Significant Univariate Relationships Research Articles

Usefulness of Impulse Oscillometry in Predicting the Severity of Bronchiectasis.

Bronchiectasis is a chronic respiratory disease that leads to airway inflammation, destruction, and airflow limitation, which reflects its severity. Impulse oscillometry (IOS) is a non-invasive method that uses sound waves to estimate lung function and airway resistance. The aim of this study was to assess the usefulness of IOS in predicting the severity of bronchiectasis. We retrospectively reviewed the IOS parameters and clinical characteristics in 145 patients diagnosed with bronchiectasis between March 2020 and May 2021. Disease severity was evaluated using the FACED score, and patients were divided into mild and moderate/severe groups. Forty-four patients (30.3%) were in the moderate/severe group, and 101 (69.7%) were in the mild group. Patients with moderate/severe bronchiectasis had a higher airway resistance at 5 Hz (R5), a higher difference between the resistance at 5 and 20 Hz (R5-R20), a higher resonant frequency (Fres), and a higher area of reactance (AX) than patients with mild bronchiectasis. R5 ≥0.43, resistance at 20 Hz (R20) ≥0.234, R5-R20 ≥28.3, AX ≥1.02, reactance at 5 Hz (X5) ≤-0.238, and Fres ≥20.88 revealed significant univariable relationships with bronchiectasis severity (p<0.05). Among these, only X5 ≤-0.238 exhibited a significant multivariable relationship with bronchiectasis severity (p=0.039). The receiver operating characteristic curve for predicting moderate- to-severe bronchiectasis of FACED score based on IOS parameters exhibited an area under the curve of 0.809. The IOS assessed by the disease severity of FACED score can effectively reflect airway resistance and elasticity in bronchiectasis patients and serve as valuable tools for predicting bronchiectasis severity.

Application of selected biochemical parameters in prediction of acute kidney injury risk at the early stage of burn disease

Introduction and objectiveAcute kidney injury (AKI) is a common, severe complication of burn disease, developing in the first days after a massive thermal injury and worsening the prognosis of patients. Early diagnosis of AKI plays a crucial role in improving health of patients and therapeutic results. Detection of AKI based on the standard parameters of renal function is insufficient due to too late changes in their values. The aim of the study is to evaluate the relationship between the selected non-renal biochemical parameters and the risk of AKI in this group of patients.Material and methodsThe prospective study involved a group of 33 adult patients (22 men, 11 women) hospitalized after massive burns. The patients were intensively monitored for the first 7 days after the injury, daily assessing the parameters of renal function. The selected parameters were also measured: platelet count (PLT), sodium (Na), potassium (K), albumin (ALB), aspartate aminotransferase (AST), creatine kinase (CK), arterial blood pH, arterial blood bicarbonate (HCO3-), 24-hour urinary sodium excretion (24hUNa) and fractional excretion of sodium (FENa).ResultsAKI was diagnosed in 15 (45.5%) patients. Statistical differences in the obtained average values of selected parameters between the AKI and non-AKI groups were confirmed. A significant univariate relationship was found between CK, AST and ALB in the blood serum and an increased risk of developing AKI in the following days. However, after adjustment for The Abbreviated Burn Severity Index score, only CK remained significant.ConclusionsThe potential clinical benefit of monitoring AST and ALB in blood serum and especially CK was confirmed. The other routine parameters did not seem to be related to the risk of AKI and require further analysis.

Phase II trial of fulvestrant plus enzalutamide in ER+/HER2− advanced breast cancer

