RU-2861528-C1 - METHOD FOR DETERMINING DEGREE OF CORONARY ARTERY STENOSIS

RU2861528C1RU 2861528 C1RU2861528 C1RU 2861528C1RU-2861528-C1

Abstract

FIELD: medicine. SUBSTANCE: invention relates to cardiology and interventional radiology, and can be used for assessing coronary artery (CA) stenoses using intravascular imaging. After performing selective angiography and selecting the target lesion, an OCT study is performed. Based on the obtained data, the reference volume of the target lesion is calculated using the truncated cone volume formula, using the areas along the external elastic membrane at the proximal and distal boundaries of the lesion, as well as its length. Then the sequence of cross-sections of the lesion is divided into segments of 5 mm length each, the lumen volume of each segment is calculated as the product of the minimum lumen area in the segment and its length, and they are summed to obtain the total lumen volume. The degree of stenosis is determined as the percentage ratio of the difference between the reference volume and the lumen volume to the reference volume. EFFECT: increased accuracy and objectivity of assessing the severity of coronary bed lesions due to volumetric analysis of stenosis, considering the anatomical features of the vessel and the length of the lesion, which makes it possible to optimise the tactics of subsequent surgical treatment and reduce the risk of adverse cardiovascular events after percutaneous coronary intervention. 1 cl, 2 dwg, 2 ex

Inventors

SUSLOV IVAN VLADIMIROVICH
Pekarskii Stanislav Evgenevich
Baev Andrei Evgenevich
Tarasov Mikhail Georgievich
Gergert Egor Sergeevich
Bogdanov Iurii Igorevich
Gorokhovskii Aleksei Aleksandrovich
Falkovskaia Alla Iurevna
Khunkhinova Simzhit Andreevna

Dates

Publication Date: 20260505
Application Date: 20250820

Claims (20)

A method for determining the degree of coronary artery (CA) stenosis, including performing selective coronary angiography, selecting a target lesion of the CA, conducting optical coherence tomography (OCT) of the target lesion of the CA with the determination of the boundaries of the target lesion of the CA, characterized in that, based on OCT data, the reference volume of the target lesion of the CA is determined using the formula for the volume of a truncated cone:
V ref = 1/3*L*(S prox +√(S prox *S dist )+S dist ), where
V ref - reference volume of the target lesion of the coronary artery;
S prox - area of the CA along the external elastic membrane at the level of the proximal border of the target lesion;
S dist - area of the CA along the external elastic membrane at the level of the distal border of the target lesion;
L - length of target lesion of the spacecraft;
then the sequence of cross-sectional images of the target lesion of the coronary artery is divided into segments of 5 mm length, and the lumen volume of each segment is calculated using the formula for calculating the volume of a cylinder:
V i = S i * l i , where
V is the volume of the lumen of the segment;
S is the minimum clearance area of the spacecraft in a given segment;
l is the length of the segment;
i is the number of the segment along the target lesion of the spacecraft in the order of measurement (i=1, 2, …, n);
The obtained values of the lumen volumes of the segments are summed up, and the lumen volume of the target lesion of the coronary artery is calculated:
V pr = ∑V i , where
V pr - volume of the lumen of the target lesion of the coronary artery;
V i is the volume of the lumen of the segment;
i is the number of the segment along the target lesion of the spacecraft in the order of measurement (i=1, 2, …, n);
Next, the volume of stenosis of the target lesion of the coronary artery is determined:
V st = V ref -V pr , where
V st - the volume of stenosis of the target lesion of the coronary artery;

Description

Coronary artery disease (CAD) remains the leading cause of death in adults in the Russian Federation. Myocardial revascularization is the primary treatment for this condition. Percutaneous coronary interventions (PCI) have rightfully become the leading method for treating CAD due to their high efficacy and low invasiveness [1]. The criterion for PCI is an anatomical assessment of the degree of coronary artery (CA) stenosis. According to current clinical guidelines, this is an angiographically detected narrowing of the lumen ≥ 50% [2,3]. However, the accuracy of angiographic measurement of stenosis based on the degree of reduction in the lumen diameter of the CA is limited due to the one-dimensional, planar image, which is critically dependent on the angiographic projection, and the relatively low resolution of the method. The introduction of intravascular imaging (IVI) techniques, such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT), has significantly improved the accuracy of anatomical assessment of stenosis significance. Analysis of coronary artery cross-sectional images allows for the asymmetry of lumen narrowing to be taken into account and the degree of stenosis to be calculated based on the actual lumen area. Furthermore, IVI techniques provide ordered series of arterial cross-sectional images, allowing for the consideration of not only the degree of maximum coronary lumen narrowing in a single cross-sectional image but also the assessment of the extent and geometry of the narrowing along its length, i.e., the change in the coronary lumen profile along the stenosis. This allows for the identification of stenoses that, despite a relatively small degree of maximum narrowing, are hemodynamically significant due to their long length, since, according to the laws of hydrodynamics, the resistance to blood flow depends not only on the diameter but also on the length of the narrowed segment. According to Poiseuille's law, traditionally used in computational hemodynamics, volumetric blood flow Q = ΔP/(8ηL/πr 4 ), where ΔP is the arteriovenous pressure difference, and 8ηL/πr 4 is the stenosis resistance, proportional to viscosity (η), stenosis length (L), and inversely proportional to the stenosis radius to the fourth power (r 4 ). For example, a 40% stenosis 35 mm long imposes no less resistance to blood flow than a 60% stenosis 5 mm long. However, existing stenosis assessment algorithms developed for modern VSV systems do not provide the ability to calculate volumetric indicators. A known method for assessing the degree of stenosis based on the results of coronary angiography (CAG) is the ratio of the lumen diameter of the coronary artery at the site of greatest narrowing to the diameter of the reference segment of the coronary artery, expressed as a percentage. The disadvantage of this method is that it is not always possible to obtain a clear idea of the significance of stenosis from CAG for a number of reasons: plaque eccentricity (occurs in 73% of cases); diffuse nature of atherosclerotic lesions with the involvement of reference (visually unaffected) areas of the coronary artery, which underestimates the degree of stenosis [4,5]. A known method for assessing the degree of coronary artery stenosis based on the lumen area measured using IVUS. Studies have shown that the cutoff value for the lumen area of the main epicardial arteries measured by IVUS is 4 mm 2 [6]. A decrease in the lumen area < 4 mm 2 leads to deterioration of myocardial perfusion in the territory of the affected coronary artery and a decrease in coronary reserve. In this case, only the maximum narrowing of the coronary artery is assessed, without taking into account its length, i.e., a local stenosis with a minimum lumen area < 4 mm 2 is considered significant, and an extended stenosis with a lumen area > 4 mm 2 is considered insignificant. The disadvantages of this method include the technical limitations of IVUS, which do not allow visualization of the intimal layer of the arterial wall and thrombi in the coronary lumen, which are often found at the site of stenosis, which overestimates the lumen area and underestimates the degree of arterial narrowing. There is a known method for assessing the degree of coronary artery stenosis based on the lumen area measured using OCT; a narrowing of coronary artery > 75%, or from 50% to 75% with a minimum lumen area <2.5 mm2 is considered significant [7]. This method is the closest to the declared one in terms of technical essence and the achieved result and was chosen as a prototype. A drawback of the prototype method is that local assessment of coronary artery stenosis, whether unidimensional by diameter or two-dimensional by area, significantly underestimates the significance of long, irregular lesions with a relatively low degree of maximal narrowing. This means that for a given degree of coronary lumen narrowing, its hemodynamic effect will vary significantly with diff