Descriptive Analysis of Amputation-Free Survival After First Time Infra-Inguinal Bypass Occlusion.

INTRODUCTION: Occlusion after infra-inguinal bypass surgery for peripheral artery disease is a major complication with potentially devastating consequences. In this descriptive analysis, we sought to describe the natural history and explore factors associated with long-term major amputation-free survival following occlusion of a first-time infra-inguinal bypass. METHODS: Using a prospective database from a tertiary care vascular center, we conducted a retrospective cohort study of all patients with peripheral artery disease who underwent a first-time infra-inguinal bypass and subsequently suffered a graft occlusion (1997-2021). The primary outcome was longitudinal rate of major amputation-free survival after bypass occlusion. Cox proportional hazard models were used to generate hazard ratios (HRs) and 95% confidence intervals (CIs) to explore predictors of outcomes. RESULTS: Of the 1318 first-time infra-inguinal bypass surgeries performed over the study period, 255 bypasses occluded and were included in our analysis. Mean age was 66.7 (12.6) years, 40.4% were female, and indication for index bypass was chronic limb threatening ischemia (CLTI) in 89.8% (n = 229). 48.2% (n = 123) of index bypass conduits used great saphenous vein, 29.0% (n = 74) prosthetic graft, and 22.8% (n = 58) an alternative conduit. Median (interquartile range) time to bypass occlusion was 6.8 (2.3-19.0) months, and patients were followed for median of 4.3 (1.7-8.1) years after bypass occlusion. Following occlusion, 38.04% underwent no revascularization, 32.94% graft salvage procedure, 25.1% new bypass, and 3.92% native artery recanalization. Major amputation-free survival following occlusion was 56.9% (50.6%-62.8%) at 1 y, 37.1% (31%-43.3%) at 5 y, and 17.2% (11.9%-23.2%) at 10 y. In multivariable analysis, factors associated with lower amputation-free survival were older age, female sex, advanced cardiorenal comorbidities, CLTI at index procedure, CLTI at time of occlusion, and distal index bypass outflow. Initial treatment after occlusion with both a new surgical bypass (HR 0.44, CI: 0.29-0.67) or a graft salvage procedure (HR 0.56, CI: 0.38-0.82) showed improved amputation-free survival. One-year rate of major amputation or death were 59.8% (50.0%-69.6%) for those who underwent no revascularization, 37.9% (28.7%-49.0%) for graft salvage, and 26.7% (17.6%-39.5%) for new bypass. CONCLUSIONS: Long-term major amputation-free survival is low after occlusion of a first-time infra-inguinal bypass. While several nonmodifiable risk factors were associated with lower amputation-free survival, treatment after graft occlusion with either a new bypass or a graft salvage procedure may improve longitudinal outcomes.

Evaluating the Effectiveness of Systemic Heparin During Arteriovenous Fistula Creation by Emulating a Target Trial.

Most of the 800,000 people living with end-stage kidney disease in the United States rely on a functioning vascular access to provide life-sustaining hemodialysis, yet one-third of arteriovenous fistulas experience early failures. Determining the safety and effectiveness of systemic heparin during fistula creation could improve the quality and quantity of life for these vulnerable patients. In this paper, a pragmatic randomized trial was emulated to assess the effect of systemic heparin administration (vs. none) during radiocephalic arteriovenous fistula creation on early bleeding and thrombosis using data from two international multicenter randomized trials performed between 2014 and 2019. Marginal risks were estimated using inverse probability weighted parametric survival analysis and confidence intervals were generated with bootstrapping. A total of 914 patients were enrolled and 61% received systemic heparin; median (IQR) age was 58 (49, 67) years and 45% were on hemodialysis at enrollment. No difference in the risk of bleeding events was observed, with a risk difference (95% CI) at 14 days of -0.1% (-1.6, 1.4). The risk of access thrombosis was lower in the heparin group, with a risk of 3.7% (2.6, 4.8) after heparin and 5.3% (3.4, 7.4) without heparin at 14 days (risk ratio 0.72, 95% CI 0.50, 0.98).

Real-World Vein Mapping Practice Patterns Before Endovascular Treatment of Limb Ischemia.