This clinical trial combined fulvestrant with the anti-androgen enzalutamide in women with metastatic ER+/HER2− breast cancer (BC). Eligible patients were women with ECOG 0–2, ER+/HER2− measurable or evaluable metastatic BC. Prior fulvestrant was allowed. Fulvestrant was administered at 500 mg IM on days 1, 15, 29, and every 4 weeks thereafter. Enzalutamide was given at 160 mg po daily. Fresh tumor biopsies were required at study entry and after 4 weeks of treatment. The primary efficacy endpoint of the trial was the clinical benefit rate at 24 weeks (CBR24). The median age was 61 years (46–87); PS 1 (0–1); median of 4 prior non-hormonal and 3 prior hormonal therapies for metastatic disease. Twelve had prior fulvestrant, and 91% had visceral disease. CBR24 was 25% (7/28 evaluable). Median progression-free survival (PFS) was 8 weeks (95% CI: 2–52). Adverse events were as expected for hormonal therapy. Significant (p < 0.1) univariate relationships existed between PFS and ER%, AR%, and PIK3CA and/or PTEN mutations. Baseline levels of phospho-proteins in the mTOR pathway were more highly expressed in biopsies of patients with shorter PFS. Fulvestrant plus enzalutamide had manageable side effects. The primary endpoint of CBR24 was 25% in heavily pretreated metastatic ER+/HER2− BC. Short PFS was associated with activation of the mTOR pathway, and PIK3CA and/or PTEN mutations were associated with an increased hazard of progression. Thus, a combination of fulvestrant or other SERD plus AKT/PI3K/mTOR inhibitor with or without AR inhibition warrants investigation in second-line endocrine therapy of metastatic ER+ BC.

The contribution of white matter pathology, hypoperfusion, lesion load, and stroke recurrence to language deficits following acute subcortical left hemisphere stroke.

Aphasia, the loss of language ability following damage to the brain, is among the most disabling and common consequences of stroke. Subcortical stroke, occurring in the basal ganglia, thalamus, and/or deep white matter can result in aphasia, often characterized by word fluency, motor speech output, or sentence generation impairments. The link between greater lesion volume and acute aphasia is well documented, but the independent contributions of lesion location, cortical hypoperfusion, prior stroke, and white matter degeneration (leukoaraiosis) remain unclear, particularly in subcortical aphasia. Thus, we aimed to disentangle the contributions of each factor on language impairments in left hemisphere acute subcortical stroke survivors. Eighty patients with acute ischemic left hemisphere subcortical stroke (less than 10 days post-onset) participated. We manually traced acute lesions on diffusion-weighted scans and prior lesions on T2-weighted scans. Leukoaraiosis was rated on T2-weighted scans using the Fazekas et al. (1987) scale. Fluid-attenuated inversion recovery (FLAIR) scans were evaluated for hyperintense vessels in each vascular territory, providing an indirect measure of hypoperfusion in lieu of perfusion-weighted imaging. We found that language performance was negatively correlated with acute/total lesion volumes and greater damage to substructures of the deep white matter and basal ganglia. We conducted a LASSO regression that included all variables for which we found significant univariate relationships to language performance, plus nuisance regressors. Only total lesion volume was a significant predictor of global language impairment severity. Further examination of three participants with severe language impairments suggests that their deficits result from impairment in domain-general, rather than linguistic, processes. Given the variability in language deficits and imaging markers associated with such deficits, it seems likely that subcortical aphasia is a heterogeneous clinical syndrome with distinct causes across individuals.

A risk calculator for postoperative urinary retention (POUR) following vaginal pelvic floor surgery: multivariable prediction modelling.

To determine the perioperative characteristics associated with an increased risk of postoperative urinary retention (POUR) following vaginal pelvic floor surgery. A retrospective cohort study using multivariable prediction modelling. A tertiary referral urogynaecology unit. Patients undergoing vaginal pelvic floor surgery from January 2015 to February 2020. Eighteen variables (24 parameters) were compared between those with and without POUR and then included as potential predictors in statistical models to predict POUR. The final model was chosen as the model with the largest concordance index (c-index) from internal cross-validation. This was then externally validated using a separate data set (n=94) from another surgical centre. Diagnosis of POUR following surgery while the patient was in hospital. Among the 700 women undergoing surgery, 301 (43%) experienced POUR. Preoperative variables with statistically significant univariate relationships with POUR included age, menopausal status, prolapse stage and uroflowmetry parameters. Significant perioperative factors included estimated blood loss, volume of intravenous fluid administered, operative time, length of stay and specific procedures, including vaginal hysterectomy with intraperitoneal vault suspension, anterior colporrhaphy, posterior colporrhaphy and colpocleisis. The lasso logistic regression model had the best combination of internally cross-validated c-index (0.73, 95%CI 0.71-0.74) and a calibration curve that showed good alignment between observed and predicted risks. Using this data, a POUR risk calculator was developed (https://pourrisk.shinyapps.io/POUR/). This POUR risk calculator will allow physicians to counsel patients preoperatively on their risk of developing POUR after vaginal pelvic surgery and help focus discussion around potential management options.

