unit (ICU) LOS, and discharge disposition after liver transplant. The psoas muscle was chosen given its ease of measurement with any radiological software. A secondary analysis assessed the relationship between the American Society for Parenteral and Enteral Nutrition and the Academy of Nutrition and Dietetics (ASPEN/AND) malnutrition diagnosis criteria and CT-derived psoas muscle measures.

METHODS

CT-derived measures of psoas muscle density (mHU) and cross-sectional area at the level of the third lumbar vertebrae were obtained from preoperative CT scans of liver transplant recipients. Cross-sectional area measures were corrected for body size to generate a psoas area index variable (cm²/m²; PAI).

RESULTS

Each 1-unit increase in PAI was associated with a reduced hospital LOS of 4 days (R² = 0.07). Each 5-unit increase in mean Hounsfield units (mHU) was associated with a reduced hospital and ICU LOS of 5 and 1.6 days, respectively (R² = 0.22 and 0.14, respectively). Mean PAI and mHU were higher in patients who discharged to home. PAI was reasonably identified through ASPEN/AND malnutrition criteria, but there was no difference in mHU between those with and without malnutrition.

CONCLUSION

Measures of psoas density were associated with both hospital and ICU LOS and discharge disposition. PAI was associated with hospital LOS and discharge disposition. CT-derived measures of psoas density may be a valuable complement to preoperative liver transplant nutrition assessment using traditional ASPEN/AND malnutrition criteria.

Sarcopenia and Cardiovascular Diseases

Sarcopenia is the loss of muscle strength, mass, and function, which is often exacerbated by chronic comorbidities including cardiovascular diseases, chronic kidney disease, and cancer. Sarcopenia is associated with faster progression of cardiovascular diseases and higher risk of mortality, falls, and reduced quality of life, particularly among older adults. Although the pathophysiologic mechanisms are complex, the broad underlying cause of sarcopenia includes an imbalance between anabolic and catabolic muscle homeostasis with or without neuronal degeneration. The intrinsic molecular mechanisms of aging, chronic illness, malnutrition, and immobility are associated with the development of sarcopenia. Screening and testing for sarcopenia may be particularly important among those with chronic disease states. Early recognition of sarcopenia is important because it can provide an opportunity for interventions to reverse or delay the progression of muscle disorder, which may ultimately impact cardiovascular outcomes. Relying on body mass index is not useful for screening because many patients will have sarcopenic obesity, a particularly important phenotype among older cardiac patients. In this review, we aimed to: (1) provide a definition of sarcopenia within the context of muscle wasting disorders; (2) summarize the associations between sarcopenia and different cardiovascular diseases; (3) highlight an approach for a diagnostic evaluation; (4) discuss management strategies for sarcopenia; and (5) outline key gaps in knowledge with implications for the future of the field.

The Multidisciplinary Heart Team in Cardiovascular Medicine: Current Role and Future Challenges

Cardiovascular multidisciplinary heart teams (MDHTs) have evolved significantly over the past decade. These teams play a central role in the treatment of a wide array of cardiovascular diseases affecting interventional cardiology, cardiac surgery, interventional imaging, advanced heart failure, adult congenital heart disease, cardio-oncology, and cardio-obstetrics. To meet the specific needs of both patients and heart programs, the composition and function of cardiovascular MDHTs have had to adapt and evolve. Although lessons have been learned from multidisciplinary cancer care, best practices for the operation of cardiovascular MDHTs have yet to be defined, and the evidence base supporting their effectiveness is limited. This expert panel review discusses the history and evolution of cardiovascular MDHTs, their composition and role in treating patients across a broad spectrum of disciplines, basic tenets for successful operation, and the future challenges facing them.

Determination of Low Muscle Mass by Muscle Surface Index of the First Lumbar Vertebra Using Low-Dose Computed Tomography

The muscle index of the first vertebra (L1MI) derived from computed tomography (CT) is an indicator of total skeletal muscle mass. Nevertheless, the cutoff value and utility of L1MI derived from low-dose chest CT (LDCT) remain unclear. Adults who received LDCT for health check-ups in 2017 were enrolled. The cutoff values of L1MI were established in subjects aged 20-60 years. The cutoff values were used in chronic obstructive pulmonary disease (COPD) patients to determine muscle quantity. A total of 1780 healthy subjects were enrolled. Subjects (n = 1393) aged 20-60 years were defined as the reference group. The sex-specific cutoff values of L1MI were 26.2 cm²/m² for males and 20.9 cm²/m² for females. Six subjects in the COPD group (6/44, 13.6%) had low L1MI. COPD subjects with low L1MI had lower forced expiratory volume in one second (0.81 ± 0.17 vs. 1.30 ± 0.55 L/s, p = 0.046) and higher COPD assessment test scores (19.5 ± 2.6 vs. 15.0 ± 4.9, p = 0.015) than those with normal L1MI. In conclusion, LDCT in health assessments may provide additional information on sarcopenia.

Muscle fat index is associated with frailty and length of hospital stay following transcatheter aortic valve replacement in high-risk patients

BACKGROUND

Aging is associated with progressive loss of muscle mass, as well as replacement of muscle with fat and fibrous tissue. We studied the contribution of muscle fat content, a surrogate marker of biological aging, to frailty and Length of Hospital Stay (LOS) following Transcatheter Aortic Valve Replacement (TAVR).