INTRODUCTION: The Best Endovascular versus Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI) trial results suggest that in patients with chronic limb-threatening ischemia (CLTI) and adequate single-segment great saphenous vein (SSGSV) by preoperative duplex ultrasonography, a surgical-first treatment strategy is superior to an endovascular-first strategy. However, the utilization of vein mapping prior to endovascular-first revascularization for CLTI in actual clinical practice is not known. METHODS: Data from a multicenter clinical data warehouse (2008-2019) were linked to Medicare claims data for patients undergoing endovascular-first treatment of infra-inguinal CLTI. Only patients who would have otherwise been eligible for enrollment in BEST-CLI were included. Adequate SSGSV was defined as healthy vein >3.0 mm in diameter from the groin through the knee. Logistic regression was used to estimate associations between preprocedure characteristics and vein mapping. Survival methods were used to estimate the risk of major adverse limb events and death. RESULTS: A total of 142 candidates for either surgical or endovascular treatment underwent endovascular-first management of CLTI. Ultrasound assessment for SSGSV was not performed in 76% of patients prior to endovascular-first revascularization. Of those who underwent preprocedure vein mapping, 44% had adequate SSGSV for bypass. Within one year postprocedure, 12.0% (95% confidence interval 7.4-18.0%) of patients underwent open surgical bypass and 54.7% (95% confidence interval 45.3-62.4%) experienced a major adverse limb event or death. CONCLUSIONS: In a real-world cohort of BEST-CLI-eligible patients undergoing endovascular-first intervention for infra-inguinal CLTI, three-quarters of patients had no preprocedure ultrasound assessment of great saphenous vein conduit. Practice patterns for vein conduit assessment in the real-world warrant reconsideration in the context of BEST-CLI trial results.

Comparative Effectiveness of Intravascular Ultrasound Versus Angiography in Abdominal and Thoracic Endovascular Aortic Repair: Systematic Review and Meta-Analysis.

The effectiveness of intravascular ultrasound (IVUS) with angiography compared with angiography guidance alone in treating aortic conditions, such as dissections, aneurysms, and blunt traumatic injuries, remains unclear. This systematic review and meta-analysis evaluates the current literature for IVUS use during thoracic endovascular aortic repair (TEVAR) and abdominal endovascular aortic repair (EVAR). A comprehensive search of MEDLINE, EMBASE, and Cochrane CENTRAL databases was conducted in March 2024 adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies comparing outcomes of TEVAR/EVAR with and without IVUS were identified. The outcomes of interest included contrast volume, fluoroscopy and procedural time, perioperative endoleak, and reinterventions and all-cause mortality during follow-up. Data with 95% confidence intervals (CIs) were extracted. Pooled analysis was performed using a random-effect model. Subgroup analysis was performed stratified by the condition being treated. Risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies. A total of 4,219 patients (n = 2,655 IVUS and n = 1,564 non-IVUS) from 9 observational studies were included. The IVUS group exhibited a reduction in contrast agent volume (weighted mean difference -34.65 mL, 95% CI -54.73 to -14.57) and fluoroscopy time (weighted mean difference -6.13 minutes, 95% CI -11.10 to -1.15), with no difference in procedural time. The perioperative type I and III endoleak occurrences were similar (risk ratio 2.36, 95% CI 0.55 to 10.11; risk ratio 0.72, 95% CI 0.09 to 5.77, respectively). Reintervention and mortality during follow-up were comparable (hazard ratio 0.80, 95% CI 0.33 to 1.97; hazard ratio 0.75, 95% CI 0.47 to 1.18, respectively). All the included studies had small risks of bias. In conclusion, this meta-analysis provides evidence that IVUS enables the safe deployment of TEVAR/EVAR with reduced contrast agent and radiation exposure.

Contemporary outcomes of surgical decompression for functional popliteal entrapment syndrome.

BACKGROUND: Functional popliteal entrapment syndrome (FPES) is an under-recognized source of leg pain caused by dynamic compression of the popliteal vessels by surrounding musculature in the absence of anatomic abnormality. Late recognition and difficulty capturing this entity across imaging modalities can lead to significant morbidity in an often young and active patient population. Surgical outcomes and optimal diagnostic strategies remain uncertain. METHODS: We performed a retrospective cohort study of all patients undergoing surgical decompression for FPES at an academic medical center between 2018 and 2022. Preoperative symptoms, patient characteristics, imaging, operative details, and follow-up were captured. The primary outcome was symptomatic improvement at last clinic visit. Secondary outcomes included symptomatic improvement at 6 months and postoperative complications. RESULTS: A total of 24 extremities (16 patients) were included. The mean ± standard deviation age was 23.3 ± 6.4 years and 75.0% of patients were female. The median symptom duration before decompression was 27 months (interquartile range, 10.7-74.6 months). Preoperative symptom severity in the affected extremity was as follows: 33.3% limited from peak exercise, 25% unable to exercise, and 41.7% with debilitating symptoms that affected activities of daily living. Preoperative imaging with provocative maneuvers included duplex ultrasound (87.5%), magnetic resonance angiography (100%), and digital subtraction angiography (100%). Using digital subtraction angiography as the gold standard, the sensitivity for detection of FPES was 85.7% for duplex examination and 58.3% for magnetic resonance angiography. The median follow-up was 451 days (interquartile range, 281-635 days). Most patients demonstrated durable improvement in the affected extremity, with 29.2% realizing complete resolution of symptoms and 37.5% reporting symptomatic improvement at last clinic visit for a total of 66.7%; 20.8% had initial improvement, but developed recurrent symptoms and were found to have elevated compartment pressures consistent with chronic exertional compartment syndrome and were treated with formal fasciotomy. Repeat decompression was required in one extremity (4.2%) owing to recurrent symptoms. Two patients (8.3%) had minimal or no improvement in their affected extremity and workup for the cause of continued discomfort was ongoing. CONCLUSIONS: Delays in diagnosis of FPES are common. Provocative maneuvers until replication of symptoms across multiple imaging modalities may be necessary to reliably identify the disease process. Surgical decompression improved or completely resolved symptoms in two-thirds of extremities. Treating physicians should maintain suspicion for comorbid chronic exertional compartment syndrome, especially if symptoms recur or persist after decompression.

