Treatment Trials

104 Clinical Trials for Various Conditions

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ENROLLING_BY_INVITATION
Renal Autotransplantation; Case Series
Description

Renal autotransplantation (RAT) is a method of removing a kidney from its place of origin in a patient, repairing it, and transplanting it in another location of the body, generally the iliac fossa of the same patient.RAT is a relatively new technique; the first ever RAT procedure in the US was performed in 1963. Advances in preservation and transplantation techniques have made RAT a modality that can be utilized in complex renal diseases. RAT is indicated for conditions such as renal vascular disease, nutcracker syndrome, pelvic venous congestion, pelvic trauma, refractory stone disease and, in some cases, loin pain hematuria syndrome and conventionally unresectable renal tumors. Irrespective of the excellent outcomes shown by RAT, the conventional open approach requires a large midline xiphoid-to-pubis or flank incision for donor nephrectomy with a second pelvic incision for renal transplantation into the iliac fossa.The current gold standard approach to RAT is a laparoscopic nephrectomy followed by open auto-transplantation. However, this approach still requires a large pelvic incision. Robotic technology enables us to perform more complex minimally invasive surgery. Gordon et al. performed and reported the first completely intracorporeal robotic RAT to repair a ureteral injury in 2014.

COMPLETED
Evaluation of Patients With Heart Disease Not Eligible for Research Protocols
Description

An important mission of the National Institutes of Health (NIH) is to develop and carry out research studies designed to improve understanding of disease processes and treatments. Clinical research continues to become more focused on specific diseases and the signs and symptoms of diseases in specific groups of people and patients. This study is designed to permit inpatient evaluation and care of patients with heart disease who do not qualify to participate in research studies being conducted by the Cardiology Branch of the National Heart, Lung, and Blood Institute (NHLBI). These patients are valuable to the Cardiology Branch of the NHLBI because they help to improve training and experience of its researchers.

RECRUITING
Efficacy and Mechanisms of Dapagliflozin in Promoting Kidney Function and Cardiovascular Health in Kidney Transplant Recipients
Description

Long-term allograft function in kidney transplant recipients (KTRs) remain suboptimal, and graft failure causes significant morbidity and mortality, with cardiovascular disease being the leading cause of death in KTRs and the most common cause of death with a functioning graft. Sodium-glucose cotransporter 2 (SGLT2) inhibitors safely lower cardiovascular and kidney disease risk in the non-transplant population, yet data in KTRs are lacking. This clinical trial seeks to establish the efficacy and safety of dapagliflozin, a SGLT2 inhibitor, for improving cardiovascular and kidney graft function in adult KTRs with type 2 diabetes and post-transplant diabetes, and to leverage innovate translational methods to define the underlying mechanisms of action.

RECRUITING
Potassium, Hydration, Cardiovascular, and Kidney Study
Description

Compared with White Adults, Non-Hispanic Black Adults are at an elevated risk of developing cardiovascular disease (CVD) and end stage chronic-kidney disease (CKD), two of the leading causes of death in the United States. Inadequate hydration status is associated with risk factors for both CVD and CKD. Prior data show that Black individuals are less likely to be adequately hydrated when compared with their White counterparts. Further, socioeconomic factors have been shown to influence hydration practices. Inadequate hydration influences certain hormones that regulate blood volume and impact blood pressure, but increasing potassium intake may provide some positive effects on normalizing these hormones and blood pressure. Black adults, in particular, are more likely to consume less potassium, have inadequate hydration, and tend to have higher blood pressure. As such, there is a critical need for effective strategies to address racial disparities in hydration and resultant health consequences; as well as establish the role of socioeconomic factors contributing to hydration. Therefore, the investigators are seeking to test the investigators' central hypothesis that water with a potassium supplement will improve hydration and cardiovascular health in young White adults (n = 20, 10 females, 10 males), and to a greater extent in young Black Adults (n = 20, 10 females, 10 males. The investigators will assess measures of blood pressure, arterial stiffness, and biomarkers in the urine and blood samples prior to and following a 14-day hydration intervention of 1) bottled water and 2) bottled water with potassium supplementation (2000mg potassium/day).