Adipsin Serum Concentrations and Adipose Tissue Expression in People with Obesity and Type 2 Diabetes.

(1) Adipsin is an adipokine that may link increased fat mass and adipose tissue dysfunction to obesity-related cardiometabolic diseases. Here, we investigated whether adipsin serum concentrations and adipose tissue (AT) adipsin mRNA expression are related to parameters of AT function, obesity and type 2 diabetes (T2D). (2) Methods: A cohort of 637 individuals with a wide range of age and body weight (Age: 18–85 years; BMI: 19–70 kg/m2) with (n = 237) or without (n = 400) T2D was analyzed for serum adipsin concentrations by ELISA and visceral (VAT) and subcutaneous (SAT) adipsin mRNA expression by RT-PCR. (3) Results: Adipsin serum concentrations were significantly higher in patients with T2D compared to normoglycemic individuals. We found significant positive univariate relationships of adipsin serum concentrations with age (r = 0.282, p < 0.001), body weight (r = 0.264, p < 0.001), fasting plasma glucose (r = 0.136, p = 0.006) and leptin serum concentrations (r = 0.362, p < 0.001). Neither VAT nor SAT adipsin mRNA expression correlated with adipsin serum concentrations after adjusting for age, sex and BMI. Independent of T2D status, we found significantly higher adipsin expression in SAT compared to VAT (4) Conclusions: Our data suggest that adipsin serum concentrations are strongly related to obesity and age. However, neither circulating adipsin nor adipsin AT expression reflects parameters of impaired glucose or lipid metabolism in patients with obesity with or without T2D.

Association of Dietary Inflammatory Index (DII) with disease activity and inflammatory cytokines in the patients with rheumatoid arthritis.

This study aimed, at first, to assess Dietary Inflammatory Index (DII) in participants with rheumatoid arthritis (RA) and compare them with healthy controls. Then, to evaluate the association of DII with the risk of RA occurrence, the severity of disease, and systemic inflammation. This case-control study enrolled 100 newly diagnosed cases with RA and 100 age and sex-matched healthy controls. DII was computed based on the individuals' FFQ-derived dietary data. Serum levels of inflammatory markers, including the high sensitivity C-reactive protein (hs-CRP) and Tumour Necrosis Factor-alpha (TNF-α), were measured using the ELISA method; and the severity of the disease was assessed based on the disease activity score 28 (DAS-28). The mean DII score was higher in the RA patients as compared with that in the controls (0.66±0.23 vs. -0.58±0.19, P=.002). Patients with the highest DII had significantly higher serum inflammatory (hs-CRP and TNF) and clinical markers (DAS-28 score and the number of tender joints). A significant univariate relationship between DII score and risk of RA incident [6.48 (95% CI: 1.79 to 23.44)] disappeared in multivariate analysis. For each 1-unit increase in DII, the DAS-28 score was raised by 1.11 times (P=.001). An inflammatory diet may act as a potential risk factor contributing to the development of RA and its severity. Therefore, dietary modification with the goal of reducing the DII score could be a beneficial strategy to improve the clinical outcomes in such patients.

P1200PERITONEAL PROTEIN LOSSES: WHAT DO WE MEAN

Abstract Background and Aims The report of peritoneal protein loss should be related with a timely collection (24-hour measurement or 4-hour PET assessment) or concentration. Standardized and reproducible estimation of peritoneal protein transport is obtained during PET. The 24-hour measurements estimate the real amount of PPL, but may be affected by other factors unrelated to the prognosis of PD patients, as inconsistencies in collection and management of the samples. Overall, PET protein loss quantification may be a more specific marker of peritoneal large-pore dysfunction and is seemingly more convenient than 24-hour measurements. The aim of this study was to compare the results of both sampling methods. Method A total of 144 adult incident PD patients were included. A standard peritoneal equilibration test, 24-hour urine and dialysate collection, and multifrequency bioimpedance analysis were performed. Independent-samples t test and Pearson correlation coefficient were performed to evaluate relevant clinical associations. Results Statistically significant univariable relationships for 24h PPL were found for continuous ambulatory PD technique (CAPD) and, with a correlation coefficient &amp;gt;0.20, for pulse pressure, 4-hour dialysate/plasma creatinine and extracellular water/total body water. Studying 240 min PPL, only with 4-hour dialysate/plasma creatinine, creatinine clearance and bicarbonate levels were statistically significant. In both samples there was no significant association with age, gender, type of effluent (biocompatible solutions or lactate plus bicarbonate comparing with bicarbonate), comorbidity Charlson Index, or presence of diabetes. Correlation between 240 min PPL and 24h PPL ensues, but it is not strong (p&amp;lt;0.001; r=0.365). Conclusion The weak correlation between 24h and 240 minutes show that these two measurements should not be considered equivalent. Measurements of a 24h sample might be more close to patients’ clinical status and prognosis, despite more frequent sampling errors. PET protein loss quantification should be regarded as a marker of peritoneal large-pore dysfunction.

