Duplex Scans Performed Immediately Following Lower Extremity Angioplasty and Stenting are of Limited Utility.

BACKGROUND: Together with clinical examination, surveillance duplex examination represents the Society of Vascular Surgery recommendations for follow-up after endovascular intervention on the superficial femoral artery (SFA) and popliteal arterial segments. Compliance with postprocedural follow-up remains challenging. To establish a postangioplasty physiologic baseline, our institution began obtaining immediate postprocedural surveillance studies following lower extremity arterial interventions. We reviewed the utility of immediate postprocedural surveillance to determine if these studies enhanced postoperative care. METHODS: Serial patients undergoing SFA and popliteal angioplasty and stenting from January 2014 to December 2020 were identified from our prospectively maintained Vascular Surgery database. Patient demographic information, procedural details, and procedural outcomes were subsequently analyzed from the electronic medical record. RESULTS: Two hundred and sixty-three patients underwent 385 SFA and/or popliteal angioplasty/stenting interventions. Mean patient age was 64.8 ± 10 years. Among these 385 procedures, 350 (90.9%) were followed by immediate (<4 hours) postprocedural lower extremity arterial duplex scans. These 350 procedures included percutaneous transluminal angioplasty and/or stenting of the SFA (n = 236), popliteal artery (n = 34), or both (n = 80). Of these studies, 25 results (7.1%) were abnormal. One asymptomatic patient was admitted to hospital for immediate thrombolysis; however, the remaining 24 patients were followed clinically with no immediate intervention required. Abnormal results included 13 abnormalities appreciated on the final angiogram with 9 patients with known occlusions or stenoses, and 4 patients with mild to moderate CFA stenosis. Abnormal findings not detected on the final angiogram included 7 patients with mild to moderate stenosis and 5 patients with short occlusions (1.4%). All 5 patients with short segmental occlusions not detected on final arteriogram had preprocedural anatomy classified as either TASC C (TransAtlantic Inter-Society Consensus: SFA occlusions > 15 cm in length, n = 1) or TASC D (SFA occlusions > 20 cm in lenth, n = 4). CONCLUSIONS: Immediate postprocedural duplex scans demonstrate significant vessel stenosis or occlusion in approximately 7% of cases but most stenoses and occlusions were noted on final arteriography. Duplex detected short segmental occlusions not noted on final arteriography were rare (1.4%), and occurred among patients with TASC C or TASC D occlusive disease. These duplex detected abnormalities rarely changed the patient's immediate plan of care. The performance of these immediate postprocedural duplex scans demonstrated limited clinical utility.

Differential engagement of inhibitory and excitatory cardiopulmonary reflexes by capsaicin and phenylbiguanide in C57BL/6 mice.

The Bezold-Jarisch reflex is a powerful inhibitory reflex initiated by activation of cardiopulmonary vagal nerves during myocardial ischemia, hemorrhage, and orthostatic stress leading to bradycardia, vasodilation, hypotension, and vasovagal syncope. This clinically relevant reflex has been studied by measuring heart rate (HR) and mean arterial pressure (MAP) responses to injections of a variety of chemical compounds. We hypothesized that reflex responses to different compounds vary due to differential activation of vagal afferent subtypes and/or variable coactivation of excitatory afferents. HR and MAP responses to intravenous injections of the transient receptor potential vanilloid-1 (TRPV1) agonist capsaicin and the serotonin 5-HT3 receptor agonist phenylbiguanide (PBG) were measured in anesthetized C57BL/6 mice before and after bilateral cervical vagotomy. Capsaicin and PBG evoked rapid dose-dependent decreases in HR and MAP followed by increases in HR and MAP above baseline. Bezold-Jarisch reflex responses were abolished after vagotomy, whereas the delayed tachycardic and pressor responses to capsaicin and PBG were differentially enhanced. The relative magnitude of bradycardic versus depressor responses (↓HR/↓MAP) in vagus-intact mice was greater with capsaicin. In contrast, after vagotomy, the magnitude of excitatory tachycardic versus pressor responses (↑HR/↑MAP) was greater with PBG. Although capsaicin-induced increases in MAP and HR postvagotomy were strongly attenuated or abolished after administration of the ganglionic blocker hexamethonium, PBG-induced increases in MAP and HR were mildly attenuated and unchanged, respectively. We conclude that responses to capsaicin and PBG differ in mice, with implications for delineating the role of endogenous agonists of TRPV1 and 5-HT3 receptors in evoking cardiopulmonary reflexes in pathophysiological states.

A meta-analysis on the effect of proximal landing zone location on stroke and mortality in thoracic endovascular aortic repair.

BACKGROUND: Thoracic endovascular aortic repair (TEVAR) involving the aortic arch may increase the opportunity for stroke owing to disruption of cerebral circulation and embolization. In this study, a systematic meta-analysis was performed to examine the impact of proximal landing zone location on stroke and 30-day mortality after TEVAR. METHODS: MEDLINE and Cochrane Library were searched for all original studies of TEVAR reporting outcomes of stroke or 30-day mortality for at least two adjacent proximal landing zones, based on the Ishimaru classification scheme. Forest plots were created using relative risks (RR) with 95% confidence intervals (CI). An I2 of <40% was regarded as minimal heterogeneity. A P value of <.05 was considered significant. RESULTS: Of the 57 studies examined, a total of 22,244 patients (male 73.1%, aged 71.9 ± 11.5 years) were included in the meta-analysis, with 1693 undergoing TEVAR with proximal landing zone 0, 1931 with zone 1, 5839 with zone 2, and 3089 with zone 3 and beyond. The overall risk of clinically evident stroke was 2.7% for zones ≥3, 6.6% for zone 2, 7.7% for zone 1, and 14.2% for zone 0. More proximal landing zones were associated with higher risks of stroke compared with distal (zone 2 vs ≥3: RR, 2.14; 95% CI, 1.43-3.20; P = .0002; I2 = 56%; zone 1 vs 2: RR, 1.48; 95% CI, 1.20-1.82; P = .0002; I2 = 0%; zone 0 vs 1: RR, 1.85; 95% CI, 1.52-2.24; P < .00001; I2 = 0%). Mortality at 30 days was 2.9% for zones ≥3, 2.4% for zone 2, 3.7% for zone 1, and 9.3% for zone 0. Zone 0 was associated with higher mortality compared with zone 1 (RR, 2.30; 95% CI, 1.75-3.03; P < .00001; I2 = 0%). No significant differences were found in 30-day mortality between zones 1 and 2 (P = .13) and between zone 2 and zones ≥3 (P = .87). CONCLUSIONS: The risk of stroke from TEVAR is lowest in zone 3 and beyond, increasing significantly as the landing zone is moved proximally. Furthermore, perioperative mortality is increased with zone 0 compared with zone 1. Therefore, risk of stent grafting in the proximal arch should be weighed against alternative surgical or nonoperative options. It is anticipated that the risk of stroke will improve with further development of stent graft technology and implantation technique.

Safety of Utilizing Ultrasound as the Sole Modality of Follow-Up after Endovascular Aneurysm Repair.

BACKGROUND: Post endovascular aneurysm repair (EVAR), surveillance with computed tomography-aortography (CTA) remains the most common practice, per Society for Vascular Surgery (SVS) guidelines. Chronic exposure to both radiation and intravenous (IV) contrast has raised concerns about long-term CTA follow-up (FU). As we have selectively used ultrasound (US) as a sole modality for post-EVAR surveillance, we sought to review our outcomes in this subset of patients. METHODS: Retrospective review of our institution's vascular database identified 213 EVAR patients from 2013 to 2021. Fenestrated-EVAR and snorkel reconstructions were excluded. Patient demographics/outcomes, abdominal aortic aneurysm (AAA) characteristics, and FU modalities and outcomes were analyzed. Unpaired Student's t-test, ANOVA, and chi-squared test were used to assess group differences. RESULTS: Eighty-five of the 213 EVAR patients (39.9%) were lost to FU within 3 months. Among the 128 remaining patients, 91 underwent FU using initial US, while 37 patients underwent post-EVAR FU initially using CTA. There were no significant differences (P > 0.05) between patient age (75.5 ± 9.4 vs. 75.3 ± 8.5), body mass index (BMI) (27.7 ± 5.4 vs. 28.9 ± 7.4), or mean AAA size (5.6 ± 1.1 vs. 5.9 ± 1.2) in US-surveilled and computed tomography (CT)-surveilled groups, respectively. Of the 91 patients, initially surveilled with US, 15 patients demonstrated endoleak and/or AAA growth (>5 mm). The 15 patients with US-demonstrated endoleak and/or growth underwent confirmatory CTA, with 3 patients eventually requiring EVAR revision. Among 37 patients initially surveilled with CT, 10 demonstrated significant growth and 2 patients eventually required EVAR revision. There were no patients with AAA rupture during post-EVAR surveillance. FU data were analyzed among a select lower-risk group of patients (preoperative AAA diameter ≤5.5 cm, BMI ≤30, and no endoleak at completion of EVAR). Among this group, there were no surveilled patients who required EVAR reintervention, regardless of surveillance modality (US n = 32; CT n = 4). The average FU was 29.5 ± 26.4 months in the US group and 26.4 ± 22.3 months in the CT group (P > 0.05). CONCLUSIONS: Although initial CT surveillance following EVAR remains ideal, in select lower-risk patients, US is a viable alternative even for the initial post-procedure study. Advantages include decreased radiation exposure and cost. Our data suggest that US is a safe sole modality for surveillance following EVAR in selective patients.

