Dry and wet wrinkling of a silk fibroin biopolymer by a shape-memory material with insight into mechanical effects on secondary structures in the silk network.

Surface wrinkling provides an approach to modify the surfaces of biomedical devices to better mimic features of the extracellular matrix and guide cell attachment, proliferation, and differentiation. Biopolymer wrinkling on active materials holds promise but is poorly explored. Here we report a mechanically actuated assembly process to generate uniaxial micro-and nanosized silk fibroin (SF) wrinkles on a thermo-responsive shape-memory polymer (SMP) substrate, with wrinkling demonstrated under both dry and hydrated (cell compatible) conditions. By systematically investigating the influence of SMP programmed strain magnitude, film thickness, and aqueous media on wrinkle stability and morphology, we reveal how to control the wrinkle sizes on the micron and sub-micron length scale. Furthermore, as a parameter fundamental to SMPs, we demonstrate that the temperature during the recovery process can also affect the wrinkle characteristics and the secondary structures in the silk network. We find that with increasing SMP programmed strain magnitude, silk wrinkled topographies with increasing wavelengths and amplitudes are achieved. Furthermore, silk wrinkling is found to increase ß-sheet content, with spectroscopic analysis suggesting that the effect may be due primarily to tensile (e.g., Poisson effect and high-curvature wrinkle) loading modes in the SF, despite the compressive bulk deformation (uniaxial contraction) used to produce wrinkles. Silk wrinkles fabricated from sufficiently thick films (roughly 250 nm) persist after 24 h in cell culture medium. Using a fibroblast cell line, analysis of cellular response to the wrinkled topographies reveals high viability and attachment. These findings demonstrate use of wrinkled SF films under physiologically relevant conditions and suggest the potential for biopolymer wrinkles on biomaterials surfaces to find application in cell mechanobiology, wound healing, and tissue engineering.

A Primary Care-Based Weight Navigation Program.

Importance: Evidence-based weight management treatments (WMTs) are underused; strategies are needed to increase WMT use and patients' weight loss. Objective: To evaluate the association of a primary care-based weight navigation program (WNP) with WMT use and weight loss. Design, Setting, and Participants: This cohort study comprised a retrospective evaluation of a quality improvement program conducted from October 1, 2020, to September 30, 2021. Data analysis was performed from August 2, 2022, to March 7, 2024. Adults with obesity and 1 or more weight-related condition from intervention and control sites in a large academic health system in the Midwestern US were propensity matched on sociodemographic and clinical factors. Exposure: WNP, in which American Board of Obesity Medicine-certified primary care physicians offered weight-focused visits and guided patients' selection of preference-sensitive WMTs. Main Outcomes and Measures: Primary outcomes were feasibility measures, including rates of referral to and engagement in the WNP. Secondary outcomes were mean weight loss, percentage of patients achieving 5% or more and 10% or more weight loss, referral to WMTs, and number of antiobesity medication prescriptions at 12 months. Results: Of 264 patients, 181 (68.6%) were female and mean (SD) age was 49.5 (13.0) years; there were no significant differences in demographic characteristics between WNP patients (n = 132) and matched controls (n = 132). Of 1159 WNP-eligible patients, 219 (18.9%) were referred to the WNP and 132 (11.4%) completed a visit. In a difference-in-differences analysis, WNP patients lost 4.9 kg more than matched controls (95% CI, 2.11-7.76; P < .001), had 4.4% greater weight loss (95% CI, 2.2%-6.4%; P < .001), and were more likely to achieve 5% or more weight loss (odds ratio [OR], 2.90; 95% CI, 1.54-5.58); average marginal effects, 21.2%; 95% CI, 8.8%-33.6%) and 10% or more weight loss (OR, 7.19; 95% CI, 2.55-25.9; average marginal effects, 17.4%; 95% CI, 8.7%-26.2%). Patients in the WNP group were referred at higher rates to WMTs, including bariatric surgery (18.9% vs 9.1%; P = .02), a low-calorie meal replacement program (16.7% vs 3.8%; P < .001), and a Mediterranean-style diet and activity program (10.6% vs 1.5%; P = .002). There were no between-group differences in antiobesity medication prescribing. Conclusions and Relevance: The findings of this cohort study suggest that WNP is feasible and associated with greater WMT use and weight loss than matched controls. The WNP warrants evaluation in a large-scale trial.

Clinical outcomes of female external urine wicking devices as alternatives to indwelling catheters: a systematic review and meta-analysis.

BACKGROUND: Female patients using indwelling urinary catheters (IUCs) are disproportionately at risk for developing catheter-associated urinary tract infections (CAUTIs) compared to males. Female external urine wicking devices (FEUWDs) have emerged as potential alternatives to IUCs for incontinence management. OBJECTIVES: To assess the clinical risks and benefits of FEUWDs as alternatives to IUCs. METHODS: Ovid MEDLINE, Embase, Scopus, Web of Science Core Collection, CINAHL Complete, and ClinicalTrials.gov were searched from inception to July 10, 2023. Included studies used FEUWDs as an intervention and reported measures of urinary tract infections and secondary outcomes related to incontinence management. RESULTS: Of 2,580 returned records, 50 were systematically reviewed. Meta-analyses assessed rates of indwelling CAUTIs and IUC utilization. Following FEUWD implementation, IUC utilization rates decreased 14% (RR = 0.86, 95% CI = [0.76, 0.97]) and indwelling CAUTI rates nonsignificantly decreased up to 32% (IRR = 0.68, 95% CI = [0.39, 1.17]). Limited only to studies that described protocols for implementation, the incidence rate of indwelling CAUTIs decreased significantly up to 54% (IRR = 0.46, 95% CI = [0.32, 0.66]). Secondary outcomes were reported less routinely. CONCLUSIONS: Overall, FEUWDs nonsignificantly reduced indwelling CAUTI rates, though reductions were significant among studies describing FEUWD implementation protocols. We recommend developing standard definitions for consistent reporting of non-indwelling CAUTI complications such as FEUWD-associated UTIs, skin injuries, and mobility-related complications.

High-Quality, Chromosome-Level Reference Genomes of the Viviparous Caribbean Skinks Spondylurus nitidus and S. culebrae.

New World mabuyine skinks are a diverse radiation of morphologically cryptic lizards with unique reproductive biologies. Recent studies examining population-level data (morphological, ecological, and genomic) have uncovered novel biodiversity and phenotypes, including the description of dozens of new species and insights into the evolution of their highly complex placental structures. Beyond the potential for this diverse group to serve as a model for the evolution of viviparity in lizards, much of the taxonomic diversity is concentrated in regions experiencing increasing environmental instability from climate and anthropogenic change. Consequently, a better understanding of genome structure and diversity will be an important tool in the adaptive management and conservation of this group. Skinks endemic to Caribbean islands are particularly vulnerable to global change with several species already considered likely extinct and several remaining species either endangered or threatened. Combining PacBio long-read sequencing, Hi-C, and RNAseq data, here we present the first genomic resources for this group by describing new chromosome-level reference genomes for the Puerto Rican Skink Spondylurus nitidus and the Culebra Skink S. culebrae. Results indicate two high quality genomes, both ∼1.4 Gb, assembled nearly telomere to telomere with complete mitochondrion assembly and annotation.

Genome Assembly of Pyrocephalus nanus: A Step Toward the Genetic Conservation of the Endangered Little Vermilion Flycatcher of the Galapagos Islands.

Incredibly powerful whole genome studies of conservation genetics, evolution, and biogeography become possible for non-model organisms when reference genomes are available. Here, we report the sequence and assembly of the whole genome of the little vermilion flycatcher (Pyrocephalus nanus; family Tyrannidae), which is an endemic, endangered, and declining species of the Galapagos Islands. Using PacBio HiFi reads to assemble long contigs and Hi-C reads for scaffolding, we assembled a genome of 1.07 Gb comprising 267 contigs in 152 scaffolds, scaffold N50 74 M, contig N50 17.8 M, with 98.9% assigned to candidate chromosomal sequences and 99.72% of the BUSCO passeriformes 10,844 single-copy orthologs present. In addition, we used the novel HiFiMiTie pipeline to fully assemble and verify all portions of the mitochondrial genome from HiFi reads, obtaining a mitogenome of 17,151 bases, containing 13 protein-coding genes, 22 tRNAs, 2 rRNAs, two control regions, and a unique structure of control region duplication and repeats. These genomes will be a critical tool for much-needed studies of phylogenetics, population genetics, biogeography, and conservation genetics of Pyrocephalus and related genera. This genome and other studies that use it will be able to provide recommendations for conservation management, taxonomic improvement, and to understand the evolution and diversification of this genus within the Galapagos Islands.

Tuning the Topography of Dynamic 3D Scaffolds through Functional Protein Wrinkled Coatings.

Surface wrinkling provides an approach to fabricate micron and sub-micron-level biomaterial topographies that can mimic features of the dynamic, in vivo cell environment and guide cell adhesion, alignment, and differentiation. Most wrinkling research to date has used planar, two-dimensional (2D) substrates, and wrinkling work on three-dimensional (3D) structures has been limited. To enable wrinkle formation on architecturally complex, biomimetic 3D structures, here, we report a simple, low-cost experimental wrinkling approach that combines natural silk fibroin films with a recently developed advanced manufacturing technique for programming strain in complex 3D shape-memory polymer (SMP) scaffolds. By systematically investigating the influence of SMP programmed strain magnitude, silk film thickness, and aqueous media on wrinkle morphology and stability, we reveal how to generate and tune silk wrinkles on the micron and sub-micron scale. We find that increasing SMP programmed strain magnitude increases wavelength and decreases amplitudes of silk wrinkled topographies, while increasing silk film thickness increases wavelength and amplitude. Silk wrinkles persist after 24 h in cell culture medium. Wrinkled topographies demonstrate high cell viability and attachment. These findings suggest the potential for fabricating biomimetic cellular microenvironments that can advance understanding and control of cell-material interactions in engineering tissue constructs.

Weight Loss Treatment and Longitudinal Weight Change Among Primary Care Patients With Obesity.

Importance: Among individuals with obesity, 5% or greater weight loss can improve health. Weight management treatments (WMT) include nutrition counseling, very low-calorie meal replacement (MR), antiobesity medications (AOM), and bariatric surgery; however, little is known about how these WMT are associated with weight change among individual patients and populations. Objective: To characterize weight status and WMT use among primary care patients and assess associations between WMT and weight trajectories. Design, Setting, and Participants: Retrospective, population-based cohort study of primary care patients from 1 academic health system in Michigan between October 2015 and March 2020 using cross-sectional analysis to compare obesity prevalence and WMT utilization. For patients with obesity and WMT exposure or matched controls, a multistate Markov model assessing associations between WMT and longitudinal weight status trajectories was used. Data were analyzed from October 2021 to October 2023. Exposures: Cross-sectional exposure was year: 2017 or 2019. Trajectory analysis exposures were WMT: nutrition counseling, MR, AOM, and bariatric surgery. Main Outcomes and Measures: Cross-sectional analysis compared mean body mass index (BMI), obesity prevalence, and, among patients with obesity, prospective WMT use. The trajectory analysis examined longitudinal weight status using thresholds of ±5% and 10% of baseline weight with primary outcomes being the 1-year probabilities of 5% or greater weight loss for each WMT. Results: Adult patients (146 959 participants) consisted of 83 636 female participants (56.9%); 8940 (6.1%) were Asian, 14 560 (9.9%) were Black, and 116 664 (79.4%) were White. Patients had a mean (SD) age of 49.6 (17.7) years and mean (SD) BMI of 29.2 (7.2). Among 138 682 patients, prevalence of obesity increased from 39.2% in 2017 to 40.7% in 2019; WMT use among patients with obesity increased from 5.3% to 7.1% (difference: 1.7%; 95% CI, 1.3%-2.2%). In a multistate model (10 180 patients; 33 549 patient-years), the 1-year probability of 5% or greater weight loss without WMT exposure was 15.6% (95% CI, 14.3%-16.5%) at reference covariates. In contrast, the probability of 5% or greater weight loss was more likely with year-long exposures to any WMT (nutrition counseling: 23.1%; 95% CI, 21.3%-25.1%; MR: 54.6%; 95% CI, 46.5%-61.2%; AOM: 27.8%; 95% CI, 25.0%-30.5%; bariatric surgery: 93.0%; 95% CI, 89.7%-95.0%). Conclusions and Relevance: In this cohort study of primary-care patients with obesity, all WMT increased the patient-level probability of achieving 5% or greater weight loss, but current rates of utilization are low and insufficient to reduce weight at the population level.

Comparative genomics of symbiotic Photobacterium using highly contiguous genome assemblies from long read sequences.

This study presents the assembly and comparative genomic analysis of luminous Photobacterium strains isolated from the light organs of 12 fish species using Oxford Nanopore Technologies (ONT) sequencing. The majority of assemblies achieved chromosome-level continuity, consisting of one large (>3 Mbp) and one small (~1.5 Mbp) contig, with near complete BUSCO scores along with varying plasmid sequences. Leveraging this dataset, this study significantly expanded the available genomes for P. leiognathi and its subspecies P. 'mandapamensis', enabling a comparative genomic analysis between the two lineages. An analysis of the large and small chromosomes unveiled distinct patterns of core and accessory genes, with a larger fraction of the core genes residing on the large chromosome, supporting the hypothesis of secondary chromosome evolution from megaplasmids in Vibrionaceae. In addition, we discovered a proposed new species, Photobacterium acropomis sp. nov., isolated from an acropomatid host, with an average nucleotide identify (ANI) of 93 % compared to the P. leiognathi and P. 'mandapamensis' strains. A comparison of the P. leiognathi and P. 'mandapamensis' lineages revealed minimal differences in gene content, yet highlighted the former's larger genome size and potential for horizontal gene transfer. An investigation of the lux-rib operon, responsible for light production, indicated congruence between the presence of luxF and host family, challenging its role in differentiating P. 'mandapamensis' from P. leiognathi. Further insights were derived from the identification of metabolic differences, such as the presence of the NADH:quinone oxidoreductase respiratory complex I in P. leiognathi as well as variations in the type II secretion system (T2S) genes between the lineages, potentially impacting protein secretion and symbiosis. In summary, this study advances our understanding of Photobacterium genome evolution, highlighting subtle differences between closely related lineages, specifically P. leiognathi and P. 'mandapamensis'. These findings highlight the benefit of long read sequencing for bacterial genome assembly and pangenome analysis and provide a foundation for exploring early bacterial speciation processes of these facultative light organ symbionts.

Targeting a cell-specific microRNA repressor of CXCR4 ameliorates atherosclerosis in mice.

The CXC chemokine receptor 4 (CXCR4) in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) is crucial for vascular integrity. The atheroprotective functions of CXCR4 in vascular cells may be counteracted by atherogenic functions in other nonvascular cell types. Thus, strategies for cell-specifically augmenting CXCR4 function in vascular cells are crucial if this receptor is to be useful as a therapeutic target in treating atherosclerosis and other vascular disorders. Here, we identified miR-206-3p as a vascular-specific CXCR4 repressor and exploited a target-site blocker (CXCR4-TSB) that disrupted the interaction of miR-206-3p with CXCR4 in vitro and in vivo. In vitro, CXCR4-TSB enhanced CXCR4 expression in human and murine ECs and VSMCs to modulate cell viability, proliferation, and migration. Systemic administration of CXCR4-TSB in Apoe-deficient mice enhanced Cxcr4 expression in ECs and VSMCs in the walls of blood vessels, reduced vascular permeability and monocyte adhesion to endothelium, and attenuated the development of diet-induced atherosclerosis. CXCR4-TSB also increased CXCR4 expression in B cells, corroborating its atheroprotective role in this cell type. Analyses of human atherosclerotic plaque specimens revealed a decrease in CXCR4 and an increase in miR-206-3p expression in advanced compared with early lesions, supporting a role for the miR-206-3p-CXCR4 interaction in human disease. Disrupting the miR-206-3p-CXCR4 interaction in a cell-specific manner with target-site blockers is a potential therapeutic approach that could be used to treat atherosclerosis and other vascular diseases.