P1172IS PERITONEAL PROTEIN LOSS A CONSEQUENCE OF OVERHIDRATATION?

Abstract Background and Aims Peritoneal protein loss (PPL) in peritoneal effluent is a well-recognised detrimental result of peritoneal dialysis treatment since its inception. Hydrostatic convection is a major drive for peritoneal protein transport; therefore venous congestion may have a role in peritoneal protein loss (Krediet RT et al Perit Dial Int. 2019 ). The aim of this study was to explore the importance of overhydration on the magnitude of peritoneal protein clearance in incident PD patients. Method A total of 97 adult incident PD patients were included. A standard peritoneal equilibration test, 24-hour urine and dialysate collection, and multifrequency bioimpedance analysis were performed. Independent-samples t test and Pearson correlation coefficient were performed to evaluate relevant clinical associations and linear multivariable regression was done. Results Statistically significant univariable relationships for 24h PPL were found for continuous ambulatory PD technique (CAPD) and, with a correlation coefficient &amp;gt;0.20, for age, pulse pressure, 4-hour dialysate/plasma creatinine and extracellular water/total body water. On multivariable analysis, type of PD technique (β=0.327, p=0.011), 4-hour dialysate/plasma creatinine (β=0.247, p=0.037), and extracellular water/total body water (β=0.304, p=0.016) were significant independent predictors of peritoneal protein loss. Conclusion Overhydration revealed the most important connection with peritoneal protein loss. Mortality has been associated with PPL in some studies, but not others. This could be a result of this relationship, as volume overload has been strongly related with lower survival.

Abstract No. 391 Frailty is predictive of complications after transarterial chemoembolization

To determine the association between frailty, 30-day complications and 1-year mortality following conventional and drug-eluting bead transarterial chemoembolization. A retrospective analysis was performed on a cohort of 125 adult patients with previously untreated hepatocellular carcinoma who underwent first time conventional TACE (cTACE) or drug-eluting beads (DEB-TACE) at our institution between 2014 and 2015. Liver function parameters, tumor stage, and all components of the Modified Frailty Index (mFI) were used to determine frailty status for each patient. Severe adverse events (SAEs) that occurred within 30 days of TACE were classified according to NCI-CTCAE v5.0. The primary outcomes were SAEs (grade 3 or above) and 1-year mortality. Univariate analysis was performed on conventional predictors of mortality and postoperative complications after TACE. Covariates were then incorporated into a multivariate model based on a statistically significant univariate relationship. Univariate logistic regression demonstrated that frailty and the use of cTACE over DEB-TACE predicted SAEs at 30 days (P <0.03, P <0.01 respectively). Subsequent multivariate analysis showed that frailty independently predicted 30-day severe AEs (P <0.02). Specifically, a 1-unit increase in mFI conferred a 60% increase in the risk of having a postoperative SAE. While higher MELD, BCLC and Child Pugh Class were predictive of higher mortality, there was no significant association between frailty and 1-year mortality in this dataset. Increasing frailty is an independent predictor of SAEs but not 1-year mortality following TACE.