METHODS

We evaluated 415 patients who underwent TAVR from February 2012 to December 2016 at Mayo Clinic, MN, USA. Densities between -190 to -30 Hounsfield Units within the abdominal muscle area were determined as muscle fat. Muscle Fat Index (MFI) was defined as muscle fat mass divided by height squared. LOS was considered as the primary outcome. Stepwise multivariable linear regression was used to identify the predictors of LOS.

RESULTS

Mean age ± SD of the study population was 81.2 ± 9.6 years and 58.07% were male. Seventy-two patients (17.35%) had frailty. Median (IQR) LOS was 4 (3-6) days. MFI was higher in patients with frailty (median (IQR); 18.1 [13.8-24.2] vs 14.4 [10.6-18.7], p < 0.001) and was positively correlated with LOS (r = 0.129, p = 0.009). In multivariable analysis of predictors of LOS, MFI (β = 0.06, p = 0.022), pre-TAVR atrial fibrillation/flutter (β = 0.5, p = 0.015), and post-TAVR complications (β = 0.91, p < 0.001) were directly, and femoral access route (β = -1.13, p < 0.001) and pre-TAVR hemoglobin (β = -0.35, p = 0.002) were inversely associated with LOS.

CONCLUSIONS

MFI can be determined from pre-TAVR CT scans and is a novel predictor of LOS following TAVR. This objective indicator can potentially be used in a pre-TAVR clinic to plan for rehabilitation programs in selected patients.

Impact of Severe Sarcopenia on Rehospitalization and Survival One Year After a TAVR Procedure in Patients Aged 75 and Older

BACKGROUND

Transcatheter aortic-valve replacement (TAVR) reduces mortality and improves quality of life in patients with severe aortic valve stenosis. One third of patients have no benefit one year after TAVR. Sarcopenia, an age-related loss of skeletal muscle mass, is associated with increased physical disability and mortality. The main purpose was to evaluate the impact of severe sarcopenia on rehospitalization one year after TAVR in older patients.

METHODS

All patients aged ≥75 referred for a TAVR in 2018 were included. Severe sarcopenia was defined by a loss of skeletal muscle mass defined on CT-scan measurement associated with a gait speed ≤0.8m/s. The main outcome was rehospitalization one year after TAVR.

RESULTS

Median age of the 182 included patients was 84, and 35% had an unplanned hospitalization at one year. Severe sarcopenia was diagnosed in 9 patients (4.9%). Univariable analysis showed that gait speed was a factor associated with readmission [HR=0.32, 95% CI (0.10-0.97), p=0.04] but not severe sarcopenia. In multivariable analysis, only diabetes was significantly associated with rehospitalization [HR=2.06, 95% CI (1.11-3.84), p=0.02]. Prevalence of severe sarcopenia varied according to different thresholds of skeletal muscle mass on CT-scan.

CONCLUSION

Even though severe sarcopenia was not correlated with rehospitalization and mortality at one year after TAVR, our results emphasize the changes in the prevalence according to cutoff used. It highlights the need to define standardized methods and international threshold for sarcopenia diagnosis by CT-scan measurements, in general population and for patients with valvular heart disease.

Frailty in patients with aortic stenosis awaiting intervention

Aortic stenosis (AS) is a common valvular disease in older age. Definitive interventions include surgical aortic valve replacement or transcatheter aortic valve implantation (TAVI). In high-risk patients, frailty is observed in up to 50% awaiting TAVI. Frailty is now an established predictor of outcomes in patients with AS who undergo intervention. There is currently no consensus definition for frailty. It is widely described as a syndrome of loss in physiological reserve predisposing to increased vulnerability for death or dependency. Frailty encompasses a holistic view including domains of physical function, cognition, depression, nutrition and medical comorbidities. Individual components of frailty have been shown to significantly predict mortality, functional recovery and quality of life after TAVI. The addition of frailty components to conventional risk prediction models traditionally used in cardiac surgery has been shown to augment overall prediction for post-operative mortality and morbidity. Identifying patients who are frail at baseline provides an opportunity to modify dynamic aspects of frailty prior to, and after definitive intervention for AS. A multidisciplinary approach including comprehensive geriatric pre-operative assessment will likely become standard of care to identify and optimise frail patients awaiting TAVI. In this review, we discuss the definition and measurement of frailty in patients with AS, evaluate recent data on risk prediction associated with frailty, and outline approaches to optimisation of dynamic components of frailty to improve outcomes after AS intervention.