RECRUITING
MANATEE-T1D: Metformin and AutomaTEd Insulin Delivery System Effects on Renal Vascular Resistance, Insulin Sensitivity, and Cardiometabolic Function in Youth with Type 1 Diabetes
Description

Diabetic kidney disease and cardiovascular disease remain the leading causes of morbidity and mortality in people with type 1 diabetes and are exacerbated with longer duration of diabetes and time outside goal glycemic range. Yet, type 1 diabetes is a complex disease with pathophysiology that extends beyond beta-cell injury and insulin deficiency to include insulin resistance and renal vascular resistance, factors that accelerate cardiovascular disease risk. We have shown that metformin improved peripheral insulin sensitivity and vascular stiffness in youth with type 1 diabetes on multiple daily insulin injections or standard insulin pumps. However, metformin's effect on kidney and endothelial outcomes, and the effects of type 1 diabetes technologies, with or without metformin, on any cardiovascular or kidney outcome, remains unknown. Automated insulin delivery systems combine an insulin pump, continuous glucose monitor, and control algorithm to modulate background insulin delivery and decrease peripheral insulin exposure while improving time in target range and reducing hypoglycemia. We hypothesize that automated insulin delivery systems, particularly when combined with metformin, may modulate renal vascular resistance and insulin sensitivity, thereby impacting cardiometabolic function. MANATEE-T1D is a randomized, double-blind, placebo-controlled trial of 4 months of metformin 2,000 mg daily in 40 youth aged 12-25 years with type 1 diabetes on automated insulin delivery systems vs. 20 control youth with type 1 diabetes on multiple daily injections plus a continuous glucose monitor or an insulin pump in manual mode plus a continuous glucose monitor which will assess for changes in calculated renal vascular resistance and gold standard measures of whole-body and adipose insulin sensitivity, arterial stiffness, and endothelial function.

RECRUITING
Effect of Alkali Therapy on Vascular and Graft Function in Kidney Transplant Recipients
Description

Lower serum bicarbonate levels, even within the normal laboratory range, in kidney transplant recipients (KTRs) are associated with an increased risk of graft loss, cardiovascular events and mortality. Because acid retention is common in KTRs, it is plausible that alkali therapy in KTRs may also result in improved vascular and graft function. The investigators will perform a randomized, double-blinded, placebo-controlled, 12 month study in 120 KTRs to examine the effect of sodium bicarbonate therapy on surrogate markers of CVD and graft function. The overall hypothesis is that treatment with bicarbonate will improve indicators of vascular and graft function in KTRs by decreasing complement activation.

COMPLETED
SPYRAL DYSTAL Renal Denervation Global Clinical Study
Description

The objective of this single arm interventional study is to determine if renal denervation performed in the distal main and first order branch renal arteries is as effective in reducing blood pressure as the procedural approach used in the SPYRAL HTN-OFF MED clinical study.

ACTIVE_NOT_RECRUITING
SPYRAL HTN-ON MED Study of Renal Denervation With the Symplicity Spyral™ Multi-electrode Renal Denervation System
Description

The purpose of this study is to test the hypothesis that renal denervation decreases blood pressure and is safe when studied in the presence of up to three standard antihypertensive medications.

COMPLETED
Efficacy and Safety of the DASH Diet in Adults With Moderate Chronic Kidney Disease: Pilot Study
Description

More than two-thirds of US adults with chronic kidney disease (CKD) have uncontrolled hypertension. Both hypertension and CKD are major independent risk factors for cardiovascular disease, which is the leading cause of death in the US. Fortunately, lowering blood pressure to recommended treatment targets not only slows the progression of CKD, but also improves cardiovascular outcomes. Controlling hypertension in this patient population, however, can be quite challenging. A lifestyle modification that effectively reduces blood pressure in both pre-hypertensive and hypertensive adults is the Dietary Approaches to Stop Hypertension (DASH) diet. The purpose of this pilot study is to (1) determine the extent to which the DASH diet lowers blood pressure in hypertensive adults with moderate chronic kidney disease (CKD) (estimated glomerular filtration rate \[eGFR\] 30-59 ml/min/1.73m2) and (2) establish that the DASH diet can be safely consumed by this patient population.

COMPLETED
Renal Denervation in Patients With Uncontrolled Hypertension - SYMPLICITY HTN-4
Description

An international, multi-center, prospective, blinded, randomized, controlled trial. The objective is to demonstrate that catheter-based renal denervation is an effective and safe treatment for uncontrolled hypertension.

