Liver transplantation perioperative period concurrent myocardial ischemia risk assessment method and system

Abstract

The invention discloses a liver transplantation perioperative concurrent myocardial ischemia risk assessment method and system, and the method comprises the steps: obtaining coronary artery image data of a liver transplantation patient, carrying out the three-dimensional reconstruction according to the coronary artery image data, and generating a personalized coronary artery geometric model; based on the geometric model of the coronary artery, performing numerical simulation on the flowing condition of blood flow in the coronary artery by utilizing a computational fluid mechanics method, obtaining the speed and pressure distribution of the blood flow of the coronary artery through the numerical simulation, and calculating the pressure ratio before and after the coronary artery stenosis; evaluating the coronary ischemia condition according to the pressure ratio, and generating a fractional flow reserve value and a myocardial ischemia risk evaluation report. The coronary artery blood flow reserve score value is calculated by simulating the coronary artery blood flow conditions under different physiological conditions, so that the myocardial ischemia risk possibly faced by a patient during an operation is comprehensively evaluated, and intra-operation decision support is provided for clinicians.

Description

Technical Field

[0001] The present invention relates to the technical field of risk assessment, and in particular to a method, system, terminal and computer-readable storage medium for assessing the risk of perioperative myocardial ischemia during liver transplantation. Background Art

[0002] During liver transplantation, patients are often at risk of serious cardiovascular complications, especially myocardial ischemia (myocardial infarction), which is crucial to the success of the operation and the patient's survival. However, traditional assessment methods are mostly invasive and cannot be applied to liver transplant patients with critical conditions and abnormal coagulation function.

[0003] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method, system, terminal and computer-readable storage medium for assessing the risk of myocardial ischemia during liver transplantation. The purpose is to solve the problem that the existing technology for assessing the risk of myocardial ischemia during liver transplantation surgery is mostly invasive, cannot be applied to liver transplant patients with critical conditions and abnormal coagulation function, and cannot accurately assess the risk of myocardial ischemia during surgery.

[0005] To achieve the above objectives, the present invention provides a method for assessing the risk of myocardial ischemia during the perioperative period of liver transplantation, the method comprising the following steps:

[0006] Acquiring coronary artery imaging data of a liver transplant patient, performing three-dimensional reconstruction based on the coronary artery imaging data, and generating a personalized coronary artery geometric model;

[0007] Based on the coronary artery geometric model, a computational fluid dynamics method is used to perform a numerical simulation of the blood flow in the coronary artery, obtain the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculate the pressure ratio before and after coronary artery stenosis;

[0008] Based on the pressure ratio, the coronary ischemia situation is assessed, and a blood flow reserve fraction value and a myocardial ischemia risk assessment report are generated.

[0009] Optionally, the method for assessing the risk of myocardial ischemia during perioperative liver transplantation, wherein the steps of obtaining coronary artery imaging data of a liver transplant patient, performing three-dimensional reconstruction based on the coronary artery imaging data, and generating a personalized coronary artery geometric model, specifically include:

[0010] Use high-resolution coronary CT angiography to obtain coronary artery imaging data of liver transplant patients;

[0011] The coronary artery image data is segmented by image processing software to extract the geometric structure of the coronary artery. After segmentation, a three-dimensional reconstruction algorithm is used to construct a patient-specific coronary artery geometric model.

[0012] Optionally, in the method for assessing the risk of myocardial ischemia during perioperative liver transplantation, the coronary artery geometric model is used to describe the morphological structure of the blood vessels, including the geometric characteristics of the stenosis site.

[0013] Optionally, the method for assessing the risk of myocardial ischemia during perioperative liver transplantation, wherein, based on the coronary artery geometric model, a computational fluid dynamics method is used to numerically simulate the flow of blood in the coronary artery, obtain the velocity and pressure distribution of coronary artery blood flow through the numerical simulation, and calculate the pressure ratio before and after coronary artery stenosis, specifically includes:

[0014] During the simulation process, the patient's personalized physiological parameters are combined to define boundary conditions and dynamically simulate the blood flow velocity and pressure distribution;

[0015] Solving the Navier-Stokes equations, which are used to describe the flow behavior of fluids within blood vessels, discretizes the Navier-Stokes equations using the finite element method or the finite volume method, divides the continuous blood flow domain into discrete grid cells, and performs numerical calculations on each grid cell to obtain the velocity distribution and pressure distribution of blood in the geometric structure of the blood vessel, as well as the flow of blood in different branching vessels;

[0016] The pressure ratio FFR before and after coronary artery stenosis is calculated based on the pressure difference obtained by solving the equation. The pressure ratio is used to evaluate the function of coronary artery stenosis and quantify the impact of coronary artery stenosis on myocardial blood supply.

[0017] Optionally, in the method for assessing the risk of myocardial ischemia during perioperative liver transplantation, the calculation formula for the pressure ratio (FFR) is:

[0018] FFR=P d / P a ;

[0019] Among them, P d Indicates the pressure distal to the coronary artery stenosis, P a Indicates the pressure proximal to the coronary artery stenosis;

[0020] P d and P a The three-dimensional unsteady incompressible Navier-Stokes equation is used to describe the control equation of coronary blood flow by solving the hemodynamic control equation:

[0021]

[0022] Where u represents the blood flow velocity, is the Cauchy stress tensor, p is the pressure, μ is the blood viscosity coefficient, I is the 3×3 unit matrix, t is the time, is the gradient operator, and Ω is the computational domain consisting of the 3D geometry of the blood vessel and the inlet and outlet boundaries.

