Flow Dysfunction of Hemodialysis Vascular Access
- Conditions
- Dialysis Access MalfunctionHemodialysis Access FailureHemodialysis Fistula ThrombosisVascular Access Malfunction
- Interventions
- Diagnostic Test: Vascular access monitoringDiagnostic Test: Vascular access blood flow measurement
- Registration Number
- NCT05906550
- Lead Sponsor
- Maastricht University Medical Center
- 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.
Recruitment & Eligibility
- Status
- ACTIVE_NOT_RECRUITING
- Sex
- All
- Target Recruitment
- 375
-
Adult patients aged 18 years or older.
-
End-stage renal disease with unlikely recovery of kidney function according to the attending nephrologist.
-
Arteriovenous fistula or arteriovenous graft as hemodialysis vascular access that fulfills both of the following criteria at the time of trial enrollment:
- Vascular access flow volume of at least 500mL/min; and
- 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.
-
Planning to remain in one of the participating dialysis centers for at least 1 year.
- 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).
- Home hemodialysis.
- Thrombosis of the current vascular access in the past year.
- Planned access-related intervention.
- Living donor kidney transplantation, switch to peritoneal dialysis, or switch to home hemodialysis planned within 6 months.
- Life expectancy of less than 6 months, in the opinion of the attending nephrologist.
- Unable to provide informed consent.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Control group Vascular access blood flow measurement 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. Intervention group Vascular access monitoring 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 Vascular access monitoring 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.
- Primary Outcome Measures
Name Time Method Access-related intervention rate Variable follow-up time of 2-3 years The number of interventions required for each patient-year of hemodialysis treatment
- Secondary Outcome Measures
Name Time Method Access-related complications per patient-year (2) Variable follow-up time of 2-3 years Access-related serious adverse events (Clavien-Dindo grade 4 and 5 complications, and vascular access thrombosis)
All-cause mortality Variable follow-up time of 2-3 years All-cause mortality
Access-related health care costs (1) Every 3 months for 2-3 years from randomization (variable follow-up time) Medical Consumption Questionnaire
Access-related complications per patient-year (1) Variable follow-up time of 2-3 years Clavien-Dindo grade 2 complications (requiring pharmacological treatment)
Access-related health care costs (2) Every 3 months for 2-3 years from randomization (variable follow-up time) Productivity Cost Questionnaire
Quality of the surveillance program (3) Variable follow-up time of 2-3 years The percentage of vascular access balloon angioplasties resulting in technical success (residual stenosis \<30%) and clinical success (increase in flow volume to \>500mL/min, restoration of vascular access function and resolution of any clinical signs of flow dysfunction)
Patient-reported outcome measures (1) Every 3 months for 2-3 years from randomization (variable follow-up time) SF-VAQ (Short-Form Vascular Access Questionnaire)
Patient-reported outcome measures (2) Every 3 months for 2-3 years from randomization (variable follow-up time) EQ-5D-5L
Quality of the surveillance program (1) Variable follow-up time of 2-3 years Repeatability and reproducibility of vascular access flow volume measurements
Primary patency Variable follow-up time of 2-3 years This outcome measure will be registered for explanatory analyses
Secondary patency Variable follow-up time of 2-3 years This outcome measure will be registered for explanatory analyses
The number of hemodialysis sessions with cannulation difficulties Variable follow-up time of 2-3 years This outcome measure will be registered for explanatory analyses
Quality of the surveillance program (2) Variable follow-up time of 2-3 years Diagnostic accuracy of vascular access flow volume measurements to predict clinical signs of flow dysfunction and access thrombosis within 1 month in the intervention group
Quality of the surveillance program (4) Variable follow-up time of 2-3 years Vascular access patency after balloon angioplasty
Assisted primary patency Variable follow-up time of 2-3 years This outcome measure will be registered for explanatory analyses
Trial Locations
- Locations (13)
Diapriva - Dialyse Centrum Amsterdam
🇳🇱Amsterdam, Netherlands
OLVG
🇳🇱Amsterdam, Netherlands
Deventer Ziekenhuis
🇳🇱Deventer, Netherlands
Medisch Spectrum Twente
🇳🇱Enschede, Netherlands
Spaarne Gasthuis
🇳🇱Haarlem, Netherlands
Zuyderland Medisch Centrum
🇳🇱Heerlen, Netherlands
Leids Universitair Medisch Centrum
🇳🇱Leiden, Netherlands
Maastricht UMC+
🇳🇱Maastricht, Netherlands
Bravis Ziekenhuis
🇳🇱Roosendaal, Netherlands
Franciscus Gasthuis & Vlietland
🇳🇱Rotterdam, Netherlands
Universitair Medisch Centrum Utrecht
🇳🇱Utrecht, Netherlands
Maxima Medisch Centrum
🇳🇱Veldhoven, Netherlands
Isala Klinieken
🇳🇱Zwolle, Netherlands