TERMINATED
Carvedilol and Micro T-Wave Alternans in Hypertensives With Chronic Kidney Disease
Description

Evaluate effectiveness of Carvedilol CR on Micro T-Wave Alternans in high risk hypertensives

RECRUITING
Nicotinamide Riboside Supplementation for Treating Arterial Stiffness and Elevated Systolic Blood Pressure in Patients With Moderate to Severe CKD
Description

Risk of cardiovascular diseases (CVD) is significantly elevated in patients with chronic kidney disease (CKD); however, this increased risk is only partially explained by traditional CV risk factors. Arterial dysfunction is an important nontraditional CV risk factor gaining increased recognition in the field of nephrology. This process is best represented, both physiologically and pathophysiologically, by increases in the gold standard measure of arterial stiffening, carotid to femoral artery pulse wave velocity (CFPWV), which reflects, in particular, increases in aortic stiffness. Aortic stiffening with CKD is mediated by structural and functional (increased vascular smooth muscle tone) changes in the arterial wall stimulated by oxidative stress and chronic low-grade inflammation. Caloric restriction (CR) is a promising strategy for prevention of CKD-associated arterial dysfunction and CVD. However, long-term adherence to chronic CR regimens with optimal nutrition is very difficult to achieve. Research has shown that boosting NAD+ bioavailability to stimulate SIRT-1, a "CR mimetic" approach, reduces CFPW and oxidative stress in old mice, and this lab recently took the first step in translating these findings in a study of adults with normal kidney function and elevated systolic blood pressure (SBP). The data found that supplementation with nicotinamide riboside, a natural, commercially available precursor of NAD+ and novel CR mimetic, increased NAD+ bioavailability and reduced CFPWV and SBP. A randomized, placebo-controlled, double-blind, single-site phase IIa clinical trial to assess the safety and efficacy of oral nicotinamide riboside (500 mg capsules 2x/day; NIAGEN®; ChromaDex Inc.) for 3 months vs. placebo for decreasing aortic stiffness and SBP in patients (35-80 years) with stage III and IV CKD is being proposed. It is hypothesized that treatment will reduce CFPWV and SBP, as related to increases in systemic NAD+ bioavailability and reductions in oxidative stress, and inflammation. Aim 1: To measure CFPWV (primary outcome) before/after nicotinamide riboside vs. placebo treatment; Aim 2: To measure casual and 24h-ambulatory SBP (secondary outcome) before and after treatment; Aim 3: To determine the safety and tolerability of treatment with nicotinamide riboside vs. placebo; Aim 4: To measure systemic NAD+ and NAD+-related metabolite concentrations, as well as circulating markers of oxidative stress, inflammation, and vasoconstriction factors before and after treatment.

RECRUITING
International (Pediatric) Peritoneal Biobank
Description

Within few years the peritoneal membrane of adult peritoneal dialysis (PD) patients undergoes substantial morphological transformation, including progressive fibrosis, vasculopathy and neoangiogenesis. Ultrafiltration capacity steadily declines and ultimately results in PD failure. In children, peritoneal biopsies demonstrating PD associated alterations have not yet been obtained. They, however, should be particularly informative, since secondary tissue and vascular pathology related to ageing or diabetes is absent. An international, prospective peritoneal membrane biopsy study in children on PD will therefore be performed. Biopsies will be obtained at time of PD catheter insertion, on occasion of intercurrent abdominal surgery (e.g. hernia repair, catheter exchange) and at time of renal transplantation. Quantitative histomorphometry and tissue protein expression analyses will be correlated with time integrated PD treatment modalities and functional characteristics as well as inflammatory and cardiovascular comorbidity surrogate parameter. Blood will be obtained during clinical routine sampling. Biopsies will be obtained during clinically indicated operations, without substantially increasing operation time and associated surgical risks. The detailed histomorphometry of the PD membrane will give additional information, potentially impacting on the individual PD regime. 3/2018: The analyses of the pediatric PD biopsy demonstrated early and major transformation of the peritoneal membrane with neutral pH low GDP fluids, and significant vasculopathy already in children with CKD stage 5, further progressing with PD. The underlying mechanisms are partly understood, only. In view of these major findings and the numerous open questions, collection of biosamples will be continued in children and also in adult PD patients. The following questions will be addressed: Molecular counterparts of peritoneal semi-permeability, solute and water transport (beyond AQP1), pathomechanisms and molecular and functional impact of peritoneal transformation with low and high GDP fluids, and the respective pathomechanisms and molecular and functional impact of vascular disease in CKD and with different PD fluids. The impact of renal transplantation following PD will be assessed in a subgroup of patients with tenckhoff catheter removal several weeks after transplantation and a functioning graft.