Temporal trends in hemodialysis access creation during the fistula first era.

OBJECTIVE: Although forearm arteriovenous fistulas (AVFs) are the preferred initial vascular access for hemodialysis based on national guidelines, there are no population-level studies evaluating trends in creation of forearm vs upper arm AVFs and arteriovenous grafts (AVGs). The purpose of this study was to report temporal trends in first-time permanent hemodialysis access type, and to assess the effect of national initiatives on rates of AVF placement. METHODS: Retrospective cross-sectional study (2012-2022) utilizing the Vascular Quality Initiative database. All patients older than 18 years with creation of first-time upper extremity surgical hemodialysis access were included. Anatomic location of the AVF or AVG (forearm vs upper arm) was defined based on inflow artery, outflow vein, and presumed cannulation zone. Primary analysis examined temporal trends in rates of forearm vs upper arm AVFs and AVGs using time series analyses (modified Mann-Kendall test). Subgroup analyses examined rates of access configuration stratified by age, sex, race, dialysis, and socioeconomic status. Interrupted time series analysis was performed to assess the effect of the 2015 Fistula First Catheter Last initiative on rates of AVFs. RESULTS: Of the 52,170 accesses, 57.9% were upper arm AVFs, 25.2% were forearm AVFs, 15.4% were upper arm AVGs, and 1.5% were forearm AVGs. From 2012 to 2022, there was no significant change in overall rates of forearm or upper arm AVFs. There was a numerical increase in upper arm AVGs (13.9 to 18.2 per 100; P = .09), whereas forearm AVGs significantly declined (1.8 to 0.7 per 100; P = .02). In subgroup analyses, we observed a decrease in forearm AVFs among men (33.1 to 28.7 per 100; P = .04) and disadvantaged (Area Deprivation Index percentile ≥50) patients (29.0 to 20.7 per 100; P = .04), whereas female (17.2 to 23.1 per 100; P = .03), Black (15.6 to 24.5 per 100; P < .01), elderly (age ≥80 years) (18.7 to 32.5 per 100; P < .01), and disadvantaged (13.6 to 20.5 per 100; P < .01) patients had a significant increase in upper arm AVGs. The Fistula First Catheter Last initiative had no effect on the rate of AVF placement (83.2 to 83.7 per 100; P=.37). CONCLUSIONS: Despite national initiatives to promote autogenous vascular access, the rates of first-time AVFs have remained relatively constant, with forearm AVFs only representing one-quarter of all permanent surgical accesses. Furthermore, elderly, Black, female, and disadvantaged patients saw an increase in upper arm AVGs. Further efforts to elucidate factors associated with forearm AVF placement, as well as potential physician, center, and regional variation is warranted.

Quantifying Pediatric Gun Violence by Location, Time of Day, and Day of Week.

BACKGROUND: Firearm injuries are the leading cause of pediatric deaths. The objective of this study was to describe the location and timing of pediatric firearm injuries and to determine the proportion of these injuries that occur within schools in the United States. METHODS: In this retrospective cohort study, we used national emergency medical services (EMS) data from 2019 to evaluate dispatches to firearm injuries involving school-aged children (age 5-18). We extracted incident location type, patient demographics, number of patients on scene, and injury intent. RESULTS: We identified 4764 EMS dispatches for firearm injuries in school-aged children during 2019. Assault was the most common cause of injury (53.9 %), followed by unintentional shootings (12.1 %) and self-inflicted injuries (6.1 %). Most incidents involved a single patient (91.4 %). Private residence (51.5 %) was the most common location, followed by street/road (23.8 %). 81 firearm injuries (1.7 %) occurred in a school. Private residence was the most common location of injury across all injury intents. During school hours, most firearm injuries occurred in a private residence (51.6 %) or on a street/road (19.9 %). A total of 63 dispatches (1.3 %) were considered a mass casualty incident, of which 9 (14 %) occurred in a school. CONCLUSIONS: Regardless of injury intent or time of day, the most common location for pediatric firearm injuries was a private home. Firearm injuries within schools were far less frequent. In designing prevention strategies, our data calls for renewed focus on preventing children from accessing firearms in the home and instituting comprehensive, community-based after school programs. TYPE OF STUDY: Retrospective cohort. LEVEL OF EVIDENCE: III.

Contemporary outcomes of distal radial artery ligation for access related hand ischemia.