Spinal drain for aortic aneurysm repairs: tool or toy?

PURPOSE OF REVIEW: Spinal cord injury (SCI) is one of the biggest complications in open and endovascular aortic repairs. Historically, cerebrospinal fluid drains (CSFD) have been one of the most effective modalities in reducing SCI and one of the most studied. CSFD placement also carries its' own set of procedural risks. This editorial intends to evaluate recent literature to determine whether CSFDs remain a valuable tool in aortic repair. RECENT FINDINGS: As the surgical management of thoracic aortic aneurysms has evolved, there has been an increasing number of endovascular repairs. Current recommendations emphasize prophylactic CSFD placement in endovascular repair cases deemed 'high risk.' However, several meta-analyses differ on whether prophylactic CSFD placement reduced the risk of SCI. The incidence of SCI decreased between 2014 and 2018, despite a similar rate of prophylactic CSFD placement suggesting other techniques are being performed and may be effective in spinal cord protection as well. SUMMARY: There has been conflicting data on whether CSFDs have a role in reducing the risk of SCI in endovascular aortic repair. Some studies suggest that there is no benefit to placement while others suggest that routine prophylactic drains should be placed for all endovascular cases. Despite this, efforts have been made to selectively place CSFDs in those patients deemed at 'high risk' for SCI. CSFDs also remain a part of rescue treatment for postoperative SCI. This suggests that CSFDs continue to be a valuable tool that we need to better comprehend. Future research is necessary to better understand how patient risk factors can be balanced with perioperative management to help identify patients who may benefit from CSFD placement.

Elevated Risk Analysis Index (RAI) Frailty Scores Are Independently Associated with Adverse Outcomes in Lower Extremity Surgical Revascularizations Similarly Across Genders.

BACKGROUND: The Risk Analysis Index (RAI) frailty scoring system has recently undergone revision and external validation using the National Surgical Quality Improvement Program (NSQIP) database. We set forth to evaluate the association of RAI-rev ranges with outcomes following lower extremity surgical revascularization and verify equivalent applicability across genders. METHODS: All elective NSQIP Targeted Lower Extremity Open cases from 2015-2019 were divided by EMR-recorded gender. Aggregate demographics, perioperative factors, and 30-day outcomes were compared using unpaired t-test and Fisher's exact test. Adjusted odds-ratios (aOR) for each outcome were generated by applying a multivariate binary logistic regression model (IBM SPSSTM) for five-point RAI-rev score increments from 25-45 and a most-frail group with scores >45 with a non-frail reference of <25. Covariates included surgical indication, prior ipsilateral revascularization, graft utilization, dirty/infected wound, smoking, hypertension, diabetes, and steroid use. RESULTS: 8,155 cases included 2,498 (31%) performed in women who demonstrated slightly lower RAI-rev scores than men (22.1 ± 5.8 vs. 24.2 ± 5.1; P = 0.0001). Univariate trends demonstrated dose-dependent increases in frequency of most outcomes with rising frailty score ranges, most substantially regarding mortality (0.4% non-frail to 14.7% most-frail), disposition to skilled nursing facility (8% non-frail to 27% most-frail), and extended length of stay (16% non-frail to 44% most-frail). After adjusting for co-variates, patients with RAI-rev scores of 26-30 had aOR of 1.4 (95% CI: 1.2-1.6; P < 0.001), 1.9 (95% CI: 1.6-2.2; P < 0.001), and 2.4 (95% CI:1.3-4.4; P < 0.001) for extended stay, disposition to skilled nursing, and mortality respectively. Trends were similar across genders in both univariate and multivariate analyses. CONCLUSIONS: Mortality, extended stay, and increased rehabilitation needs after surgical revascularization were associated with higher RAI-rev score ranges in a dose dependent manner similarly across genders.

The failure mode of a mechanically loaded equine medial femoral condyle analog with a void and the impact of lag and neutral screw placement.

