Pilot Study to Evaluate Safety, Tolerability, and Performance of the FAST PV Technology™ in Chronic Dialysis Patients

Inclusion Criteria: Subjects/patients must meet all inclusion criteria to be eligible for study participation. 1. Males or females ≥ 18 years of age. 2. Females must be of non-childbearing potential (eg, postmenopausal \[defined cessation of regular menstrual periods for at least 1 year confirmed by age =\> 60 or surgically sterile by hysterectomy, bilateral oophorectomy, or bilateral tubal ligation \[documentation required\]) or be using a medically acceptable form of birth control (a barrier method, intrauterine device, or hormonal contraception) from screening through 30 days after administration of the last dose of VFI. 3. Males who are sexually active and whose partners are females of childbearing potential must agree to practice abstinence or use condoms from screening through 90 days after administration of the last dose of VFI, and their partners must be willing to use a medically acceptable method of contraception (a barrier method, intrauterine device, or hormonal contraception) from screening through 90 days after administration of the last dose of VFI. 4. Males must agree to not donate sperm from screening through 90 days after administration of the last dose of VFI. 5. Subjects/patients must be able to communicate effectively with the study personnel. 6. Patients must be on chronic hemodialysis for \>= 3 months and oliguric defined as \<= 2 urinary voids per day. 7. Patients must have an average interdialytic weight gain of at least 2 kg. 8. Patients must have an A-V dialysis shunt. 9. Patients must have a functioning A-V dialysis shunt, either fistula or graft. Exclusion Criteria Subjects/patients will not be eligible for study participation if they meet any of the exclusion criteria, or will be discontinued at the discretion of the investigator if they develop any of the exclusion criteria during the study. 1. Subject is a pregnant or nursing (lactating) woman, where pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive human chorionic gonadotropin (hCG) laboratory test. 2. History or presence of conditions which, in the judgment of the investigator, are known to interfere with the distribution, metabolism, or excretion of drugs 3. History or presence of conditions that may place the subject/patient at increased risk as determined by the investigator. 4. History of surgery or major trauma within 12 weeks of screening or surgery planned within 4 weeks of the study, including during study participation. 5. Has taken other investigational drugs within 30 days or 5 half-lives of the investigational drug's PK, PD, or biological activity, whichever is longer, prior to first dose of VFI in this study. 6. Prior exposure to VFI or known allergy or hypersensitivity to dextran, 5-aminofluorescein dye, or 2-sulfohexamine rhodamine dye. 7. History of any clinically significant allergic or negative reactions, side effects, or anaphylaxis to iodine, dyes, shellfish, isotopes, or dextran molecules. 8. Significant blood loss (\> 450 mL) or has donated 1 or more units of blood or plasma within 4 weeks prior to study participation. 9. Presence of significant hemodynamic instabilities defined as systolic BP \<100 on dialysis requiring saline infusion in the past 4 weeks. 10. Presence of ascites and/or 4+ anasarca. 11. Any other condition or prior therapy that, in the investigator's opinion, would make the subject unsuitable for the study, or unable or unwilling to comply with the study procedures. 12. Involved in the planning or conduct of this study. 13. Unwilling or unlikely to comply with the requirements of the study. 14. Clinically significant ongoing bleeding, changing hemoglobin, or experienced significant blood loss within the last 4 weeks. 15. Had a PRBC transfusion in the prior 2 weeks 16. Use of midodrine. 17. Any other condition or prior therapy that, in the investigator's opinion, is likely to deteriorate during study participation 18. Subjects suffering from significant non-cardiac diseases of other organ systems (e. g. Malignancies, significant neurological diseases). 19. Subject has a psychiatric disease or a history of illicit drug use that would prohibit them from complying with study requirements. 20. Use of hemodialysis catheter as primary vascular access for hemodialysis