Prognostic Value of Baseline Sarcopenia on 1-year Mortality in Patients Undergoing Transcatheter Aortic Valve Implantation

There is limited data regarding the association between sarcopenia and clinical outcomes in patients who underwent transcatheter aortic valve implantation (TAVI). From the prospective ASAN-TAVI registry, we evaluated a total of 522 patients with severe aortic stenosis who underwent TAVI between March 2010 and November 2018. Routine pre-TAVI computed tomography scan was used to calculate the skeletal muscle index (SMI), which was defined as skeletal muscle area at the L3 level divided by height squared; subject patients were classified into the gender-specific tertile groups of SMI. The patients' mean age was 79 years and 49% were men. Mean SMI values were 41.3 ± 6.7 cm²/m² in men and 34.1 ± 6.5 cm²/m² in women. The Kaplan-Meier estimates of all-cause mortality at 12 months were higher in the low-tertile group than in the mid- and high-tertile groups (15.5%, 7.1%, and 6.2%, respectively; p = 0.036). In multivariate analysis, low-tertile of SMI was an independent predictor of mortality (vs high-tertile of SMI, hazard ratio 2.69; 95% confidence interval, 1.18 to 6.12; p = 0.019). The all-cause mortality was substantially higher in the groups with high-surgical risk plus low SMI tertile. The risk assessment with addition of SMI on conventional STS-PROM score was significantly improved by statistical measures of model reclassification and discrimination. In patients who underwent TAVI, sarcopenia measured by SMI was significantly associated with an increased risk of 1-year mortality. The prognostic impact of SMI-measured sarcopenia was more prominent in patients with high surgical risks.

Sarcopenia in Patients Undergoing Transcatheter Aortic Valve Implantation (TAVI): A Systematic Review of the Literature

BACKGROUND

In older patients, sarcopenia is a prevalent disease associated with negative outcomes. Sarcopenia has been investigated in patients undergoing transcatheter aortic valve implantation (TAVI), but the criteria for diagnosis of the disease are heterogeneous. This systematic review of the current literature aims to evaluate the prevalence of sarcopenia in patients undergoing TAVI and to analyse the impact of sarcopenia on clinical outcomes.

METHODS

A comprehensive search of the literature has been performed in electronic databases from the date of initiation until March 2020. Using a pre-defined search strategy, we identified studies assessing skeletal muscle mass, muscle quality and muscle function as measures for sarcopenia in patients undergoing TAVI. We evaluated how sarcopenia affects the outcomes mortality at ≥1 year, prolonged length of hospital stay, and functional decline.

RESULTS

We identified 18 observational studies, enrolling a total number of 9'513 patients. For assessment of skeletal muscle mass, all included studies used data from computed tomography. Cut-off points for definition of low muscle mass were heterogeneous, and prevalence of sarcopenia varied between 21.0% and 70.2%. In uni- or multivariate regression analysis of different studies, low muscle mass was found to be a significant predictor of mortality, prolonged length of hospital stay, and functional decline. No interventional study was identified measuring the effect of nutritional or physiotherapy interventions on sarcopenia in TAVI patients.

CONCLUSIONS

Sarcopenia is highly prevalent among patients undergoing TAVI, and negatively affects important outcomes. Early diagnosis of this condition might allow a timely start of nutritional and physiotherapy interventions to prevent negative outcomes in TAVI patients.

The Utility of Psoas Muscle Assessment in Predicting Frailty in Patients Undergoing Transcatheter Aortic Valve Replacement

Background

The rise in an ageing population has resulted in an increase in the prevalence of aortic stenosis. With the advent and rapid expansion in the use of transcatheter aortic valve replacements (TAVRs), patients with severe aortic stenosis, traditionally thought too high risk for surgical intervention, are now being treated with generally favourable results. Frailty is an important factor in determining outcome after a TAVR, and an assessment of frailty is fundamental in the identification of appropriate patients to treat.

Objective

The objective of the study was to identify if the psoas muscle area is associated with frailty in TAVR patients and outcome after intervention.

Method

In this prospective study, we measured outcomes of 62 patients who underwent TAVR procedures against the psoas muscle area and the Reported Edmonton Frail Scale (REFS). Our aim was to assess if psoas muscle assessment can be used as a simple method to predict frailty in our population group.

Results

A total of 60 patients met the study criteria. Mean psoas-lumbar vertebral index was 0.61, with a lower value in the frail group. There was not a statistically significant correlation between the psoas measures, REFS score (indicative of frailty), and mortality. However, there was a statistically significant relationship between the psoas size and REFS score (p=0.043).

Conclusion

Psoas assessment can be useful in providing additional information when planning for patients to undergo a TAVR and can be used as a screening tool to help identify frail patients within this high-risk group.

Development of a new risk model for a prognostic prediction after transcatheter aortic valve replacement

BACKGROUND

Current guidelines for transcatheter aortic valve replacement (TAVR) recommend that TAVR should be performed in patients with a life expectancy > 1 year. However, it is challenging to estimate the patients' life expectancy because it is related to various factors, including frailty and nutritional status.

HYPOTHESIS

A new risk model can estimate the prognosis of patients after TAVR.

METHODS

We randomly divided 388 patients with aortic stenosis (AS) undergoing TAVR from October 2009 to August 2016 into two groups (2:1 ratio; training cohort, 259; validation cohort, 129). Using 94 baseline factors in the training cohort, we developed possible scoring models by the Cox proportional hazard regression model with the overall survival as the endpoint. Then, cross-validated 5-year C-statistics were calculated to assess the accuracy of the model.

RESULTS

Of 94 baseline factors, 12 factors were finally identified (5-year C-statistics in the training cohort: 0.709)-age, gender, body mass index, left ventricular ejection fraction, % vital capacity, forced expiratory volume 1.0 (s) %, albumin, hemoglobin, creatine, platelet, creatine kinase, and prothrombin time-international normalized ratio. The cross-validated 1-, 3-, and 5-year C-statistics in the validation cohort were 0.792, 0.758, and 0.778, respectively. Furthermore, calibration plots in the validation cohort revealed that 5-year survival is well predicted (r = 0.962).

