MR Lymphangiography in Lymphatic Disorders: Clinical Applications, Institutional Experience, and Practice Development.

Lymphatic flow and anatomy can be challenging to study, owing to variable lymphatic anatomy in patients with diverse primary or secondary lymphatic pathologic conditions and the fact that lymphatic imaging is rarely performed in healthy individuals. The primary components of the lymphatic system outside the head and neck are the peripheral, retroperitoneal, mesenteric, hepatic, and pulmonary lymphatic systems and the thoracic duct. Multiple techniques have been developed for imaging components of the lymphatic system over the past century, with trade-offs in spatial, temporal, and contrast resolution; invasiveness; exposure to ionizing radiation; and the ability to obtain information on dynamic lymphatic flow. More recently, dynamic contrast-enhanced (DCE) MR lymphangiography (MRL) has emerged as a valuable tool for imaging both lymphatic flow and anatomy in a variety of congenital and acquired primary or secondary lymphatic disorders. The authors provide a brief overview of lymphatic physiology, anatomy, and imaging techniques. Next, an overview of DCE MRL and the development of an MRL practice and workflow in a hybrid interventional MRI suite incorporating cart-based in-room US is provided, with an emphasis on multidisciplinary collaboration. The spectrum of congenital and acquired lymphatic disorders encountered early in an MRL practice is provided, with emphasis on the diversity of imaging findings and how DCE MRL can aid in diagnosis and treatment of these patients. Methods such as DCE MRL for assessing the hepatic and mesenteric lymphatic systems and emerging technologies that may further expand DCE MRL use such as three-dimensional printing are introduced. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Racial and Ethnic Disparities in Treatment of Critical Limb Ischemia: A National Perspective.

Background Recent guidelines have emphasized the use of medical management, early diagnosis, and a multidisciplinary team to effectively treat patients with critical limb ischemia (CLI). Previous literature briefly highlighted the current racial disparities in its intervention. Herein, we analyze the trend over a 14-year time period to investigate whether the disparities gap in CLI management is closing. Methods and Results The National Inpatient Sample was queried between 2005 and 2018 for hospitalizations involving CLI. Nontraumatic amputations and revascularization were identified. Utilization trends of these procedures were compared between races (White, Black, Hispanic, Asian and Pacific Islander, Native American, and Other). Multivariable regression assessed differences in race regarding procedure usage. There were 6 904 562 admissions involving CLI in the 14-year study period. The rate of admissions in White patients who received any revascularization decreased by 0.23% (P<0.001) and decreased by 0.25% (P=0.025) for Asian and Pacific Islander patients. Among all patients, the annual rate of admission in White patients who received any amputation increased by 0.21% (P<0.001), increased by 0.19% (P=0.001) for Hispanic patients, and increased by 0.19% (P=0.012) for the Other race patients. Admissions involving Black, Hispanic, Asian and Pacific Islander, or Other race patients had higher odds of receiving any revascularization compared with White patients. All races had higher odds of receiving major amputation compared with White patients. Conclusions Our analysis highlights disparities in CLI treatment in our nationally representative sample. Non-White patients are more likely to receive invasive treatments, including major amputations and revascularization for CLI, compared with White patients.

Value-Based Payment for Clinicians Treating Cardiovascular Disease: A Policy Statement From the American Heart Association.

Clinician payment is transitioning from fee-for-service to value-based payment, with reimbursement tied to health care quality and cost. However, the overarching goals of value-based payment-to improve health care quality, lower costs, or both-have been largely unmet. This policy statement reviews the current state of value-based payment and provides recommended best practices for future design and implementation. The policy statement is divided into sections that detail different aspects of value-based payment: (1) key program design features (patient population, quality measurement, cost measurement, and risk adjustment), (2) the role of equity during design and evaluation, (3) adjustment of payment, and (4) program implementation and evaluation. Each section introduces the topic, describes important considerations, and lists examples from existing programs. Each section includes recommended best practices for future program design. The policy statement highlights 4 key themes for successful value-based payment. First, programs should carefully weigh the incentives between lowering cost and improving quality of care and ensure that there is adequate focus on quality of care. Second, the expansion of value-based payment should be a tool for improving equity, which is central to quality of care and should be a focal point of program design and evaluation. Third, value-based payment should continue to move away from fee for service toward more flexible funding that allows clinicians to focus resources on the interventions that best help patients. Last, successful programs should find ways to channel clinicians' intrinsic motivation to improve their performance and the care for their patients. These principles should guide the future development of clinician value-based payment models.

