Objectives and Design of the Hemodialysis Fistula Maturation Study

Abstract

Background A large proportion of newly created arteriovenous fistulas cannot be used for dialysis because they fail to mature adequately to support the hemodialysis blood circuit. The Hemodialysis Fistula Maturation (HFM) Study was designed to elucidate clinical and biological factors associated with fistula maturation outcomes. Study Design Multicenter prospective cohort study. Setting & Participants Approximately 600 patients undergoing creation of a new hemodialysis fistula will be enrolled at 7 centers in the United States and followed up for as long as 4 years. Predictors Clinical, anatomical, biological, and process-of-care attributes identified pre-operatively, intra-operatively, or post-operatively. Outcomes The primary outcome is unassisted clinical maturation defined as successful use of the fistula for dialysis for four weeks without any maturation-enhancing procedures. Secondary outcomes include assisted clinical maturation, ultrasound-based anatomical maturation, fistula procedures, fistula abandonment, and central venous catheter use. Measurements Pre-operative ultrasound arterial and venous mapping, flow-mediated and nitroglycerin-mediated brachial artery dilation, arterial pulse wave velocity, and venous distensibility; intra-operative vein tissue collection for histopathological and molecular analyses; post-operative ultrasounds at 1 day, 2 weeks, 6 weeks, and prior to fistula intervention and initial cannulation. Results Assuming complete data, no covariate adjustment, and unassisted clinical maturation of 50%, there will be 80% power to detect ORs of 1.83 and 1.61 for dichotomous predictor variables with exposure prevalences of 20% and 50%, respectively. Limitations Exclusion of two-stage transposition fistulas limits generalizability. The requirement for study visits may result in a cohort that is healthier than the overall population of patients undergoing fistula creation. Conclusions The HFM Study will be of sufficient size and scope to 1) evaluate a broad range of mechanistic hypotheses, 2) identify clinical practices associated with maturation outcomes, 3) assess the predictive utility of early indicators of fistula outcome, and 4) establish targets for novel therapeutic interventions to improve fistula maturation.

Arteriovenous Fistula Development in the First 6 Weeks after Creation

“…Written informed consent was obtained from all participants. The HFM study design has been detailed previously (6 (8,9). Therefore, postoperative US images were obtained about 1 day after surgery (from immediately after surgery to 2 days after surgery, subsequently referred to as the 1-day visit) and at 2 weeks and 6 weeks.…”

Predictive Models for Arteriovenous Fistula Maturation

“…(7) Compared to models used in other topics, those available to this review use few variables. The results of haemodialysis fistula maturation study (18) will hopefully yield more data for predictive modelling with a higher number of patients and potentially more predictive variables.…”

Peripherally Inserted Central Catheters and Hemodialysis Outcomes

“…Vascular access was determined by the modifier codes on individual HD treatment claims. Conversion to fistula or graft access was defined as the first day of the first 30-day period in which all available vascular access modifiers on all HD treatment claims were for AVF only (modifier V7) or AVG only (modifier V6) with no intervening codes for catheter use (modifier V5) on the basis of established working definitions for a working AVF (19,20).…”