Clinical trial NCT05906550: Flow Dysfunction of Hemodialysis Vascular Access
Official title: Flow Dysfunction of Hemodialysis Vascular Access: a Randomized Controlled Trial on the Effectiveness of Surveillance of Arteriovenous Fistulas and Grafts
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: NA
Conditions: Dialysis Access Malfunction
Hemodialysis Access Failure
Hemodialysis Fistula Thrombosis
Vascular Access Malfunction
Lead sponsor: Maastricht University Medical Center
Sponsor class: OTHER
Collaborators: name: ZonMw: The Netherlands Organisation for Health Research and Development
First posted: 2023-06-18
Enrollment: 375
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Double blind randomized controlled trial with hybrid parallel-crossover design
Primary purpose: TREATMENT

Brief summary: The FLOW trial evaluates the follow-up of the vascular access for hemodialysis. In current clinical care, vascular access flow volume is periodically assessed to detect and treat asymptomatic stenosis. The FLOW trial will determine whether it is safe to abandon this practice of active surveillance. Vascular access stenosis will then be treated only when clinical problems of flow dysfunction occur during hemodialysis. The investigators expect that the intervention rate and medical costs will be reduced by 40% when correction of vascular access stenosis is triggered by clinically apparent access dysfunction rather than asymptomatic flow reduction.

Detailed description: Study design: Multicenter randomized controlled trial with 375 patients. Patients will be followed up for 2 to 3 years. The trial is powered to detect a reduction in the intervention rate of 0.25 per year between study groups in a superiority analysis (this is associated with cost savings of 1 million euros per year in the Netherlands). Subgroup analyses of arteriovenous fistulas and grafts and of successful and failed interventions will be done.

On 25-02-2025, the sample size was reduced from 417 to 375 patients because updated calculations based on actual event and loss to follow-up rates in the trial population showed sufficient power to detect the prespecified clinically relevant difference.

Study population: Chronic hemodialysis patients with a functioning arteriovenous fistula or graft.

Intervention group: Patients are referred for correction of the underlying stenosis when clinical signs of flow dysfunction are present. These include physical signs, problems during dialysis, or an unexplained, sustained fall in dialysis adequacy.

Control group: Monthly surveillance of vascular access blood flow volume by ultrasound dilution measurements during hemodialysis sessions. Patients will be referred for correction of the underlying stenosis at an access flow volume \<500mL/min, or when clinical signs of flow dysfunction are present.

Eligibility criteria: Inclusion Criteria:

1. Adult patients aged 18 years or older.
2. End-stage renal disease with unlikely recovery of kidney function according to the attending nephrologist.
3. Arteriovenous fistula or arteriovenous graft as hemodialysis vascular access that fulfills both of the following criteria at the time of trial enrollment:

   1. Vascular access flow volume of at least 500mL/min; and
   2. Functional vascular access: the vascular access was cannulated with 2 needles and achieved the prescribed access circuit flow in at least 6 dialysis sessions over the past 30 days. Patients who have single needle hemodialysis for reasons other than vascular access dysfunction (e.g. for nocturnal hemodialysis) but who can be cannulated with 2 needles for flow measurements and fulfill the other requirements for a functional vascular access can be enrolled as well.
4. Planning to remain in one of the participating dialysis centers for at least 1 year.

Exclusion Criteria:

1. Arteriovenous fistulas with multiple venous outflow paths upstream of the cannulation sites, that are not suitable for flow volume measurements using ultrasound dilution (e.g. Gracz fistulas and Ellipsys or WavelinQ endovascular fistulas).
2. Home hemodialysis.
3. Thrombosis of the current vascular access in the past year.
4. Planned access-related intervention.
5. Living donor kidney transplantation, switch to peritoneal dialysis, or switch to home hemodialysis planned within 6 months.
6. Life expectancy of less than 6 months, in the opinion of the attending nephrologist.
7. Unable to provide informed consent.

Primary outcomes:
measure: Access-related intervention rate
timeFrame: Variable follow-up time of 2-3 years
Secondary outcomes:
measure: Access-related complications per patient-year (1)
timeFrame: Variable follow-up time of 2-3 years
measure: Access-related complications per patient-year (2)
timeFrame: Variable follow-up time of 2-3 years
measure: All-cause mortality
timeFrame: Variable follow-up time of 2-3 years
measure: Access-related health care costs (1)
timeFrame: Every 3 months for 2-3 years from randomization (variable follow-up time)
measure: Access-related health care costs (2)
timeFrame: Every 3 months for 2-3 years from randomization (variable follow-up time)
measure: Patient-reported outcome measures (1)
timeFrame: Every 3 months for 2-3 years from randomization (variable follow-up time)
measure: Patient-reported outcome measures (2)
timeFrame: Every 3 months for 2-3 years from randomization (variable follow-up time)
measure: Quality of the surveillance program (1)
timeFrame: Variable follow-up time of 2-3 years
measure: Quality of the surveillance program (2)
timeFrame: Variable follow-up time of 2-3 years
measure: Quality of the surveillance program (3)
timeFrame: Variable follow-up time of 2-3 years
measure: Quality of the surveillance program (4)
timeFrame: Variable follow-up time of 2-3 years
measure: Primary patency
timeFrame: Variable follow-up time of 2-3 years
measure: Assisted primary patency
timeFrame: Variable follow-up time of 2-3 years
measure: Secondary patency
timeFrame: Variable follow-up time of 2-3 years
measure: The number of hemodialysis sessions with cannulation difficulties
timeFrame: Variable follow-up time of 2-3 years
Other outcomes:
Locations:
city: Amsterdam
country: Netherlands
facility: Diapriva - Dialyse Centrum Amsterdam
city: Amsterdam
country: Netherlands
facility: OLVG
city: Deventer
country: Netherlands
facility: Deventer Ziekenhuis
city: Enschede
country: Netherlands
facility: Medisch Spectrum Twente
city: Haarlem
country: Netherlands
facility: Spaarne Gasthuis
city: Heerlen
country: Netherlands
facility: Zuyderland Medisch Centrum
city: Leiden
country: Netherlands
facility: Leids Universitair Medisch Centrum
city: Maastricht
country: Netherlands
facility: Maastricht UMC+
city: Roosendaal
country: Netherlands
facility: Bravis Ziekenhuis
city: Rotterdam
country: Netherlands
facility: Franciscus Gasthuis & Vlietland
city: Utrecht
country: Netherlands
facility: Universitair Medisch Centrum Utrecht
city: Veldhoven
country: Netherlands
facility: Maxima Medisch Centrum
city: Zwolle
country: Netherlands
facility: Isala Klinieken
Study officials:
affiliation: Maastricht University Medical Center
name: Maarten G Snoeijs, MD PhD
role: PRINCIPAL_INVESTIGATOR
References: