BACKGROUND:Skeletal muscle mass decreases in end-stage heart failure and is predictive of clinical outcomes in several disease states. Skeletal muscle attenuation and quantity as quantified on preoperative chest computed tomographic scans may be predictive of mortality after continuous flow (CF) left ventricular assist device (LVAD) implantation.
METHODS AND RESULTS:A single-center continuous flow-LVAD database (n=354) was used to identify patients with chest computed tomographies performed in the 3 months before LVAD implantation (n=143). Among patients with computed tomography data available, unilateral pectoralis muscle mass indexed to body surface area and attenuation (approximated by mean Hounsfield units [PHU m ]) were measured in each patient with a high intrarater and inter-rater reliability (intraclass correlation coefficients 0.98 and 0.97, respectively). Multivariate Cox regression analyses were performed, censoring at cardiac transplantation, to assess the impact of preoperative pectoralis muscle index and pectoralis muscle mean Hounsfield unit on survival after LVAD implantation. Each unit increase in pectoralis muscle index was associated with a 27% reduction in the hazard of death after LVAD (adjusted hazard ratio, 0.73; 95% confidence interval, 0.58-0.92; P=0.007). Each 5-U increase in pectoralis muscle mean Hounsfield unit was associated with a 22% reduction in the hazard of death after LVAD (adjusted hazard ratio, 0.78; 95% confidence interval, 0.68-0.89; P<0.0001). Pectoralis muscle index and pectoralis muscle mean Hounsfield unit outperformed other traditional measures in the data set, including the HeartMate II risk score.
CONCLUSIONS:Pectoralis muscle size and attenuation were powerful predictors of outcomes after LVAD implantation in this data set. This one time, repeatable, internal assessment of patient substrate added valuable prognostic information that was not available on standard preoperative testing.
EN and PN management strategies are relatively consistent among U.S. centers. Collaborative initiatives are necessary to define better practices and establish laboratory monitoring guidelines.
Measures of skeletal muscle CSA at the L3 were found to be ∼1.53 cm higher with ImageJ than sliceOmatic. This difference was not found to affect interpretation against a published cut point. The importance of accounting for the ImageJ tutorial corrigendum was shown to be clinically significant when applied to published cut points.
Monitoring whole body composition (fat mass and fat‐free mass) in preterm infants may assist in optimizing nutrition and promoting growth and neurodevelopment in the neonatal intensive care unit. Currently, body composition assessment is not part of routine clinical evaluation of premature infants. Instead, weight and length are used to assess growth but are known to be poor predictors of adiposity shortly after birth. Although body composition methods, such as magnetic resonance imaging, stable‐isotope dilution, and dual‐energy x‐ray absorptiometry, have been examined in infants, they involve exposure to radiation and are invasive, expensive, and/or unsuitable for repeated measurements in a medically fragile population. Several body composition methods with potential for clinical use have been explored in premature infants, including air displacement plethysmography, bioimpedance, skinfold measurements, and ultrasound. In this review, we examine each method and evaluate its feasibility for incorporation into clinical care. Although these methods show promise for use in premature infants, further research is needed before they can be recommended for routine body composition assessment in the clinical setting.
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