Please select the eligibility criteria that correspond to the clinical trial below.
Title: Impact of Vitamin D on Arteriovenous Fistulae Maturation Among ESRD Patients
Brief Summary: Patients requiring hemodialysis following kidney failure need a form of dialysis vascular access in order to undergo the dialysis procedure. Dialysis vascular access dysfunction is an enormous clinical problem. While the best form of vascular access is the arteriovenous fistula (AVF), its primary problem is early, aggressive cellular ingrowth that leads to poor maturation of the vessel, preventing its use for dialysis. Strategies to prevent AVF failure are needed.

Vitamin D is a hormone present in all human bodies and is important for good bone formation and immune function. There is new information that links vitamin D to the function of our veins and arteries, which are used in the creation of an arteriovenous fistulae. Our bodies can make vitamin D and can also get vitamin D from our diet. However, a majority of patients with chronic kidney disease and end-stage renal disease (ESRD) have low vitamin D levels (vitamin D deficiency). There are several benefits to correcting low vitamin D levels, however, it is not know whether correcting low vitamin D in the body will lead to better function of the vein and artery used for arteriovenous fistulae creation. The main goal of this pilot study is to examine the role of vitamin D supplementation on AVF maturation and useability for dialysis. Study results will be used to develop larger studies to examine the specific effect that vitamin D supplementation has on the vessels used for AVF creation and whether vitamin D promotes AVF maturation.


Options:
A: Inclusion Criteria:

* Primary arteriovenous fistulas

  * Brachiocephalic
  * Radiocephalic (both proximal and distal)
* \>18 yrs old
* Diabetics and smokers will be eligible for inclusion

Exclusion Criteria:

* All complex vascular access procedures

  * Re-do brachiocephalic and radiocephalic fistulas
  * Brachiobasilic fistulas
  * Prosthetic grafts
* Cardiovascular dysfunction

  * Hypotension (systolic \<90)
  * Obstructive Cardiomyopathy
  * Severe Aortic stenosis (gradient \>40mmhg)
  * Confirmed myocardial infarction within the last 6 months
* Marked anaemia (Hb\<8)
* Migraine
* Medications

  * Sildenafil
  * Pre-existing nitrate use
* Nitrate allergy
* Closed-angle glaucoma
* Chronically raised intra-cranial pressure
* History of hypothyroid disease
* \< 18 years old
B: Inclusion Criteria

* Patients with patients with end-stage renal disease (ESRD) who are suitable candidates for AVF creation (as assessed by pre-operative vein mapping) and plan to undergo AVF creation are eligible to participate
* Study subjects must agree to participate in the study and provide written informed consent
* Age: Study subjects must be \> 18 years old
* Sites: Emory University affiliated hospitals (including Emory University Hospital, Emory Midtown Hospital, Grady Memorial Hospital) and Emory University affiliated outpatient dialysis units
* Informed consent requirements: All study subjects must agree to participate in the study and provide written informed consent.

Exclusion Criteria

* Age \< 18 years
* Patients with a corrected serum calcium \> 10.5 mg/dL within 4 weeks of study screening
* Current intake of \> 2000 IU per day of Vitamin D3
* Subjects unable to provide informed consent or who plan to relocate outside of Atlanta during the study duration
C: Inclusion Criteria:

1. Age of at least 18 years.
2. Life expectancy of at least 6 months.
3. Chronic kidney disease on hemodialysis, or with anticipated start of hemodialysis within 6 months.
4. Planned creation of a new radiocephalic or brachiocephalic AVF. Revisions of an existing AVF and transposed AVF are not acceptable.

Exclusion Criteria:

1. History or presence of an arterial aneurysm.
2. Malignancy or treatment for malignancy within the previous 12 months with the exception of the following cancers if they have been resected: localized basal cell cancer, squamous cell skin cancer, or any cancer in situ.
3. Hepatic dysfunction defined as bilirubin, ALT \[SGPT\] or AST \[SGOT\] \>2.5 times the upper limit of normal, decompensated cirrhosis, ascites, or known esophageal or gastric varices.
4. Treatment with any investigational drug within the previous 30 days or investigational antibody therapy within 90 days prior to signing informed consent.
D: Inclusion Criteria:

* Patients referred for creation of a new brachiocephalic fistula who consent to take part in the study.
* Aged \> 18
* Male and female participants
* Patients willing and able to attend follow up visits over a period of 6 months

Exclusion Criteria:

* Patients who require revision surgery.
* Having had previous arteriovenous fistula surgery is not a contraindication to recruitment provided the new procedure is not revision surgery
* Target arteries smaller than 3 mm in diameter
* Target vein smaller than 3 mm in diameter
* Stenotic veins on the side of surgery as diagnosed on pre-op ultrasound
* Patients with prior central venous stenosis or obstruction on the side of surgery
* Depth of vein greater than 8 mm (on US) on side of surgery
* Known coagulation disorder
* Prior steal
* Known allergy to nitinol
* Life expectancy less than 6 months
* Inability to give consent and/or comply with the study follow up schedule
* Women of child bearing age

Answer: B