VasQ and Hemodynamic Conditions in AVFs (RESHAPE)

Arterovenous Fistula Surgery With the VasQ Support Device: The Effects on Hemodynamic Conditions - Pilot Study

End-stage renal disease (ESRD) is a growing global health problem, strictly connected with progressive ageing population and longer survival of patients living on renal replacement therapy. The majority of ESRD patients is on hemodialysis (HD) treatment. A successful HD procedure requires a functional vascular access (VA) to provide safe and long-lasting way to connect patient circulation to the artificial kidney. To date, VA dysfunction is the major cause of morbidity and hospitalisation in HD patients, and the major limitation of HD treatment. The current recommendation for VA is the native artero-venous fistula (AVF), surgically created in the forearm, but is still affected by high non-maturation and early failure rates. The most common cause of AVF early-failure is vascular stenosis due to neointimal hyperplasia (NH). Despite the exact mechanisms underlying stenosis development remain tentative, there is general consensus that hemodynamic conditions play a key role in the formation of NH. Previous computational fluid dynamics (CFD) investigations inside patient-specific AVF models conducted by our group revealed transitional laminar-to-turbulent flow in the juxta-anastomotic vein.

Various vascular access devices have been designed to incorporate features to regularize the hemodynamics and favour spiral flow development in the venous segment of the AVF. The VasQ external support device (Laminate Medical Technologies, Israel) is a novel Nitinol implant, externally surrounding and supporting the vein and "hugging" the artery near the junction site, without being in contact with the blood flow.

VasQ attempts at constraining and shaping geometrical parameters of the AVF, as well as reinforcing the vulnerable perianastomotic vein against high pressure, wall tension and flow levels. A prospective single-centre study demonstrated the safety of the VasQ external support device, but the effect of its use on hemodynamic conditions and the advantages in terms of flow regularization in patient-specific AVFs still need to be investigated.

A detailed analysis of the local blood flow field in patient-specific AVFs can be obtained coupling non contrast-enhanced MRI (NCE-MRI) and high-resolution CFD simulations, using a NCE-MRI protocol recently optimized by our group. Our MRI sequence has the advantage of providing high-quality images in a short acquisition time of 5-10 minutes compared to other MRI protocols that require more than 45 minutes for a single acquisition. Combined with high-resolution CFD, our MRI-to-CFD pipeline allowed us to characterize morphological and hemodynamic changes in the AVF of one patient at two timepoints, immediately after AVF surgery and at AVF maturation. Therefore, it seems to be a promising approach to perform morphological and hemodynamic analysis also in AVF created using the VasQ device and can be used to elucidate the effects of VasQ device on hemodynamic conditions, as compared to hemodynamic conditions present in AVFs created using conventional surgery without the use of any device.

Study Overview

• Status: Completed
• Conditions: Renal Insufficiency, Chronic
• Intervention / Treatment: Device: Implantation of VasQ device

• Study Type: Interventional
• Enrollment (Actual): 6
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • BG
    • Bergamo, BG, Italy, 24100
      • ASST - Papa Giovanni XXIII - U.O. Nefrologia e Dialisi/ Mario Negri Institute for Pharmacological Research - Clinical Research Center for Rare Diseases Aldo e Cele Daccò

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Age > 18 years and < 75 years
2. Patients that entered the pre-dialysis program because of ESRD
3. Patients in need of a new VA for HD treatment
4. Treatment of first choice is creation of a distal autogenous AVF
5. Written informed consent

Exclusion Criteria:

1. Contraindication for creating an autogenous AVF
2. Life expectancy less than 1 year
3. Prior VA, central venous stenosis or obstructions in the arm selected for AVF surgery
4. Patient not suitable for MRI examination (ferro-magnetic prosthesis, pacemaker, aneurysm clips, obesity, spastic paralysis, severe claustrophobia or other contraindications or exclusions interfering with MRI)
5. Unusual anatomy or vessel dimensions (observed on pre-operative US or intraoperatively) and which preclude adequate fit of the VasQ.
6. Depth of vein greater than 8 mm (on ultrasound) on side of surgery
7. Known coagulation disorder
8. Known allergy to nitinol
9. Patients expected to undergo kidney transplant within 12 months of enrollment
10. Females who are pregnant or planning to become pregnant during the study
11. Inability to give consent and/or comply with the study follow up schedule

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Device Feasibility
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: AVF surgery with device	Device: Implantation of VasQ device; The VasQ external support device (Laminate Medical Technologies, Israel) is a novel Nitinol implant, externally surrounding and supporting the vein and "hugging" the artery near the junction site, without being in contact with the blood flow.
No Intervention: AVF surgery conventional

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Wall shear stress in AVFs.	Hemodynamic parameter (wall shear stress) obtained by combining MRI acquisition/ processing and computational fluid dynamics.	Changes from 3 days after surgery and 40 days after surgery.
Oscillatory shear index in AVFs.	Hemodynamic parameter (oscillatory shear index) obtained by combining MRI acquisition/ processing and computational fluid dynamics.	Changes from 3 days after surgery and 40 days after surgery.

Collaborators and Investigators

• Sponsor: Mario Negri Institute for Pharmacological Research
• Collaborators: Laminate Medical Technologies

Study record dates

Study Major Dates

• Study Start (Actual): October 11, 2019
• Primary Completion (Actual): July 22, 2021
• Study Completion (Actual): July 22, 2021

Study Registration Dates

• First Submitted: October 11, 2019
• First Submitted That Met QC Criteria: October 24, 2019
• First Posted (Actual): October 28, 2019

Study Record Updates

• Last Update Posted (Actual): November 26, 2021
• Last Update Submitted That Met QC Criteria: November 24, 2021
• Last Verified: November 1, 2021

More Information

Terms related to this study

• Keywords: hemodynamics; artero-venous fistula; non-Contrast Enhanced MRI; CFD simulations; VasQ
• Additional Relevant MeSH Terms: Kidney Diseases; Urologic Diseases; Renal Insufficiency, Chronic; Renal Insufficiency
• Other Study ID Numbers: RESHAPE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No