OBJECTIVE: To determine the failure method of simulated equine medial femoral condyle (MFC) subchondral bone defects under compression and the influence of screw placement on failure resistance. STUDY DESIGN: In vitro study. SAMPLE POPULATION: Composite disks (CD) simulating the moduli of yearling bone in the MFC. METHODS: Four CD conditions were tested, all with a 12.7 mm void (n = 6 per condition): intact (no void), void only, void with a 4.5 mm screw placed in neutral fashion, and void with a 4.5 mm screw placed in lag fashion. Composite disks of each condition were tested under monotonic compression to 6000 N and cyclic compression to 10 000 cycles. Observable failure, load at first observable failure, and displacement at peak 2000 N load were compared among conditions. RESULTS: Specimens failed by cracking at the superior aspect of the void or the screw exit hole. After monotonic loading, cracks were observed 6/6 CD with a void, 6/6 CD with a void/lag screw, and 5/6 CD with a void/neutral screw. After cyclical testing, cracks were noted only on the superior aspect of 6/6 CD with a void and 3/6 CD with a void/lag screw. Displacement at peak load was 0.06 mm (intact), 0.32 mm (void), 0.24 mm (void/lag screw), and 0.11 mm (void/neutral screw). CONCLUSION: Model MFC voids failed by superior cracking that was resisted by lag and neutral screw placement. CLINICAL SIGNIFICANCE: Neutral screws may be an acceptable treatment for subchondral lucencies in the MFC.

Healthcare worker choice and low back force between self-chosen and highest bed height when boosting a patient up in bed.

Healthcare workers have a high rate of low back injury due to patient handling tasks. These workers receive training in patient handling methods such as adjusting bed height, but often ignore them. In this study, 35 healthcare workers completed patient boosts at a self-chosen bed height and again with the bed in a higher standardised position. Motion capture and force data were collected for analysis. Given the choice, less than half of participants adjusted the bed at all and none of them moved the bed to the highest position (99.1 cm). The self-chosen bed position yielded significantly higher low back force than the higher position at L4-L5 and L5-S1 (p = 0.02, p = 0.01 respectively). Low back forces can be reduced by raising the bed prior to engaging in patient handling tasks, which is a simple step that can reduce forces placed on healthcare workers' low backs. Practitioner summary: Healthcare workers experience high rates of low back pain secondary to patient handling tasks. In this cross-sectional crossover study, healthcare workers consistently chose a low bed height when boosting a patient, which resulted in higher low back loads compared to the highest bed height.

Analysis of a Novel Inpatient Acute Limb Ischemia Alert System.

OBJECTIVES: Acute limb ischemia (ALI) is a surgical emergency that generally develops in the outpatient setting. Hospitalized patients are also at risk for acute limb ischemia, but their presentation may be atypical or altered by medical therapy. Our institution developed an alert system to facilitate the prompt recognition and treatment of ALI that occurs in the inpatient population. We aimed to evaluate the usage of the system after the first 2 years of operation. METHODS: All ALI alerts from October 2017 to December 2019 were collected from paging records and analyzed for location, timing, and the need for intervention. Alerts undergoing vascular intervention were classified as urgent (within 8 hours) or delayed (after 8 hr). Time and location data were evaluated to determine patterns of usage and true-positive rate of the system. RESULTS: From October 2017 to December 2019, there were 237 ALI alerts obtained from paging records containing time and location information for the alert. More alerts originated from ICUs relative to non-ICU floors (68% vs. 33%, P< 0.001), however a greater proportion of non-ICU floor alerts required intervention compared to ICU alerts (32.0% vs. 5.1%, P < .0001). The highest number of ALI alerts were from the Medical ICU (MRICU) (45.9%) and medical/surgical floors (33.3%), followed by Surgical ICU (20.2%). Alerts were more common within 3 hr of morning and evening nursing shift changes (47.3%, P < 0.001). From the 237 total alerts, the patient was able to be identified retrospectively in 186 cases, and of these 27 resulted in operative interventions (14.5%, positive predictive value), with 11 patients (40.7%) requiring urgent intervention with a median time to intervention of 3.5 hr (range 2.2-4.8), and 16 (59%) alerts undergoing a delayed intervention at a mean of 3 days (range 2-4). A total of 73 (39.2%) alert patients died during their admission, of which 65 (89.0%) were in an ICU, and no deaths were directly related to ALI. The median time to death was 2 days (range 0-95 days), and in 22 cases death occurred <24 hr from time of alert. CONCLUSION: Our novel hospital-wide ALI alert system demonstrates a 14.5% positive predictive value for ischemia that resulted in an intervention. Alerts were more likely to originate from the ICU setting and during nursing shift changes. Alerts originating from non-ICU floors were 5 times more likely to undergo surgical intervention for ALI. Further analysis is required to assess the effect of this system on patient safety, outcome, and allocation of institutional resources.