National Trends in Complications of Vascular Access for Hemodialysis and Analysis of Racial Disparities Among Patients With End-Stage Renal Disease in the Inpatient Setting.

Introduction: The aim of this study is to assess the trends in access-related complications, as well as the impact of race on these complications, among admitted patients with end-stage kidney disease (ESKD) receiving hemodialysis. Methods: A retrospective cohort study between 2005 and 2018 was performed using the National Inpatient Sample (NIS). Hospitalizations involving ESKD and hemodialysis were identified. There were 9,246,553 total admissions involving ESKD and hemodialysis, of which 1,167,886 (12.6%) had complications. Trends in complications were assessed and compared among races. Results: There was a decreasing trend in rates of mechanical (trend: -0.05% per year; P < 0.001), inflammatory or infectious (-0.48%; P < 0.001), and other (-0.19%; P < 0.001) complications from 2005 to 2018. Non-White patients had a greater magnitude in the decrease in trends in rates of complications compared to White patients (-0.69% per year vs. -0.57%; P < 0.001). Compared to the White patients, Black patients (odds ratio [OR]: 1.26; P < 0.001) and those of the other races (OR: 1.11; P < 0.001) had higher odds of complications. These differences were also statistically significant among lower socioeconomic classes (75 percentile vs. 0-25 percentile: P = 0.009) and within southern states (vs. Northeast: P < 0.001). Conclusion: Although there was an overall decrease in the trends of dialysis-associated complications requiring hospitalization among ESKD patients receiving hemodialysis, non-White patients have higher odds of complications compared to White patients. The findings in this study emphasize the need for more equitable care for hemodialysis patients.

Endoscopic approach for management of dropped gallstones using percutaneous cholangioscopy.

Video 1Endoscopic approach for management of dropped gallstones using percutaneous cholangioscopy.

An Overview of Telehealth in the Management of Cardiovascular Disease: A Scientific Statement From the American Heart Association.

Telehealth enables the remote delivery of health care through telecommunication technologies and has substantially affected the evolving medical landscape. The COVID-19 pandemic accelerated the utilization of telehealth as health care professionals were forced to limit face-to-face in-person visits. It has been shown that information delivery, diagnosis, disease monitoring, and follow-up care can be conducted remotely, resulting in considerable changes specific to cardiovascular disease management. Despite increasing telehealth utilization, several factors such as technological infrastructure, reimbursement, and limited patient digital literacy can hinder the adoption of remote care. This scientific statement reviews definitions pertinent to telehealth discussions, summarizes the effect of telehealth utilization on cardiovascular and peripheral vascular disease care, and identifies obstacles to the adoption of telehealth that need to be addressed to improve health care accessibility and equity.

Impact of anticoagulation and antiplatelet therapy on dialysis catheter fibrin sheath formation.