[0023] Optionally, in the method for assessing the risk of myocardial ischemia during perioperative liver transplantation, the blood vessels are truncated when constructing the computational domain, and artificial boundary conditions are given on the truncation surface. Under the assumption of a rigid blood vessel wall, the boundary condition of ΓW at the blood vessel wall is:

[0024] u=0 on Γ W ;

[0025] According to the average blood flow velocity in the aorta during one cardiac cycle provided by cardiovascular ultrasound and combined with the recommended cardiovascular blood waveform, an instantaneous velocity g is obtained and applied to the inlet boundary ΓI:

[0026] u=g on Γ I ;

[0027] The vascular elasticity is imposed on the coronary outlet boundary ΓO using the aortic elastic reservoir effect model. At time t, the time-varying blood pressure p at the kth arterial outlet is k (t):

[0028]

[0029] Among them, R k Represents resistance, Q k represents the volume flow rate through the kth outlet, C k Capacitance used to characterize arterial deformation, p k (0) and They represent the blood pressure at the kth arterial outlet and the downstream distal pressure at the initial moment, represents the distal pressure downstream of the kth arterial outlet at time t, s represents the integral variable from time 0 to time t, τ k =R k C k ;

[0030] R k and C k Calculated by the rules of parallel circuits and the area of ​​the corresponding outlets:

[0031]

[0032] Among them, d k and Represent the diameter and area of ​​the kth artery outlet, n represents the number of kth artery outlets, R total and C total Represent the total resistance and capacitance of all arterial outlets, R total =αP b / Q c , where P b represents the mean brachial pressure, α represents the empirical constant, and Qc represents the flow rate in the coronary artery;

[0033] Q k The calculation formula is:

[0034]

[0035] in, represents the kth outlet section, u(t) is the velocity vector at time t, and dΓ is the boundary The small area element on indicates that the integration is performed over the entire outlet cross section.

[0036] Optionally, the method for assessing the risk of myocardial ischemia during perioperative liver transplantation, wherein the step of assessing coronary ischemia based on the pressure ratio and generating a blood flow reserve fraction value and a myocardial ischemia risk assessment report, specifically includes:

[0037] Points were taken from the patient's three coronary arteries, and the blood flow reserve fraction was calculated based on the different physiological conditions of blood pressure and heart rate in perioperative liver transplant patients;

[0038] The coronary ischemia situation is assessed based on the calculation results, and the blood flow reserve fraction value is output and a myocardial ischemia risk assessment report is generated.

[0039] In addition, to achieve the above-mentioned purpose, the present invention further provides a liver transplantation perioperative myocardial ischemia risk assessment system, wherein the liver transplantation perioperative myocardial ischemia risk assessment system comprises:

[0040] a three-dimensional reconstruction module, configured to obtain coronary artery imaging data of a liver transplant patient, perform three-dimensional reconstruction based on the coronary artery imaging data, and generate a personalized coronary artery geometric model;

[0041] a numerical simulation module for numerically simulating the flow of blood in the coronary arteries using a computational fluid dynamics method based on the coronary artery geometric model, obtaining the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculating the pressure ratio before and after coronary artery stenosis;

[0042] The risk assessment module is used to assess the coronary ischemia situation according to the pressure ratio and generate a blood flow reserve fraction value and a myocardial ischemia risk assessment report.

[0043] In addition, to achieve the above-mentioned purpose, the present invention also provides a terminal, wherein the terminal includes: a memory, a processor, and a liver transplant perioperative myocardial ischemia risk assessment program stored on the memory and runnable on the processor, wherein the liver transplant perioperative myocardial ischemia risk assessment program implements the steps of the liver transplant perioperative myocardial ischemia risk assessment method as described above when executed by the processor.

[0044] In addition, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a liver transplant perioperative myocardial ischemia risk assessment program, and when the liver transplant perioperative myocardial ischemia risk assessment program is executed by a processor, the steps of the liver transplant perioperative myocardial ischemia risk assessment method as described above are implemented.

[0045] In the present invention, coronary artery imaging data of a liver transplant patient is obtained, and three-dimensional reconstruction is performed based on the coronary artery imaging data to generate a personalized coronary artery geometric model; based on the coronary artery geometric model, computational fluid dynamics methods are used to numerically simulate the flow of blood in the coronary arteries, and the velocity and pressure distribution of coronary blood flow are obtained through numerical simulation, and the pressure ratio before and after coronary artery stenosis is calculated; based on the pressure ratio, the coronary ischemia is assessed, and a blood flow reserve fraction value and a myocardial ischemia risk assessment report are generated. The present invention simulates coronary artery blood flow under different physiological conditions and calculates the coronary blood flow reserve fraction value, thereby comprehensively assessing the risk of myocardial ischemia that patients may face during surgery. The purpose is to quickly and accurately assess the risk of perioperative myocardial ischemia in patients through non-invasive means, and provide intraoperative decision support for clinicians. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of a preferred embodiment of a method for assessing the risk of myocardial ischemia during perioperative liver transplantation according to the present invention;

[0047] Figure 2 Schematic diagram of a patient's individualized coronary CTA image and three-dimensional vascular geometry image in a preferred embodiment of the method for assessing the risk of perioperative myocardial ischemia during liver transplantation of the present invention;

[0048] Figure 3 2. It is a schematic diagram of the coronary artery calculation grid and regional decomposition in a preferred embodiment of the method for assessing the risk of perioperative myocardial ischemia during liver transplantation of the present invention;

[0049] Figure 4 This is a schematic diagram of the three points taken from the coronary arteries of a patient in a preferred embodiment of the method for assessing the risk of perioperative myocardial ischemia during liver transplantation of the present invention;

[0050] Figure 52 is a schematic diagram of numerical calculation results of blood flow reserve fraction at different stages of perioperative liver transplantation in a preferred embodiment of the method for assessing the risk of myocardial ischemia during perioperative liver transplantation of the present invention;

[0051] Figure 6 This is a structural diagram of a preferred embodiment of the liver transplantation perioperative myocardial ischemia risk assessment system of the present invention;

[0052] Figure 7 FIG. 4 is a structural diagram of a preferred embodiment of the terminal of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the present invention more clear and distinct, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0054] Liver transplantation is a highly complex and high-risk surgical procedure, and patients often suffer from a variety of serious complications, especially perioperative cardiovascular events. Among them, myocardial ischemia is one of the most serious complications. Myocardial ischemia may lead to insufficient blood supply to the myocardium, unable to meet the metabolic needs of the myocardium, and then cause myocardial infarction and even endanger the patient's life. For such patients, accurate assessment of coronary ischemia status is crucial. However, due to the drastic fluctuations in intraoperative hemodynamics, the cardiovascular system of liver transplant patients is under great pressure. Therefore, how to conduct efficient and accurate preoperative myocardial ischemia assessment has become a major clinical challenge.