Differences between predicted outer membrane proteins of genotype 1 and 2 Mannheimia haemolytica.

BACKGROUND: Mannheimia haemolytica strains isolated from North American cattle have been classified into two genotypes (1 and 2). Although members of both genotypes have been isolated from the upper and lower respiratory tracts of cattle with or without bovine respiratory disease (BRD), genotype 2 strains are much more frequently isolated from diseased lungs than genotype 1 strains. The mechanisms behind the increased association of genotype 2 M. haemolytica with BRD are not fully understood. To address that, and to search for interventions against genotype 2 M. haemolytica, complete, closed chromosome assemblies for 35 genotype 1 and 34 genotype 2 strains were generated and compared. Searches were conducted for the pan genome, core genes shared between the genotypes, and for genes specific to either genotype. Additionally, genes encoding outer membrane proteins (OMPs) specific to genotype 2 M. haemolytica were identified, and the diversity of their protein isoforms was characterized with predominantly unassembled, short-read genomic sequences for up to 1075 additional strains. RESULTS: The pan genome of the 69 sequenced M. haemolytica strains consisted of 3111 genes, of which 1880 comprised a shared core between the genotypes. A core of 112 and 179 genes or gene variants were specific to genotype 1 and 2, respectively. Seven genes encoding predicted OMPs; a peptidase S6, a ligand-gated channel, an autotransporter outer membrane beta-barrel domain-containing protein (AOMB-BD-CP), a porin, and three different trimeric autotransporter adhesins were specific to genotype 2 as their genotype 1 homologs were either pseudogenes, or not detected. The AOMB-BD-CP gene, however, appeared to be truncated across all examined genotype 2 strains and to likely encode dysfunctional protein. Homologous gene sequences from additional M. haemolytica strains confirmed the specificity of the remaining six genotype 2 OMP genes and revealed they encoded low isoform diversity at the population level. CONCLUSION: Genotype 2 M. haemolytica possess genes encoding conserved OMPs not found intact in more commensally prone genotype 1 strains. Some of the genotype 2 specific genes identified in this study are likely to have important biological roles in the pathogenicity of genotype 2 M. haemolytica, which is the primary bacterial cause of BRD.

Experience with Eversion Endarterectomy of the Common Femoral Artery with Comparison to Standard Endarterectomy with Patch.

In this retrospective study, we review the outcome of femoral eversion endarterectomy (EE) and standard endarterectomy with patch angioplasty (SEP) over a 10-year period. EE technique involves transection of common femoral artery (CFA), eversion endarterectomy of the distal CFA, and primary end-to-end reconstruction. One hundred forty-two patients underwent femoral endarterectomy, among which 38 (26.8%) endarterectomies were performed using the eversion technique. The cumulative 2-year primary patency of EE with or without a concurrent procedure was greater than 86% and did not statistically differ from SEP. EE is a feasible technique when the use of a patch needs to be avoided.

The Application of Virtual Reality in Patient Education.

BACKGROUND: Virtual reality (VR) provides an immersive image-viewing experience that has recently been expanding in use in clinical medicine. We developed a three-dimensional (3D) model of an abdominal aortic aneurysm (AAA) for patients with a diagnosis of an AAA to view in VR to assess the use of VR in patient education. METHODS: This was a cross-sectional study using an educational intervention. A standardized 3D model of an AAA was generated from a computed tomography scan and uploaded onto a 3D image-hosting website. Patients with an AAA who participated in the study wore a Google Cardboard VR headset, with a mobile device displaying the digital 3D AAA image in VR. Patients completed a survey afterward for assessing satisfaction with VR on a 5-point agreement Likert scale. RESULTS: Between September 2017 and January 2018, 19 patients participated in our study (90% participation rate). Most participants had no prior experience with VR (n = 15; 79%), and the mean age was 69 ± 8 years. Seventeen (89%) participants agreed or strongly agreed that they felt better informed about their health status after using VR and would like to see VR used more in their health care, while sixteen (84%) agreed or strongly agreed that they felt more engaged in their health care because of using VR. Almost all participants felt comfortable using VR (n = 17; 90%) and enjoyed using the technology (n = 16; 84%). CONCLUSIONS: VR proved to be an engaging learning tool that patients perceived as beneficial in understanding their health status. Further efforts to investigate the role of VR in education and health care should be explored.

Increased activity of the orexin system in the paraventricular nucleus contributes to salt-sensitive hypertension.

The orexin system is involved in arginine vasopressin (AVP) regulation, and its overactivation has been implicated in hypertension. However, its role in salt-sensitive hypertension (SSHTN) is unknown. Here, we tested the hypothesis that hyperactivity of the orexin system in the paraventricular nucleus (PVN) contributes to SSHTN via enhancing AVP signaling. Eight-week-old male Dahl salt-sensitive (Dahl S) and age- and sex-matched Sprague-Dawley (SD) rats were placed on a high-salt (HS; 8% NaCl) or normal-salt (NS; 0.4% NaCl) diet for 4 wk. HS intake did not alter mean arterial pressure (MAP), PVN mRNA levels of orexin receptor 1 (OX1R), or OX2R but slightly increased PVN AVP mRNA expression in SD rats. HS diet induced significant increases in MAP and PVN mRNA levels of OX1R, OX2R, and AVP in Dahl S rats. Intracerebroventricular infusion of orexin A (0.2 nmol) dramatically increased AVP mRNA levels and immunoreactivity in the PVN of SD rats. Incubation of cultured hypothalamus neurons from newborn SD rats with orexin A increased AVP mRNA expression, which was attenuated by OX1R blockade. In addition, increased cerebrospinal fluid Na+ concentration through intracerebroventricular infusion of NaCl solution (4 µmol) increased PVN OX1R and AVP mRNA levels and immunoreactivity in SD rats. Furthermore, bilateral PVN microinjection of the OX1R antagonist SB-408124 resulted in a greater reduction in MAP in HS intake (-16 ± 5 mmHg) compared with NS-fed (-4 ± 4 mmHg) anesthetized Dahl S rats. These results suggest that elevated PVN OX1R activation may contribute to SSHTN by enhancing AVP signaling.NEW & NOTEWORTHY To our best knowledge, this study is the first to investigate the involvement of the orexin system in salt-sensitive hypertension. Our results suggest that the orexin system may contribute to the Dahl model of salt-sensitive hypertension by enhancing vasopressin signaling in the hypothalamic paraventricular nucleus.

Genomic signatures of Mannheimia haemolytica that associate with the lungs of cattle with respiratory disease, an integrative conjugative element, and antibiotic resistance genes.

BACKGROUND: Mannheimia haemolytica typically resides in cattle as a commensal member of the upper respiratory tract microbiome. However, some strains can invade their lungs and cause respiratory disease and death, including those with multi-drug resistance. A nucleotide polymorphism typing system was developed for M. haemolytica from the genome sequences of 1133 North American isolates, and used to identify genetic differences between isolates from the lungs and upper respiratory tract of cattle with and without clinical signs of respiratory disease. RESULTS: A total of 26,081 nucleotide polymorphisms were characterized after quality control filtering of 48,403 putative polymorphisms. Phylogenetic analyses of nucleotide polymorphism genotypes split M. haemolytica into two major genotypes (1 and 2) that each were further divided into multiple subtypes. Multiple polymorphisms were identified with alleles that tagged genotypes 1 or 2, and their respective subtypes. Only genotype 2 M. haemolytica associated with the lungs of diseased cattle and the sequence of a particular integrative and conjugative element (ICE). Additionally, isolates belonging to one subtype of genotype 2 (2b), had the majority of antibiotic resistance genes detected in this study, which were assorted into seven combinations that ranged from 1 to 12 resistance genes. CONCLUSIONS: Typing of diverse M. haemolytica by nucleotide polymorphism genotypes successfully identified associations with diseased cattle lungs, ICE sequence, and antibiotic resistance genes. Management of cattle by their carriage of M. haemolytica could be an effective intervention strategy to reduce the prevalence of respiratory disease and supplemental needs for antibiotic treatments in North American herds.

Large genomic differences between Moraxella bovoculi isolates acquired from the eyes of cattle with infectious bovine keratoconjunctivitis versus the deep nasopharynx of asymptomatic cattle.

Moraxella bovoculi is a recently described bacterium that is associated with infectious bovine keratoconjunctivitis (IBK) or "pinkeye" in cattle. In this study, closed circularized genomes were generated for seven M. bovoculi isolates: three that originated from the eyes of clinical IBK bovine cases and four from the deep nasopharynx of asymptomatic cattle. Isolates that originated from the eyes of IBK cases profoundly differed from those that originated from the nasopharynx of asymptomatic cattle in genome structure, gene content and polymorphism diversity and consequently placed into two distinct phylogenetic groups. These results suggest that there are genetically distinct strains of M. bovoculi that may not associate with IBK.

