Microvascular Resistance Reserve Calculation for Coronary Assessment
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Solution Overview
Problem
Current methods for assessing microvascular coronary disease are inaccurate, operator-dependent, and fail to distinguish between epicardial and microvascular contributions to heart disease, hindering optimal diagnosis and treatment.
Innovation Solution
A method and system for calculating microvascular resistance reserve (MRR) under resting conditions, which measures microvascular function independently of epicardial disease, using measurements under both resting and hyperemic conditions, and involves calculating MRR as Qmax/Qrest*Pa_rest/Pd_hyper, where Qrest and Qmax are blood flows, and Pa_rest and Pd_hyper are pressures measured proximal and distal to any stenosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods are used to assess microvascular coronary disease, then diagnosis can be performed, but the assessment is inaccurate and operator-dependent
Solution Approach 1:
The patent replaces subjective operator assessment with an automated computational system that calculates microvascular resistance reserve (MRR) using objective hemodynamic measurements. The processing unit automatically computes MRR from pressure and flow data, eliminating operator dependency and improving measurement precision through standardized algorithms.
Solution Approach 2:
The patent introduces MRR as an intermediary parameter that mediates between raw hemodynamic measurements (pressure and flow) and clinical diagnosis. This intermediate calculation layer provides a standardized, quantifiable metric that improves assessment accuracy while reducing operator influence.
2Loss of information
If current assessment methods are used, then a general evaluation can be obtained, but the contribution of epicardial arteries and microvasculature cannot be distinguished
Solution Approach 1:
The patent segments the coronary circulation into two distinct functional components: epicardial arteries and microvasculature. By calculating MRR specifically for the microvascular component while accounting for epicardial resistance, the system provides separate assessments of each segment's contribution to disease, preventing information loss about their differential roles.
Solution Approach 2:
The patent applies local quality by providing location-specific resistance measurements. MRR specifically characterizes microvascular resistance independent of epicardial artery conditions, allowing localized assessment of microvascular function even in the presence of epicardial disease.
3Measurement precision
If absolute microvascular resistance is measured during maximum vasodilation, then some microvascular information is obtained, but the measurement is limited by lack of uniform normal values and large variation
Solution Approach 1:
The patent changes the measured parameter from absolute microvascular resistance to microvascular resistance reserve (MRR). This parameter transformation creates a ratio-based metric that normalizes variations due to myocardial mass and physiological conditions, providing uniform reference ranges across different patients and improving measurement precision through standardized comparison.
Data Source
AI summary
The invention relates to a method for determining the microvascular resistance reserve, MRR, in the myocardium perfused by a normal or a stenotic coronary artery of a human patient, which method comprises the step of during rest condition of the patient: measuring the blood flow, Qrest, through the coronary artery; and further comprising the step of during rest condition or during maximum hyperemia of the patient: measuring the blood pressure, Pa, at a position proximal in the coronary artery or proximally of any stenosis, if present; and further comprising the steps of during maximum hyperemia of the patient: measuring the blood flow, Qmax, through the coronary artery; and measuring the blood pressure, Pd, at a position distal in the coronary artery or distally of any stenosis, if present, and wherein the microvascular resistance reserve, MRR, is determined by the additional step of calculating the microvascular resistance reserve asMRR=QmaxQrestPaPd,hyper.