RECRUITING
SPYRAL GEMINI Pilot Study
Description

The purpose of the SPYRAL GEMINI Pilot Study is to evaluate that multi-organ denervation with the Gemini System is safe and provide evidence of blood pressure reduction when studied in an uncontrolled hypertensive population with and without high cardiovascular risk.

RECRUITING
Global Paradise System US Post Approval Study
Description

The objective of the Global Paradise® System US Post Approval Study (US GPS) is to evaluate the real-world use of the Paradise Ultrasound Renal Denervation System indicated for patients who are unable to lower their blood pressure with lifestyle changes and medication. This system is comprised of a catheter, cable, balloon, and generator and has received FDA approval in the United States. Information collected in this study will be analyzed to better understand the long-term safety and effectiveness of treatment with the Paradise System for patients with high blood pressure.

RECRUITING
SGC Stimulation, Perioperative Vascular Reactivity, and Organ Injury in Cardiac Surgery
Description

The goal of this mechanistic clinical trial is to learn about the effects of medications called soluble guanylyl cyclase stimulators on vascular function and markers of kidney and brain injury in patients having heart surgery. The main questions it aims to answer are: 1. Does soluble guanylyl cyclase stimulation improve blood vessel function compared to placebo? 2. Does soluble guanylyl cyclase stimulation decrease markers of kidney injury and brain injury compared to placebo? Participants will be randomized to a soluble guanylyl cyclase stimulator called vericiguat or placebo, and researchers will compare vascular function and markers of brain and kidney injury to see if vericiguat improves vascular function and reduces markers of injury. This will provide important information to determine the underlying reasons that patients have some kidney and brain function problems after having heart surgery.

RECRUITING
Promoting Goals-of-Care Discussions for Patients With Memory Problems and Their Caregivers
Description

The goal of this clinical trial is to improve communication among clinicians, patients with memory problems, and their family members. We are testing a way to help clinicians have better conversations to address patients' goals for their healthcare. To do this, we created a simple, short guide called the "Jumpstart Guide." The goal of this research study is to show that using this kind of guide is possible and can be helpful for patients and their families. Patients' clinicians may receive a Jumpstart Guide before the patient's clinic visit. Researchers will compare patients whose clinician received a Jumpstart Guide to patients whose clinician did not receive a guide to see if more patients in the Jumpstart Guide group had conversations about the patient's goals for their healthcare. Patients and their family members will also be asked to complete surveys after the visit with their clinician.

RECRUITING
Mitochondria Oxidative Stress and Vascular Health Study
Description

Cardiovascular diseases (CVDs) are the number one cause of death in America and most of the post-industrial world. Hypertension is a leading risk factor for CVDs including stroke, myocardial infarction, and heart failure. Black Americans suffer from the highest rates of hypertension of any racial/ethnic group in America, among the highest in the world. There are also well-documented racial disparities in vascular dysfunction (e.g., endothelial dysfunction, arterial stiffening). Thus, racial disparities in hypertension and vascular dysfunction exacerbate the burden of CVDs, with Black Americans being 30% more likely to die from CVD than any other race in the US. It is established that mitochondrial dysfunction contributes to vascular dysfunction. However, there is a knowledge gap regarding whether targeting mitochondrial dysfunction attenuates oxidative stress, vascular dysfunction, and CVD risk among Black adults at heightened CVD risk. Thus, the investigators will conduct an 8-week trial with the mitochondrial antioxidant MitoQ in middle-aged and older Black and non-Black adults. Our overarching hypothesis is that mitochondrial dysfunction contributes to heightened oxidative stress, vascular dysfunction, and higher BP in Black adults; and that MitoQ will attenuate these racial differences. Importantly, the investigators will also assess social determinants of health (e.g., income, neighborhood disadvantage, discrimination) and health behaviors (e.g., diet, physical activity) and uncover their role in oxidative stress, vascular function, and BP Regarding methodology, the investigators will perform blood draws, vascular testing, preceding and following an 8-week, 20mg daily consumption of MitoQ and placebo. The investigators will also measure urine biomarkers of kidney function and blood pressure in adults (45-75 years old).