PURPOSE Fibrin sheaths are a significant cause of dialysis catheter dysfunction. This study aimed to determine the role of anticoagulation, antiplatelet medications, and other factors in delaying fibrin sheath formation. METHODS An institutional review board-approved retrospective review of all patients treated for tunneled dialysis catheter fibrin sheaths from January 2014 to January 2020 was undertaken. All catheters were symmetric tipped, 14.5 F in diameter, and placed via the internal jugular vein. Seventy patients with venographically confirmed fibrin sheaths that developed after de novo catheter placement were identified. Recurrent fibrin sheaths were excluded. The impact of anticoagulation and antiplatelet therapy, as well as statin therapy, catheter side (right or left), hematocrit, platelet count, prothrombin time (PT), and international normalized ratio (INR), on the time to fibrin sheath formation was determined. RESULTS Patients on anticoagulation had a longer median catheter implantation time of 109.2 days (interquartile range (IQR): 29.3-178.5 days) compared to 80.7 days (IQR: 28.0-168.6 days) among patients not on anticoagulation. Catheter dwell time among patients taking antiplatelet therapy was 86.0 days (IQR: 31.5-160.7 days) versus 74.4 days (IQR: 27.5-202.4 days) for patients not on antiplatelet medication. Patients taking statins versus those not taking statins had median catheter dwell times of 97.5 days (IQR: 27.5-138.5 days) and 62.4 days (IQR: 29.9-259.6 days), respectively. Time to fibrin sheath formation was not significantly associated with hematocrit (P =.16), platelet count (0.12), PT (P =.51), or INR (P =.74). CONCLUSION Anticoagulation has no significant benefit in delaying sheath formation in patients with tunneled dialysis catheters. Hematologic and coagulation parameters at the time of catheter placement were also not associated with catheter dwell time.

Technical success and safety of peripherally inserted central catheters in the great saphenous and anterior accessory great saphenous veins.

BACKGROUND: Peripherally inserted central catheters (PICC) are occasionally placed in the great saphenous vein (GSV) and anterior accessory great saphenous vein (AAGSV) in patients with inadequate upper extremity veins or contraindications to upper extremity placement. Outcomes on the placement of PICCs in these veins are limited. OBJECTIVES: This study aimed to determine technical success and safety of GSV/AAGSV PICCs. MATERIALS AND METHODS: This is a retrospective study that reviewed all GSV/AAGSV PICC placements between January 2011 and December 2019. A total of 29 PICC placements procedures were identified. The electronic medical record was queried for demographic, procedural, and complication data. Technical success was defined by whether the vein could be accessed and a PICC could be placed. Catheter-associated infections, dislodgement or migration, malfunction, and PICC-associated thrombosis were recorded. RESULTS: Technical success of placement was 100%. Twenty-one (72%) catheters were placed in the GSV in the mid to upper thigh and eight (28%) were placed in the AAGSV. The median PICC dwell time was 13 days with a range of 3-155 days. PICC-associated complications occurred after 11 (37.9%) placements. Line associated infection was the most common complication (17.2%). CONCLUSION: Due to a high complication rate, GSV/AAGSV PICC placement should be considered only when upper extremity or cervical PICC placement is not feasible or contraindicated.

Long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring selective transarterial embolization.

PURPOSE: To determine long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring transarterial embolization compared to patients who underwent uncomplicated renal cryoablation without major hemorrhage. METHODS: Utilizing a matched cohort study design, retrospective review identified 23 patients who underwent percutaneous image-guided renal cryoablation complicated by major hemorrhage requiring ipsilateral transarterial embolization (TAE group) and a control group of 23 patients who underwent uncomplicated renal cryoablation matched 1:1 by age, gender and RENAL Nephrometry score at a single institution from 1/1/2005 to 12/31/2019. Primary outcome parameters included change in creatinine (mg/dl) and estimated glomerular filtration rate (ml/min/1.73 m2; eGFR) from baseline and were compared between TAE and control group using a paired t-test. RESULTS: There was a significantly higher proportion of patients on pre-ablation anticoagulation in the TAE v. control group (30% v. 4%; p = 0.047), but all patients were off anticoagulation and with normal coagulation parameters at the time of cryoablation. Otherwise there were no significant differences in clinical, renal tumor, Charlson co-morbidity index, baseline renal function or cryoablation parameters between the TAE and control group. In the post-ablation period, there was trend toward greater increase in creatinine from baseline to worst post-ablation creatinine in the TAE v. the control group (+ 0.5 ± 0.7 mg/dl v. 0.2 ± 0.1 mg/dl; p = 0.056). However, at a mean follow-up of 42.7 ± 35.7 months, there was no significant difference between the TAE and control group in creatinine (p = 0.68), eGFR (p = 0.60) or change from baseline in creatinine (p = 0.28), eGFR (p = 0.80) or CKD stage (p = 0.74). No patient required initiation of hemodialysis. CONCLUSION: Selective transarterial embolization for post-renal cryoablation hemorrhage does not significantly affect long-term renal function compared to cryoablation alone. Pre-ablation anticoagulation despite normal coagulation at time of ablation may be a risk factor for post-ablation hemorrhage, and warrants further evaluation when considering pre-ablation embolization.