OBJECTIVES: Access related hand ischemia (ARHI) is a rare albeit morbid complication of hemodialysis access creation. Distal radial artery ligation (DRAL) has been described as a strategy to improve perfusion to the hand while maintaining the access. The objective of this study was to report longitudinal outcomes of DRAL for ARHI. METHODS: Retrospective cohort study (2015-2021) of all patients who underwent DRAL for ARHI at a tertiary care vascular center. Subjects were identified using the Mass General Brigham clinical data warehouse and data collection was supplemented with chart adjudication. Outcomes captured included 30-day complications and improvement in ARHI-related symptoms at 1 year. RESULTS: Thirty-one patients were included. Mean (SD) age was 59.9 (14.5) and 67.7% were male. Wrist radial-cephalic (74.2%) and proximal radial-cephalic (9.7%) configurations were most common. ARHI severity was: 9.7% stage 1 (retrograde flow without symptoms); 38.7% stage 2 (pain during exercise or dialysis); 41.9% stage 3 (pain at rest); and 9.7% stage 4 (tissue loss). High flow was present in 35.5% of patients at baseline with median (IQR) flow of 1670 ml/min (1478-1954). After DRAL, median (IQR) flow reduction in the high flow group was 953 ml/min (645-993); concurrent precision banding was performed in 29% to reduce flow. The 30-day risk of complication was 3.2% (n = 1 access thrombosis). During follow-up, 82.1% showed improvement in symptoms and 3.6% of patients needed an additional procedure for ARHI. Carpal tunnel surgery was required for improvement in 7.1% of patients and was suspected as the culprit of symptoms in 7.1%. CONCLUSION: Distal radial artery ligation for ARHI is safe and can improve ischemic symptoms in most patients while salvaging access function. Precision banding can serve as a useful adjunct in high flow accesses. Carpal tunnel syndrome should be considered as part of the differential diagnosis of hand pain in this population.

Predicting recurrent interventions after radiocephalic arteriovenous fistula creation with machine learning and the PREDICT-AVF web app.

OBJECTIVE: Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines discourage ongoing access salvage attempts after two interventions prior to successful use or more than three interventions per year overall. The goal was to develop a tool for prediction of radiocephalic arteriovenous fistula (AVF) intervention requirements to help guide shared decision-making about access appropriateness. METHODS: Prospective cohort study of 914 adult patients in the United States and Canada undergoing radiocephalic AVF creation at one of the 39 centers participating in the PATENCY-1 or -2 trials. Clinical data, including demographics, comorbidities, access history, anatomic features, and post-operative ultrasound measurements at 4-6 and 12 weeks were used to predict recurrent interventions required at 1 year postoperatively. Cox proportional hazards, random survival forest, pooled logistic, and elastic net recurrent event survival prediction models were built using a combination of baseline characteristics and post-operative ultrasound measurements. A web application was created, which generates patient-specific predictions contextualized with the KDOQI guidelines. RESULTS: Patients underwent an estimated 1.04 (95% CI 0.94-1.13) interventions in the first year. Mean (SD) age was 57 (13) years; 22% were female. Radiocephalic AVFs were created at the snuffbox (2%), wrist (74%), or proximal forearm (24%). Using baseline characteristics, the random survival forest model performed best, with an area under the receiver operating characteristic curve (AUROC) of 0.75 (95% CI 0.67-0.82) at 1 year. The addition of ultrasound information to baseline characteristics did not substantially improve performance; however, Cox models using either 4-6- or 12-week post-operative ultrasound information alone had the best discrimination performance, with AUROCs of 0.77 (0.70-0.85) and 0.76 (0.70-0.83) at 1 year. The interactive web application is deployed at https://predict-avf.com. CONCLUSIONS: The PREDICT-AVF web application can guide patient counseling and guideline-concordant shared decision-making as part of a patient-centered end-stage kidney disease life plan.

Gentrification as a Factor in the Incidence of Firearm Injuries.

