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BackgroundFrailty is a known risk factor for adverse outcomes following surgery and affects at least 3 of every 10 US Veterans aged 65 years and older. We designed a study to characterize the association between frailty and complications after endovascular aneurysm repair (EVAR) compared to open aneurysm repair (OAR) at our regional Veterans Affairs Medical Center.MethodsVeterans who underwent either OAR or EVAR at our institution between January 1, 2000 and December 31, 2020 were identified. We examined medical history, procedure characteristics, perioperative complications, and frailty as measured by the 5-factor modified frailty index (mFI-5). Frailty was defined as an mFI-5 score ≥2. Primary endpoints were postoperative complications, duration of surgery, and length of hospital stay. Tests of association were performed with t-test and chi-squared analysis.ResultsOver the 21-year period, we identified 314 patients that underwent abdominal aortic aneurysm (AAA) repair with 115 (36.6%) OAR and 199 EVAR (63.4%) procedures. Patients undergoing EVAR were older on average (72.1 years vs. 70.2 years) and had a higher average mFI-5 compared to the open repair group (1.49 vs. 1.23, P = 0.036). When comparing EVAR and OAR cohorts, patients undergoing OAR had a larger AAA diameter (6.5 cm, standard deviation [SD]: 1.5) compared to EVAR (5.5 cm, SD: 1.1 P

BackgroundVeterans are disproportionately affected by housing insecurity (HI), which can lead to adverse health outcomes and reduced life expectancy. We sought to examine the impact of HI on the outcomes of veterans who underwent abdominal aortic aneurysm (AAA) repair at our regional Veterans Affairs medical center.MethodsRetrospective chart review was performed on patients who underwent AAA repair at our institution between January 1, 2000, and December 31, 2020. We examined medical history, procedure details, hospitalization course, and postoperative outcomes. Primary endpoints were a 30-day mortality and median survival. Secondary endpoints were hospital length of stay, readmission rate, and perioperative complications. Hypothesis testing was performed with t-test and chi-squared analysis. Survival analysis was conducted using Kaplan-Meier estimation.ResultsOf the 314 veterans that underwent AAA repair (mean age of 71.4 ± 7.8 years, 99.7% male) over the 21-year period, we identified 39 (12.4%) patients with a history of HI. The HI was associated with a positive smoking history (100% vs. 88.0%, P = 0.022), lower rate of hypertension diagnosis (69.2% vs. 84.0%, P = 0.024), and increased rate of surgical site infections (SSI) (10.3% vs. 1.8%, P = 0.016). The median postoperative survival was lower in the HI group (7.6 years [CI 6.0-11.2] vs. 8.9 [CI 6.9-10.3]).ConclusionsHI was associated with reduced median postoperative survival, greater readmission rate, and increased risk of SSI following AAA repair.

BackgroundThoracic outlet syndrome (TOS) is an infrequent condition which results in disability in use of upper extremity. While TOS is often associated with manual labor, industrial workers, and accidents, it has not been reported in a physician (MD) population. Given the investment of time and effort in training to become a MD, the impact of TOS may be devastating. Our objective is to report the presentation and outcome of TOS in MDs.MethodsA prospectively surgical database was reviewed for MDs who sought care of disabling TOS between 1997 and 2022. Demographic, clinical, outcome and pathological data were reviewed. Outcomes were assessed based on Somatic Pain Scale (SPS), Quick Disabilities of Arm, Shoulder and Hand (DASH) scores, and Derkash scores. Results were also assessed based on return to employment.ResultsA total of 19 MDs were identified, from 1,687 TOS cases. The group included 13 (63%) men, 6 (31%) women, average age 45 years (range 27-57). Presentations included 1 (5.3%) arterial TOS (ATOS), 9 (47.4%) venous TOS (VTOS), and 9 (47.4) neurogenic TOS (NTOS). All patients were right-handed, and symptomatic side was dominant hand in 7 (37%) patients. Etiologies included repetitive motion injury, athletic injury, and congenital bony abnormalities. Repetitive motion was associated with 3/9 (33%) NTOS. Significant athletic activities were noted in 12 of 19 (63%) MDs, including 8/9 (89%) VTOS and 4/9 (44%) NTOS. Athletic activities associated with VTOS included triathletes (2), rock climbing (1), long distance swimming (2), and weightlifting (3). Of the 9 NTOS cases, 3 were associated with weightlifting and 1 with skiing. Congenital causes included 1 (5%) abnormal first rib and 1 (5%) cervical rib. Time from symptom onset to consultation varied significantly according to diagnosis: ATOS 6 days, VTOS 97 days, and NTOS 2,335 days (P