Sympathoexcitation in ANG II-salt hypertension involves reduced SK channel function in the hypothalamic paraventricular nucleus.

Hypertension (HTN) resulting from subcutaneous infusion of ANG II and dietary high salt (HS) intake involves sympathoexcitation. Recently, we reported reduced small-conductance Ca(2+)-activated K(+) (SK) current and increased excitability of presympathetic neurons in the paraventricular nucleus (PVN) in ANG II-salt HTN. Here, we hypothesized that ANG II-salt HTN would be accompanied by altered PVN SK channel activity, which may contribute to sympathoexcitation in vivo. In anesthetized rats with normal salt (NS) intake, bilateral PVN microinjection of apamin (12.5 pmol/50 nl each), the SK channel blocker, remarkably elevated splanchnic sympathetic nerve activity (SSNA), renal sympathetic nerve activity (RSNA), and mean arterial pressure (MAP). In contrast, rats with ANG II-salt HTN demonstrated significantly attenuated SSNA, RSNA, and MAP (P < 0.05) responses to PVN-injected apamin compared with NS control rats. Next, we sought to examine the individual contributions of HS and subcutaneous infusion of ANG II on PVN SK channel function. SSNA, RSNA, and MAP responses to PVN-injected apamin in rats with HS alone were significantly attenuated compared with NS-fed rats. In contrast, sympathetic nerve activity responses to PVN-injected apamin in ANG II-treated rats were slightly attenuated with SSNA, demonstrating no statistical difference compared with NS-fed rats, whereas MAP responses to PVN-injected apamin were similar to NS-fed rats. Finally, Western blot analysis showed no statistical difference in SK1-SK3 expression in the PVN between NS and ANG II-salt HTN. We conclude that reduced SK channel function in the PVN is involved in the sympathoexcitation associated with ANG II-salt HTN. Dietary HS may play a dominant role in reducing SK channel function, thus contributing to sympathoexcitation in ANG II-salt HTN.

Sympathoexcitation and pressor responses induced by ethanol in the central nucleus of amygdala involves activation of NMDA receptors in rats.

The central nervous system plays an important role in regulating sympathetic outflow and arterial pressure in response to ethanol exposure. However, the underlying neural mechanisms have not been fully understood. In the present study, we tested the hypothesis that injection of ethanol in the central nucleus of the amygdala (CeA) increases sympathetic outflow, which may require the activation of local ionotropic excitatory amino acid receptors. In anesthetized rats, CeA injection of ethanol (0, 0.17, and 1.7 µmol) increased splanchnic sympathetic nerve activity (SSNA), lumbar sympathetic nerve activity (LSNA), and mean arterial pressure (MAP) in a dose-dependent manner. A cocktail containing ethanol (1.7 µmol) and kynurenate (KYN), an ionotropic excitatory amino acid receptor blocker, showed significantly blunted sympathoexcitatory and pressor responses compared with those elicited by CeA-injected ethanol alone (P < 0.01). A cocktail containing ethanol and d-2-amino-5-phosphonovalerate, an N-methyl-d-aspartate (NMDA) receptor antagonist, elicited attenuated sympathoexcitatory and pressor responses that were significantly less than ethanol alone (P < 0.01). In addition, CeA injection of acetate (0.20 µmol, n = 7), an ethanol metabolite, consistently elicited sympathoexcitatory and pressor responses, which were effectively blocked by d-2-amino-5-phosphonovalerate (n = 9, P < 0.05). Inhibition of neuronal activity of the rostral ventrolateral medulla (RVLM) with KYN significantly (P < 0.01) attenuated sympathoexcitatory responses elicited by CeA-injected ethanol. Double labeling of immune fluorescence showed NMDA NR1 receptor expression in CeA neurons projecting to the RVLM. We conclude that ethanol and acetate increase sympathetic outflow and arterial pressure, which may involve the activation of NMDA receptors in CeA neurons projecting to the RVLM.

Sleep efficiency and nocturnal hemodynamic dipping in young, normotensive adults.

