WO2023089866A1

WO2023089866A1 - Standardization processing device and standardization processing method for pressure waveform

Info

Publication number: WO2023089866A1
Application number: PCT/JP2022/027956
Authority: WO
Inventors: 拓也水上; 世史明川瀬; 雅文中山
Original assignee: 拓也水上; 合同会社Medboost; 世史明川瀬
Priority date: 2021-11-18
Filing date: 2022-07-18
Publication date: 2023-05-25
Also published as: JP2023074595A

Abstract

A standardization processing device 10 according to the present invention comprises: a time phase division unit 16 that identifies a cardiac cycle, subdivides one heartbeat into a plurality of time phases, and standardizes the time scale within each time phase; and an index value calculation unit 17 that calculates an index value for assessing heart disease from pressure data of a pressure waveform which represents changes over time in intravascular pressure of a subject, and associates the index value with the time scale. The time phase division unit 16 sets one or more predetermined feature points in one heartbeat and converts, into a time on a unified time scale, the time of each time zone which is obtained by division by the feature points. The index value calculation unit 17 generates a standardized waveform which represents the relationship between each time on the time scale and the intravascular pressure and index value.

Description

Pressure waveform standardization processing device and standardization processing method

The present invention relates to a pressure waveform standardization processing apparatus and a pressure waveform standardization processing method that performs standardization processing for evaluating heart disease based on a pressure waveform representing temporal changes in intravascular pressure at a predetermined site of a subject.

As one of the methods for diagnosing the severity of ischemic heart disease, a method using a guide wire with a pressure sensor called a pressure wire is known. In this technique, first, pressure wires are used to measure the aortic pressure Pa (aortic pressure), which is the coronary artery inlet pressure, and the coronary artery pressure Pd (distal pressure), which is downstream of the stenosis site in the coronary artery. The presence or absence of myocardial ischemia is determined using the pressure ratio (Pd/Pa) of these aortic pressure Pa and coronary artery pressure Pd as a diagnostic index. Here, as the pressure ratio, there are a myocardial blood flow reserve ratio (FFR: Fractional Flow Reserve) and a resting non-hyperemic pressure ratio (NHPR: Non-Hyperemic Pressure Ratio) depending on the measurement conditions (Patent Document 1. etc.). All of these are diagnostic indices based on the pressure gradient, which is the pressure difference that occurs when blood flows through a lesion in the coronary artery.

The FFR is an index obtained in a state of maximal hyperemia in which microvascular resistance is lowered by administering a drug to a patient, and when it falls below a predetermined value (e.g., 0.80), it is diagnosed as myocardial ischemia. It is used as a guideline for treatment such as coronary artery stent placement.

On the other hand, the NHPR is measured without administering drugs to the patient, and all pressure ratios Pd /Pa, and when the NHPR is below a predetermined value, it is determined that there is myocardial ischemia.

WO 2020/22232 pamphlet

The blood flow in the coronary arteries is not a constant amount, but the blood flow velocity and blood flow volume differ between the systole and diastole in the cardiac cycle. In addition, blood flow patterns in coronary arteries are affected by various factors such as blood pressure, pulse rate, right and left coronary arteries, severity of coronary artery stenosis and microcirculatory disorder, and presence or absence of valvular disease. However, the FFR and the NHPR are calculated by a uniform formula regardless of the coronary artery to be measured and the condition of the patient. For example, in the FFR and NHPR, if the blood pressure at the time of measurement is high, the blood flow in the coronary arteries becomes faster, the pressure gradient at the stenosis site is more likely to occur, and the myocardium is likely to be diagnosed as being in an ischemic state. . Thus, conventionally, there is no method for evaluating coronary artery lesions by analyzing the pressure waveform in the coronary arteries in detail.

Also, for example, the coronary arteries of patients with hypertrophic myocardium due to aortic stenosis are generally considered to have microcirculatory disorders. The present inventors have found that patients with and without aortic stenosis have different coronary artery pressure waveforms, and that changes in pressure waveforms with respect to drug-induced maximal hyperemia are different. Therefore, in a diagnosis based on the above-mentioned index from the conventional pressure waveform, for example, even for a patient who can be treated only for valvular disease and does not need to be treated for coronary artery disease, the above-mentioned index can be used to treat coronary heart disease. You might get the recommended results.

Here, the coronary artery microcirculatory disorder is calculated from the blood flow waveform in the coronary artery measured using a catheter-type wire called a Doppler flow wire, or is calculated by the thermodilution method of the coronary artery. It is possible. However, the method of measuring blood flow using such a Doppler flow wire is reported to have a probability of obtaining satisfactory data of about 69%, and is not widely used due to high technical hurdles.

On the other hand, in the above-mentioned conventional method using the pressure waveform, the time of one heartbeat in the pressure waveform, the time of systole and diastole, etc. differ from patient to patient, and data on the pressure waveform of the coronary arteries in each patient is not available. It is difficult to obtain data for analyzing tendencies of heart disease by synthesizing pressure waveforms of many patients in order to perform accurate evaluation of heart disease because it cannot be simply compared for each pathological condition.