BackgroundWe hypothesize among patients undergoing lower extremity amputation, access to pre-, and post operative rehabilitation services; as well as improved medical care, have led to higher rates of postoperative ambulation, and improved survival.MethodsRetrospective single center review of all major lower extremity amputations performed at the Greater Los Angeles Veterans Affairs Healthcare System from 2000-2020 stratified into multiyear cohorts. We abstracted demographics, operative indication, comorbidities, preoperative medical management, perioperative complications, discharge location, and pre and postoperative ambulatory status. Odds of ambulation after amputation were analyzed using multivariate logistic regression. Survival was analyzed using multivariate logistic regression and Kaplan-Meier survival analysis. Multivariate logistic predictors were selected based on prior literature and clinical experience.ResultsWe identified 654 operations in our study, noting fewer amputations performed in the latest 3 cohort years as compared to the initial cohort (2000-2004). Patients undergoing below-knee amputations (BKA) had 2.7 times (P

IntroductionAccess to surgical service is limited by provider availability and geographic barriers. Telemedicine ensures that patients can access medical care.ObjectiveThe objective is to describe our use of telemedicine in delivering vascular surgery services to remote locations before and during the COVID-19 pandemic.MethodsWe conducted a retrospective chart review analyzing care delivered at six vascular surgery telemedicine clinics over a 22-month period. We examined vascular diagnoses, recommended interventions, referrals placed, and emergency department visits within 30 days of evaluation. We calculated travel distance saved for patients between their local clinic and our main hospital.ResultsWe identified 94 patients and 144 telemedicine visits, with an average of 1.5 visits per patient (SD = 0.73). The most common referrals were for peripheral artery disease (20.2%) and abdominal aortic aneurysm (14.9%). Three patients were immediately referred to the emergency department due to concern for acute limb ischemia (2) or questionable symptomatic AAA (1). Telemedicine visit recommendations were distributed between no intervention (n = 30, 31.9%), medical management (n = 41, 43.6%), and surgical intervention (n = 23, 24.5%).The surgical intervention cohort was most commonly referred to arterial revascularization (n = 4), venous ablation (n = 4), and arteriovenous fistula procedures (n = 4). Fourteen patients came to our main hospital for surgery and four to local providers. Average travel distance saved per telemedicine visit was 104 miles (SD = 43.7).ConclusionsTelemedicine provided safe, efficient care during the COVID-19 pandemic and saved patients an average of 104 travel miles per visit.

