RU2642748C1 - Method for non-invasive pressure determination in lower cavopulmonary link in children with functionally single ventricle after total cavopulmonary link surgery - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: peak linear speed of blood flow in the hepatic vein is determined in pulse-wave mode on exhalation (HV1) and inhalation (HV2), at a distance of 3-5 cm from hepatic vein confluence into the lower hollow vein. To do this, an ultrasonic system with a convex sensor is used, the control volume of which is 1/3 of the diameter of the middle hepatic vein, and the pressure value in the lower cavopulmonary link is determined by the original formula.

EFFECT: method allows non-invasive monitoring of the pressure index in the lower cavopulmonary link in dynamics without additional preparation.

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Description

The invention relates to medicine and can be used in cardiology and cardiac surgery for non-invasive determination of pressure in the lower cavopulmonary joint in children with functionally single ventricle of the heart after the operation of total cavopulmonary joint (TCPS).

Congenital heart defects account for 0.8% of the total number of newborns [1]. A separate category of study are heart defects with a functionally single ventricle (PEF). Performing radical, bifacial correction in this category of patients is impossible, optimal results are ensured by the use of stepwise hemodynamic correction. The first stage - with increased pulmonary blood flow - narrowing of the pulmonary artery or with decreased pulmonary blood flow - application of a systemic-pulmonary anastomosis (modified Blok-Taussig shunt (MBTS)). The second stage is the application of a bidirectional cavopulmonary anastomosis (DKPA). The third stage is the operation of total cavopulmonary anastomosis (TKPS) in the extracardiac conduit variant with fenestration, followed by the closure of the latter 6-12 months after TKPS surgery.

Since its first description in 1971 (Fontan and Baudet), the Fonten classical procedure has undergone a number of modifications, the purpose of which was to reduce the risk of postoperative complications and mortality rates [4]. The purpose of this operation was to create a circulatory model in which systemic venous return was directed to the pulmonary blood circulation system, bypassing the right ventricle.

Systemic and pulmonary blood flows in this circulation do not interact with each other, but exist in parallel to each other. The advantages of this circulation were the normalization of arterial saturation, as well as the elimination of chronic volume overload. However, the drawback of this circulation is the progressive increase in pulmonary vascular resistance, compensatory chronic hypertension in the system of the inferior vena cava and a decrease in the filling of the systemic ventricle, due to the absence of the right ("pulmonary") ventricle, which helps to reduce stroke volume and minute volume of blood circulation. Cardiac output in such a circulation is no longer determined by contraction of the left ventricle, but by transpulmonary flow. Venous congestion and decreased perfusion are a hallmark of such circulation.

The return of blood from the periphery to the heart is carried out through the veins. Normally, the blood flow in the venules and terminal veins is constant, in larger veins there are small fluctuations in pressure and blood flow velocity due to the transmission of pulsations from adjacent arteries. Fluctuations in the velocity of blood flow in the large main veins are associated with breathing and contractions of the heart, these fluctuations increase as we approach the right atrium [3].

Normally, a negative pressure in the pleural cavity during inspiration creates a pressure gradient between the right atrium and the inferior vena cava, due to which blood flows from it into the right atrium, and the vein itself drops. By the diameter of the inferior vena cava and its response to inspiration, one can determine the pressure in the right atrium and, accordingly, characterize the pressure in the inferior vena cava.

The main way to determine the pressure in the TKPS conduit is direct manometry under x-ray conditions against the background of intravenous sedation with propofol and systemic heparinization, or in the early postoperative period in the intensive care unit. However, this method has several disadvantages: the invasiveness of the procedure, a high risk of complications, the difficulty of assessing in dynamics.

Taking into account the fact that during the FEZhS hemodynamics after the operation of total cavopulmonary junction there is no communication between the inferior vena cava and the atrium, an ultrasound examination of the degree of collapse of the inferior vena cava cannot give an exact pressure value in the inferior cavopulmonary joint, it is only possible to determine its approximate value. Accordingly, at present, it is necessary to use other methods for assessing pressure in the lower cavopulmonary joint in patients with FEZhS.

Using ultrasound diagnostics from subcostal access, in addition to examining the inferior vena cava, it is also possible to evaluate the hepatic veins. The latter begin in the zone of the hepatic lobule as the central veins, then pass into the collective veins, from which large veins of the liver flow into the inferior vena cava. The increase in pressure in the inferior vena cava is directly transmitted to the hepatic veins, given the lack of valves in the hepatic veins.

Spectral Doppler mode is a mode that allows you to judge the distribution of the flow in the vessel in real time, the analysis of which can be used to calculate various velocity and spectral parameters of blood flow, as well as a number of indices that are important in assessing the degree and nature of hemodynamic disorders. The shape of the Doppler wave depends on the proximity of the investigated venous group to the heart [2].

Normally, the spectrum of blood flow in the hepatic veins, as well as in the pulmonary, three- or four-phase, is represented by waves of antegrade systolic (S), diastolic (D) and retrograde (AR) blood flow to the atrial systole. The amplitude of the waves in the hepatic veins during TKPS circulation depends on the phases of respiration. Normally, on inspiration, blood flow through the veins decreases, while on exhalation it increases.

An adequate prototype was not found in the analyzed patent and medical literature.

The objective of the invention is to provide a method for non-invasively determining the pressure in the lower cavopulmonary joint in children with a functionally single ventricle of the heart after the operation of total cavopulmonary joint.

