Citations

Transcatheter aortic valve replacement (TAVR) is a transformational and rapidly evolving treatment for patients with aortic stenosis who require valve replacement. Novel technological advancements have made this percutaneous minimally invasive therapy a first-line treatment for many patients at extreme risk for conventional cardiac surgery. New devices and improvements in existing devices have reduced procedural complications, and scientific trials are investigating the role of TAVR in lower-risk aortic stenosis populations, in patients with aortic regurgitation, and in patients with bicuspid aortic valve disease. Finally, there is intense interest in identifying patients in whom the risk-benefit ratio of TAVR is not favorable and should not be performed.

Bladder wall mechanical properties are important indicators of bladder compliance. This study compares the effectiveness of the Kelvin-Voigt, Maxwell, and fractional Kelvin-Voigt rheological models in capturing the mechanical properties of normal (compliant) and aberrant (non-compliant) ex-vivo pig bladder walls. Bladders were filled to different volumes, varying their thickness and internal pressure, and excited by the acoustic radiation force. Pulse-echo ultrasound imaged anti-symmetrical Lamb waves traveling along the bladder wall. Two-dimensional Fourier analysis generated velocity-frequency dispersion curves for the Lamb wave propagation. Fitting these experimental curves against theoretical curves from the models yielded values for bladder elasticity and viscosity. Pressure, measured simultaneously, was used as a point of comparison with elasticity. Our findings indicate an increasing trend in both elasticity for the rheological models and recorded pressure with increasing volume. This rate was observed to be significantly higher in aberrant bladders than intact bladders for the Maxwell and fractional Kelvin-Voigt models (p-value of 0.0082). Additionally, all three models showed a similar strong correlation (greater than 0.9) between pressure and elasticity. These findings provide a foundation for selecting an appropriate bladder wall rheology model which can potentially be used in evaluation of human bladder mechanical properties. [Work supported by NIH grant DK99231.]

Kidney transplantation is one treatment for end-stage renal disease. Transplant rejection is typically evaluated with an invasive biopsy. Noninvasive methods for evaluating renal transplants would be beneficial for frequent evaluation. We propose the use of shear wave elastography (SWE) to evaluate viscoelastic properties in renal transplants. Further, we also use acoustoelasticity to measure the nonlinear modulus of the renal transplants. Acoustoelasticity is the phenomenon where the shear wave velocity (SWV) in a material varies with applied stress and is quantified by a nonlinear modulus, A. By applying pressure with the ultrasound transducer, stress is applied to the kidney under investigation and B-mode imaging was used to measure induced strain and SWE was used to make measurements of SWV. Using relationships involving the measured strain and shear moduli at different compression levels, we can obtain estimates of A. In our ongoing study, we use a General Electric Logiq E9 to perform SWE measurements in renal transplant patients coming for protocol biopsies. We have studied 63 patients with SWE to quantify viscoelastic properties of the transplanted kidney. We have obtained data from 19 patients for estimation of the nonlinear modulus, A. We compared the measured viscoelastic and nonlinear shear parameters with clinical variables such as the serum creatinine, Banff biopsy scores, and resistive index. We continue to evaluate these methods and their efficacy as indicators for transplant rejection.