Thermally and Photothermally Triggered Cytocompatible Triple-Shape-Memory Polymer Based on a Graphene Oxide-Containing Poly(ε-caprolactone) and Acrylate Composite.

Triple-shape-memory polymers (triple-SMPs) are a class of polymers capable of fixing two temporary shapes and recovering sequentially from the first temporary shape to the second temporary shape and, last, to the permanent shape. To accomplish a sequential shape change, a triple-SMP must have two separate shape-fixing mechanisms triggerable by distinct stimuli. Despite the biomedical potential of triple-SMPs, a triple-SMP that with cells present can undergo two different shape changes via two distinct cytocompatible triggers has not previously been demonstrated. Here, we report the design and characterization of a cytocompatible triple-SMP material that responds separately to thermal and light triggers to undergo two distinct shape changes under cytocompatible conditions. Tandem triggering was achieved via a photothermally triggered component, comprising poly(ε-caprolactone) (PCL) fibers with graphene oxide (GO) particles physically attached, embedded in a thermally triggered component, comprising a tert-butyl acrylate-butyl acrylate (tBA-BA) matrix. The material was characterized in terms of thermal properties, surface morphology, shape-memory performance, and cytocompatibility during shape change. Collectively, the results demonstrate cytocompatible triple-shape behavior with a relatively larger thermal shape change (an average of 20.4 ± 4.2% strain recovered for all PCL-containing groups) followed by a smaller photothermal shape change (an average of 3.5 ± 0.8% strain recovered for all PCL-GO-containing groups; samples without GO showed no recovery) with greater than 95% cell viability on the triple-SMP materials, establishing the feasibility of triple-shape memory to be incorporated into biomedical devices and strategies.

Using Machine Learning to Predict Suitability for Surgery at an Ambulatory Surgical Center.

This Surgical Innovation describes the use of a site optimization model that uses machine learning to stratify patients according to whether they can have surgery at an ambulatory surgical center vs a hospital-based outpatient department.

Comparative Evaluation of Electron Ionization Mass Spectral Prediction Methods.

During the past decade promising methods for computational prediction of electron ionization mass spectra have been developed. The most prominent ones are based on quantum chemistry (QCEIMS) and machine learning (CFM-EI, NEIMS). Here we provide a threefold comparison of these methods with respect to spectral prediction and compound identification. We found that there is no unambiguous way to determine the best of these three methods. Among other factors, we find that the choice of spectral distance functions play an important role regarding the performance for compound identification.

Printing Parameters of Fused Filament Fabrication Affect Key Properties of Four-Dimensional Printed Shape-Memory Polymers.

Extrusion-based (fused filament fabrication) three-dimensional (3D) printing of shape-memory polymers (SMPs) has the potential to rapidly produce highly customized smart-material parts. Yet, the effects of printing parameters on the shape-memory properties of printed SMPs remain poorly understood. To study the extent to which the 3D printing process affects the shape-memory properties of a printed SMP part, here temperature, extrusion rate multiplier, and fiber orientation were systematically varied, and their effect on shape-memory fixing and recovery ratios was evaluated. Fiber orientation, as determined by print path relative to the direction(s) of loading during shape-memory programming, was found to significantly impact the fixing ratio and the recovery ratio. Temperature and multiplier had little effect on either fixing ratio or recovery ratio. To facilitate the use of printed SMP parts in biomedical applications, a cell viability assay was performed on 3D-printed samples prepared using varied temperature and multiplier. Reduction in multiplier was found to increase cell viability. The results indicate that fiber orientation can critically impact the shape-memory functionality of 3D-printed SMP parts, and that multiplier can affect cytocompatibility of those parts. Thus, researchers and manufacturers employing SMPs in 3D-printed parts and devices could achieve improved part functionality if print paths are designed to align fiber direction with the axis(es) in which strain will be programmed and recovered and if the multiplier is optimized in biomedical applications in which a part will contact cells.

Surface Functionalization of 4D Printed Substrates Using Polymeric and Metallic Wrinkles.

Wrinkle topographies have been studied as simple, versatile, and in some cases biomimetic surface functionalization strategies. To fabricate surface wrinkles, one material phenomenon employed is the mechanical-instability-driven wrinkling of thin films, which occurs when a deforming substrate produces sufficient compressive strain to buckle a surface thin film. Although thin-film wrinkling has been studied on shape-changing functional materials, including shape-memory polymers (SMPs), work to date has been primarily limited to simple geometries, such as flat, uniaxially-contracting substrates. Thus, there is a need for a strategy that would allow deformation of complex substrates or 3D parts to generate wrinkles on surfaces throughout that complex substrate or part. Here, 4D printing of SMPs is combined with polymeric and metallic thin films to develop and study an approach for fiber-level topographic functionalization suitable for use in printing of arbitrarily complex shape-changing substrates or parts. The effect of nozzle temperature, substrate architecture, and film thickness on wrinkles has been characterized, as well as wrinkle topography on nuclear alignment using scanning electron microscopy, atomic force microscopy, and fluorescent imaging. As nozzle temperature increased, wrinkle wavelength increased while strain trapping and nuclear alignment decreased. Moreover, with increasing film thickness, the wavelength increased as well.

ANXA11 biomolecular condensates facilitate protein-lipid phase coupling on lysosomal membranes.

Phase transitions of cellular proteins and lipids play a key role in governing the organisation and coordination of intracellular biology. The frequent juxtaposition of proteinaceous biomolecular condensates to cellular membranes raises the intriguing prospect that phase transitions in proteins and lipids could be co-regulated. Here we investigate this possibility in the ribonucleoprotein (RNP) granule-ANXA11-lysosome ensemble, where ANXA11 tethers RNP granule condensates to lysosomal membranes to enable their co-trafficking. We show that changes to the protein phase state within this system, driven by the low complexity ANXA11 N-terminus, induce a coupled phase state change in the lipids of the underlying membrane. We identify the ANXA11 interacting proteins ALG2 and CALC as potent regulators of ANXA11-based phase coupling and demonstrate their influence on the nanomechanical properties of the ANXA11-lysosome ensemble and its capacity to engage RNP granules. The phenomenon of protein-lipid phase coupling we observe within this system offers an important template to understand the numerous other examples across the cell whereby biomolecular condensates closely juxtapose cell membranes.

Frequency and impact of musculoskeletal symptoms on quality of life in MEN2B.

OBJECTIVE: To investigate the impact of musculoskeletal (MSK)-related symptoms on the quality of life of patients with multiple endocrine neoplasia Type 2b (MEN2B). DESIGN: An online survey was distributed by the Association for Multiple Endocrine Neoplasia Disorders (AMEND) to their members and worldwide via a social media group for MEN2B patients. METHODS: The survey consisted of a detailed questionnaire analysing the MSK-related symptoms and structural deformities of MEN2B patients and their impact on patient's lives. PARTICIPANTS: Forty-eight participants completed the survey. RESULTS: Participants reported several musculoskeletal complaints; the most prevalent being musculoskeletal weakness at 73% (n = 35) and pain 58% (n = 28). The median pain score was 7 (interquartile range [IQR]: 5-8) and the frequency of pain was daily in 44% (n = 15) and constant in 21% (n = 7). Structural complaints were common with 63% (n = 30) stating their physique was 'different' and 40% (n = 19) describing marfanoid body features. Spinal curvature and foot deformities were the commonest structural abnormalities with scoliosis 70% (n = 16) and pes cavus 63% (n = 22) prevailing. Dental problems were mentioned by 69% (n = 33) with interdental spacing being the most common complaint at 61% (n = 20). The musculoskeletal symptoms of MEN2B had a median impact of 6 (IQR: 3-9) on quality of life (QOL) with structural deformities 53% (n = 18) and pain 26% (n = 9) listed as having the highest impact. Poor MSK health affected exercise, work and mobility. CONCLUSIONS: We report a high prevalence of musculoskeletal-related complaints in MEN2B which significantly affects QOL. This suggests a need to provide better holistic care including a multidisciplinary team with physiotherapist, orthopaedic and dental specialist input.