[0055] Traditional assessment methods include electrocardiograms (ECGs), Holter monitoring, radionuclide myocardial perfusion imaging, and coronary angiography. These methods have limitations, some of which are invasive, involve radiation exposure, or are only suitable for specific patient groups (e.g., ECGs require patients to be able to withstand a certain level of exercise). In particular, for liver transplant patients, most invasive testing methods are not suitable due to their abnormal coagulation function and the severity of their condition, making it impossible to accurately assess the risk of myocardial ischemia during surgery. Furthermore, most of these methods are performed at rest and cannot comprehensively assess the patient's risk of myocardial ischemia under different physiological conditions (e.g., changes in blood pressure and heart rate).

[0056] Currently, the main technical options for clinically assessing the risk of perioperative myocardial ischemia during liver transplantation include:

[0057] (1) Functional blood flow reserve fraction measurement: The blood flow reserve fraction is an important indicator for assessing the functional significance of coronary artery stenosis. The blood flow reserve fraction measurement method involves inserting a catheter into the coronary artery, injecting a pressure sensor, and measuring the blood pressure ratio before and after stenosis to assess the risk of myocardial ischemia. Blood flow reserve fraction measurement is considered the gold standard for assessing coronary artery stenosis, but its invasive procedure increases intraoperative risks and patient discomfort.

[0058] (2) Holter monitoring combined with cardiac ultrasound: Holter monitoring combined with cardiac ultrasound is a non-invasive assessment method that captures the patient's cardiac electrical activity in daily life through 24 hours or longer ECG monitoring and combines it with cardiac ultrasound to assess cardiac structure and function. This method can identify transient ischemic events, but its main limitation is that it has limited direct assessment of myocardial ischemia and cannot provide detailed information on the location and extent of myocardial ischemia.

[0059] (3) Radionuclide myocardial perfusion imaging combined with exercise testing: Radionuclide myocardial perfusion imaging combined with exercise testing is a commonly used assessment method. It uses radionuclide labeling to assess myocardial blood flow and perfusion, and combines it with exercise testing to induce cardiac stress and observe electrocardiographic changes. The advantages of this method are high sensitivity and specificity, but its main limitations are radiation exposure and poor applicability to patients who cannot exercise.

[0060] While existing technologies can assess the risk of perioperative myocardial ischemia in liver transplant patients to varying degrees, they all have limitations, making it difficult to comprehensively and accurately assess the risk under different physiological conditions. Therefore, there is an urgent need for a rapid, noninvasive method that can comprehensively assess the risk of perioperative myocardial ischemia in liver transplant patients by simulating different blood pressure and heart rate conditions under non-invasive conditions, and provide preoperative planning and intraoperative decision-making support to the surgical team.

[0061] The shortcomings of the existing technology mainly include:

[0062] (1) Electrophysiological examination and ultrasound examination: The results may be affected by the operator's experience and technical level, resulting in inconsistent evaluation results.

[0063] (2) Stress testing: It is not suitable for weak or seriously ill patients because these patients may not be able to withstand the load brought by exercise.

[0064] (3) Myocardial perfusion imaging: It is expensive and requires injection of contrast agents, which increases the burden and potential risks for patients.

[0065] (4) Dynamic electrocardiogram and cardiac ultrasound, etc.: lack of direct quantification of specific hemodynamic conditions.

[0066] (5) Blood flow reserve fraction measurement technology: Traditional blood flow reserve fraction measurement technology is considered the "gold standard" for myocardial ischemia risk assessment. It assesses blood flow obstruction by measuring the blood flow pressure ratio before and after coronary artery stenosis. However, this method requires the use of a guidewire and a pressure sensor for direct measurement, which is an invasive procedure and increases patient discomfort and the risk of complications. For liver transplant patients with critical conditions and coagulation abnormalities, invasive coronary artery examinations are often not possible, making it difficult to accurately predict the occurrence of perioperative myocardial infarction and to develop individualized and precise treatment plans.

[0067] Existing technologies have multiple limitations when assessing the risk of myocardial ischemia in liver transplant patients. First, invasive techniques such as functional blood flow reserve fraction measurement require catheter insertion into the coronary artery and the use of a pressure sensor to measure the blood pressure difference. This operation is risky for liver transplant patients, especially those who are critically ill and have abnormal coagulation function, who cannot withstand invasive testing. Secondly, traditional non-invasive detection methods, such as electrocardiograms and dynamic electrocardiograms, can often only provide limited data at rest, lack the ability to perform dynamic assessments under different physiological conditions, and are unable to fully and accurately reflect the risk of myocardial ischemia.

[0068] To address these shortcomings, the present invention rapidly calculates the functional fractional flow reserve (FFR) of the coronary arteries by simulating blood flow under different physiological conditions during liver transplantation, without relying on invasive testing methods. This allows for a comprehensive assessment of perioperative myocardial ischemia risk in liver transplant patients. Through an efficient parallel computing architecture, the present invention enables rapid processing of individualized patient blood flow data, meeting the need for real-time cardiac assessment during surgery, providing more accurate preoperative planning and intraoperative decision support, and improving surgical safety and success rates.