Importance: Firearm injuries are an epidemic in the US; more than 45 000 fatal injuries were recorded in 2020 alone. Gaining a deeper understanding of socioeconomic factors that may contribute to increasing firearm injury rates is critical to prevent future injuries. Objective: To explore whether neighborhood gentrification is associated with firearm injury incidence rates over time. Design, Setting, and Participants: This cross-sectional study used nationwide, urban US Census tract-level data on gentrification between 2010 and 2019 and firearm injuries data collected between 2014 and 2019. All urban Census tracts, as defined by Rural Urban Commuting Area codes 1 to 3, were included in the analysis, for a total of 59 379 tracts examined from 2014 through 2019. Data were analyzed from January 2022 through April 2023. Exposure: Gentrification, defined to be an area in a central city neighborhood with median housing prices appreciating over the median regional value and a median household income at or below the 40th percentile of the median regional household income and continuing for at least 2 consecutive years. Main Outcomes and Measures: The number of firearm injuries, controlling for Census tract population characteristics. Results: A total of 59 379 urban Census tracts were evaluated for gentrification; of these tracts, 14 125 (23.8%) were identified as gentrifying, involving approximately 57 million residents annually. The firearm injury incidence rate for gentrifying neighborhoods was 62% higher than the incidence rate in nongentrifying neighborhoods with similar sociodemographic characteristics (incidence rate ratio [IRR], 1.62; 95% CI, 1.56-1.69). In a multivariable analysis, firearm injury incidence rates increased by 57% per year for low-income Census tracts that did not gentrify (IRR, 1.57; 95% CI, 1.56-1.58), 42% per year for high-income tracts that did not gentrify (IRR, 1.42; 95% CI, 1.41-1.43), and 49% per year for gentrifying tracts (IRR, 1.49; 95% CI, 1.48-1.50). Neighborhoods undergoing the gentrification process experienced an additional 26% increase in firearm injury incidence above baseline increase experienced in neighborhoods not undergoing gentrification (IRR, 1.26; 95% CI, 1.23-1.30). Conclusions and Relevance: Results of this study suggest that gentrification is associated with an increase in the incidence of firearm injuries within gentrifying neighborhoods. Social disruption and residential displacement associated with gentrification may help explain this finding, although future research is needed to evaluate the underlying mechanisms. These findings support use of targeted firearm prevention interventions in communities experiencing gentrification.

Comparative effectiveness of bovine carotid artery xenograft and polytetrafluoroethylene in hemodialysis access revision.

BACKGROUND: When hemodialysis arteriovenous accesses fail, autogenous options are often limited. Non-autogenous conduit choices include bovine carotid artery xenografts (BCAG) and expanded polytetrafluoroethylene (PTFE), yet their comparative effectiveness in hemodialysis access revision remains largely unknown. METHODS: A cohort study was performed from a prospectively collected institutional database from August 2010 to July 2021. All patients undergoing an arteriovenous access revision with either BCAG or PTFE were followed for up to 3 years from their index access revision. Revision was defined as graft placement to address a specific problem of an existing arteriovenous access while maintaining one or more of the key components of the original access (e.g. inflow, outflow, and cannulation zone). Outcomes were measured starting at the date of the index revision procedure. The primary outcome was loss of secondary patency at 3 years. Secondary outcomes included loss of post-intervention primary patency, rates of recurrent interventions, and 30-day complications. Pooled logistic regression was used to estimate inverse probability weighted marginal structural models for the time-to-event outcomes of interest. RESULTS: A total of 159 patients were included in the study, and 58% received access revision with BCAG. Common indications for revision included worn out cannulation zones (32%), thrombosis (18%), outflow augmentation (16%), and inflow augmentation (13%). Estimated risk of secondary patency loss at 3 years was lower in the BCAG group (8.6%, 3.9-15.1) compared to the PTFE group (24.8%, 12.4-38.7). Patients receiving BCAG experienced a 60% decreased relative risk of secondary patency loss at 3 years (risk ratio 0.40, 0.14-0.86). Recurrent interventions occurred at similar rates in the BCAG and PTFE groups, with 1.86 (1.31-2.43) and 1.60 (1.07-2.14) interventions at 1 year, respectively (hazard ratio 1.22, 0.74-1.96). CONCLUSIONS: Under the conditions of this contemporary cohort study, use of BCAG in upper extremity hemodialysis access revision decreased access abandonment when compared to PTFE.

Staged autogenous to prosthetic hemodialysis access creation strategy to maximize forearm options.

OBJECTIVE: When an adequate cephalic vein is not available for fistula construction, surgeons often turn to basilic vein or prosthetic constructions. Single-stage forearm prosthetic hemodialysis accesses are associated with poor durability, and upper arm non-autogenous access options are often limited by axillary outflow failure, which inevitably drives transition to the contralateral arm or lower extremity. We hypothesized that initial creation of a modest flow proximal forearm arterial-venous anastomosis to dilate ("develop") inflow and outflow vessels, followed by a planned second-stage procedure to create a cannulation zone with a prosthetic graft in the forearm, would result in reliable and durable hemodialysis access in patients with limited options. METHODS: We performed an institutional cohort study from 2017 to 2021 using a prospectively maintained database supplemented with adjudicated chart review. Patients without traditional autogenous hemodialysis access options in the forearm underwent an initial non-wrist arterial-venous anastomosis creation in the forearm as a first stage, followed by a second-stage interposition graft sewn to the existing inflow and venous outflow segments to create a useable cannulation zone in the forearm while leveraging vascular development. Outcomes included time from second-stage access creation to loss of primary and secondary patency, frequency of subsequent interventions, and perioperative complications. RESULTS: The cohort included 23 patients; first-stage radial artery-based (74%) configurations were more common than brachial artery-based (26%). Mean age was 63 years (standard deviation, 14 years), and 65% were female. Median follow-up was 340 days (interquartile range [IQR], 169-701 days). Median time to cannulation from second-stage procedure was 28 days (IQR, 18-53 days). Primary, primary assisted, and secondary patency at 1 year was 16.7% (95% confidence interval [CI], 5.3%-45.8%), 34.6% (95% CI, 15.2%-66.2%), and 95.7% (95% CI, 81.3%-99.7%), respectively. Subsequent interventions occurred at a rate of 3.02 (IQR, 1.0-4.97) per person-year, with endovascular thrombectomy with or without angioplasty/stenting (70.9%) being the most common. There were no cases of steal syndrome. Infection occurred in two cases and were managed with antibiotics alone. CONCLUSIONS: For patients without adequate distal autogenous access options, staged prosthetic graft placement in the forearm offers few short-term complications and excellent durability with active surveillance while strategically preserving the upper arm for future constructions.