CONCLUSIONS

The new survival prediction model after TAVR could provide appropriate guidance during decision making regarding the TAVR implementation.

Sarcopenia and health-related quality of life in older adults after transcatheter aortic valve replacement

BACKGROUND

Skeletal muscle wasting, or sarcopenia, affects a significant proportion of patients undergoing transcatheter aortic valve replacement (TAVR). However, its influence on post-TAVR recovery and 1-year health-related quality of life (HR-QOL) remains unknown. We examined the relationship between skeletal muscle index (SMI), post-TAVR length of hospital stay (LOS), and 1-year QOL.

METHODS

The study sample consisted of 300 consecutive patients undergoing TAVR from 2012 to 2018 who had pre-TAVR computed tomographic scans suitable for analysis of body composition. Skeletal muscle mass was quantified as cm² of skeletal mass per m² of body surface area from the cross-sectional computed tomographic image at the third lumbar vertebra. Sarcopenia was defined using established sex-specific cutoffs (women: SMI < 39 cm²/m²; men: < 55 cm²/m²). Multivariable linear regression analysis was used to determine the relationship between SMI, LOS, and HR-QOL using the Kansas City Cardiomyopathy Questionnaire.

RESULTS

Sarcopenia was present in most (59%) patients and associated with older age (82 vs 76 years; P < .001) and lower body mass index (27 vs 33 kg/m²; P < .001). There were no other differences in baseline clinical or echocardiographic characteristics among the 4 quartiles of SMI. SMI was positively correlated with LOS and 1-year QOL. After adjusting for age, gender, race, and body mass index, SMI remained a significant predictor of both LOS (P = .01) and 1-year QOL (P = .012). For every 10 cm²/m² higher SMI, there was an 8-point increase in Kansas City Cardiomyopathy Questionnaire score, a difference that is clinically meaningful.

CONCLUSIONS

Sarcopenia is prevalent in TAVR patients. Higher SMI is associated with shorter LOS and better 1-year HR-QOL. To achieve optimal TAVR benefits, further study into how body composition influences post-TAVR recovery and durable improvement in QOL is warranted.

Computed Tomography-Determined Muscle Quality Rather Than Muscle Quantity Is a Better Determinant of Prolonged Hospital Length of Stay in Patients Undergoing Transcatheter Aortic Valve Implantation

RATIONALE AND OBJECTIVES

Computed tomography (CT)-determined skeletal muscle measures have been used for predicting postoperative outcomes in patients undergoing transcatheter aortic valve implantation (TAVI). We investigated the impact of CT-determined muscle quantity (measured as psoas muscle area [PMA] and psoas muscle index [PMI]) and quality (measured as psoas muscle density [PMD]) on hospital length of stay (LOS) after TAVI.

METHODS

We retrospectively identified 182 consecutive patients who underwent TAVI between March 2013 and August 2017 with adequate preprocedural CT imaging. Baseline demographic and clinical data, the Society of Thoracic Surgeons score, the essential frailty toolset (EFT) frailty rating, and precontrast PMD, PMA, and PMI were obtained in all study patients. The primary outcome was prolonged postoperative LOS defined as greater than 14 days.

RESULTS

Patients with prolonged LOS had a significantly higher Society of Thoracic Surgeons score (p < 0.001) and significantly lower PMD (p < 0.001) than those with LOS ≤14 days. More patients with prolonged LOS had concomitant peripheral vascular disease (p  = 0.001), had undergone percutaneous coronary interventions (p = 0.022), and had an EFT score ≥4 (p < 0.001) compared to those without prolonged LOS. Neither PMA (p = 0.123) nor PMI (p = 0.271) were associated with prolonged LOS. Multivariate analysis identified EFT score ≥4, the presence of peripheral vascular disease, and PMD as independent predictors of prolonged LOS.

CONCLUSION

The precontrast CT-determined muscle quality measurement PMD is a simple and objective predictor of prolonged LOS after TAVI.

Tutorial: A Step-by-Step Guide (Version 2.0) for Measuring Abdominal Circumference and Skeletal Muscle From a Single Cross-Sectional Computed-Tomography Image Using the National Institutes of Health ImageJ

BACKGROUND

In patients with acute and chronic illness, depleted skeletal muscle (SM) mass, also referred to as sarcopenia, is a condition associated with an underlying disease process and adverse outcomes. Because of software upgrades and errors related to installation, clarifications and a revised tutorial were needed for calculating SM cross-sectional area (CSA) using the National Institutes of Health (NIH) ImageJ.

METHODS

A pilot study was conducted to determine the usability of the tutorial version 2.0. Eight adults (≥18 years of age) who had no previous experience or background in body composition or computed-tomography imaging and owned a personal laptop computer (Mac or PC) were included in the pilot study. Participants were tested on the completion of 4 tasks: (1) installation of software, (2) updating the software, (3) following revised tutorial (version 2.0), and (4) transferring information from the software to a spreadsheet for calculation of SM CSA.

RESULTS

All participants completed the tutorial and all assigned tasks, 4/4 (100%). However, 38% (3/8) of the participants made errors while cutting and pasting values from the ImageJ results box to a spreadsheet for calculating SM CSA.