Renal Dysfunction and Arrhythmia Association in Patients Receiving Milrinone After Cardiac Surgery.

OBJECTIVE: The altered pharmacokinetics of milrinone in renal impairment could result in an increased risk of cardiac arrhythmias. This study aimed to determine if there is an association between new-onset arrhythmias and renal impairment after cardiac surgery following milrinone administration. DESIGN: A retrospective cohort study. SETTING: A single-center tertiary care hospital. PARTICIPANTS: Adult patients who received a milrinone infusion in the intensive care unit (ICU) setting after coronary artery bypass graft, valvuloplasty, annuloplasty, or a combination of these surgeries from July 1, 2014 to July 1, 2021. Renal impairment was defined using a creatinine clearance <60 mL/min, calculated using the Cockcroft-Gault equation. INTERVENTIONS: Patients received a weight-based continuous intravenous infusion of milrinone. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the presence of new arrhythmias after the initial administration of a weight-based continuous intravenous infusion of milrinone postcardiac surgery. Of the 197 patients who met inclusion, there was no difference in the presence of new arrhythmias (42.9% v 40.3%, p = 0.76) or in the time to first new arrhythmia from milrinone initiation in those with renal impairment compared to those without renal impairment (29.1 hours v 33.3 hours, p = 0.54). Patients with renal impairment had a longer hospital stay than patients without renal impairment (17.5 days v 13.9 days, p = 0.016). Arrhythmia type, length of ICU stay, ICU mortality, and hospital mortality were not different between the cohorts. CONCLUSIONS: There was no association between new arrhythmias, milrinone, and renal impairment in patients postcardiac surgery.

Comprehensive History and Physicals are Common Before Low-Risk Surgery and Associated With Preoperative Test Overuse.

INTRODUCTION: The Centers for Medicare and Medicaid Services (CMS) recently eliminated the requirement for preoperative history and physicals (H&Ps) prior to ambulatory surgery. We sought to assess variations in separately billed preoperative H&P utilization prior to low-risk ambulatory surgery, describe any relationship with preoperative testing, and identify independent predictors of these consultations prior to this policy change to help characterize the potential unnecessary utilization of these consultations and potential unnecessary preoperative testing prior to low-risk surgery. MATERIALS AND METHODS: A retrospective cohort study was performed using claims data from a hospital value collaborative in Michigan from January 2015 to June 2019 and included patients undergoing one of three ambulatory procedures: breast lumpectomy, laparoscopic cholecystectomy, and laparoscopic inguinal hernia repair. Rates of preoperative H&P visits within 30 d of surgical procedure were determined. H&P and preoperative testing associations were explored, and patient-level, practice-level, and hospital-level determinants of utilization were assessed with regression models. Risk and reliability-adjusted caterpillar plots were generated to demonstrate hospital-level variations in utilization. RESULTS: 50,775 patients were included with 50.5% having a preoperative H&P visit, with these visits being more common for patients with increased comorbidities (1.9 ± 2.2 vs 1.4 ± 1.9; P < 0.0001). Preoperative testing was associated with H&P visits (57.2% vs 41.4%; P < 0.0001). After adjusting for patient case-mix and interhospital and intrahospital variations in H&P visits, utilization remained with significant associations in patients with increased comorbidities. CONCLUSIONS: Preoperative H&P visits were common before three low-risk ambulatory surgical procedures across Michigan and were associated with higher rates of low-value preoperative testing, suggesting that preoperative H&P visits may create clinical momentum leading to unnecessary testing. These findings will inform strategies to tailor preoperative care before low-risk surgical procedures and may lead to reduced utilization of low-value preoperative testing.