Evaluating national guideline concordance of recurrent interventions after radiocephalic arteriovenous fistula creation.

OBJECTIVE: Radiocephalic arteriovenous fistulas have been historically perceived as requiring multiple follow-up procedural interventions to achieve maturation and maintain patency. Recent clinical practice guidelines from the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) emphasize a patient-centered hemodialysis access strategy with new maximum targets for intervention rates, potentially conflicting with concomitant recommendations to prioritize autogenous forearm hemodialysis access creation. The present descriptive study seeks to assess whether radiocephalic fistulas can meet the KDOQI guideline benchmarks for interventions following access creation, and to elucidate clinical and anatomic characteristics associated with the timing and frequency of interventions following radiocephalic arteriovenous fistula creation. METHODS: Prospective patient-level data from the multicenter PATENCY-1 and PATENCY-2 randomized trials, which enrolled patients undergoing new radiocephalic arteriovenous fistula creation, was analyzed (ClinicalTrials.govNCT02110901 and NCT02414841). The primary outcome was the rate of interventions at 1 year postoperatively. Incidence rates were calculated, and time to surgical or endovascular intervention following fistula creation was modeled using recurrent event extensions of the Cox proportional hazards model. Confidence intervals at the 95% level were calculated using nonparametric bootstrapping. RESULTS: The cohort consisted of 914 patients; mean age was 57 years (standard deviation, 13 years), and 22% were female. Median follow-up was 707 days (interquartile range, 447-1066 days). The incidence of interventions per person-year was 1.04 (95% confidence interval [CI], 0.95-1.13) overall; 1.10 (95% CI, 0.98-1.21) before fistula use, and 0.96 (95% CI, 0.82-1.11) after fistula use. The most common interventions overall were balloon angioplasty (54.9% of all interventions), venous side-branch ligation (16.4%), and open revisions (eg, proximalization from snuffbox to wrist, 16.4%). The locations requiring balloon angioplasty included the juxta-anastomotic segment (51.7% of angioplasties), the outflow vein (29.2%), the inflow artery (14.8%), the central veins (3.8%), and the cephalic arch (0.5%). Common indications were to restore or maintain patency (75.6% of all interventions), assist maturation (14.9%), improve depth (4.4%), or improve augmentation (3.0%). In the multivariable regression analysis, female sex (adjusted hazard ratio [HR], 1.21; 95% CI, 1.05-1.45), diabetes (HR, 1.21; 95% CI, 1.01-1.46), and intraoperative vein diameter <3.0 mm (vs ≥4.0 mm: HR, 1.33; 95% CI, 1.02-1.66) were associated with earlier and more frequent interventions. Patients not on hemodialysis at the time of fistula creation underwent less frequent interventions (HR, 0.69; 95% CI, 0.59-0.81). CONCLUSIONS: Patients with radiocephalic arteriovenous fistulas can expect to undergo one intervention, on average, in the first year after creation, which aligns with current KDOQI guidelines. Patients already requiring hemodialysis, female patients, patients with diabetes, and patients with intraoperative vein diameters <3.0 mm were at increased risk for repeated intervention. No subgroup exceeded guideline-suggested maximum thresholds for recurrent interventions. Overall, the results demonstrate that creation of radiocephalic arteriovenous fistula remains a guideline-concordant strategy when part of an end-stage kidney disease life-plan in appropriately selected patients.

Central concepts for randomized controlled trials and other emerging trial designs.

Randomized controlled trials (RCTs) are widely considered to provide the highest-quality evidence for the comparative efficacy and safety of competing clinical strategies. The strength of using RCTs for causal inference is derived from random treatment assignment and prospective data collection. Randomization eliminates confounding at the time of treatment group assignment, achieving exchangeability of the baseline study groups, such that they are the same, on average, except for the study intervention. Prospective data collection helps ensure that eligibility assessment, treatment assignment, and the start of follow-up are aligned temporally. Temporal alignment prevents biases that are common in observational research (eg, immortal time bias). In ideal settings, the results of an RCT provide the average causal effect of the intervention on the selected outcomes in the study population. Although observational research can estimate similar causal effects, observational designs require more assumptions and more advanced analytic frameworks than an RCT designed to answer the same question. Emerging trial designs, also discussed here, seek to address certain limitations of traditional RCT designs. The purpose of this review was to provide a broad overview of the central concepts in RCT design, implementation, conduct, and data analysis.