[0069] The purpose of the present invention is to solve the shortcomings of the above-mentioned prior art, and the specific objectives include:

[0070] Non-invasive assessment: Provides a non-invasive method that avoids the invasive procedures of traditional blood flow reserve fraction methods and reduces intraoperative risks and discomfort for patients.

[0071] Simulate various physiological conditions: Based on the patient's personalized coronary artery model and estimated blood pressure and heart rate data, numerical simulation technology is used to evaluate the blood flow reserve fraction under different blood pressure and heart rate conditions, fully understanding the patient's possible risk of myocardial ischemia during surgery.

[0072] Rapidly obtain blood flow reserve fraction values: Using high-performance computers and efficient parallel algorithms, non-invasive blood flow reserve fraction values ​​can be quickly obtained to assess the risk of myocardial ischemia.

[0073] The method for assessing the risk of myocardial ischemia during perioperative liver transplantation according to a preferred embodiment of the present invention is as follows: Figure 1 As shown, the method for assessing the risk of myocardial ischemia during perioperative liver transplantation includes the following steps:

[0074] Step S10: Obtain coronary artery image data of a liver transplant patient, perform three-dimensional reconstruction based on the coronary artery image data, and generate a personalized coronary artery geometric model.

[0075] Specifically, high-resolution coronary computed tomography angiography (CCTA) is used to obtain coronary artery imaging data from liver transplant patients. CCTA is a non-invasive imaging technique that can clearly display the anatomy of the coronary arteries and has high spatial resolution. Image processing software is used to segment the coronary artery imaging data and extract the geometric structure of the coronary arteries. After segmentation, a 3D reconstruction algorithm is used to construct a personalized coronary artery geometric model (i.e., a 3D coronary artery model) for the patient. This coronary artery geometric model is used to accurately describe the morphological structure of the blood vessels, particularly the geometric features of the stenosis site.

[0076] like Figure 2 As shown, Figure 2 Shown are patient-specific coronary CTA images (left) and three-dimensional vascular geometry (right).

[0077] Step S20: Based on the coronary artery geometric model, a computational fluid dynamics method is used to perform numerical simulation on the flow of blood in the coronary artery, obtain the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculate the pressure ratio before and after coronary artery stenosis.

[0078] Specifically, based on the obtained coronary artery geometric model (i.e., a three-dimensional coronary artery model), computational fluid dynamics (CFD) methods are used to numerically simulate the flow of blood in the coronary arteries. The core of hemodynamic simulation is to solve the Navier-Stokes equations, which describe the flow behavior of fluid in the coronary arteries. During the simulation process, boundary conditions are defined in combination with the patient's personalized physiological parameters (such as blood pressure, heart rate, etc.), and dynamic simulation of blood flow velocity, pressure distribution, etc. is performed. Through numerical simulation, the velocity and pressure distribution of coronary blood flow are obtained, and the system calculates the pressure ratio before and after coronary artery stenosis (i.e., the blood flow reserve fraction, denoted as FFR). The blood flow reserve fraction is a key indicator for assessing the functional significance of coronary artery stenosis and can quantify the impact of coronary artery stenosis on myocardial blood supply. When the blood flow reserve fraction is lower than 0.8, it indicates an increased risk of myocardial ischemia.

[0079] The core of hemodynamic simulation lies in solving the Navier-Stokes equations, which describe the flow behavior of blood as a fluid within blood vessels. The Navier-Stokes equations are a set of partial differential equations that describe the conservation of momentum and mass in a fluid and are typically solved using numerical methods. In hemodynamics, solving the Navier-Stokes equations requires discretization. Common methods include the finite element method (FEM) or the finite volume method (FVM), which divide the continuous blood flow domain into discrete grid cells and then perform numerical calculations on each grid cell. The results of the Navier-Stokes equations include the velocity and pressure fields within the blood vessels. This means that by solving the equations, the velocity and pressure distribution of blood in complex vascular geometries such as coronary arteries and cerebral vessels can be determined, as well as the flow of blood in different branching vessels. Blood flow velocity and pressure are key indicators for assessing hemodynamic status, particularly at sites of coronary artery stenosis and cerebral vascular stenosis. The pressure difference obtained by solving the equations can be further used to calculate the pressure ratio (FFR) before and after coronary artery stenosis.

[0080] The calculation formula of the pressure ratio FFR is:

[0081] FFR=P d / P a ;

[0082] Among them, P d Indicates the pressure distal to the coronary artery stenosis (distal pressure), that is, downstream pressure, P a It indicates the pressure proximal to the coronary artery stenosis (proximal pressure), that is, the upstream pressure.

[0083] P d and P a By solving the hemodynamic control equation, the present invention adopts the three-dimensional unsteady incompressible Navier-Stokes equation as the control equation to describe the coronary blood flow:

[0084]

[0085] Where u represents the blood flow velocity, is the Cauchy stress tensor, p is the pressure, μ is the blood viscosity coefficient, I is the 3×3 unit matrix, t is the time, is the gradient operator, and Ω is the computational domain consisting of the 3D geometry of the blood vessel and the inlet and outlet boundaries.

[0086] In terms of boundary conditions, due to the complexity of human blood vessels, existing imaging technology and computational conditions cannot simulate the entire coronary artery network. It is necessary to truncate the blood vessels when constructing the computational domain and impose artificial boundary conditions on the truncation surface. The selection of these boundary conditions directly affects the accuracy and reliability of the numerical simulation. Under the assumption of a rigid blood vessel wall, the boundary condition for ГW at the blood vessel wall is:

[0087] u=0 on Γ W ;

[0088] In the cardiovascular system, blood is pumped from the left ventricle by the heart and delivered to the myocardium and other organs and tissues throughout the body. The inlet is located at the junction of the left ventricle and the aorta, the largest artery in the human body. Based on the average blood flow velocity in the aorta during a cardiac cycle provided by cardiovascular ultrasound and combined with the recommended cardiovascular blood waveform, an instantaneous velocity g is obtained and applied to the inlet boundary ΓI:

[0089] u=g on Γ I ;

[0090] The vascular elasticity is imposed on the coronary artery outlet boundary ΓO using the aortic elastic reservoir effect (Windkessel) model. Specifically, at time t, the time-varying blood pressure p at the kth artery outlet is k (t):

[0091]

[0092] Among them, R k Represents resistance, Q k represents the volume flow rate through the kth outlet, C k Capacitance used to characterize arterial deformation, p k (0) and They represent the blood pressure at the kth arterial outlet and the downstream distal pressure at the initial moment, represents the distal pressure downstream of the kth arterial outlet at time t, s represents the integral variable from time 0 to time t, reflecting the cumulative effect in the dynamic process, that is, how the previous blood flow situation affects the blood pressure at the current moment, τ k =R k C k .

