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Completed

NCT Number: NCT05911451

Optimizing Access Surgery In Senior Hemodialysis Patients

The number of elderly hemodialysis patients is growing. Vascular access complications are a major determinant of the quality of life and health care costs for these vulnerable patients. The three different types of vascular access, i.e. autologous arteriovenous fistulas, arteriovenous grafts, and central venous catheters, have never been compared in randomized controlled trials. This project will deliver the much-needed evidence to determine the optimal strategy for vascular access creation in elderly hemodialysis patients in order to deliver better health care at lower costs.

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Key information

About this study

Objective: To compare surgical strategies for vascular access creation in elderly hemodialysis patients.

Hypothesis: Arteriovenous grafts and central venous catheters lead to fewer interventions, more quality of life, and lower health care costs than autologous arteriovenous fistulas.

Study design: Parallel group, multicenter randomized controlled trial.

Study population: Patients >65 years with a life expectancy <2 years who are expected to start hemodialysis treatment within 6 months or who have started hemodialysis treatment with a catheter in the past 6 months.

Study groups:

  • Autologous arteriovenous fistula creation
  • Arteriovenous graft implantation
  • Central venous catheter placement

Sample size calculation: 3x65 patients for superiority with multiplicity correction based on a clinically relevant difference of 0.80 interventions/year. Due to slow enrollment, follow-up time per participant was much longer than anticipated at trial initiation. After enrollment of 166 participants, calculations based on actual event and mortality rates showed that the trial had sufficient statistical power to detect a relative difference in event rate of 0.67, corresponding to an absolute difference below the minimal clinically relevant difference of 0.80 access-related interventions per year. Therefore, enrollment was closed at 166 participants.

Data analysis: Poisson regression analysis with time as off-set variable.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult patients aged 65 years or older
  • End-stage renal disease with unlikely recovery of kidney function according to the attending nephrologist
  • Hemodialysis is the intended long-term modality of treatment for end-stage renal disease
  • Fit for vascular access surgery as determined by the local multidisciplinary vascular access team 5a. Expected to start hemodialysis treatment within 6 months at the time of treatment assignment; or 5b. Treated with hemodialysis for 6 months or less at the time of treatment assignment using a tunneled or non-tunneled central venous catheter for vascular access
  • Planning to remain in one of participating dialysis centers for at least 1 year 7. Suitable vascular anatomy for all types of vascular access based on duplex ultrasound of the arms, defined as:
  • at least one suitable configuration for an arteriovenous fistula using minimal arterial and venous diameters of 2mm for radiocephalic fistulas and 3mm for brachiocephalic and brachiobasilic fistulas;
  • at least one suitable configuration for an arteriovenous graft using minimal arterial and venous diameters of 3mm and 4mm, respectively; and
  • at least one open internal jugular vein for a central venous catheter.

Exclusion criteria

  • Patent arteriovenous fistula or graft already in place
  • Prior unsuccessful arteriovenous fistula or graft vascular access surgery
  • Kidney transplantation planned within 6 months
  • Metastatic malignancies or other condition associated with a life expectancy of <6 months, in the opinion of the attending nephrologist
  • Unable to provide informed consent
  • Dusseux risk score <5, indicating an usually long life expectancy for elderly patients starting hemodialysis treatment (the Dusseux risk score was adapted for patients between 65 and 70 years by assigning -3 points to this age category)

Treatment and study plan

Arteriovenous fistula creation

Procedure

It is recommended to create the arteriovenous fistula 3 to 6 months before the expected start of hemodialysis treatment using locoregional anesthesia. It is recommended to use minimal venous and arterial diameters of 2mm for radiocephalic fistulas and 3mm for brachiocephalic and brachiobasilic fistulas. It is recommended to avoid creating an arteriovenous fistula at the same side as a pacemaker, central venous catheter, or arterial stenosis. It is recommended to use the following order of preference for arteriovenous fistula creation: radiocephalic fistula as first choice, brachiocephalic fistula as second choice, and brachiobasilic fistula as third choice.

Arteriovenous graft placement

Procedure

It is recommended to implant the arteriovenous graft 2 weeks before the expected start of hemodialysis treatment under antibiotic prophylaxis. Implantation of an early-cannulation graft is recommended for patients who require more urgent start of hemodialysis to avoid the use of a temporary central venous catheter. It is recommended to use minimal arterial and venous diameters of 3mm and 4mm, respectively. It is recommended to avoid placing an arteriovenous graft at the same side as a pacemaker, central venous catheter, or arterial stenosis.

Central venous catheter placement

Procedure

It is recommended to place a tunneled central venous catheter just before the start of hemodialysis treatment under local anesthesia, with conscious sedation if preferred by the patient. The catheter should preferably be placed in the right internal jugular vein with ultrasound-guided puncture and fluoroscopy control under sterile conditions. According to usual practice at the trial center, catheters may be implanted by surgeons, interventional radiologists, or nephrologists.

Primary outcomes

  1. Access-related intervention rate

    Time frame: Variable follow-up time of at least 1 year

    The number of access-related interventions required for each person-year of hemodialysis treatment. This outcome measure includes all percutaneous access interventions (including central venous catheter placement, removal and guidewire exchange, angioplasty, stent placement, and percutaneous thrombectomy) and surgical access procedures (including initial access creation, subsequent access placements if the first access failed, and surgical revisions to promote maturation or maintain long-term patency, including open thrombectomy) from randomization and treatment assignment until the end of the study period or death.

Secondary outcomes

  1. Patient-reported outcome measures (1)

    Time frame: Every 3 months in the first year after enrollment and in the first year after dialysis start

    Short Form 12 Dialysis Symptom Index (SF-12 / DSI)

  2. Patient-reported outcome measures (2)

    Time frame: Every 3 months in the first year after enrollment and in the first year after dialysis start

    Short Form Vascular Access Questionnaire (SF-VAQ)

  3. Patient-reported outcome measures (3)

    Time frame: Every 3 months in the first year after enrollment and in the first year after dialysis start

    EuroQol - 5 dimensions - 5 levels (EQ-5D-5L)

  4. Health care costs

    Time frame: Every 3 months in the first year after enrollment and in the first year after dialysis start

    Medical Consumption Questionnaire

  5. Access-related complications

    Time frame: Variable follow-up time of at least 1 year

    Access-related complications requiring pharmacological treatment (Clavien-Dindo grade 2)

  6. Days in hospital

    Time frame: Variable follow-up time of at least 1 year

    The number of days admitted to hospital or visiting out-patient clinics for any reason per person-year (including hemodialysis sessions).

  7. Mortality

    Time frame: Variable follow-up time of at least 1 year

    All-cause mortality

  8. Primary patency

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

  9. Assisted primary patency

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

  10. Secondary patency

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

  11. Primary functional patency

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

  12. Time until mature vascular access

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

  13. Time until functional vascular access

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

  14. The number of hemodialysis sessions with cannulation difficulties

    Time frame: Variable follow-up time of at least 1 year

    Outcome measure registered for exploratory analysis

Sponsors and collaborators

Lead sponsor

Maastricht University Medical Center

Other

Collaborators

  • ZonMw: The Netherlands Organisation for Health Research and Development

Registry information

Official study title

Optimizing Access Surgery In Senior Hemodialysis Patients: a Multicenter Randomized Controlled Trial of Fistulas, Grafts, and Catheters

Acronym: OASIS

Important dates

Study start
2019
Primary completion
2026
Study completion
2026
First posted
Jun 22, 2023
Registry last updated
Jun 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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