Relationship of CT Radiomics and Dose Texture to Radiation-Induced Swallow Dysfunction in Head and Neck Cancer

Recent studies have shown that radiotherapy (RT) dosimetry is associated with an increased incidence of dysphagia in head and neck cancer (HNC) patients. The purpose of this work was to develop a dysphagia model using a comprehensive atlas of swallow-related structures to determine the predictive value of imaging and dose features of HNC patients who were evaluated for dysphagia after RT. We hypothesized that imaging and dosimetry features would be significantly correlated to patient reported scores of dysphagia. CT images and dysphagia scores were prospectively collected in HNC patients. We used the 3 month post-RT patient reported Sydney Swallow Questionnaire (SSQ) that has been validated to measure pharyngeal swallow as the primary endpoint. CT images were acquired prior to RT at the time of simulation. Swallow-related structures identified as important to swallow function (e.g. ipsi/contralateral parotid and submandibular glands [iPG, cPG, iSG, cSG], middle constrictors [MPC], anterior and posterior digastrics [ADM, PDM], mylohyoid [MHM], genioglossus [GGM], hyoglossus [HM], and cricopharyngeus [CP]) were segmented. For each segmented salivary gland, high-dimensional image features were extracted from CT images using a python software package. For each swallow-related structure, high-dimensional features were extracted from the structure’s dose distribution. Major categories of extracted features included shape, first order statistics, gray level co-occurrence matrix (GLCM), gray level run length matrix (GLRLM), and gray level size zone matrix (GLSZM). Multivariate regression was performed using the Enter method to identify the predictors of SSQ. The variables considered for modeling were chosen based on statistically significant univariate relationships with SSQ (p<0.005). All statistical analysis was performed in statistical software. In 136 patients, total SSQ at 3 months post-RT was correlated with the MHM D10, GLCM informational measure of correlation of dose, and GLSZM gray level non-uniformity of dose; cSG minimum dose and D10, HM minimum dose; and MPC GLCM inverse difference of dose (r>0.30, p<0.005). In terms of CT image features, SSQ was related to cPG GLCM cluster shade and prominence, iSG GLCM difference variance, and iPG GLCM correlation (r>0.30, p<0.005). In a multivariate analysis (R=0.65, p<0.001), CT iPG GLCM correlation, iSG GLCM difference variance, MPC inverse difference of dose and MHM D10 contributed significantly to the model (p<0.05). Salivary gland image features of CT intensity heterogeneity such as the iSG difference variance as well as the dose to 10% of the MHM and homogeneity of the dose to the MPC (identified by the inverse difference of dose) were significant predictors of dysphagia post-RT. These results suggest that both salivary structure and dose to swallow muscles are important dysphagia predictors and the promise of this approach for a comprehensive RT-dysphagia model.

Relationships Between Peritoneal Protein Clearance and Parameters of Fluid Status Agree with Clinical Observations in Other Diseases that Venous Congestion Increases Microvascular Protein Escape.

Peritoneal effluent from peritoneal dialysis (PD) patients contains proteins, mainly transported from the circulation through large pores in the venular part of the peritoneal microvessels. Hydrostatic convection is the major driver for peritoneal protein transport, although in PD there is additional diffusion. Consequently, venous pressure may have a role in peritoneal protein transport. The aim of the study was to investigate the importance of venous congestion on the magnitude of peritoneal protein clearance in incident PD patients using non-invasive measurements. A total of 316 adult PD patients, on PD for 8 - 12 weeks and collecting 24-hour urine and dialysate for total protein determination, underwent standard peritoneal equilibration testing (PET) along with measurement of N terminal pro-brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP), multifrequency bioimpedance analysis, and a transthoracic echocardiogram. Statistically significant univariate relationships for peritoneal protein clearance with a Spearman correlation coefficient > 0.25 were present for 4-hour dialysate/plasma (D/P) creatinine, NT-proBNP, extracellular/total body water, extracellular water excess, left ventricular mass, and right atrial area. Negative correlations were found with serum total protein and residual renal function. On multivariate analysis, logNTproBNP (β 0.11, p = 0.007) and right atrial area (β 0.01, p = 0.03) were significant independent predictors of peritoneal protein clearance. Indicators of venous congestion showed the most important relationships with peritoneal protein clearance. These indicators have not been assessed in previous studies on the presence or absence of relationships between peritoneal protein clearance and mortality.

Hidradenitis suppurativa of the nape: Description of an atypical phenotype related to severe early-onset disease in men.