BackgroundEndovenous ablation techniques have replaced greater saphenous vein (GSV) ligation and stripping for treatment of venous insufficiency. Our objective was to investigate our initial procedural experience and clinical presentation of patients undergoing mechanochemical ablation (MOCA) at a single institution. We hypothesized that closure level and success rate improved over time and were comparable to other endovenous ablation techniques.MethodsWe retrospectively reviewed all MOCA procedures performed at the Greater Los Angeles Veterans Affairs Hospital from 2015 - 2020. Variables included CEAP and VCSS scores, patient symptoms, post procedure duplex ultrasound, closure level, and need for anticoagulation. Success was defined as GSV thrombosis on initial post procedure duplex ultrasound. Procedure associated extension of thrombus into the deep veins was defined using the American Venous Forum (AVF) endothermal heat induced thrombosis (EHIT) classification.Results104 venous ablation procedures were performed on 86 patients. Eleven (12.8%) patients received bilateral interventions, and six (7%) patients had asynchronous interventions on the same leg. The average age was 58.4 years (SD 12) and 93% were male. Pre-procedural symptoms included pain (102, 98.1%), varicose veins (87, 83.7%), edema (58, 55.8%), and active ulcers (19, 18.3%). A CEAP category of C2 was the most common indication (34.6%), followed by C3 (22.1%) and C6 (21.2%). Forty-five (43.2%) patients had deep system reflux, and 53% had concomitant phlebectomies. Average VCSS score was 7.5 (SD 3.5).We observed a GSV ablation rate of 92.7% (n = 89) in the 96 procedures which had post-procedure follow up, with no temporal evidence of a learning curve. On post procedure duplex of the 89 technically successful ablations, 77 (86.5%) patients had AVF EHIT level 1 closure, three (3.4%) had level 2 closure, eight (8.9%) had level 3 closure, and one had a level 4 closure. Fourteen (15.7%) patients were newly started on anticoagulation for an average of 33.2 days (SD 34.1). Of the 19 legs treated for active venous ulcers, 13 (68.4%) had improvement or resolution of their venous ulcers. No pulmonary embolic complications were reported.ConclusionsWe observed a successful GSV thrombosis rate of 92.7% using MOCA without evidence of a learning curve and comparable to that reported in the literature. The rate of thrombus extension into the deep veins was 14.6%, with no adverse effects associated with anticoagulation or clinically significant sequelae of AVF EHIT level 2 or greater. Comparisons with MOCA associated thrombus extension into deep veins in the literature are limited as post procedure screening duplex are not standard of care. However, we demonstrated that MOCA ablation of the GSV is a safe procedure that may be performed with good technical success.

ObjectiveSpontaneous subclavian vein (SCV) thrombosis (Paget-Schroetter syndrome [PSS]) has been attributed to venous compression at the thoracic outlet and traditionally diagnosed using venography. Intravascular ultrasonography (IVUS) allows for a multidimensional view of vascular structures and might be more accurate in revealing venous compression. The goal of the present study was to compare venography and IVUS in patients presenting with PSS to assess the relative accuracy of each modality.MethodsPatients presenting for evaluation of PSS from 2013 to 2019 were evaluated for SCV compression using venography and IVUS. Venography and IVUS measurements of stenosis were performed of the index and contralateral limbs in both neutral and stress (arm overhead) positions. The IVUS data included the SCV diameters in the anteroposterior (AP) plane, craniocaudal (CC) plane, and cross-sectional area (CSA). Stenosis was reported as the percentage of reduction from a reference point (lateral margin of the first rib) for the venography and IVUS data.ResultsFor the 35 subjects, the average age was 35 years, 57% were women, 20% had presented with a documented pulmonary embolus, and 70% had initially been treated with thrombolysis. Venography demonstrated SCV occlusion in 3 patients (16%) with the index limb in the neutral position and in 18 patients (54%) with the limb in the stress position. The average stenosis in the index limbs was 41.5% (venography), and the average IVUS stenosis was 41.9% (CC), 61.8% (AP), and 74.5% (CSA; P < .05). A subset analysis revealed that in 10 of 35 patients (28%) in whom venography had identified no significant stenosis (average, 10%), IVUS had identified significant stenosis (33.5% CC, 54.3% AP, 68.7% CSA; P < .05).ConclusionsIVUS proved more sensitive than venography in detecting significant stenosis leading to SCV thrombosis. A reduction in the CSA was the most sensitive measure of stenosis. IVUS identified significant stenosis in patients in whom venography failed to do so. The greatest utility of IVUS is in the evaluation of patients with PSS in whom venography shows no evident compression.