Adventitial delivery of nanoparticles encapsulated with 1α, 25-dihydroxyvitamin D3 attenuates restenosis in a murine angioplasty model.

Percutaneous transluminal angioplasty (PTA) of stenotic arteriovenous fistulas (AVFs) is performed to maintain optimal function and patency. The one-year patency rate is 60% because of venous neointimal hyperplasia (VNH) and venous stenosis (VS) formation. Immediate early response gene X-1 (Iex-1) also known as Ier3 increases in response to wall shear stress (WSS), and can cause VNH/VS formation in murine AVF. In human stenotic samples from AVFs, we demonstrated increased gene expression of Ier3. We hypothesized that 1α, 25-dihydroxyvitamin D3, an inhibitor of IER3 delivered as 1α, 25-dihydroxyvitamin D3 encapsulated in poly lactic-co-glycolic acid (PLGA) nanoparticles loaded in Pluronic F127 hydrogel (1,25 NP) to the adventitia of the stenotic outflow vein after PTA would decrease VNH/VS formation by reducing Ier3 and chemokine (C-C motif) ligand 2 (Ccl2) expression. In our murine model of AVF stenosis treated with PTA, increased expression of Ier3 and Ccl2 was observed. Using this model, PTA was performed and 10-µL of 1,25 NP or control vehicle (PLGA in hydrogel) was administered by adventitial delivery. Animals were sacrificed at day 3 for unbiased whole genome transcriptomic analysis and at day 21 for immunohistochemical analysis. Doppler US was performed weekly after AVF creation. At day 3, significantly lower gene expression of Ier3 and Ccl2 was noted in 1,25 NP treated vessels. Twenty-one days after PTA, 1,25 NP treated vessels had increased lumen vessel area, with decreased neointima area/media area ratio and cell density compared to vehicle controls. There was a significant increase in apoptosis, with a reduction in CD68, F4/80, CD45, pro-inflammatory macrophages, fibroblasts, Picrosirius red, Masson's trichrome, collagen IV, and proliferation accompanied with higher wall shear stress (WSS) and average peak velocity. IER3 staining was localized to CD68 and FSP-1 (+) cells. After 1,25 NP delivery, there was a decrease in the proliferation of α-SMA (+) and CD68 (+) cells with increase in the apoptosis of FSP-1 (+) and CD68 (+) cells compared to vehicle controls. RNA sequencing revealed a decrease in inflammatory and apoptosis pathways following 1,25 NP delivery. These data suggest that adventitial delivery of 1,25 NP reduces VNH and venous stenosis formation after PTA.

1α,25-Dihydroxyvitamin D3 Encapsulated in Nanoparticles Prevents Venous Neointimal Hyperplasia and Stenosis in Porcine Arteriovenous Fistulas.