[0093] R k and C k Calculated by the rules of parallel circuits and the area of ​​the corresponding outlets:

[0094]

[0095] Among them, d k and Represent the diameter and area of ​​the kth artery outlet, n represents the number of kth artery outlets, R total and C total Represent the total resistance and capacitance of all arterial outlets, R total =αP b / Q c , where P b represents the mean brachial pressure, α represents the empirical constant, and Qc represents the flow rate in the coronary artery.

[0096] At every stage of liver transplant surgery, P b The systolic and diastolic blood pressures were estimated by empirical formulas. Since studies have reported that the total blood flow delivered to the myocardium by the coronary artery is proportional to cardiac output, Q c Set to 4% of the inlet flow. Let n be the outward unit surface perpendicular to the kth outlet; then, Q k The calculation formula is:

[0097]

[0098] in, represents the kth outlet section, u(t) is the velocity vector at time t, and dΓ is the boundary The small area element on indicates that the integration is performed over the entire outlet cross section.

[0099] In addition, the present invention adopts a parallel computing method based on regional decomposition, and optimizes the computing efficiency through the Newton-Krylov-Schwarz algorithm and RAS (Restricted Additive Schwarz) preprocessing technology. Figure 3 As shown, Figure 3 Schematic diagram of the coronary computational grid (left) and regional decomposition (right). The computational domain is divided into a fraction equal to the number of processors used for the calculation (displayed in different colors) for parallel calculation. The hemodynamic calculation task is decomposed into multiple subtasks and assigned to different computing nodes for parallel execution, thereby improving the efficiency of the blood flow reserve fraction calculation and ensuring the real-time performance of the results. That is, during the calculation process, the hemodynamic numerical calculation area is divided into blocks using multi-core processors or computing nodes. Accordingly, the simulation task is also decomposed into multiple subtasks and assigned to each processor to accelerate the calculation.

[0100] Step S30: Evaluate the coronary ischemia condition according to the pressure ratio, and generate a blood flow reserve fraction value and a myocardial ischemia risk assessment report.

[0101] Specifically, the system measures points on the patient's three coronary arteries and calculates the blood flow reserve fraction based on the patient's varying blood pressure and heart rate physiological conditions during the liver transplantation period. The system then assesses coronary ischemia and outputs the blood flow reserve fraction and generates a myocardial ischemia risk assessment report. This value and assessment report are then provided to clinicians for their assessment of the patient's myocardial ischemia risk and decision-making support during surgery.

[0102] like Figure 4 and Figure 5 As shown, Figure 4 The figure shows the schematic diagram of the points taken from the three coronary arteries of the patient, such as 5, which shows the numerical calculation results of the blood flow reserve fraction at different stages of the perioperative period of liver transplantation.

[0103] This invention aims to provide accurate preoperative and perioperative myocardial ischemia risk assessment for liver transplant patients. By simulating coronary blood flow under different physiological conditions and calculating the coronary flow reserve fraction, the invention comprehensively assesses the patient's potential risk of myocardial ischemia during surgery.

[0104] This invention provides a non-invasive myocardial ischemia risk assessment technology, particularly suitable for perioperative assessment during liver transplantation. By combining computational fluid dynamics simulations with coronary artery CCTA data, it avoids the invasive procedures of traditional invasive tests (such as fractional flow reserve measurement). This technology can accurately assess myocardial ischemia risk in liver transplant patients, even when invasive assessment is not possible.

[0105] The present invention reconstructs a three-dimensional model of the patient's coronary arteries based on high-resolution CCTA data, and calculates coronary artery hemodynamic parameters through non-invasive computational fluid dynamics simulation. The core indicator of myocardial ischemia risk assessment, the coronary blood flow reserve fraction, is obtained through non-invasive technology to assess the patient's myocardial ischemia risk during the perioperative period of liver transplantation. The method can non-invasively assess the risk of myocardial ischemia during liver transplantation surgery, provide fast and accurate assessment results, and avoid the risks and discomfort caused by invasive operations.

[0106] The present invention is based on the patient's individualized physiological data (such as blood pressure, heart rate, etc.) under different physiological conditions before, during and after surgery, sets different physiological boundary conditions, and predicts the risk of myocardial ischemia under different states through numerical simulation; dynamically adjusts the boundary conditions in the simulation, combines real-time physiological data changes, and provides myocardial ischemia risk assessment under multiple physiological states, providing support for clinicians in intraoperative and postoperative decision-making.

[0107] Compared to existing myocardial ischemia risk assessment methods based on functional fractional flow reserve measurement and computational fluid dynamics, the present invention offers significant advantages in multiple aspects, particularly in non-invasive perioperative liver transplantation assessment and individualized risk assessment under multiple physiological conditions. The following are the main advantages of the present invention over existing technologies:

[0108] (1) Non-invasive assessment, reducing patient risks and discomfort:

[0109] Existing techniques for measuring fractional flow reserve typically require invasive procedures, such as catheter insertion and the use of pressure sensors. These invasive procedures carry significant risks for liver transplant patients, particularly those with coagulation abnormalities. In contrast, this new method, based on coronary artery CCTA data and utilizing computational fluid dynamics simulation technology, provides a completely non-invasive assessment method, avoiding the risks and discomfort of surgery.