CONCLUSION

The tutorial version 2.0 was easy to follow and provided sufficient information for adults to install, update, and perform the steps of body composition for the NIH ImageJ software without major issues. Care should be taken when cutting and pasting results from the software as well as when using the Microsoft Excel spreadsheet for calculating SM CSA.

Older Adults in the Cardiac Intensive Care Unit: Factoring Geriatric Syndromes in the Management, Prognosis, and Process of Care: A Scientific Statement From the American Heart Association

Longevity is increasing, and more adults are living to the stage of life when age-related biological factors determine a higher likelihood of cardiovascular disease in a distinctive context of concurrent geriatric conditions. Older adults with cardiovascular disease are frequently admitted to cardiac intensive care units (CICUs), where care is commensurate with high age-related cardiovascular disease risks but where the associated geriatric conditions (including multimorbidity, polypharmacy, cognitive decline and delirium, and frailty) may be inadvertently exacerbated and destabilized. The CICU environment of procedures, new medications, sensory overload, sleep deprivation, prolonged bed rest, malnourishment, and sleep is usually inherently disruptive to older patients regardless of the excellence of cardiovascular disease care. Given these fundamental and broad challenges of patient aging, CICU management priorities and associated decision-making are particularly complex and in need of enhancements. In this American Heart Association statement, we examine age-related risks and describe some of the distinctive dynamics pertinent to older adults and emerging opportunities to enhance CICU care. Relevant assessment tools are discussed, as well as the need for additional clinical research to best advance CICU care for the already dominating and still expanding population of older adults.

Transcatheter aortic valve replacement outcomes in patients with sarcopaenia

AIMS

Sarcopaenia is a prevalent disease of ageing, associated with adverse clinical outcomes. We aimed to compare in-hospital adverse outcomes and overall mortality in sarcopaenic and non-sarcopaenic patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

This was a retrospective cohort study including 602 patients who underwent TAVR. Sarcopaenia was defined as skeletal muscle mass index <55.4 cm2/m2 in males and <38.9 cm2/m2 in females obtained through pre-TAVR CT scan. Mortality, length of hospital stay, ICU admission, and Valve Academic Research Consortium (VARC)-2-defined post-TAVR complications were defined as outcomes. Study participants (mean age 80.9±8.9 years and 56.8% male) were followed for a median of 1.5 years. Two thirds of the TAVR population was sarcopaenic. In-hospital outcomes were similar in both groups; however, overall survival was worse in sarcopaenic patients (HR for mortality=1.46 [1.06-2.14], p=0.02). In a multivariable model, sarcopaenia, porcelain aorta, pre-TAVR atrial fibrillation/flutter, severe chronic kidney disease, chronic pulmonary disease, VARC-2 bleeding, acute renal failure following TAVR, and post-TAVR cardiac arrest were predictors of mortality.

CONCLUSIONS

Sarcopaenic patients had similar in-hospital clinical outcomes to non-sarcopaenic patients following TAVR which reveals TAVR safety in sarcopaenic patients. However, sarcopaenia was an independent risk factor for midterm mortality indicating its potential value in systematic evaluation of this highly comorbid population in order to decide the best treatment approaches.

Reliable and robust method for abdominal muscle mass quantification using CT/MRI: An explorative study in healthy subjects

Background

Quantification of abdominal muscle mass by cross-sectional imaging has been increasingly used to diagnose sarcopenia; however, the technical method for quantification has not been standardized yet. We aimed to determine an optimal method to measure the abdominal muscle area.

Methods

Among 50 consecutive subjects who underwent abdominal CT and MRI for possible liver donation, total abdominal muscle area (TAMA) and total psoas muscle area (TPA) at the L3 inferior endplate level were measured by two blinded readers. Inter-scan agreement between CT and MRI and inter-reader agreement between the two readers were evaluated using intraclass correlation coefficient (ICC) and within-subject coefficient of variation (WSCV). To evaluate the effect of measurement level, one reader measured TAMA and TPA at six levels from the L2 to L4 vertebral bodies.

Results

TAMA was a more reliable biomarker than TPA in terms of inter-scan agreement (ICC: 0.928 vs. 0.788 for reader 1 and 0.853 vs. 0.821 for reader 2, respectively; WSCV: 8.3% vs. 23.4% for reader 1 and 10.4% vs. 22.3% for reader 2, respectively) and inter-reader agreement (ICC: 0.986 vs. 0.886 for CT and 0.865 vs. 0.669 for MRI, respectively; WSCV: 8.2% vs. 16.0% for CT and 11.6% vs. 29.7% for MRI, respectively). In terms of the measurement level, TAMA did not differ from the L2_inf to L4_inf levels, whereas TPA increased with a decrease in measurement level.

Conclusions

TAMA is a better biomarker than TPA in terms of inter-scan and inter-reader agreement and robustness to the measurement level. CT was a more reliable imaging modality than MRI. Our results support the use of TAMA measured by CT as a standard biomarker for abdominal muscle area measurement.

Is rectus abdominis thickness associated with survival among patients with liver cirrhosis? A prospective cohort study

BACKGROUND

Sarcopenia may affect patients with liver cirrhosis and worsen disease outcomes.

OBJECTIVES

To evaluate ultrasound-measured psoas major (PM) and rectus abdominis (RA) thickness for predicting survival among patients with liver cirrhosis.