The present invention has been devised with a focus on such problems, and its object is to more accurately evaluate heart disease based on pressure waveforms representing temporal changes in intravascular pressure of a subject. The object of the present invention is to provide a pressure waveform standardization processing device and a standardization processing method for performing data processing for the purpose.

In order to achieve the above object, the present invention provides an apparatus that performs standardization processing for evaluating heart disease based mainly on pressure data of a pressure waveform representing changes in the intravascular pressure of a subject over time. is specified, and subdivides one heartbeat into a plurality of time phases, a time phase dividing unit that standardizes the time scale within each time phase, and an index value for evaluating the heart disease from the pressure data. and an index value calculation unit that associates the index value with the time scale, and the time phase division unit sets one or more predetermined feature points within one heartbeat, and divides each time zone by the feature points. is converted to the time on the unified time scale.

According to the present invention, a standardized waveform is generated by associating intravascular pressure in pressure waveforms that differ according to patients and pathological conditions and index values calculated based thereon with time scales that are unified among a plurality of subjects. becomes possible. Therefore, by using a standardized waveform standardized based on the pressure waveform, instead of pressure waveforms under different conditions, which was difficult to compare and evaluate between subjects, comparative evaluation between subjects can be performed, and it becomes possible to grasp the tendency on the standardized waveform for each pathological condition. As a result, it will be possible to sensitively evaluate changes in blood flow corresponding to the underlying pathology of the coronary arteries, for example, to evaluate microcirculatory disturbances in the coronary arteries.

1 is a block diagram schematically showing the configuration of a heart disease evaluation support system including a standardization processing device according to the present invention; FIG. 1 is a graph of pressure waveforms for aortic pressure and coronary artery pressure in one heartbeat; 1 is a graph of normalized waveforms for aortic pressure and coronary artery pressure in one heartbeat; FIG. 10 is a graph of normalized waveforms with respect to pressure ratio in one heartbeat; FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram schematically showing the configuration of a heart disease evaluation support system including a standardization processing device according to the present invention. In this figure, the evaluation support system 10 is a system that performs data processing for supporting the evaluation of heart disease based on pressure waveforms in which the intravascular pressure at a predetermined site of a subject such as a patient is associated with the acquisition time. be. This evaluation support system 10 includes an intravascular pressure measuring device 11 for measuring the intravascular pressure of a subject, and pressure waveform data based on the intravascular pressure acquired by the intravascular pressure measuring device 11 for evaluating heart disease. and a display device 13 such as a display for displaying various information including information based on the processing result of the standardization processing device 12 .

As the intravascular pressure measuring device 11, a known cardiac catheterization device capable of measuring intravascular pressure by inserting a guide wire with a pressure sensor called a pressure wire into the blood vessel is used. In this embodiment, the aortic pressure Pa and the coronary artery pressure Pd are measured as pressure data at predetermined time intervals, and pressure waveforms (see FIG. 2) representing changes over time are acquired for each. For example, when the intravascular pressures on the upstream and downstream sides of a stenotic lesion in a coronary artery are measured, the pressure at the proximal stenotic region on the upstream side is taken as the aortic pressure Pa, and the pressure at the distal stenotic region on the downstream side is taken as Pa. is taken as the coronary artery pressure Pd.

The standardization processing device 12 is composed of a computer comprising an arithmetic device such as a CPU and a storage device such as a memory and a hard disk, and programs are installed to make the computer function as the following units.

The standardization processing device 12 includes a storage unit 15 that stores pressure data (pressure waveform) consisting of the aortic pressure Pa and the coronary artery pressure Pd acquired by the intravascular pressure measuring device 11 at each acquisition time, and a cardiac cycle from the pressure data. A time phase dividing unit 16 that identifies and subdivides one heartbeat into a plurality of time phases and standardizes the time scale within each time phase, and calculates an index value for evaluating heart disease from pressure data, and calculates the index value and an index value calculator 17 that associates a value with a time scale.

As an example, the time-phase dividing unit 16 divides the pressure waveform (solid line in FIG. 2) of the aortic pressure Pa during one heartbeat into a dicrotic notch (DN) in which the pressure intensity fluctuates greatly when the aortic valve is closed. A corresponding time (a dashed dotted line in the figure) is specified as a feature point. Then, the time zone before and after the DN portion is divided into a first time phase T1 corresponding to systole and a second time phase T2 corresponding to diastole. Then, in each of the time phases T1 and T2, the time scale is unified and converted into standardized time. For example, as shown on the horizontal axis of FIG. 3, in one heartbeat cycle, the DN time is set to zero, and each time in the first phase T1 is the ratio of the elapsed time from the beginning of the systole to the DN. It is converted to the corresponding time (-100 to 0 (sec)). On the other hand, each time in the second phase T1 is converted into a time (0 to 100 (sec)) corresponding to the ratio of elapsed time from DN to the end of diastole.