BACKGROUND: Few therapies prevent venous neointimal hyperplasia (VNH) and venous stenosis (VS) formation in arteriovenous fistulas (AVF). Expression of the immediate early response gene X-1 (Iex-1), also known as Ier3, is associated with VNH and stenosis in murine AVFs. The study aimed to determine if local release of Ier3 long-acting inhibitor 1α,25(OH)2D3 from poly(lactic-co-glycolic acid) (PLGA) nanoparticles embedded in a thermosensitive Pluronic F127 hydrogel (1,25 NP) could affect VNH/VS formation in a large animal model. METHODS: Immediately after AVF creation in a porcine model of renal failure, 1,25 NP or vehicle control was injected into the adventitia space of AVF outflow veins. Scanning electron microscopy and dynamic light scattering characterized drug and control nanoparticles. Animals were sacrificed 3 and 28 days later for gene expression, immunohistologic, magnetic resonance imaging and angiography, and ultrasound analyses. Whole transcriptome RNA sequencing with differential gene expression analysis was performed on outflow veins of AVF. RESULTS: Encapsulation of 1α,25(OH)2D3 in PLGA nanoparticles formed nanoparticles of uniform size that were similar to nanoparticles without 1α,25(OH)2D3. The 1,25 NP-treated AVFs exhibited lower VNH/VS, Ier3 gene expression, and IER-3, MCP-1, CD68, HIF-1α, and VEGF-A immunostaining, fibrosis, and proliferation. Blood flow and lumen area increased significantly, whereas peak systolic velocity and wall shear stress decreased. Treatment increased Young's modulus and correlated with histologic assessment of fibrosis and with no evidence of vascular calcification. RNA sequencing analysis showed changes in the expression of genes associated with inflammatory, TGFß1, and apoptotic pathways. CONCLUSIONS: Local release of 1,25 NP improves AVF flow and hemodynamics, and reduces stenosis in association with reduction in inflammation, apoptosis, and fibrosis in a porcine model of arteriovenous fistula.

Novel Clinical Therapies and Technologies in Dialysis Vascular Access.

The hemodialysis population continues to grow. Although procedures for dialysis have existed for >60 years, significant challenges with vascular access to support hemodialysis persist. Failure of arteriovenous fistulas (AVFs) to mature, loss of AVF and graft patency, thrombosis, and infection hinder long-term access, and add extra health care costs and patient morbidity. There have been numerous innovations over the last decade aimed at addressing the issues. In this study, we review the literature and summarize the recent evolution of drug delivery, graft development, minimally invasive AVF creation, and stem-cell therapy for hemodialysis access.

Rationale and Trial Design of MesEnchymal Stem Cell Trial in Preventing Venous Stenosis of Hemodialysis Vascular Access Arteriovenous Fistula (MEST AVF Trial).

Background: Hemodialysis arteriovenous fistulas (AVFs) are the preferred vascular access for patients on hemodialysis. In the Hemodialysis Fistula Maturation Study, 44% of the patients achieved unassisted maturation of their fistula without needing an intervention. Venous neointimal hyperplasia (VNH) and subsequent venous stenosis are responsible for lack of maturation. There are no therapies that can prevent VNH/VS formation. The goal of this paper is to present the background, rationale, and trial design of an innovative phase 1/2 clinical study that is investigating the safety of autologous adipose-derived mesenchymal stem cells delivered locally to the adventitia of newly created upper extremity radiocephalic (RCF) or brachiocephalic fistula (BCF). Methods: The rationale and preclinical studies used to obtain a physician-sponsored investigational new drug trial are discussed. The trial design and end points are discussed. Results: This is an ongoing trial that will complete this year. Conclusion: This is a phase 1/2 single-center, randomized trial that will investigate the safety and efficacy of autologous AMSCs in promoting maturation in new upper-extremity AVFs.Clinical Trial registration number: NCT02808208.

Transjugular Renal Biopsy Bleeding Risk and Diagnostic Yield: A Systematic Review.

This study aimed to better define the safety and efficacy of transjugular renal biopsy (TJRB) based on published studies. Seventeen published articles were included (1,321 biopsies). Complications were classified as major if they resulted in blood transfusion or additional invasive procedures. All other bleeding complications were considered minor. Diagnostic tissue was obtained in 1,193 procedures (90.3%). The total incidence of bleeding complications among 15 articles with complete data was 202 of 892 procedures (22.6%): 162 (18.2%) minor and 40 (4.5 %) major. These results show that TJRB is a feasible procedure for obtaining renal tissue for diagnosis and that most complications are self-limiting.

Endovascular Arteriovenous Dialysis Fistula Intervention: Outcomes and Factors Contributing to Fistula Failure.