[0110] Effect: The present invention greatly reduces perioperative operation risks, eliminates complications and patient discomfort caused by traditional invasive operations, and is particularly suitable for critically ill patients who cannot undergo invasive assessment.

[0111] (2) Individualized, dynamic risk assessment under multiple physiological conditions:

[0112] Traditional myocardial ischemia risk assessment methods are often limited to resting states or assessments under a single physiological condition, and cannot dynamically reflect changes in the cardiovascular system during surgery. This invention, based on the patient's personalized data, can dynamically adjust physiological boundary conditions such as blood pressure and heart rate during simulation to assess the patient's myocardial ischemia risk under different physiological conditions. By calculating the coronary artery blood flow reserve fraction in real time, clinicians can fully understand the patient's cardiovascular risk at different stages of the perioperative period, thereby making more accurate surgical decisions.

[0113] Effect: The present invention can provide risk assessment for multiple scenarios during surgery, offering comprehensive individualized support to clinicians and significantly improving the accuracy of assessment and the success rate of surgery.

[0114] (3) Efficient parallel computing significantly improves evaluation speed:

[0115] Existing risk assessment techniques based on computational fluid dynamics (CFD) are often time-consuming and difficult to provide real-time support during surgery. This invention leverages high-performance parallel computing technology to decompose computational tasks onto multiple computing nodes for parallel processing, significantly improving the efficiency of numerical simulations. This allows for rapid calculation of blood flow reserve fractions in a short period of time, meeting the need for rapid intraoperative assessment.

[0116] Effect: Compared with traditional computational fluid dynamics simulation, this invention can significantly shorten the calculation time and effectively improve the efficiency and timeliness of clinical application.

[0117] This invention has been initially validated in a real-world clinical setting. For example, in collaboration with a hospital, a retrospective study of a liver transplant patient was conducted. Using coronary CCTA images and physiological data from varying blood pressure and heart rate during the liver transplant surgery, the noninvasive Fractional Flow Reserve (FFR) simulation was performed at each stage of the liver transplant. This method effectively predicted abnormalities in the coronary FFR during the transplant, demonstrating good feasibility and practicality.

[0118] Furthermore, the present invention also provides the following design changes and alternatives. These alternatives cover the replacement of some structures and method steps, and also include complete technical solutions adapted to different clinical applications.

[0119] (1) Alternative 1: Individualized assessment using multimodal imaging.

[0120] In addition to the three-dimensional model constructed based on coronary CCTA data, the present invention can also be combined with other types of imaging data for multimodal comprehensive analysis. For example, imaging data such as magnetic resonance imaging and echocardiography can further supplement the anatomical structure and functional information of the coronary arteries. The evaluation method combined with multimodal imaging can provide more comprehensive cardiovascular information and further improve the accuracy of the evaluation. Design change: CCTA is combined with multimodal imaging such as magnetic resonance imaging and echocardiography to comprehensively establish an individualized cardiovascular model, analyze the patient's cardiovascular health status from multiple angles, and provide a more accurate myocardial ischemia risk assessment.

[0121] (2) Alternative 2: Automated modeling based on deep learning.

[0122] The present invention currently uses an image segmentation algorithm to process coronary CT image data and construct a three-dimensional geometric model. To further improve the efficiency and accuracy of model construction, the present invention can automatically process image data and automatically generate a coronary artery model by integrating deep learning technologies, such as deep convolutional neural networks. This method can reduce manual intervention and improve the accuracy of image segmentation. Design change: Use a deep learning model to automatically process CCTA data, automatically segment vascular regions, and generate a personalized three-dimensional model, thereby optimizing the current manual operation process and further improving the efficiency and accuracy of the assessment.

[0123] (3) Alternative 3: Cardiovascular risk assessment for different types of surgery.

[0124] Although the present invention is mainly aimed at perioperative myocardial ischemia risk assessment in liver transplantation surgery, its technical principles are also applicable to other types of high-risk surgeries, such as heart surgery, kidney transplantation, cerebrovascular surgery, etc. By evaluating the cardiovascular risks that may occur during the operation, especially in scenarios with large dynamic blood flow fluctuations during the operation, the non-invasive assessment method of the present invention can provide intraoperative support for various types of operations. Design change: The present invention can be extended to other large-scale surgical scenarios, such as cerebrovascular surgery, heart bypass surgery, kidney transplantation, etc., and by adjusting the corresponding physiological parameters and blood flow simulation methods, dynamic cardiovascular risk assessment of multiple types of operations can be achieved.

[0125] (4) Alternative 4: Alternative parallel computing architecture.

[0126] One of the core elements of the present invention is a hemodynamic simulation framework based on high-performance parallel computing. However, this parallel computing architecture can be replaced by different algorithms and platforms. For example, GPU (graphics processing unit) accelerated computing can be used instead of the traditional CPU multi-core parallel method, or cloud computing platform can be used in combination with distributed computing system to further improve computing efficiency and reduce hardware costs. Design change: Replace the existing parallel computing architecture, further optimize computing performance by using GPU acceleration or cloud computing platform, and reduce dependence on traditional high-performance computing resources, thereby achieving rapid evaluation on ordinary computing devices.

[0127] (5) Alternative 5: Non-coronary risk assessment.

[0128] Although the present invention is primarily used to assess the risk of myocardial ischemia in the coronary arteries, its principles are equally applicable to risk assessments in other vascular systems, such as the carotid arteries and peripheral arteries. In the hemodynamic simulations of these locations, the present invention can be used to assess the impact of arterial stenosis on blood flow and predict local vascular obstruction and associated risks. Design modification: The hemodynamic simulation method of the present invention can be extended to non-coronary vascular systems, such as the carotid arteries or lower limb arteries, to assess arterial stenosis and blood flow obstruction in other locations, enabling non-invasive assessment of a variety of vascular diseases.