The Belowground Ecosystem Resiliency Model (BERM) is a geoinformatics tool that was developed to predict belowground biomass (BGB) of Spartina alterniflora in salt marshes based on remote sensing of aboveground characteristics and other readily available hydrologic, climatic, and physical data. We sought to characterize variation in S. alterniflora BGB over both temporal and spatial gradients through extensive marsh field observations in coastal Georgia, USA, to quantify their relationship with a suite of predictor variables, and to use these results to improve performance and expand the parameter space of BERM. We conducted pairwise comparisons of S. alterniflora growth metrics measured at nine sites over 3–8 years and found that BGB grouped by site differed in 69% of comparisons, while only in 21% when grouped by year. This suggests that BGB varies more spatially than temporally. We used the BERM machine learning algorithms to evaluate how variables relating to biological, climatic, hydrologic, and physical attributes covaried with these BGB observations. Flooding frequency and intensity were most influential in predicting BGB, with predictor variables related to hydrology composing 61% of the total feature importance in the BERM framework. When we used this expanded calibration dataset and associated predictors to advance BERM, model error was reduced from a normalized root‐mean‐square error of 13.0%–9.4% in comparison with the original BERM formulation. This reflects both an improvement in predictive performance and an expansion in conditions for potential model application. Finally, we used regression commonality analysis to show that model estimates reflected the spatiotemporal structure of BGB variation observed in field measurements. These results can help guide future data collection efforts to describe landscape‐scale BGB trends. The advanced BERM is a robust tool that can characterize S. alterniflora productivity and resilience over broad spatial and temporal scales. [ABSTRACT FROM AUTHOR]

A Cooperative Adaptive Cruise Control (CACC) system has been developed by adding a wireless vehicle-vehicle communication system and new control logic to an existing commercially available adaptive cruise control (ACC) system. The CACC is intended to enhance the vehicle-following capabilities of ACC so that drivers will be comfortable using it at shorter vehicle-following gaps than ACC. This can offer a significant opportunity to increase traffic flow density and efficiency without compromising safety or expanding roadway infrastructure.This report describes the design and implementation of the CACC system on two Infiniti FX-45 test vehicles, as well as the data acquisition system that has been installed to measure how drivers use the system, so that the impacts of such a system on highway traffic flow capacity and stability can be estimated. The results of quantitative performance testing of the CACC on a test track are presented, followed by the experimental protocol for on-road testing with human subjects. Finally, the results from the field testing by 16 naïve drivers are presented to show the user acceptance and quantitative measurements of how these drivers used the ACC and CACC systems, and how these systems affected their choice of car following gap.

A Cooperative Adaptive Cruise Control (CACC) system has been developed by adding a wireless vehicle-vehicle communication system and new control logic to an existing commercially available adaptive cruise control (ACC) system. The CACC is intended to enhance the vehicle-following capabilities of ACC so that drivers will be comfortable using it at shorter vehicle-following gaps than ACC. This can offer a significant opportunity to increase traffic flow density and efficiency without compromising safety or expanding roadway infrastructure.This report describes the design and implementation of the CACC system on two Infiniti FX-45 test vehicles, as well as the data acquisition system that has been installed to measure how drivers use the system, so that the impacts of such a system on highway traffic flow capacity and stability can be estimated. The results of quantitative performance testing of the CACC on a test track are presented, followed by the experimental protocol for on-road testing with human subjects. Finally, the results from the field testing by 16 naïve drivers are presented to show the user acceptance and quantitative measurements of how these drivers used the ACC and CACC systems, and how these systems affected their choice of car following gap.

This report describes the development of two of the three mobility applications that PATH is developing and evaluating under the sponsorship of the FHWA Exploratory Advanced Research Program, with cost share funding provided by PATH TO 6224. These applications are intended to use DSRC wireless communications among vehicles and between vehicles and the roadway infrastructure to improve mobility on limited-access highways. The first application combines ramp metering with variable speed limits to enhance control of traffic so that traffic flow breakdowns can be deferred or avoided at bottleneck locations. The second application uses vehicle-vehicle communication to improve the performance of adaptive cruise control systems so that they can operate safely with smaller longitudinal gaps and vehicle-roadside communication to provide adjustments to their set speed and gap settings to adapt to changes in local traffic conditions.