Blunted dipping of nocturnal systolic arterial pressure (SAP) and heart rate (HR) are independent risk factors for hypertension and all-cause mortality. While several epidemiological studies report a significant association between short sleep duration and hypertension, associations between sleep efficiency and the nocturnal drop of SAP remain controversial. Moreover, relations between sleep efficiency and HR diurnal patterns have been overlooked. We hypothesized that low sleep efficiency (<85%) would be associated with blunted nocturnal SAP and HR dipping. Twenty-two normotensive subjects (13 men, 9 women; age: 18-28 yr) wore an actigraphy watch for 7 days and nights, and an ambulatory blood pressure monitor for 24 h on a nonactigraph night. There were no differences in age, sex, body mass index, mean sleep time, number of awakenings, or 24-h blood pressure between the low (n = 12) and high (n = 10) sleep efficiency groups. However, the low sleep efficiency subjects demonstrated a blunted dip of nocturnal SAP (10 ± 1% vs. 14 ± 1%, P = 0.04) and HR (12 ± 3% vs. 21 ± 3%, P = 0.03) compared with the high sleep efficiency group. The low sleep efficiency group also demonstrated a higher mean nocturnal HR (63 ± 2 vs. 55 ± 2 beats/min; P = 0.02). These findings support growing evidence that sleep efficiency, independent of total sleep time, may be an important cardiovascular risk factor.

Outcomes following interval delayed first rib resection for acute axillosubclavian deep venous thrombosis.

BACKGROUND: Current management of axillosubclavian deep venous thrombosis (DVT) often uses thrombolysis for the DVT, prompt first rib removal, and occasional venoplasty or stenting. Our institution has increasingly used anticoagulation alone followed by interval first rib resection. We sought to analyze the effectiveness of this simplified technique. METHODS: Between September 2012 and April 2021, 27 patients were identified within the institution's electronic medical record as having undergone first rib resection for upper extremity DVT. Seven of these patients had undergone preoperative thrombolysis before referral and were excluded. Among the remaining 20 patients, preoperative clinic charts were evaluated for age, venous segment involvement, contralateral limb involvement, presence of documented hypercoagulable state, duration of preoperative and postoperative anticoagulation, and postoperative outcomes. RESULTS: Of the 20 patients (mean age, 26.2 years; 13 males) presenting with acute axillosubclavian DVT, all patients had right (n = 8) or left (n = 12) arm swelling. Five patients had extremity pain and four had extremity discoloration. Ten had axillosubclavian vein involvement, 9 had subclavian vein involvement, and 1 had axillary vein involvement. Two patients were on oral contraceptives and no patients had any other diagnosed hypercoagulable conditions. The mean duration of preoperative and postoperative anticoagulation was 3.2 ± 2.6 months and 2.1 ± 2.1 months, respectively. Nineteen patients underwent supraclavicular first rib resection and 1 patient underwent transaxillary resection. Twelve patients (60%) demonstrated complete DVT resolution by venous duplex examination during the postoperative period and 8 patients (40%) demonstrated partial recanalization/chronic DVT. Complications included one hemothorax and one thoracic duct injury. All 20 patients remain asymptomatic without arm swelling, with a mean follow-up of 55.1 ± 34.7 months. CONCLUSIONS: Among patients presenting with acute axillosubclavian DVT, anticoagulation alone followed by interval first rib resection proved to be successful in providing symptomatic relief in the short to medium term. By eliminating the need for preoperative thrombolysis and postoperative venograms, this potentially cost-saving algorithm simplifies our management for acute venous thoracic outlet syndrome while maintaining good clinical outcomes. Because this study only analyzed our management algorithm's effectiveness in the short to medium term, the long-term effectiveness of this treatment will need to be demonstrated.

Economic impact of mortality prediction by predictive model at first and second treatment for bovine respiratory disease.

OBJECTIVE: To evaluate a predictive model's ability to determine cattle mortality following first and second treatment for bovine respiratory disease and to understand the differences in net returns comparing predictive models to the status quo. METHODS: 2 boosted decision tree models were constructed, 1 using data known at first treatment and 1 with data known at second treatment. Then, the economic impact of each outcome (true positive, true negative, false positive, and false negative) was estimated using various market values to determine the net return per head of using the predictive model to determine which animals should be culled at treatment. This was compared to the status quo to determine the difference in net return. RESULTS: The models constructed for the prediction of mortality performed with moderate accuracy (areas under the curve > 0.7). The economic analysis found that the models at a high specificity (> 90%) could generate a positive net return in comparison to status quo. CONCLUSIONS: This study showed that predictive models may be a useful tool to make culling decisions and could result in positive net returns. CLINICAL RELEVANCE: Bovine respiratory disease is the costliest health condition experienced by cattle on feed. Feedyard record-keeping systems generate vast amounts of data that could be used in predictive models to make management decisions. It is essential to understand the accuracy of predictions made via machine learning. However, the economic impact of implementing predictive models in a feedyard will influence adoption.