AV Fistula Flow Restriction via Intravascular Feedback
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Solution Overview
Problem
High flow through arteriovenous fistulas or grafts can lead to adverse consequences such as distal ischemia and cardiac overload, as they are not adequately restricted during hemodialysis, posing a challenge in maintaining healthy blood flow levels.
Innovation Solution
Intravascular detection methods using instruments like IVUS catheters or instrumented guidewires with measuring capabilities are employed to assess and restrict blood flow through AV fistulas or grafts, ensuring it remains within a target volume, thereby preventing excessive flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an AV fistula is created to provide adequate blood flow for hemodialysis, then hemodialysis access is improved, but excessive flow can cause distal ischemia and cardiac overload
Solution Approach 1:
The patent employs intravascular measurement devices (IVUS catheters, instrumented guidewires) to continuously monitor flow parameters within the fistula. This feedback mechanism allows real-time assessment of flow volume and pressure gradients, enabling operators to adjust banding procedures to achieve target flow levels (e.g., 600-800 mL/min) while preventing harmful excessive flow that causes distal ischemia and cardiac overload
Solution Approach 2:
The patent changes the flow parameter of the fistula from uncontrolled high flow to controlled moderate flow through intravascular measurement and restriction procedures. By measuring pressure gradients and flow velocities before and during banding, the system adjusts the restriction level to achieve optimal flow parameters that balance hemodialysis requirements with prevention of distal ischemia and cardiac complications
2Manufacturing precision
If intravascular measurement devices are used to assess and restrict flow, then flow control precision is improved, but procedure complexity increases
Solution Approach 1:
The patent introduces intravascular measurement devices (IVUS catheters, instrumented guidewires with pressure sensors and Doppler flow sensors) as intermediaries between the operator and the fistula. These devices provide objective measurement data that mediates the decision-making process for banding restriction levels, enabling precise flow control without requiring the operator to rely solely on visual estimation or empirical rules
Solution Approach 2:
The patent replaces subjective mechanical assessment methods with objective sensor-based measurements. Instead of relying on visual inspection or manual pressure assessment, the system uses electronic sensors (pressure transducers, Doppler flow sensors) to quantify flow parameters, substituting mechanical judgment with electronic measurement and computer-assisted decision support
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the maintenance of healthy blood flow levels, preventing complications like distal ischemia and cardiac overload, thereby ensuring successful hemodialysis and improved patient quality of life.
Implementation Method 1
An IVUS catheter can be used to image the fistula/graft
Implementation Method 2
Doppler flow velocity
Data Source
AI summary
The invention relates to restricting flow through a vascular access site such as an arteriovenous (AV) fistula or a graft using intravascular measurements to guide the procedure. The invention provides systems and methods for using intravascular detection to guide the restriction of flow through an AV fistula or graft. An intravascular instrument such as an imaging catheter or guidewire with measuring capabilities is inserted into a vessel proximal to an access site and used to evaluate the access site, which is banded to obtain healthy flow as indicated by the intravascular instrument. In certain aspects, the invention provides a method for improving a hemodialysis fistula or graft by inserting an intravascular instrument into a vessel proximal to the fistula or graft, making a measurement with the intravascular instrument, and restricting flow through the fistula or graft until the measurement obtains a predetermined value.