RATIONALE & OBJECTIVE: Primary patency is variable with arteriovenous fistulas, and many patients require angiographic procedures to obtain patency. Accordingly, we determined postintervention patency rates and contributing factors for fistula failure following intervention to establish secondary patency in non-dialysis-dependent patients with advanced chronic kidney disease following creation of an arteriovenous fistula. STUDY DESIGN: Observational study from a single referral center. SETTING & PARTICIPANTS: 210 non-dialysis-dependent patients with advanced chronic kidney disease who underwent upper-extremity fistula creation for anticipated dialysis between October 1995 and January 2015 and who required subsequent endovascular therapy to establish or maintain patency were reviewed. EXPOSURE: Endovascular therapy for dialysis arteriovenous fistula primary patency failure. OUTCOMES: Postintervention patency duration following endovascular therapy. ANALYTICAL APPROACH: Descriptive study with outcomes determined using Cox proportional hazards models. RESULTS: Multiple fistula configurations were reviewed: 138 (65.7%) brachiocephalic, 39 (18.6%) radiocephalic, 30 (14.3%) brachiobasilic, 2 (1.0%) ulnocephalic, and 1 (0.5%) radiobasilic. There were 261 initial stenoses treated. Postintervention primary patency is defined as the time from the index intervention to repeat intervention for stenosis. Postintervention primary-assisted patency is the time from the index intervention to thrombectomy for fistula thrombosis or change in modality. Postintervention secondary patency is the time from the index intervention to fistula abandonment. Median postintervention primary patency, postintervention primary-assisted patency, and secondary patency were 2.7, 3.2, and 3.6 years, respectively. The overall 1-year primary, primary-assisted, and secondary patency rates in this cohort were 53.0%, 87.7%, and 83.5%, respectively. Compared with radiocephalic fistulas, brachiocephalic fistulas had higher risk for postintervention primary patency loss (HR, 1.90; 95% CI, 1.13-3.20; P = 0.02). LIMITATIONS: Dialysis fistula revascularization techniques varied. CONCLUSIONS: The radiocephalic fistula configuration had the best postintervention primary patency in this cohort. Postintervention primary-assisted patency and secondary patency were not significantly different among different fistula configurations.

Deep-learning-based model observer for a lung nodule detection task in computed tomography.

Purpose: Task-based image quality assessment using model observers (MOs) is an effective approach to radiation dose and scanning protocol optimization in computed tomography (CT) imaging, once the correlation between MOs and radiologists can be established in well-defined clinically relevant tasks. Conventional MO studies were typically simplified to detection, classification, or localization tasks using tissue-mimicking phantoms, as traditional MOs cannot be readily used in complex anatomical background. However, anatomical variability can affect human diagnostic performance. Approach: To address this challenge, we developed a deep-learning-based MO (DL-MO) for localization tasks and validated in a lung nodule detection task, using previously validated projection-based lesion-/noise-insertion techniques. The DL-MO performance was compared with 4 radiologist readers over 12 experimental conditions, involving varying radiation dose levels, nodule sizes, nodule types, and reconstruction types. Each condition consisted of 100 trials (i.e., 30 images per trial) generated from a patient cohort of 50 cases. DL-MO was trained using small image volume-of-interests extracted across the entire volume of training cases. For each testing trial, the nodule searching of DL-MO was confined to a 3-mm thick volume to improve computational efficiency, and radiologist readers were tasked to review the entire volume. Results: A strong correlation between DL-MO and human readers was observed (Pearson's correlation coefficient: 0.980 with a 95% confidence interval of [0.924, 0.994]). The averaged performance bias between DL-MO and human readers was 0.57%. Conclusion: The experimental results indicated the potential of using the proposed DL-MO for diagnostic image quality assessment in realistic chest CT tasks.

Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization.

