Sensor Delivery Device for Accurate FFR Measurement
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Solution Overview
Problem
Current methods for measuring pressure gradients across stenotic lesions and heart valves using catheters introduce errors due to blockage and leakage, making it difficult to accurately calculate Fractional Flow Reserve (FFR) and requiring time-consuming guidewire repositioning, which can deter physicians from using diagnostic measurements.
Innovation Solution
A sensor delivery device with a distal and proximal sensor system that allows for accurate pressure measurements without repositioning the guidewire, using a distal sleeve and communication channel to generate signals proportional to fluid pressure, and calibrating sensors with low thermal coefficients to minimize errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a catheter is used to measure pressure gradient across a stenotic lesion, then pressure measurements can be obtained, but the catheter introduces additional blockage that exaggerates the measured pressure gradient
Solution Approach 1:
The sensor is extracted from the catheter structure and integrated directly into the guidewire. This allows pressure measurement without the catheter body being present in the vessel, eliminating the catheter-induced blockage effect while maintaining measurement capability.
Solution Approach 2:
A fluid communication channel serves as an intermediary between the measurement location and the sensor. The channel transmits fluid pressure signals from the distal side of the lesion to the sensor without requiring a physical catheter structure at the measurement site, thus avoiding additional obstruction.
2Measurement precision
If a catheter is used to measure pressure drop across a heart valve, then pressure measurements can be obtained, but leakage around the catheter contributes to inaccurate readings
Solution Approach 1:
The sensing function is extracted from a catheter-based system and integrated into a thin guidewire structure. This eliminates the need for a bulky catheter that would interfere with valve sealing, thereby preventing catheter-induced leakage while maintaining pressure measurement capability.
Solution Approach 2:
The mechanical catheter structure is replaced with a minimally invasive guidewire-based sensor system. The sensor communicates pressure through a fluid channel rather than requiring direct mechanical contact with a large catheter body, eliminating the leakage problem associated with catheter presence.
3Measurement precision
If a pressure sensing guidewire is used to measure both distal and proximal pressures, then FFR calculation is enabled, but the guidewire must be repositioned which consumes time
Solution Approach 1:
The pressure measurement system is segmented into two independent sensors: one fixed at the distal end for measuring distal pressure, and another movable sensor for measuring proximal pressure. This segmentation allows simultaneous or sequential measurement without repositioning the entire guidewire, reducing time loss.
Solution Approach 2:
The guidewire is designed with multi-functionality, incorporating both a fixed distal sensor and a movable proximal sensor. This universal design enables the single guidewire to perform both distal and proximal pressure measurements without requiring repositioning, unlike single-sensor systems.
4Measurement precision
If sensors with high thermal coefficients are used, then sensor response is sensitive to pressure changes, but temperature variations cause calibration errors
Solution Approach 1:
The sensor material properties are changed to have low thermal coefficients. This parameter change reduces the sensor's sensitivity to temperature variations while maintaining adequate pressure sensitivity, thereby minimizing thermal drift errors during procedures.
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
Enables precise FFR calculations and reduces procedural time by eliminating the need for guidewire repositioning, improving diagnostic accuracy and facilitating better therapy decisions.
Implementation Method 1
a sensor adapted to generate a signal proportional to the fluid pressure
Data Source
AI summary
Sensor delivery devices and methods of measuring Fractional Flow Reserve in a patient are disclosed. One sensor delivery device includes a distal sleeve, a proximal portion, and a pressure sensor. The distal sleeve is configured to be advanced through a patient's vasculature over a guidewire. The pressure sensor is located on the distal sleeve or the proximal portion. The pressure sensor is adapted to generate a signal proportional to fluid pressure. The pressure sensor includes a material having a low thermal coefficient of pressure.