Radiocephalic Arteriovenous Fistula Patency and Use: A Post Hoc Analysis of Multicenter Randomized Clinical Trials.

We sought to confirm and extend the understanding of clinical outcomes following creation of a common distal autogenous access, the radiocephalic arteriovenous fistula (RCAVF). Background: Interdisciplinary guidelines recommend distal autogenous arteriovenous fistulae as the preferred hemodialysis (HD) access, yet uncertainty about durability and function present barriers to adoption. Methods: Pooled data from the 2014-2019 multicenter randomized-controlled PATENCY-1 and PATENCY-2 trials were analyzed. New RC-AVFs were created in 914 patients, and outcomes were tracked prospectively for 3-years. Cox proportional hazards and Fine-Gray regression models were constructed to explore patient, anatomic, and procedural associations with access patency and use. Results: Mean (SD) age was 57 (13) years; 45% were on dialysis at baseline. Kaplan-Meier estimates of 3-year primary, primary-assisted, and secondary patency were 27.6%, 56.4%, and 66.6%, respectively. Cause-specific 1-year cumulative incidence estimates of unassisted and overall RC-AVF use were 46.8% and 66.9%, respectively. Patients with larger baseline cephalic vein diameters had improved primary (per mm, hazard ratio [HR] 0.89, 95% confidence intervals 0.81-0.99), primary-assisted (HR 0.75, 0.64-0.87), and secondary (HR 0.67, 0.57-0.80) patency; and higher rates of unassisted (subdistribution hazard ratio 1.21, 95% confidence intervals 1.02-1.44) and overall RCAVF use (subdistribution hazard ratio 1.26, 1.11-1.45). Similarly, patients not requiring HD at the time of RCAVF creation had better primary, primary-assisted, and secondary patency. Successful RCAVF use occurred at increased rates when accesses were created using regional anesthesia and at higher volume centers. Conclusions: These insights can inform patient counseling and guide shared decision-making regarding HD access options when developing an individualized end-stage kidney disease life-plan.

Predicting radiocephalic arteriovenous fistula success with machine learning.

After creation of a new arteriovenous fistula (AVF), assessment of readiness for use is an important clinical task. Accurate prediction of successful use is challenging, and augmentation of the physical exam with ultrasound has become routine. Herein, we propose a point-of-care tool based on machine learning to enhance prediction of successful unassisted radiocephalic arteriovenous fistula (AVF) use. Our analysis includes pooled patient-level data from 704 patients undergoing new radiocephalic AVF creation, eligible for hemodialysis, and enrolled in the 2014-2019 international multicenter PATENCY-1 or PATENCY-2 randomized controlled trials. The primary outcome being predicted is successful unassisted AVF use within 1-year, defined as 2-needle cannulation for hemodialysis for ≥90 days without preceding intervention. Logistic, penalized logistic (lasso and elastic net), decision tree, random forest, and boosted tree classification models were built with a training, tuning, and testing paradigm using a combination of baseline clinical characteristics and 4-6 week ultrasound parameters. Performance assessment includes receiver operating characteristic curves, precision-recall curves, calibration plots, and decision curves. All modeling approaches except the decision tree have similar discrimination performance and comparable net-benefit (area under the ROC curve 0.78-0.81, accuracy 69.1-73.6%). Model performance is superior to Kidney Disease Outcome Quality Initiative and University of Alabama at Birmingham ultrasound threshold criteria. The lasso model is presented as the final model due to its parsimony, retaining only 3 covariates: larger outflow vein diameter, higher flow volume, and absence of >50% luminal stenosis. A point-of-care online calculator is deployed to facilitate AVF assessment in the clinic.

Patient-reported outcomes 6 to 12 months after isolated rib fractures: A nontrivial injury pattern.

BACKGROUND: Despite the ubiquity of rib fractures in patients with blunt chest trauma, long-term outcomes for patients with this injury pattern are not well described. METHODS: The Functional Outcomes and Recovery after Trauma Emergencies (FORTE) project has established a multicenter prospective registry with 6- to 12-month follow-up for trauma patients treated at participating centers. We combined the FORTE registry with a detailed retrospective chart review investigating admission variables and injury characteristics. All trauma survivors with complete FORTE data and isolated chest trauma (Abbreviated Injury Scale score of ≤1 in all other regions) with rib fractures were included. Outcomes included chronic pain, limitation in activities of daily living, physical limitations, exercise limitations, return to work, and both inpatient and discharge pain control modalities. Multivariable logistic regression models were built for each outcome using clinically relevant demographic and injury characteristic univariate predictors. RESULTS: We identified 279 patients with isolated rib fractures. The median age of the cohort was 68 years (interquartile range, 56-78 years), 59% were male, and 84% were White. Functional and quality of life limitations were common among survivors of isolated rib fractures even 6 to 12 months after injury. Forty-three percent of patients without a preexisting pain disorder reported new daily pain, and new chronic pain was associated with low resilience. Limitations in physical functioning and exercise capacity were reported in 56% and 51% of patients, respectively. Of those working preinjury, 28% had not returned to work. New limitations in activities of daily living were reported in 29% of patients older than 65 years. Older age, higher number of rib fractures, and intensive care unit admission were independently associated with higher odds of receiving regional anesthesia. Receiving a regional nerve block did not have a statistically significant association with any patient-reported outcome measures. CONCLUSION: Isolated rib fractures are a nontrivial trauma burden associated with functional impairment and chronic pain even 6 to 12 months after injury. LEVEL OF EVIDENCE: Prognostic/epidemiologic, level III.