DESIGN AND SETTING

Prospective cohort study in a tertiary-level hospital.

METHODS

61 patients with liver cirrhosis were prospectively included during a 15-month period and followed up for at least six months. Cirrhosis was classified using the Child-Pugh score. Sarcopenia was assessed using surrogate parameters: handgrip strength (HGS), mid-arm muscle circumference (MAMC) and SGA (subjective global assessment). We used ultrasound to measure RA and PM thickness at admission.

RESULTS

There were 41 men. The patients' mean age was 58.03 ± 10.8 years. 26.22% of them were Child-Pugh A, 45.9% B and 27.86% C. The patients were followed up for 11.9 ± 5.63 months. RA thickness correlated moderately with MAMC (r = 0. 596; P < 0.0001) and HGS (r = 0.515; P < 0.0001) and decreased with increasing SGA class (A, 10.6 ± 2.8 mm; B, 8.3 ± 1.9 mm; C, 6.5 ± 1.9 mm; P < 0.0001). Survival at six months was independently predicted by using the model for end-stage liver disease-serum sodium score (odds ratio, OR 1.305; 95% OR confidence interval 1.083-1.572; P = 0.005). Survival during follow-up was independently predicted by RA thickness (hazard ratio, HR 0.701; 95% HR confidence interval 0.533-0.922; P = 0.011) and ascites (HR 1.876; 95% HR confidence interval 1.078-3.267; P = 0.026). PM thickness did not have any predictive value.

CONCLUSIONS

As a surrogate marker of sarcopenia, RA thickness may predict survival among patients with liver cirrhosis.

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.

Comparing Frailty Markers in Predicting Poor Outcomes after Transcatheter Aortic Valve Replacement

INTRODUCTION

Frailty is an important component of risk prognostication in transcatheter aortic valve replacement (TAVR). Objective markers of frailty, including sarcopenia, the modified Frailty Index (mFI), and albumin levels, have emerged, but little is known how such markers compare to each other in predicting outcomes after TAVR. We sought to define and compare these markers in predicting long-term outcomes after TAVR.

METHODS

Patients who underwent TAVR at our institution from 2011 to 2016 were included. Indexed cross-sectional areas of the lumbosacral muscles on preoperative computed tomography scans were used to assess sarcopenia. Optimal cutoffs for sarcopenia were defined using a statistically validated method. mFI was calculated using an 11-point scale of clinical characteristics. The primary outcome was 2-year all-cause mortality. Adjusted survival analysis was used to analyze outcomes.

RESULTS

A total of 381 patients were included in this study. Sarcopenia of the psoas muscles was associated with an increased risk of mortality on univariate (HR: 2.3, P = 0.01) and multivariate (HR: 2.5, P = 0.01) analysis. Sarcopenia of the paravertebral muscles was associated with increased risk of mortality only on univariate analysis (HR: 2.1, P = 0.03). Increased preoperative albumin levels were associated with decreased risk of mortality on univariate (HR: 0.3, P < 0.01) and multivariate analysis (HR: 0.3, P < 0.01). The (mFI) was not associated with mortality on univariate or multivariate analysis.

DISCUSSION

Novel cutoffs for sarcopenia of the psoas muscles were determined and associated with decreased survival after TAVR. Sarcopenia and albumin levels may be better tools for risk prediction than mFI in TAVR.

Presence of Sarcopenia and Its Rate of Change Are Independently Associated with Long-term Mortality in Patients with Liver Cirrhosis

BACKGROUND

Sarcopenia is associated with a poor prognosis in patients with liver cirrhosis. However, it is not known whether the rate of skeletal muscle depletion is also associated with a poor prognosis. We investigated the prognostic impact of the rate of skeletal muscle depletion in patients with liver cirrhosis.

METHODS

We included retrospectively all patients with liver cirrhosis who underwent both multiple computed tomography scans and hepatic venous pressure gradient (HVPG) measurements.

RESULTS

A total of 131 patients with liver cirrhosis were enrolled. The mean age of the patients was 53.7 years and alcoholic liver disease was the most common cause (61.8%). Sixty-four patients (48.9%) were diagnosed with sarcopenia. The median changes in skeletal muscle area per year (ΔSMA/y) were -0.89%. During a median follow-up period of 46.2 months (range, 3.4-87.6), 45 patients (34.4%) died. In multivariate analyses, age, Child-Pugh score, HVPG, presence of sarcopenia and ΔSMA/y were independently associated with mortality. Cumulative mortality was significantly higher in patients with ΔSMA/y < -2.4% than those with ΔSMA/y ≥ -2.4% (log-rank test, P < 0.001).

CONCLUSION

Both the presence and rate of change of sarcopenia are independently associated with long-term mortality in patients with liver cirrhosis.

Implications of low muscle mass across the continuum of care: a narrative review

Abnormalities in body composition can occur at any body weight. Low muscle mass is a predictor of poor morbidity and mortality and occurs in several populations. This narrative review provides an overview of the importance of low muscle mass on health outcomes for patients in inpatient, outpatient and long-term care clinical settings. A one-year glimpse at publications that showcases the rapidly growing research of body composition in clinical settings is included. Low muscle mass is associated with outcomes such as higher surgical and post-operative complications, longer length of hospital stay, lower physical function, poorer quality of life and shorter survival. As such, the potential clinical benefits of preventing and reversing this condition are likely to impact patient outcomes and resource utilization/health care costs. Clinically viable tools to measure body composition are needed for routine screening and intervention. Future research studies should elucidate the effectiveness of multimodal interventions to counteract low muscle mass for optimal patient outcomes across the healthcare continuum. Key messages Low muscle mass is associated with several negative outcomes across the healthcare continuum. Techniques to identify and counteract low muscle mass in clinical settings are needed.