Some patients with hidradenitis suppurativa (HS) develop severe inflammatory lesions of the nape. Through a single-center, cross-sectional study with a total of 377 patients, we sought to compare patients with and without nape involvement, to determine whether disease severity is greater in these patients and to describe their clinical characteristics. Thirty patients (90% male) were identified as having nape involvement. Patients with versus without nape involvement had greater disease severity, earlier disease onset, a family history of HS, lower body mass, and higher Dermatological Life Quality Index and pain scores. Amongst them, involvement of the trunk and gluteal regions predominated. A significant univariate relationship existed between patients with nape involvement and male sex, early disease onset, family history, scalp and gluteal involvement, Canoui-Poitrine phenotypes II and III, and Dowling-Degos disease. A significant multivariate relationship existed with early disease onset, Dowling-Degos disease, and phenotypes II and III.

Short communication: Field study to investigate the associations between herd-level risk factors for milk fat depression and bulk tank milk fat percent in dairy herds feeding monensin

Fat is the most variable milk component, and maintaining milk fat continues to be a challenge on commercial dairy farms. Our objectives were to establish associations between herd-level risk factors for milk fat depression and bulk tank milk fat content in commercial dairy herds feeding monensin. Seventy-nine Holstein commercial dairy herds in the northeast and Upper Midwest United States were enrolled in an observational study. Data were collected on herd characteristics, total mixed ration (TMR) samples, all component silage samples, and bulk tank milk samples. The unconditional univariable association of each explanatory variable and bulk tank milk fat percentage was evaluated using simple linear regression and multivariable regression models. Milk fat content of trans-10 C18:1 had an exponentially negative relationship to herd milk fat percentage. In general, milk fat content of fatty acids synthesized de novo in the mammary gland were positively related to herd milk fat, and the content of several trans-C18:1 fatty acids, which would be products of alternate pathways of ruminal biohydrogenation, were negatively related to herd milk fat. Variables related to TMR composition did not have univariable relationships with herd milk fat percentage. Herds that had >49.8% of the TMR particles on the middle screen of the Penn State particle separator had higher milk fat percentage than those with ≤49.8%, and herds with >54.0% of TMR particles in the bottom pan had lower milk fat percentage than herds with ≤54.0%. Dietary content of monounsaturated fatty acids (C16:1 and C18:1) had negative relationships with herd milk fat percentage; however, no single diet component accounted for more than 11% of the variation in herd-level milk fat percentage. Univariable monensin dose was not associated with herd milk fat percentage. The relative lack of significant univariate relationships with herd-level milk fat suggests many factors contribute to milk fat content, and herds experiencing low milk fat will need to examine many potential risk factors when working to troubleshoot this challenge.

Endurance Exercise Training and Male Sexual Libido.

This article aimed to study the associations between aspects of endurance exercise training and sexual libido in healthy men using a cross-sectional online survey study design. A developed online survey questionnaire was used. The questionnaire was based on preexisting validated questionnaires and was used to assess elements of physical characteristics, exercise training habits, and libido of participants (n = 1077). Three evidence-based categories were created for the primary outcome of total libido score and low, normal, and high-response category sets. The high and normal categories were combined to form a high/normal score group, and the low category formed a low score group. Odds ratio (OR) values were calculated to examine group categorization. Age, training intensity, and training duration of participants had significant (P < 0.02) univariate relationships, with libido scores, and were thus included in the multivariate model. In the multivariate model, training intensity (P < 0.0001) and duration (P < 0.002) components were the most significantly associated with libido group designation (high/normal vs low). Participants with the lowest (OR = 6.9, 95% confidence interval [CI] = 2.6-17.9) and mid-range training intensities (OR = 2.8, 95% CI = 1.4-5.3) had greater odds of high/normal libido state than those with the highest training intensity. Participants with the shorter (OR = 4.1, 95% CI = 1.6-10.0) and mid-range training durations (OR = 2.5, 95% CI = 1.3-4.8) at their current intensity also had greater odds of high/normal libido score than those with a greatest duration. Exposure to higher levels of chronic intense and greater durations of endurance training on a regular basis is significantly associated with a decreased libido scores in men. Clinicians who treat male patients for sexual disorders and/or council couples on infertility issues should consider the degree of endurance exercise training a man is performing as a potential complicating factor.

Diffusion-compensated tofts model suggests contrast leakage through aneurysm wall.