Short-Term Pre-Operative Protein Caloric Restriction in Elective Vascular Surgery Patients: A Randomized Clinical Trial.

(1) Background: Vascular surgery operations are hampered by high failure rates and frequent occurrence of peri-operative cardiovascular complications. In pre-clinical studies, pre-operative restriction of proteins and/or calories (PCR) has been shown to limit ischemia-reperfusion damage, slow intimal hyperplasia, and improve metabolic fitness. However, whether these dietary regimens are feasible and safe in the vascular surgery patient population remains unknown. (2) Methods: We performed a randomized controlled trial in patients scheduled for any elective open vascular procedure. Participants were randomized in a 3:2 ratio to either four days of outpatient pre-operative PCR (30% calorie, 70% protein restriction) or their regular ad-libitum diet. Blood was drawn at baseline, pre-operative, and post-operative day 1 timepoints. A leukocyte subset flow cytometry panel was performed at these timepoints. Subcutaneous/perivascular adipose tissue was sampled and analyzed. Follow-up was one year post-op. (3) Results: 19 patients were enrolled, of whom 11 completed the study. No diet-related reasons for non-completion were reported, and there was no intervention group crossover. The PCR diet induced weight loss and BMI decrease without malnutrition. Insulin sensitivity was improved after four days of PCR (p = 0.05). Between diet groups, there were similar rates of re-intervention, wound infection, and cardiovascular complications. Leukocyte populations were maintained after four days of PCR. (4) Conclusions: Pre-operative PCR is safe and feasible in elective vascular surgery patients.

Contemporary outcomes of a "snuffbox first" hemodialysis access approach in the United States.

OBJECTIVE: The Society for Vascular Surgery guidelines for permanent hemodialysis (HD) access creation recommend prioritizing the most distal possible autogenous access to minimize complications and preserve more proximal options. The "snuffbox" arteriovenous fistula (AVF) is the most distal radial artery-cephalic vein AVF. Despite the theoretical benefits of the snuffbox approach, recent trends have been toward upper arm access. Our study sought to investigate the feasibility of a snuffbox-first strategy for HD access in all anatomically appropriate candidates. METHODS: From January 2016 to August 2019, all patients with end-stage renal disease (ESRD) or pre-ESRD under consideration for HD access were evaluated for a snuffbox-first approach by a team of vascular surgeons and nephrologists at a single, urban academic medical center in the United States. Data were collected prospectively and supplemented by medical record review. A survival analysis was performed to evaluate primary unassisted and secondary patency and clinical and functional maturation. Patients were censored if they had received a kidney transplant or had died. Cox proportional hazards regression was used to determine the risk factors for prolonged clinical maturation and functional maturation. RESULTS: A total of 55 snuffbox AVFs were created. The median patient age was 60 years (interquartile range [IQR], 52-70 years), and 52.7% of the patients were men. The median follow-up was 369 days (IQR, 166-509 days). The median survival for primary unassisted patency was 90 days (95% confidence interval [CI], 79-111). Secondary patency at 1 year was 92.3% (95% CI, 85.3%-99.9%). The clinical maturation rate at 1 year was 83.7% (n = 55; 95% CI, 66.8%-91.9%), and the functional maturation rate at 1 year was 85.6% (n = 40; 95% CI, 63.3%-94.4%). Of the patients who were pre-ESRD at AVF creation and had initiated HD during the study period, 87.5% had successfully received incident HD with their snuffbox AVF. Twenty-four patients were receiving HD via a catheter at snuffbox creation. Of those patients, the functional maturation rate at 1 year was 82.5% (95% CI, 44.8%-94.4%). The patients had undergone a median of two interventions (IQR, zero to seven interventions) in the first year. Of these, 46.9% were percutaneous angioplasty and 31.2% were side-branch ligation. Diabetes was associated with slower AVF clinical maturation (multivariate hazard ratio, 0.35; 95% CI, 0.15-0.82; P = .016). A larger artery diameter was associated with earlier AVF clinical maturation (multivariate hazard ratio, 6.64; 95% CI, 2.11-20.9). CONCLUSIONS: A snuffbox-first approach to HD access is a viable option for distal access creation in a cohort of patients requiring HD in the United States. Subsequent ancillary interventions to facilitate access maturation were required for most patients.