Frailty and Exercise Training: How to Provide Best Care after Cardiac Surgery or Intervention for Elder Patients with Valvular Heart Disease

The aim of this literature review was to evaluate existing evidence on exercise-based cardiac rehabilitation (CR) as a treatment option for elderly frail patients with valvular heart disease (VHD). Pubmed database was searched for articles between 1980 and January 2018. From 2623 articles screened, 61 on frailty and VHD and 12 on exercise-based training for patients with VHD were included in the analysis. We studied and described frailty assessment in this patient population. Studies reporting results of exercise training in patients after surgical/interventional VHD treatment were analyzed regarding contents and outcomes. The tools for frailty assessment included fried phenotype frailty index and its modifications, multidimensional geriatric assessment, clinical frailty scale, 5-meter walking test, serum albumin levels, and Katz index of activities of daily living. Frailty assessment in CR settings should be based on functional, objective tests and should have similar components as tools for risk assessment (mobility, muscle mass and strength, independence in daily living, cognitive functions, nutrition, and anxiety and depression evaluation). Participating in comprehensive exercise-based CR could improve short- and long-term outcomes (better quality of life, physical and functional capacity) in frail VHD patients. Such CR program should be led by cardiologist, and its content should include (1) exercise training (endurance and strength training to improve muscle mass, strength, balance, and coordination), (2) nutrition counseling, (3) occupational therapy (to improve independency and cognitive function), (4) psychological counseling to ensure psychosocial health, and (5) social worker counseling (to improve independency). Comprehensive CR could help to prevent, restore, and reduce the severity of frailty as well as to improve outcomes for frail VHD patients after surgery or intervention.

Associations of pre-existing co-morbidities with skeletal muscle mass and radiodensity in patients with non-metastatic colorectal cancer

BACKGROUND AND AIM

Co-morbidities and computerized tomography-measured muscle abnormalities are both common in cancer patients and independently adversely influence clinical outcomes. Muscle abnormalities are also evident in other diseases, such as diabetes and obesity. This study examined for the first time the association between co-morbidities and muscle abnormalities in patients diagnosed with colorectal cancer (CRC).

METHODS

This cross-sectional study included 3051 non-metastatic patients with Stages I-III CRC. Muscle abnormalities, measured at diagnosis, were defined as low skeletal muscle mass index (SMI) or low skeletal muscle radiodensity (SMD) quantified using computerized tomography images using optimal stratification. Co-morbidities included in the Charlson index were ascertained. χ2 tests were used to compare the prevalence of co-morbidities by the presence or absence of each muscle abnormality. Logistic regressions were performed to evaluate which co-morbidities predicted muscle abnormalities adjusting for age, sex, body mass index, weight change, cancer stage, cancer site, race/ethnicity, and smoking.

RESULTS

Mean age was 63 years; 50% of patients were male. The prevalence of low SMI and low SMD were 43.1% and 30.2%, respectively. Co-morbidities examined were more prevalent in patients with low SMD than in those with normal SMD, and most remained independent predictors of low SMD after adjustment for covariates. Co-morbidities associated with higher odds of low SMD included myocardial infarction [odds ratio (OR) = 1.77, P = 0.023], congestive heart failure (OR = 3.27, P < 0.001), peripheral vascular disease (OR = 2.15, P = 0.002), diabetes with or without complications (OR = 1.61, P = 0.008; OR = 1.46, P = 0.003, respectively), and renal disease (OR = 2.21, P < 0.001). By contrast, only diabetes with complications was associated with lower odds of low SMI (OR = 0.64, P = 0.007).

CONCLUSIONS

Prevalence of muscle abnormalities was high in patients with non-metastatic CRC. Pre-existing co-morbidities were associated with low SMD, suggestive of a potential shared mechanism between fat infiltration into muscle and each of these co-morbidities.

Computed Tomography Assessment for Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement has become a mainstream therapeutic option for patients with severe aortic stenosis who are at intermediate risk or high risk for surgical valve replacement. Computed tomography (CT) is now the standard imaging modality for preoperative vascular access planning an aortic annular sizing. This article reviews the established and potential future roles of CT in transcatheter aortic valve replacement.

Reconsideration of frailty in relation to surgical indication

Given that an increasing number of elderly patients are undergoing surgical procedures for a diversity of indications, the concept of frailty is currently being examined in more depth in clinical medicine. Established surgical risk scores designed to predict mortality are mainly focused on general demographic information and clinical factors; however, these do not account for the frailty condition. With vulnerability and low resiliency in the frail elderly, these conventional scores are unable to accurately predict postoperative outcomes including adverse complications, disability, the need for additional rehabilitation, and prolonged length of hospitalization. Over the last decade, it has been demonstrated that frailty is an independent risk factor of surgery and strongly associated with adverse postoperative outcomes and mortality. It is essential today that surgeons assimilate the concept of frailty and the relationship between frailty and surgical outcomes. A preoperative frailty assessment can assist in determining surgical indication and optimal perioperative management, ultimately impacting the postoperative functional state and quality of life. Here we review the validity of preoperative frailty assessments for surgical intervention, possible treatments for frailty, and indicate future directions in this field.