The US DOT RITA Volpe Center entered into a cooperative agreement with the California Department of Transportation (Caltrans) to establish the inaugural SafeTrip 21 field test site in the San Francisco Bay area [named Connected Traveler].  Specifically, the site encompasses I-880 from Oakland to San Jose on the east bay and from San Jose to just south of the San Francisco International Airport, along U.S. 101 and California State Route (SR) 82. The site includes the SR-84 Dumbarton Bridge toll crossing, which links I-880 and U.S. 101. Caltrans's partners include the Metropolitan Transportation Commission, the University of California-Berkeley's California Partners for Advanced Transit and Highways (PATH), the California Center  for Innovative Transportation, Nokia, Inc., NAVTEQ, Santa Clara  Valley Transportation Authority, and Nissan. The cost of the $12.4 million field test was funded by private and public sector partners, including the USDOT contribution, equally. (Public Roads, September/October 2008)

A Cooperative Adaptive Cruise Control (CACC) system has been developed by adding a wireless vehicle-vehicle communication system and new control logic to an existing commercially available adaptive cruise control (ACC) system. The CACC is intended to enhance the vehicle-following capabilities of ACC so that drivers will be comfortable using it at shorter vehicle-following gaps than ACC. If this is shown to be the case, it offers a significant opportunity to increase traffic flow density and efficiency without compromising safety or expanding roadway infrastructure.This report describes the design and implementation of the CACC system on two Infiniti FX-45 test vehicles, as well as the data acquisition system that has been installed to measure how drivers use the system, so that the impacts of such a system on highway traffic flow capacity and stability can be estimated. The results of quantitative performance testing of the CACC on a test track are presented, followed by the experimental protocol to be followed for on-road testing with human subjects. Finally, the results from the first pilot test are presented to show how the data are analyzed to reveal the implications of CACC for driving behavior and user acceptance.

Each year in the United States over 450,000 large trucks are involved in crashes, resulting in about 5000 fatalities and 120,000 injuries. Significantly, truck driver error is a major causal factor to truck-involved crashes. This points toward onboard monitoring as a promising means to encourage good driving behavior, it would recognizing and provide necessary feedback to correct self-induced hazardous driving situations. This is the basis for our past prototype development effort, which has produced under Task Orders 5509 and 6609 a suite of hardware on a Freightliner Century Class.This suite allows for online measurement of a set of driving characteristics which are indicators of unsafe driving behavior, with feedback given in real time to the driver, and offline to the carrier (and ultimately, back to the driver). Under this Task Order, we extended our work to detail a Field Operational Test. While that FOT began with 15 trucks, the work undertaken was expanded at US DOT’s request to consider additional teammates and a scope of over 200 trucks where the FOT could be collateral compared to the naturalistic data collection that could be accrued. We describe the original SOW, some of the transforming work in-between, then the finally-conceived FOT which in the end was submitted but not awarded to the PATH-Caltrans team.

Gene expression is a regulated process fueled by ATP consumption. Therefore, regulation must be coupled to constraints imposed by the level of energy metabolism. Here, we explore this relationship both theoretically and experimentally. A stylized mathematical model predicts that activators of gene expression have variable impact depending on metabolic rate. Activators become less essential when metabolic rate is reduced and more essential when metabolic rate is enhanced. We find that, in the Drosophila eye, expression dynamics of the yan gene are less affected by loss of EGFR-mediated activation when metabolism is reduced, and the opposite effect is seen when metabolism is enhanced. The effects are also seen at the level of pattern regularity in the adult eye, where loss of EGFR-mediated activation is mitigated by lower metabolism. We propose that gene activation is tuned by energy metabolism to allow for faithful expression dynamics in the face of variable metabolic conditions. [ABSTRACT FROM AUTHOR]