RECRUITING
SPYRAL AFFIRM Global Study of RDN With the Symplicity Spyral RDN System in Subjects With Uncontrolled HTN
Description

The purpose of this single-arm interventional study is to evaluate the long-term safety, efficacy, and durability of the Symplicity Spyral system in subjects treated with renal denervation. Additionally, long-term follow-up data will also be collected from eligible subjects previously treated in the SPYRAL PIVOTAL-SPYRAL HTN-OFF MED and SPYRAL HTN-ON MED studies.

ACTIVE_NOT_RECRUITING
Project to Improve Communication About Serious Illness--Hospital Study: Comparative Effectiveness Trial (Trial 2)
Description

The objective of this protocol is to test the effectiveness of a Jumpstart intervention on patient-centered outcomes for patients with chronic illness by ensuring that they receive care that is concordant with their goals over time, and across settings and providers. This study is particularly interested in understanding the effect of the intervention to improve quality of palliative care for patients with Alzheimer's disease and related dementias (ADRD) but will also include other common chronic, life-limiting illnesses. The specific aims are: 1. To evaluate the efficacy of the EHR-based clinician-facing Jumpstart, drawn from the electronic medical record (EHR), the survey-based bi-directional Jumpstart, drawn from patient or family completed surveys, and usual care for improving quality of care provided to patients with chronic illness experiencing a hospitalization. The primary outcome is EHR documentation of a goals-of-care discussion, assessed from randomization through 30 days. Secondary outcomes include: a) intensity of care outcomes (e.g., ICU use, ICU and hospital free days, hospital readmissions, costs of hospital care); and b) patient- and family-reported outcomes assessed by surveys at 3-5 days and 4-6 weeks after randomization, including occurrence and quality of goals-of-care discussions in the hospital, goal-concordant care, psychological symptoms, and quality of life. 2. To conduct a mixed-methods evaluation of the implementation of the interventions, guided by the RE-AIM and CFIR frameworks for implementation science, incorporating quantitative evaluation of the interventions' reach and adoption, as well as qualitative analyses of interviews with participants, to explore barriers and facilitators to future implementation and dissemination.

COMPLETED
Project to Improve Communication About Serious Illness--Hospital Study: Pragmatic Trial (Trial 1)
Description

The objective of this protocol is to test the effectiveness of a Jumpstart intervention on patient-centered outcomes for patients with chronic illness by ensuring that they receive care that is concordant with their goals over time, and across settings and providers. This study will examine the effect of the EHR-based intervention to improve quality of palliative care for patients 55 years or older with chronic, life-limiting illness with a particular emphasis on Alzheimer's disease and related dementias (ADRD). The specific aims are: 1. To evaluate the effectiveness of a novel EHR-based (electronic health record) clinician Jumpstart guide, compared with usual care, for improving the quality of care; the primary outcome is documentation of a goals-of-care discussion in the period between randomization and 30 days following randomization. Secondary outcomes focus on intensity of care: ICU use, ICU and hospital length of stay, costs of care during the hospitalization, and 7 and 30-day hospital readmissions. 2. To conduct a mixed-methods evaluation of the implementation of the intervention, guided by the RE-AIM framework for implementation science, incorporating quantitative evaluation of the intervention's reach and adoption, as well as qualitative analyses of interviews with participants, to explore barriers and facilitators to future implementation and dissemination.

COMPLETED
Project to Improve Communication About Serious Illness - Pilot Study
Description

This two-year pilot study will test whether a one-page "Jumpstart Form" will affect goals-of-care discussions in the hospital. This form will be provided to clinicians and will include patient-specific information about preferences for goals-of-care communication and for care, as well as tips to improve this communication. Jumpstart forms will also be provided to patients or, if they are unable to communicate, their surrogates/family members. The information on the form will be obtained from questionnaires. The form is tailored to help patients and surrogates talk with clinicians about goals of care. This study is based on a successful application of Jumpstart Form in the outpatient clinic setting.

