Intermittent Pneumatic Compression Device for Vein Dilation in Kidney Disease Patients to Enable AVF Creation (FACT)

METHODOLOGY:

Intervention: The Fist Assist® device will be assigned to each enrolled subject by randomization code. All subjects will be asked to use their assigned device twice daily, for two 2-hour sessions, once in the morning and once in the evening. Patients will apply the device to the non-dominant arm above the level of the elbow, and to keep a written log to record use, complications and any problems.

Blood Draws: 10 mL of blood will be obtained from patients being enrolled at the time of their next routine standard of care phlebotomy. These samples will be frozen for future assays of endothelial biomarkers of nitric oxide production and venous dilation, such as asymmetric dimethyl arginine (ADMA) and its metabolites.

Doppler: Patients will undergo examination of their cephalic veins in the Nephrology Clinic, using a portable vascular ultrasound device operated by a co-investigator trained by the University of Chicago Medical Center Vascular Lab in this technique. The cephalic vein, a superficial vein originating in the wrist, is the most common vein used for AVF creation. In order to standardize these measurements, the diameter of the cephalic vein and vein wall thickness will be measured in both arms at: (a) 5 cm proximal to the styloid process of the radius, and (b) at the antecubital fossa. The diameter and thickness of the vein will be measured using a B-mode image acquired using a standard ultrasound machine with vascular probe going from outer walls per protocol. Patients will be seated with arms supported at the level of the heart on an exam table with in a room with a temperature of at least 20 degrees Celsius. A layer of at least 1 cm of gel will be applied locally to optimize the ultrasound image quality. Vascular Doppler measurements will be obtained on both arms at the time of consent (baseline), and at the conclusion of therapy. Measurements will be recorded.

Follow Up: Those who are subsequently able to undergo successful AVF creation will be followed clinically for up to 12 months.

Protocol: Informed consent will be obtained by the co-investigators using a written consent form approved by the Institutional Review Board. After informed consent is obtained, patients will receive: physical examination of both forearms; and a vascular Doppler to determine cephalic vein diameters of the nondominant arm. A 10 mL blood sample will be drawn at the next routine phlebotomy.

Patients will be asked to apply the Fist Assist® to the upper half of the non-dominant arm. Patients will be asked to use the device twice daily for two 2-hour periods, and report any complications or problems, using a log (see log attached at end of References). Patients will have follow up examinations with measurement of cephalic vein diameter at three months after enrollment.

DURATION OF STUDY: All subjects will be enrolled and treated for three months. The duration of the study including data analysis and statistical analysis is expected to be 12 months.

STATISTICAL ANALYSES: The primary outcome of interest will be the difference in the diameter of the cephalic vein between baseline (Pre) and 3 months (Post) in patients treated with the Fist Assist® device. Based on prior work, mean vein diameters at baseline are anticipated to be approximately 1.8 mm with a standard deviation of 0.5 mm,44 and investigators anticipate that the standard deviation of the change in diameter is likely to be approximately 0.75 mm.

Effect =[(DSPost)-(DSPre)]

Investigators would consider calculated effect sizes of 0.25-1.0 mm to be clinically meaningful changes that would increase the numbers of patients with vein diameters that meet commonly accepted thresholds for surgical suitability (normally 2.5-3.0 mm). Sample size calculations for a variety of effects are presented in table 1 (below), based on paired t-tests with alpha error of 0.05, standard deviation of the effect size of 0.75 mm, for power of 80% and 90%.