[0129] Alternative solutions to the present invention also include improvements in the collection and input methods of different physiological parameters (such as blood pressure, heart rate, blood flow, etc.). In addition to current real-time monitoring equipment, wearable devices and remote monitoring technologies can also be introduced to collect and transmit patients' physiological data in real time, further improving the real-time and convenience of the system.

[0130] Furthermore, if Figure 6As shown, based on the above-mentioned liver transplantation perioperative myocardial ischemia risk assessment method, the present invention also provides a liver transplantation perioperative myocardial ischemia risk assessment system, wherein the liver transplantation perioperative myocardial ischemia risk assessment system includes:

[0131] A three-dimensional reconstruction module 51 is used to obtain coronary artery image data of a liver transplant patient, perform three-dimensional reconstruction based on the coronary artery image data, and generate a personalized coronary artery geometric model;

[0132] a numerical simulation module 52 for numerically simulating the flow of blood in the coronary arteries using a computational fluid dynamics method based on the coronary artery geometric model, obtaining the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculating the pressure ratio before and after coronary artery stenosis;

[0133] The risk assessment module 53 is used to assess the coronary ischemia situation according to the pressure ratio, and generate a blood flow reserve fraction value and a myocardial ischemia risk assessment report.

[0134] Furthermore, if Figure 7 As shown, based on the above-mentioned method and system for assessing the risk of myocardial ischemia during perioperative liver transplantation, the present invention also provides a terminal, which includes a processor 10, a memory 20 and a display 30. Figure 7 Only some of the components of the terminal are shown, but it should be understood that implementation of all of the shown components is not required, and more or fewer components may be implemented instead.

[0135] In some embodiments, the memory 20 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. In other embodiments, the memory 20 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the terminal. Furthermore, the memory 20 may also include both an internal storage unit of the terminal and an external storage device. The memory 20 is used to store application software and various types of data installed on the terminal, such as the program code of the installation terminal. The memory 20 may also be used to temporarily store data that has been output or is to be output. In one embodiment, a liver transplantation perioperative myocardial ischemia risk assessment program 40 is stored on the memory 20, and the liver transplantation perioperative myocardial ischemia risk assessment program 40 can be executed by the processor 10, thereby realizing the liver transplantation perioperative myocardial ischemia risk assessment method in this application.

[0136] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor, or other data processing chip, configured to execute program codes or process data stored in the memory 20, such as executing the method for assessing the risk of perioperative myocardial ischemia during liver transplantation.

[0137] In some embodiments, the display 30 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. The display 30 is used to display information on the terminal and to display a visual user interface. The components 10-30 of the terminal communicate with each other via a system bus.

[0138] In one embodiment, when the processor 10 executes the liver transplantation perioperative myocardial ischemia risk assessment program 40 in the memory 20 , the steps of the liver transplantation perioperative myocardial ischemia risk assessment method described above are implemented.

[0139] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a liver transplant perioperative myocardial ischemia risk assessment program, and when the liver transplant perioperative myocardial ischemia risk assessment program is executed by a processor, the steps of the liver transplant perioperative myocardial ischemia risk assessment method as described above are implemented.

[0140] In summary, the present invention provides a method, system, terminal, and storage medium for assessing the risk of myocardial ischemia during the perioperative period of liver transplantation. The method comprises: obtaining coronary artery imaging data of a liver transplant patient, performing three-dimensional reconstruction based on the coronary artery imaging data, and generating a personalized coronary artery geometric model; based on the coronary artery geometric model, using computational fluid dynamics methods to numerically simulate the flow of blood in the coronary arteries, obtaining the velocity and pressure distribution of coronary blood flow through the numerical simulation, and calculating the pressure ratio before and after coronary artery stenosis; based on the pressure ratio, assessing coronary ischemia and generating a blood flow reserve fraction value and a myocardial ischemia risk assessment report. The present invention simulates coronary artery blood flow under different physiological conditions and calculates the coronary blood flow reserve fraction value, thereby comprehensively assessing the risk of myocardial ischemia that a patient may face during surgery. The present invention aims to quickly and accurately assess a patient's risk of perioperative myocardial ischemia through non-invasive means, providing intraoperative decision support for clinicians.

[0141] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or terminal comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or terminal comprising the element.

[0142] Of course, those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing related hardware (such as a processor, controller, etc.) through a computer program. The program can be stored in a computer-readable storage medium that can be read by a computer. When the program is executed, it can include the processes in the above-described method embodiments. The computer-readable storage medium can be a memory, a magnetic disk, an optical disk, etc.

[0143] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for assessing the risk of myocardial ischemia during perioperative liver transplantation, characterized in that: The method for assessing the risk of myocardial ischemia during perioperative liver transplantation includes: Acquiring coronary artery imaging data of a liver transplant patient, performing three-dimensional reconstruction based on the coronary artery imaging data, and generating a personalized coronary artery geometric model; Based on the coronary artery geometric model, a computational fluid dynamics method is used to perform a numerical simulation of the blood flow in the coronary artery, obtain the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculate the pressure ratio before and after coronary artery stenosis; Based on the pressure ratio, the coronary ischemia situation is assessed, and a blood flow reserve fraction value and a myocardial ischemia risk assessment report are generated.

2. The method for assessing the risk of perioperative myocardial ischemia during liver transplantation according to claim 1, characterized in that: The obtaining of coronary artery image data of a liver transplant patient, performing three-dimensional reconstruction based on the coronary artery image data, and generating a personalized coronary artery geometric model specifically includes: Use high-resolution coronary CT angiography to obtain coronary artery imaging data of liver transplant patients; The coronary artery image data is segmented by image processing software to extract the geometric structure of the coronary artery. After segmentation, a three-dimensional reconstruction algorithm is used to construct a patient-specific coronary artery geometric model.