As another example, the maximum aortic pressure Pmax during one heartbeat is defined as a feature point, and the pressure data during one heartbeat in the time zones before and after the feature point are obtained in the first and second time phases T1, It can also be partitioned as T2 and converted to standardized time as before. Furthermore, a plurality of feature points are set in the time zone when the aortic pressure Pa and the coronary artery pressure P decrease from the maximum aortic pressure Pmax during one heartbeat, and the time zone is divided at each feature point and standardized as described above. You can also set the time scale that is used. In addition, in the diastolic phase during one heartbeat, the mid-diastolic to end-diastolic phase (WFP (see FIG. 2): Wave free period) of the heart used in the resting non-hyperemic pressure ratio (NHPR) is used as a feature point. It is also possible to extract a part of the time zone, such as cutting out the time zone, and set the above-mentioned time scale for each time zone. Furthermore, a predetermined feature point is specified in the Pd/Pa waveform representing the relationship of the pressure ratio Pd/Pa to the time during one heartbeat, and the time scale described above is set in each time zone divided by the feature point. You can also In short, a device capable of measuring a predetermined intravascular pressure, or based on the measurement results of an electrocardiogram (not shown) or the like, identifies a cardiac cycle, and determines one or more timings having predetermined characteristics within the cardiac cycle. Various aspects can be adopted as long as the time of one heartbeat is divided at the feature point and the time of each time zone is converted into a standardized time.

At each time when the aortic pressure Pa and the coronary artery pressure Pd are acquired, the index value calculation unit 17 calculates the pressure ratio Pd/Pa obtained by dividing the coronary artery pressure Pd by the aortic pressure Pa, and the maximum aortic pressure Pa and the coronary artery pressure Pd. Standardized blood pressure Pa/Pmax and Pd/Pmax (%) divided by Pmax are calculated as index values.

In addition, as shown in FIGS. 3 and 4, the index value calculation unit 17 calculates a standardized time within one heartbeat, which varies between subjects, and a standardized blood pressure Pa/ A standardized waveform corresponding to Pmax, Pd/Pmax and pressure ratio Pd/Pa is generated.

Then, the aortic pressure Pa, the coronary artery pressure Pd, the pressure value Pd/Pa, and the standardized blood pressure Pa/Pmax, Pd/Pmax are the average value, the median value, or the predetermined Calculated values are determined and these values are also available as indicators in assessing heart disease.

Therefore, according to such an embodiment, it is possible to unify the time scale between subjects from the feature points in one heartbeat in the pressure waveform in one heartbeat and the waveform of the pressure ratio Pd/Pa, and the pressure ratio Pd /Pa, the standardized blood pressure Pa/Pmax and Pd/Pmax can be obtained to standardize the index values related to pressure to 1.0 (100%) or less. As a result, conventionally, it was not possible to simply compare pressure waveforms in which the elapsed time of each event of one heartbeat differs from subject to subject, but in the present invention, the waveform corresponding to the intravascular pressure is converted into a standardized waveform. As a result, it is possible to perform comparative analysis of various data of subjects, and it is expected that trends such as valvular disease and myocardial ischemia, which cause microcirculatory disorders in the coronary arteries, will be more precisely understood.

In addition, the configuration of each part of the device in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as substantially the same effect is achieved.

REFERENCE SIGNS LIST 10 evaluation support system 11 intravascular pressure measuring device 12 standardization processing device 13 display device 15 storage unit 16 time phase division unit 17 index value calculation unit T1 first time phase T2 second time phase

Claims

In a device that performs standardization processing for evaluating heart disease based on pressure data of a pressure waveform representing temporal changes in intravascular pressure of a subject,
A time phase division unit that specifies a cardiac cycle, subdivides one heart beat into a plurality of time phases, standardizes the time scale in each time phase, and an index value for evaluating the heart disease from the pressure data. an index value calculation unit that calculates and associates the index value with the time scale,
The time phase division unit sets one or more predetermined feature points in one heart beat, and converts the time of each time zone divided by the feature points into the time on the unified time scale. Pressure waveform standardization processing equipment.
The pressure waveform standardization processing apparatus according to claim 1, wherein the index value calculation unit generates a standardized waveform representing the relationship between each time on the time scale and the intravascular pressure or the index value.
The pressure waveforms represent changes over time in aortic pressure and coronary artery pressure, respectively;
In the index value calculation unit, a pressure ratio between the coronary artery pressure and the aortic pressure obtained at the same time is calculated as the index value,
3. The pressure waveform according to claim 1 or 2, wherein the feature point is set at a predetermined point in the pressure waveform or in the waveform representing the temporal change in the pressure ratio in the time phase division unit. Standardization processor.
4. The pressure waveform according to claim 3, wherein the index value calculation unit calculates standardized blood pressure obtained by dividing each of the aortic pressure and the coronary artery pressure by the maximum aortic pressure during one heartbeat, as the index value. Standardization processor.
In a method for performing standardization processing for evaluating heart disease based on pressure data of a pressure waveform representing changes in intravascular pressure of a subject over time,
When one heartbeat is subdivided into a plurality of time phases after specifying the cardiac cycle, one or more predetermined feature points are set in one heartbeat, and the time of each time zone divided by the feature points is unified. standardize the time scale in each time phase by converting to the time on the time scale, calculate an index value for evaluating the heart disease from the pressure data, and convert the index value to the time scale A pressure waveform standardization processing method characterized by corresponding to.