Determine the Safety/Efficacy of Ticagrelor for Maintaining Patency of Arterio-Venous Fistulae Created for Hemodialysis

This study is a randomized, placebo-controlled, single blind clinical trial. Seventy patients with ESRD on chronic HD and a functioning AVF will be recruited. The following data will be documented on each patient: 1-Age/gender/race/body weight/cause of ESRD 2-Vintage of HD 3-Time since access was placed 4-Type and place of access and blood flow rate of access 5-History of prior access problems 6-Comorbid conditions (Hypertension, coronary artery disease, Diabetes Mellitus, Bleeding problems, peripheral vascular disease). 7-Current medications (Coumadin, Erythropoiesis stimulating agents, heparin, other antiplatelets, digoxin, statins). Patients will be randomized into two groups to receive: Group 1: Ticagrelor 90 mg PO BID Group 2: Placebo drug PO BID.

This study is a randomized, placebo-controlled, single blind clinical trial. Seventy patients with ESRD on chronic HD and a functioning AVF will be recruited. Consent form will be obtained. History and physical, dialysis parameters and laboratory data (CBC, CMP, PTT \& INR) will be obtained throughout the study. The following data will be documented on each patient: 1-Age/gender/race/body weight/cause of ESRD 2-Vintage of HD 3-Time since access was placed 4-Type and place of access and blood flow rate of access 5-History of prior access problems 6-Comorbid conditions (Hypertension, coronary artery disease, Diabetes Mellitus, Bleeding problems, peripheral vascular disease). 7-Current medications (Coumadin, Erythropoiesis stimulating agents, heparin, other antiplatelets, digoxin, statins). Patients will be randomized into two groups to receive: Group 1: Ticagrelor 90 mg PO BID Group 2: Placebo drug PO BID.

Subjects will have a screening visit and if they qualify for the study they will have 18 additional visits. All of these visits will occur while the subjects are at their normal dialysis treatment. Subjects will be randomized to either the Ticagrelor group or the placebo group. Subjects will be on study medication for 6 months then they will have a follow up period off drug for 6 months. Subjects will be seen twice a month while on study medication and once a month in the follow up period. While the subjects are on study medication the study team will assess any side effects of the study medication and put their relation to the study drug at each study visit. The study team will use clinical monitoring as suggested by Beathard (21). The study team will document the subject's adherence to the study, if they are hospitalized and what caused their hospitalization. A monthly intra-access flow will be obtained using ultrasound dilution by transonics as part of standard of care. Any change in the clinical assessment of the access, prolonged bleeding (\>20 minutes) after removal of needles, trend of decreasing intra-access blood flow as determined by transonic (\> 25% or original flow), or an access flow rate \< 400 ml/min, will prompt a referral for a fistulogram. If confirmed stenosis (\>50% stenosis of the access diameter) an intervention (angioplasty) will be performed. This intervention is part of the subjects standard of care.

Eligibility Criteria:
Inclusion Criteria:

- Patients on chronic hemodialysis with a functioning arterio-venous fistula

Exclusion Criteria:

* Recent history of bleeding over the last 3 months preceding enrollment
* History of bleeding disorder (hemophilia, Von Willebrandt disease, etc....)
* Recent history of blood transfusion over the last 3 months preceding enrollment
* Recent serious injury or surgery over the last 3 months preceding enrollment
* History of gastro-intestinal ulcers
* Moderate-severe hepatic impairment
* Uncontrolled blood pressure (SBP\> 200 or DBP \>110) post dialysis
* History of stroke
* Pregnant females-self reported
* Hypersensitivity to Aspirin /antiplatelets
* Subjects using peroral anticoagulants