Mechanical Anisotropy Assessment in Kidney Cortex Using ARFI Peak Displacement: Preclinical Validation and Pilot In Vivo Clinical Results in Kidney Allografts.

The kidney is an anisotropic organ, with higher elasticity along versus across nephrons. The degree of mechanical anisotropy in the kidney may be diagnostically relevant if properly exploited; however, if improperly controlled, anisotropy may confound stiffness measurements. The purpose of this study is to demonstrate the clinical feasibility of acoustic radiation force (ARF)-induced peak displacement (PD) measures for both exploiting and obviating mechanical anisotropy in the cortex of human kidney allografts, in vivo. Validation of the imaging methods is provided by preclinical studies in pig kidneys, in which ARF-induced PD values were significantly higher ( , Wilcoxon) when the transducer executing asymmetric ARF was oriented across versus along the nephrons. The ratio of these PD values obtained with the transducer oriented across versus along the nephrons strongly linearly correlated ( R2 = 0.95 ) to the ratio of shear moduli measured by shear wave elasticity imaging. On the contrary, when a symmetric ARF was implemented, no significant difference in PD was observed ( p > 0.01 ). Similar results were demonstrated in vivo in the kidney allografts of 14 patients. The symmetric ARF produced PD measures with no significant difference ( p > 0.01 ) between along versus across alignments, but the asymmetric ARF yielded PD ratios that remained constant over a six-month observation period post-transplantation, consistent with stable serum creatinine level and urine protein-to-creatinine ratio in the same patient population ( p > 0.01 ). The results of this pilot in vivo clinical study suggest the feasibility of 1) implementing symmetrical ARF to obviate mechanical anisotropy in the kidney cortex when anisotropy is a confounding factor and 2) implementing asymmetric ARF to exploit mechanical anisotropy when mechanical anisotropy is a potentially relevant biomarker.

Longitudinal Self-Management and/or Transition Readiness per the TRxANSITION Index among Patients with Chronic Conditions in Pediatric or Adult Care Settings.

OBJECTIVE: To evaluate the roles of key individual, family, and illness characteristics on the levels of and gains in longitudinal healthcare transition (HCT) readiness in the pediatric setting and/or self-management skills (SMS) in the adult-focused setting, we used a large dataset with longitudinal measurements from 2006 to 2015. STUDY DESIGN: This longitudinal observational study followed 566 adolescents and young adults with chronic conditions at University of North Carolina Hospitals. TRxANSITION Index measurements, which represent learning outcomes rather than health outcomes, were collected multiple times per patient and analyzed using a novel application of an education-based approach. RESULTS: Levels of and gains in HCT/SMS scores increased with age (P < .001) with smaller increases at older ages. Mastery of skills varied by age with self-management achieved after 20 years of age. Scores varied positively by father's education and negatively by mother's education and duration of diagnosis. Gains in scores further varied positively with private insurance and negatively with mother's education and duration of diagnosis. CONCLUSIONS: We found diminishing positive increases in HCT/SMS scores as patients become older and smaller levels of and gains in readiness among younger patients with more educated mothers. Risk factors for absolute level of HCT/SMS readiness and inadequate longitudinal gains are not always the same, which motivates a deeper understanding of this dynamic process through additional research. This information can guide providers to focus HCT/SMS preparation efforts on skills mastered at particular ages and to identify patients at risk for inadequate development of HCT/SMS skills.

Pretransplantation erythropoiesis-stimulating agent hyporesponsiveness is associated with increased kidney allograft failure and mortality.

BACKGROUND: Poor response to erythropoiesis-stimulating agents (ESA) is associated with morbidity and mortality among dialysis patients. It is unclear whether the risk associated with poor ESA response during dialysis extends beyond kidney transplantation. We examined pretransplantation ESA response and its effect on allograft failure and mortality. METHODS: The cohort included all adult Medicare recipients from the U.S. Renal Data System who had received a kidney transplant during years 2000 to 2007 and had at least 6 months of hemodialysis immediately before transplantation. ESA hyporesponsiveness was primarily defined as a monthly ESA dose of 75,000 units or higher and hematocrit 33% or less for at least 3 consecutive months in the pretransplantation period. Crude and adjusted Cox proportional hazards models and Kaplan-Meier methods were used to estimate the effect of ESA hyporesponsiveness on allograft failure and all-cause mortality. RESULTS: The study group consisted of 36,450 patients; 1004 exhibited hyporesponsiveness. The adjusted hazard ratios (95% confidence interval) for allograft failure and mortality after transplantation were 1.23 (1.10-1.42) and 1.61 (1.43-1.81), respectively, supporting that poor ESA response during hemodialysis is associated with adverse posttransplantation outcomes. CONCLUSIONS: ESA hyporesponsiveness may be useful in identifying potential allograft recipients who are at high risk for subsequent morbidity and mortality and may benefit from more intensive pretransplantation and posttransplantation monitoring.