The purpose of this study was to investigate the diffusional transport of contrast agent and its effects on kinetic modeling of dynamic contrast enhanced (DCE) images. We performed simulations of our diffusion-compensated model and compared these results to human intracranial aneurysms (IAs). We derive an easy-to-use parameterization of diffusional effects that can provide an accurate estimate of diffusion corrected contrast agent leakage rates (ktrans ). Finally, we performed re-ansalysis of an existing data set to determine whether diffusion-corrected kinetic parameters improve the identification of high-risk IAs, thereby providing a new MRI-based imaging metric of IA stability based on wall integrity. Probability distributions of simulated versus measured data show contrast leakage away from the aneurysm wall. Parameterization of diffusional effects on ktrans showed high correlation with long-chain methods in both surrounding tissue and near the aneurysm wall (r2 = 0.91 and r2 = 0.90, respectively). Finally, size, ktrans , and ( ktrans-kDCtrans) showed significant univariate relationships with rupture risk (P < 0.05). We report the first evidence of diffusion-compensated permeability modeling in intracranial aneurysms and propose a parameterization of diffusional effects on ktrans . Furthermore, a comparison of measured versus simulated data suggests that contrast leakage occurs across the aneurysm wall. Magn Reson Med 78:2388-2398, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

Birmingham Hip Resurfacing in Patients 55 Years or Younger: Risk Factors for Poor Midterm Outcomes

BackgroundBirmingham hip resurfacing (BHR) is the only Food and Drug Administration–approved hip resurfacing system available in the United States and is used as an alternative to conventional total hip arthroplasty in younger patients. The purpose of this study is to report on the midterm outcomes of BHR in patients 55 years and younger, and specifically to examine the risk factors for aseptic failure, all-cause revision, and complications in this patient population. MethodsFour hundred forty-two consecutive patients with 5-year follow-up were retrospectively reviewed. Multivariate analyses were conducted to control for potential confounding factors identified by univariate analyses. ResultsMean follow-up was 71.68 ± 10.24 months. Among the potential risk factors, only female gender and smaller head sizes had a significant univariate relationship with aseptic revision, all-cause revision, and all-cause complications. When both risk factors were included in a multivariable logistic regression model, analyses showed both variables were closely related, with female gender a better predictor of adverse outcomes than head size (ie, small head size can be thought of as a proxy for female gender). The 5-year implant survival is 95.1% females compared to 99.0% in males. ConclusionHip resurfacing with BHR has excellent survival rates in young patients with degenerative hip disease. Although this study suggests that females with small templated head sizes may not be suitable candidates for BHR, further studies are needed to better understand the underlying differences in gender.

Abstract 16276: A Web-based Tool for Predicting Acute Kidney Injury in ST-elevation Myocardial Infarction

ST-elevation myocardial infarction (STEMI) requires emergent diagnostic catheterization and therapeutic percutaneous coronary intervention. These therapies may cause acute kidney injury (AKI), a serious procedural complication that contributes to morbidity and mortality in STEMI patients. Identifying patients at risk for renal complications may save lives and reduce healthcare costs, but there is no validated tool for predicting AKI in STEMI patients. Methods: The UT-Methodist STEMI program is a racially diverse series of 1144 consecutive patients. We derived and validated the UT-AKI score to predict the risk of AKI in patients referred for STEMI (and not currently on dialysis). AKI was categorized by the modified AKI Network and RIFLE indices. The UT-AKI score was derived from logistic regression analysis performed on a randomly selected derivation dataset using variables with significant univariate relationships to AKI and markers of renal function. Receiver operator characteristic (ROC) curves for the UT-AKI were assessed in the derivation and validation datasets. Statistical significance was measured by appropriate parametric and non-parametric tests; a p&lt;0.05 was considered significant. Results: The incidence of AKI was similar in patients undergoing diagnostic catheterization with or without PCI (12% vs. 14%, p=0.34). ROC curve analysis of the validation data set showed that the UT-AKI score (AUC 0.76 (95% CI 0.70-0.82)) was significantly better at classifying patients at risk for AKI than the ACEF (AUC 0.65 (95% CI: 0.58-0.73)), AGEF (AUC 0.65 (95% CI: 0.58-0.72)), or Mehran (AUC 0.67 (95% CI: 0.59-0.75)). The classification accuracy for the UT-AKI index was comparable for milder and severe forms of AKI. Conclusions: In the largest analysis of STEMI patients to date, we found no significant difference in the risk of AKI from PCI vs. diagnostic catheterization. The validation study indicates that the UT-AKI index was significantly better than other scores at classifying which patients will develop AKI. Accurate prediction of AKI may help physicians to personalize therapies and develop novel strategies to reduce kidney injury in patients with STEMI.