3. The method for assessing the risk of perioperative myocardial ischemia during liver transplantation according to claim 1 or 2, characterized in that: The coronary artery geometric model is used to describe the morphological structure of the blood vessel, including the geometric features of the stenosis site.

4. The method for assessing the risk of perioperative myocardial ischemia during liver transplantation according to claim 1, wherein: The method of numerically simulating the flow of blood in the coronary artery using a computational fluid dynamics method based on the coronary artery geometric model, obtaining the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculating the pressure ratio before and after coronary artery stenosis specifically includes: During the simulation process, the patient's personalized physiological parameters are combined to define boundary conditions and dynamically simulate the blood flow velocity and pressure distribution; Solving the Navier-Stokes equations, which are used to describe the flow behavior of fluids within blood vessels, discretizes the Navier-Stokes equations using the finite element method or the finite volume method, divides the continuous blood flow domain into discrete grid cells, and performs numerical calculations on each grid cell to obtain the velocity distribution and pressure distribution of blood in the geometric structure of the blood vessel, as well as the flow of blood in different branching vessels; The pressure ratio FFR before and after coronary artery stenosis is calculated based on the pressure difference obtained by solving the equation. The pressure ratio is used to evaluate the function of coronary artery stenosis and quantify the impact of coronary artery stenosis on myocardial blood supply.

5. The method for assessing the risk of perioperative myocardial ischemia during liver transplantation according to claim 4, characterized in that: The calculation formula of the pressure ratio FFR is: FFR=P d / P a ; Among them, P d Indicates the pressure distal to the coronary artery stenosis, P a Indicates the pressure proximal to the coronary artery stenosis; P d and P a The three-dimensional unsteady incompressible Navier-Stokes equation is used to describe the control equation of coronary blood flow by solving the hemodynamic control equation: Where u represents the blood flow velocity, is the Cauchy stress tensor, p is the pressure, μ is the blood viscosity coefficient, I is the 3×3 unit matrix, t is the time, is the gradient operator, and Ω is the computational domain consisting of the 3D geometry of the blood vessel and the inlet and outlet boundaries.

6. The method for assessing the risk of perioperative myocardial ischemia during liver transplantation according to claim 5, characterized in that: When constructing the computational domain, the blood vessel is truncated and artificial boundary conditions are given on the truncation surface. Under the assumption of a rigid blood vessel wall, the boundary condition of ГW at the blood vessel wall is: u=0 on Γ W ; According to the average blood flow velocity in the aorta during one cardiac cycle provided by cardiovascular ultrasound and combined with the recommended cardiovascular blood waveform, an instantaneous velocity g is obtained and applied to the inlet boundary ΓI: u=g on Γ I ; The vascular elasticity is imposed on the coronary outlet boundary ΓO using the aortic elastic reservoir effect model. At time t, the time-varying blood pressure p at the kth arterial outlet is k (t): Among them, R k Represents resistance, Q k represents the volume flow rate through the kth outlet, C k Capacitance used to characterize arterial deformation, p k (0) and They represent the blood pressure at the kth arterial outlet and the downstream distal pressure at the initial moment, represents the distal pressure downstream of the kth arterial outlet at time t, s represents the integral variable from time 0 to time t, τ k =R k C k ; R k and C k Calculated by the rules of parallel circuits and the area of ​​the corresponding outlets: Among them, d k and Represent the diameter and area of ​​the kth artery outlet, n represents the number of kth artery outlets, R total and C total Represent the total resistance and capacitance of all arterial outlets, R total =αP b / Q c , where P b represents the mean brachial pressure, α represents the empirical constant, and Qc represents the flow rate in the coronary artery; Q k The calculation formula is: Among them, Γ O k represents the kth outlet section, u(t) is the velocity vector at time t, and dΓ is the boundary Γ O k The small area element on indicates that the integration is performed over the entire outlet cross section.

7. The method for assessing the risk of perioperative myocardial ischemia during liver transplantation according to claim 1, characterized in that: The coronary ischemia condition is assessed based on the pressure ratio, and a blood flow reserve fraction value and a myocardial ischemia risk assessment report are generated, specifically including: Points were taken from the patient's three coronary arteries, and the blood flow reserve fraction was calculated based on the different physiological conditions of blood pressure and heart rate in perioperative liver transplant patients; The coronary ischemia situation is assessed based on the calculation results, and the blood flow reserve fraction value is output and a myocardial ischemia risk assessment report is generated.

8. A liver transplant perioperative myocardial ischemia risk assessment system, characterized in that: The liver transplantation perioperative myocardial ischemia risk assessment system includes: a three-dimensional reconstruction module, configured to obtain coronary artery imaging data of a liver transplant patient, perform three-dimensional reconstruction based on the coronary artery imaging data, and generate a personalized coronary artery geometric model; a numerical simulation module for numerically simulating the flow of blood in the coronary arteries using a computational fluid dynamics method based on the coronary artery geometric model, obtaining the velocity and pressure distribution of the coronary artery blood flow through the numerical simulation, and calculating the pressure ratio before and after coronary artery stenosis; The risk assessment module is used to assess the coronary ischemia situation according to the pressure ratio and generate a blood flow reserve fraction value and a myocardial ischemia risk assessment report.

9. A terminal, characterized in that: The terminal includes: a memory, a processor, and a liver transplant perioperative myocardial ischemia risk assessment program stored in the memory and executable on the processor. When the liver transplant perioperative myocardial ischemia risk assessment program is executed by the processor, the steps of the liver transplant perioperative myocardial ischemia risk assessment method as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a liver transplant perioperative myocardial ischemia risk assessment program, and when the liver transplant perioperative myocardial ischemia risk assessment program is executed by a processor, the steps of the liver transplant perioperative myocardial ischemia risk assessment method as described in any one of claims 1 to 7 are implemented.

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