ObjectiveSystemic lupus erythematosus (SLE) and other autoimmune diseases cause significant morbidity. Identifying populations at risk of developing SLE is essential for curtailing irreversible inflammatory damage. The aim of this study was to identify factors associated with transition to classified disease that would inform our understanding of the risk of SLE.MethodsPreviously identified blood relatives of patients with SLE, who had <4 American College of Rheumatology (ACR) classification criteria for SLE at baseline, were enrolled in this follow‐up study (n = 409 unaffected relatives). Participants provided detailed family, demographic, and clinical information, including the SLE‐specific portion of the Connective Tissue Disease Screening Questionnaire (SLE‐CSQ). Serum and plasma samples were tested for the presence of lupus‐associated autoantibodies and 52 soluble mediators. Generalized estimating equations (GEEs) were applied to identify factors predictive of disease transition.ResultsOf the 409 unaffected relatives of SLE patients, 45 (11%) had transitioned to classified SLE at follow‐up (mean time to follow‐up 6.4 years). Relatives who transitioned to SLE displayed more lupus‐associated autoantibody specificities and higher SLE‐CSQ scores (P < 0.0001) at baseline than did relatives who did not transition. Importantly, those who had developed SLE during the follow‐up period also had elevated baseline plasma levels of inflammatory mediators, including B lymphocyte stimulator, stem cell factor (SCF), and interferon‐associated chemokines (P ≤ 0.02), with concurrent decreases in the levels of regulatory mediators, transforming growth factor β (TGFβ), and interleukin‐10 (P ≤ 0.03). GEE analyses revealed that baseline SLE‐CSQ scores or ACR scores (number of ACR criteria satisfied) and plasma levels of SCF and TGFβ, but not autoantibodies, were significant and independent predictors of SLE transition (P ≤ 0.03).ConclusionPreclinical alterations in levels of soluble mediators may predict transition to classified disease in relatives of SLE patients. Thus, immune perturbations precede SLE classification and can help identify high‐risk relatives for rheumatology referral and potential enrollment in prevention trials.

OBJECTIVE With improving medical therapies for chronic conditions, elderly patients increasingly present as candidates for operative intervention for degenerative diseases of the spine. To date, there is a paucity of studies examining complications in lumbar decompression, without fusion, that include patients older than 80 years. Using a multicenter national database, the authors of this study evaluated lumbar decompression in the elderly, including octogenarians, to evaluate for associations between age and patient outcomes. METHODS The 2011–2013 American College of Surgeons' National Surgical Quality Improvement Program data set was queried for patients 65 years and older with diagnosis and procedure codes inclusive of degenerative spine disease and lumbar decompression without fusion. Morbidity and mortality within the 30-day postoperative period were the primary outcomes. Secondary outcomes of interest included unplanned readmission within 30 days or discharge to a nonhome facility. Outcomes and operative characteristics were compared using chi-square tests, Kruskal-Wallis tests, and multivariable logistic regression models. RESULTS A total of 8744 patients were identified; of these patients 4573 (52.30%) were 65 years and older. Elderly patients were stratified into 3 age categories: 85 years or older (n = 314), 75–84 years (n = 1663), and 65–74 years (n = 2596). Univariate analysis showed that, compared with age younger than 65 years, increased age was associated with the number of levels (≥ 3), readmissions within 30 days, nonhome discharge, any complication, length of stay, and blood transfusion (all p < 0.001). On multivariable analysis and with younger than 65 years as the reference, increased age was associated with any minor complication (p < 0.001; ≥ 85 years: OR 3.47, 95% CI 1.69–7.13; 75–84 years: OR 2.34, 95% CI 1.45–3.78; and 65–74 years: OR 1.44, 95% CI 0.94–2.20), as well as discharge location other than home (p < 0.001; ≥ 85 years: OR 13.59, 95% CI 9.47–19.49; 75–84 years: OR 5.64, 95% CI 4.33–7.34; and 65–74 years: OR 2.61, 95% CI 2.05–3.32). CONCLUSIONS The authors' high-powered, multicenter analysis of lumbar decompression without fusion in the elderly, specifically including patients older than 80 years, demonstrates that increased age is associated with more extensive operations, resulting in longer hospital stays, increased rates of nonhome discharge, and minor complications.

AbstractThe last decade has seen a substantial increase in research focused on the identification of blood‐based biomarkers that have utility in Alzheimer's disease (AD). Blood‐based biomarkers have significant advantages of being time‐ and cost‐efficient as well as reduced invasiveness and increased patient acceptance. Despite these advantages and increased research efforts, the field has been hampered by lack of reproducibility and an unclear path for moving basic discovery toward clinical utilization. Here we reviewed the recent literature on blood‐based biomarkers in AD to provide a current state of the art. In addition, a collaborative model is proposed that leverages academic and industry strengths to facilitate the field in moving past discovery only work and toward clinical use. Key resources are provided. This new public‐private partnership model is intended to circumvent the traditional handoff model and provide a clear and useful paradigm for the advancement of biomarker science in AD and other neurodegenerative diseases.