Relationship Between Accelerometer-Measured Activity and Self-Reported or Performance-Based Function in Older Adults with Severe Aortic Stenosis.

In older adults with aortic stenosis, we evaluated whether accelerometer-measured physical activity provides distinct clinical information apart from self-reported surveys or performance-based function tests. We employed wrist-mounted accelerometry in 52 subjects with severe aortic stenosis prior to transcatheter aortic valve replacement (TAVR). Daily daytime activity was estimated using the maximum 10 h of daily accelerometer-measured activity (M10) reported in activity counts. Subjects completed baseline surveys (New York Heart Association (NYHA), Short Form 12 (SF12), Kansas City Cardiomyopathy Questionnaire (KCCQ), EuroQol-5D (EQ-5D), Revised Life Orientation Test (LOT-R), Life Space, Detailed Activity Form) and performance-based function tests (Short Physical Performance Battery, 6-min walk test distance, grip strength) to estimate functional status. Simple and multiple linear regression models were used to evaluate the relationship between accelerometer-measured activity and survey data and performance-based function tests. Among all baseline surveys and performance-based function tests, the only statistically significant univariable relationships identified were weak, negative associations between M10 and SF-12 Mental Composite Score (R2=0.1970, P=0.04) and between M10 and grip strength (R2=0.1568, P=0.004). Neither multiple linear regression of overall survey data (R2=0.6159, P=0.23) nor performance-based function tests (R2=0.1743, P=0.10) correlated with M10. Self-reported surveys and performance-based function tests are not meaningfully correlated with daytime accelerometer-measured activity. The results of our study suggest that accelerometer-measured physical activity provides distinct clinical information apart from self-reported surveys or performance-based function tests.

Evaluation of the Pharmacokinetics and Pharmacodynamics of Liposomal Amikacin for Inhalation in Cystic Fibrosis Patients with Chronic Pseudomonal Infections Using Data from Two Phase 2 Clinical Studies

The pharmacokinetic-pharmacodynamic (PK-PD) relationships between serum exposure measures of liposomal amikacin for inhalation (LAI) and the change in pulmonary function test (PFT) measures and number of CFU from baseline were evaluated in cystic fibrosis (CF) patients chronically infected with Pseudomonas aeruginosa. A dose of 70, 140, 280, or 560 mg of LAI or placebo was administered to CF patients once daily for 28 days. PFTs and sputum samples for microbiology were assessed on days 7, 14, 21, 28, 35 (for log10 CFU), and 56 (for PFTs). Serum, urine, and sputum samples were collected for PK evaluation. The relationships between efficacy endpoints (relative change in forced expiratory volume in 1 s [FEV1 {expressed in liters}] and FEV1% predicted and the absolute change in log10 CFU of P. aeruginosa from baseline) and exposure measures (dose, day 1 area under the curve [AUC], dose/MIC ratio, and day 1 AUC/MIC ratio) and baseline MIC value were assessed. The serum and urine PK data were best fit by a 3-compartment model (lung, serum, and urine) with linear clearance and interoccasional variation on total and renal clearance. Significant univariable relationships between dose or day 1 AUC and the relative change in PFT measures (P≤0.017) or the absolute change in log10 CFU from baseline (P≤0.037) on the study days were identified. Repeated-measures mixed-effects models, which showed dose- and AUC-related improvements for each efficacy endpoint (P≤0.041), predicted the observed data well. The increases in the relative change in FEV1 and FEV1% predicted of 11% and 9.9%, respectively, and a 1.23-log10 CFU reduction per 560 mg of LAI estimated on day 7 were comparable to the observed increases of 10.7% and 10.3%, respectively, and a 1.24-log10 CFU reduction on the same day. The model-estimated PFT effects were predicted to be sustained to day 28. An additional 0.451-log10 CFU reduction (P=0.022) was estimated on day 14 relative to day 7, with a persistence of effect predicted to day 35.