COMPLETED
Point of Care 3D Ultrasound for Various Applications: A Pilot Study
Description

Summary 1. Purpose and Objective: The purpose of this study is to test the feasibility of rapid acquisition of point of care 3D ultrasound in obtaining abdominal and/or pelvic images. The study will use a newly developed acquisition method and post-processing technique to create three dimensional image models of the abdomen and/or pelvis. 2. Study activities and population group. The study population will be a convenience sample of patients of any age presenting to the Emergency Department with complaints necessitating a clinical abdominal and/or pelvic imaging. The study intervention includes acquisition of research ultrasound images, which will not be used for clinical care, and comparison of these images with clinically obtained images. Other clinical data such as surgical and pathology reports will also be reviewed. 3.Data analysis and risk/safety issues. This is a pilot study intended to determine feasibility and to refine image reconstruction algorithms. Research images will be compared to clinical images. Comparison of research images with final diagnosis will also occur. The research intervention, an ultrasound exam, has no known safety risks. The only risk to subjects is loss of confidentiality. This study is observational, not interventional, because the experimental ultrasound will be performed in all subjects and will not be used in the clinical care of patients (consequently, will not have the opportunity to affect clinical outcomes). Experimental images will be reviewed after completion of clinical care and will not be provided to the clinicians caring for the subjects. The investigators are not measuring the effect of the ultrasound examination on the subjects' outcomes.

COMPLETED
SPYRAL PIVOTAL - SPYRAL HTN-OFF MED Study
Description

The purpose of this study is to test the hypothesis that renal denervation decreases blood pressure and is safe when studied in the absence of antihypertensive medications.

WITHDRAWN
Pilot Study: Cardiovascular Events in High Risk Orthopedic Surgical Patients
Description

This is a non-randomized, non-interventional pilot observational study designed to follow high-risk patients through their surgical and hospital stay. The investigators will collect 2 4ml vial's of blood (total of 8ml) prior to surgery to assess CV biomarkers - inflammatory, metabolic, hypercoagulable and platelet.

ACTIVE_NOT_RECRUITING
Tacrolimus/Everolimus vs. Tacrolimus/MMF in Pediatric Heart Transplant Recipients Using the MATE Score
Description

The TEAMMATE Trial will enroll 210 pediatric heart transplant patients from 25 centers at 6 months post-transplant and follow each patient for 2.5 years. Half of the participants will receive everolimus and low-dose tacrolimus and the other half will receive tacrolimus and mycophenolate mofetil. The trial will determine which treatment is better at reducing the cumulative risk of coronary artery vasculopathy, chronic kidney disease and biopsy proven-acute cellular rejection without an increase in graft loss due to all causes (e.g. infection, PTLD, antibody mediated rejection).

COMPLETED
Evaluate Heart Failure Patients With Specially Designed Patient Adherence and Monitoring Software on Standard Mobile Devices
Description

This is planned as a feasibility study. The objective is to evaluate a specially designed patient adherence and monitoring software on standard mobile devices in remote monitoring of heart failure patients.

UNKNOWN
BRINK (BRain In Kidney Disease) Memory Study 2.0
Description

In this study, the investigators will be looking at results of tests of memory and thinking and daily activities in a group of people without known chronic kidney disease (CKD) , and a group of CKD patients, and follow the participants for up to four more years, including after the participants start dialysis or receive a transplant. The investigators are doing this study to compare how often memory loss, confusion and difficulty with daily activities occur in those without and those with CKD. Additionally, the investigators are doing this study to identify risk factors for memory and thinking problems in CKD patients. The information received through the NDI will be utilized to help track our study population and help provide useful information regarding cause of death of those in our study.

COMPLETED
The Effect of Dietary Nitrates on Physical Performance and Vascular Function in Chronic Kidney Disease
Description

The purpose of this study is to examine the effect of acute ingestion of a concentrated beetroot juice supplement on vascular function and exercise capacity in patients with moderate to severe chronic kidney disease

COMPLETED
Phosphodiesterase Type 5 Inhibition to Improve Endothelial Function and Vascular Remodeling in Chronic Kidney Disease and End Stage Renal Disease Patients Requiring New Arteriovenous Fistula
Description

Patients with stage IV and V chronic kidney disease and end stage renal disease requiring hemodialysis at University of Alabama at Birmingham (UAB) Dialysis Clinics will be recruited from the UAB Vascular Access Clinic, which has been the site for recruitment of patients requiring new vascular access for the last 10 years.