PURPOSE: To determine the impact of renal function trajectory, defined as the change in renal function over time before and after renal artery stent placement, on long-term risk for renal replacement therapy (RRT) and mortality. MATERIALS AND METHODS: Estimated glomerular filtration rates (eGFRs) 6-12 months before renal artery stent placement, at the time of intervention, and 6-12 months after intervention were determined in 398 patients. The effect of eGFR change before and after renal artery stent placement was calculated. Cox proportional-hazards ratio was used to determine the risks for RRT and all-cause mortality. RESULTS: The risk for RRT was significantly influenced by eGFR change from the time of intervention to follow-up at 6-12 month after treatment (P = .02). In addition, among patients with a postintervention eGFR ≤ 40 mL/min/1.73 m2, for every 1 unit of eGFR increase, there was a significant decrease in RRT and all-cause mortality (P < .001 and P < .001, respectively). Secondary parameters that increased RRT risk included diabetes at the time of intervention (P = .03), increased baseline proteinuria (P < .001), and stage 4 or 5 chronic kidney disease (CKD; P = .01 and P = .003, respectively). Multivariate analysis demonstrated higher all-cause mortality rates among patients with diabetes at the time of intervention (P = .009). CONCLUSIONS: Postintervention eGFR trajectory improvement approaching 40 mL/min/1.73 m2 was associated with decreased RRT and mortality risk. These findings suggest that patients with advanced CKD and renal artery stenosis may benefit from revascularization regardless of their preinterventional renal function measurement.

Perfusion Assessment in Critical Limb Ischemia: Principles for Understanding and the Development of Evidence and Evaluation of Devices: A Scientific Statement From the American Heart Association.

There are >12 million patients with peripheral artery disease in the United States. The most severe form of peripheral artery disease is critical limb ischemia (CLI). The diagnosis and management of CLI is often challenging. Ethnic differences in comorbidities and presentation of CLI exist. Compared with white patients, black and Hispanic patients have higher prevalence rates of diabetes mellitus and chronic renal disease and are more likely to present with gangrene, whereas white patients are more likely to present with ulcers and rest pain. A thorough evaluation of limb perfusion is important in the diagnosis of CLI because it can not only enable timely diagnosis but also reduce unnecessary invasive procedures in patients with adequate blood flow or among those with other causes for ulcers, including venous, neuropathic, or pressure changes. This scientific statement discusses the current tests and technologies for noninvasive assessment of limb perfusion, including the ankle-brachial index, toe-brachial index, and other perfusion technologies. In addition, limitations of the current technologies along with opportunities for improvement, research, and reducing disparities in health care for patients with CLI are discussed.

Restenosis Rates After Drug-Eluting Stent Treatment for Stenotic Small-Diameter Renal Arteries.

PURPOSE: To determine primary rates in small-diameter renal arteries, including complex bifurcation lesions, treated with drug-eluting stents (DES) in patients with atherosclerotic renal artery stenosis. MATERIALS AND METHODS: This is a retrospective single-institution study. A total of 37 patients with 39 stented renal arteries were included. Patient and procedural data were obtained from the electronic medical record. Survival free from restenosis was estimated using the Kaplan-Meier method with patients stratified into two groups based on renal artery diameters (≤ 3.5 mm or > 3.5 mm). Univariate Cox proportional models were used to estimate hazard ratios associated with clinical and angiographic variables. RESULTS: Average renal artery diameter at time of treatment was 3.4 mm ± 0.4 mm. The median survival free from restenosis was 992 days, with 11 out of 37 (29.7%) developing an in-stent restenosis. Renal arteries < 3.5 mm in diameter had similar patency rates as renal arteries > 3.5 mm (P = 0.33). The 1-, 2-, and 5-year patency rates were 71%, 63%, and 38%, respectively. History of stroke was the only comorbidity to portend a significantly greater rate of restenosis (hazard ratio 3.77; 95%CI, 1.05-13.6; P = 0.04). Medications did not statistically alter the risk of restenosis. CONCLUSION: Revascularization of renal arteries with DES achieved similar primary patency rates irrespective of renal artery diameter. Stent configuration was not associated with time to renal replacement therapy or all-cause mortality. LEVEL OF EVIDENCE: Level 3, Cohort Study.