Muscle mass and physical recovery in ICU: innovations for targeting of nutrition and exercise

PURPOSE OF REVIEW

We have significantly improved hospital mortality from sepsis and critical illness in last 10 years; however, over this same period we have tripled the number of 'ICU survivors' going to rehabilitation. Furthermore, as up to half the deaths in the first year following ICU admission occur post-ICU discharge, it is unclear how many of these patients ever returned home or a meaningful quality of life. For those who do survive, recent data reveals many 'ICU survivors' will suffer significant functional impairment or post-ICU syndrome (PICS). Thus, new innovative metabolic and exercise interventions to address PICS are urgently needed. These should focus on optimal nutrition and lean body mass (LBM) assessment, targeted nutrition delivery, anabolic/anticatabolic strategies, and utilization of personalized exercise intervention techniques, such as utilized by elite athletes to optimize preparation and recovery from critical care.

RECENT FINDINGS

New data for novel LBM analysis technique such as computerized tomography scan and ultrasound analysis of LBM are available showing objective measures of LBM now becoming more practical for predicting metabolic reserve and effectiveness of nutrition/exercise interventions. 13C-Breath testing is a novel technique under study to predict infection earlier and predict over-feeding and under-feeding to target nutrition delivery. New technologies utilized routinely by athletes such as muscle glycogen ultrasound also show promise. Finally, the role of personalized cardiopulmonary exercise testing to target preoperative exercise optimization and post-ICU recovery are becoming reality.

SUMMARY

New innovative techniques are demonstrating promise to target recovery from PICS utilizing a combination of objective LBM and metabolic assessment, targeted nutrition interventions, personalized exercise interventions for prehabilitation and post-ICU recovery. These interventions should provide hope that we will soon begin to create more 'survivors' and fewer victim's post-ICU care.

Prognostic Value of Psoas Muscle Area and Density in Patients Who Undergo Cardiovascular Surgery

BACKGROUND

Low skeletal muscle density, determined using computed tomography (CT), has yet to be examined in terms of muscle function and prognostic capability in patients who require open cardiovascular surgery. This study was performed to examine whether psoas muscle area and density, determined using CT, are associated with postoperative mortality in patients who undergo cardiovascular surgery.

METHODS

We reviewed the findings in 773 consecutive patients who underwent preoperative CT imaging, including the level of the third lumbar vertebra for clinical purposes. We measured grip strength, gait speed, and 6-minute walking distance to assess muscle function before hospital discharge. Skeletal muscle area was calculated from psoas muscle cross-sectional area (in squared centimeters) on preoperative CT images at the level of the third lumbar vertebra divided by the square of the patient's height in metres to give the skeletal muscle index (SMI). Skeletal muscle density determined by muscle attenuation (MA) was calculated by measuring the average Hounsfield units of the psoas muscle cross-sectional area.

RESULTS

The mean age of the study population was 65.0 ± 13.1 years, and 64.7% of the patients were male. Multivariate logistic regression analysis and multivariate Cox regression analysis showed that low MA, but not SMI, was significantly associated with muscle function, and all-cause mortality (P < 0.05). Kaplan-Meier analysis showed that low MA, but not low SMI, predicted mortality (P = 0.014).

CONCLUSIONS

Low skeletal muscle density, but not skeletal muscle area, predicted poorer muscle function and mortality in patients who undergo cardiac surgery.

Diagnosing Sarcopenia on Thoracic Computed Tomography: Quantitative Assessment of Skeletal Muscle Mass in Patients Undergoing Transcatheter Aortic Valve Replacement

RATIONALE AND OBJECTIVES

This study aims to assess the use of skeletal muscle mass measurements at two thoracic levels to diagnose sarcopenia on computed tomography (CT) chest examinations and to analyze the impact of these measurements on clinical outcome parameters following transcatheter aortic valve replacement.

MATERIALS AND METHODS

This study retrospectively included 157 patients who underwent preoperative CT examinations. The total muscle area was measured on transverse CT images at the 3rd lumbar and 7th and 12th thoracic levels with skeletal muscle indices (SMIs) calculated at each level. SMIs were then compared to clinical outcome parameters, and thoracic cutoff values for sarcopenia at the 7th and 12th thoracic levels were calculated.

RESULTS

Correlation between SMIs at the third lumbar vertebra (L3) and the 12th thoracic vertebra (T12) was stronger (r = 0.724, P < 0.001) than that between L3 and the seventh thoracic vertebra (T7) (r = 0.594, P < 0.001). SMIs at L3 and T12 significantly correlated with prolonged length of stay. Thoracic cutoff values for the 12th thoracic level were 42.6 cm²/m² (men) and 30.6 cm²/m² (women), and those for the 7th thoracic level were 46.5 cm²/m² (men) and 32.3 cm²/m² (women).

CONCLUSIONS

Skeletal muscle measurements at the T12 level could permit the diagnosis of sarcopenia and could be used to correlate sarcopenia with outcome parameters in patients undergoing CT limited to the chest.