The problem is solved by the use of a pulsed wave doppler with registration of the displacement curve of the Doppler frequency spectrum. The study is carried out in a supine position with slightly bent legs at the knees, for maximum relaxation of the anterior abdominal wall. The recording sensor, with a contact hypoallergenic gel applied to it, is located slightly to the right of the white line of the abdomen, while the study is carried out starting from the proximal sections, displacing the sensor in the distal direction to the umbilical region. The control volume takes 1/3 of the diameter of the middle hepatic vein, at a distance of 3-5 cm from its flow into the inferior vena cava, while achieving the minimum angle between the blood flow in the hepatic veins and the angle of insonation. A study is made of the blood flow velocity in the hepatic vein, and the measurement of the peak linear blood flow velocity on expiration (HV1) and on inspiration (HV2). Using the linear regression equation, the pressure value in the lower cavopulmonary compound (FP) was presented as the following formula:

FP = 5.408 + 0.25128 × ([HV1] - [HV2]),

where FP is the pressure in the lower cavopulmonary connection, mm Hg;

HV1 - peak linear blood flow velocity in the hepatic vein on exhalation, cm / s;

HV2 - peak linear blood flow velocity in the hepatic vein on inspiration, cm / s.

The technical result of the method proposed as an invention is that it is non-invasive, does not require additional preparation, the entire study takes no more than 5 minutes, and also provides control of the pressure in the lower cavopulmonary joint in dynamics.

Distinctive features showed in the inventive combination of new properties that are not explicitly derived from the prior art in this field and are not obvious to a specialist.

An identical set of features was not found in the patent and medical literature.

Proposed as an invention, the method can be applied in medical practice to improve the quality of treatment.

Based on the foregoing, the proposed invention should be considered relevant to the eligibility conditions of "Novelty", "Inventive step", "Industrial applicability".

The method is as follows:

The method is performed on an IE-33 X-Matrix ultrasound system (Philips) using a C5-1 convex sensor. However, the method can be performed on any ultrasound system using a convex sensor.

To visualize the inferior vena cava, a convex sensor with a frequency of 3.5-5 MHz is used, the study is carried out in the supine position with slightly bent legs at the knees, for maximum relaxation of the anterior abdominal wall. A recording sensor with a contact hypoallergenic gel applied to it is located slightly to the right of the white line of the abdomen, while the study is carried out starting from the proximal sections, moving the sensor in the distal direction to the umbilical region.

The pressure measurement in the lower cavopulmonary connection is carried out in a pulse-wave mode with the registration of the displacement curve of the Doppler frequency spectrum. A study is made of the blood flow velocity in the hepatic vein, the measurement of the peak linear blood flow velocity on the exhale and on the inspiration. The control volume takes 1/3 of the diameter of the middle hepatic vein, at a distance of 3-5 cm from its flow into the inferior vena cava, while achieving the minimum angle between the blood flow in the hepatic veins and the angle of insonation.

Using the linear regression equation, the pressure in the lower cavopulmonary joint is determined by the formula:

FP = 5.408 + 0.25128 × ([HV1] - [HV2]),

where FP is the pressure in the lower cavopulmonary connection, mm Hg;

HV1 - peak linear blood flow velocity in the hepatic vein on exhalation, cm / s;

HV2 - peak linear blood flow velocity in the hepatic vein on inspiration, cm / s.

All the necessary information about the patient (age, gender, height and weight) was entered into the database. Saving the obtained data was carried out in the DICOM program, which makes it possible to evaluate the pressure indicator in the conduit of TSCC for each patient in dynamics.

Clinical example 1. Patient S., 3 years. Diagnosis: Congenital heart disease (functionally the only ventricle). Hypoplasia syndrome of the left heart (atresia of the mitral and aortic valves). The operation of a bidirectional cavopulmonary joint from 08/29/2013 The operation of total cavopulmonary joint with an extracardial conduit with fenestration from 04/19/2016. NK I. FC II (Ross). The child was admitted to the department 6 months after the operation of total cavopulmonary joint with fenestration for planned occlusion of the discharge fistula. The patient underwent standard laboratory examinations, echocardiography and cardiac catheterization to determine the main indicators of cardiopulmonary hemodynamics and to decide on the possibility of endovascular occlusion of fenestration. When conducting an echocardiographic examination using a pulse wave Doppler, the blood flow in the hepatic vein was measured. The peak linear velocity of the blood flow in the hepatic vein (cm / s) on exhalation was 28 cm / s, on inspiration - 9 cm / s. Using the above formula, the pressure in the lower cavopulmonary compound was 10.2 mm Hg. (5.408 + 0.25128 × ([28] - [19])). According to cardiac catheterization, the pressure in the hepatic veins was 10/10 (10) mm Hg, the pressure in the lower cavopulmonary joint was 13/9 (11) mm Hg. Thus, the determination of pressure in the lower cavopulmonary joint by ultrasound examination of the peak linear blood flow velocity in the hepatic vein on exhalation and inhalation did not significantly differ from the pressure in the lower cavopulmonary joint measured by direct manometry.

On the basis of examinations of 50 children with FEZhS, a correlation was made between direct manometry and pressure in the TKPS conduit according to echocardiography, and the regression equation was derived. Predictive correlation - 0.75%.

Proposed as an invention, the method was applied in 50 patients. There were no complications when using this method to diagnose changes in the liver.

The application of the proposed method allows to evaluate the pressure in the lower cavopulmonary joint in patients with a functionally single ventricle of the heart after the operation of the total cavopulmonary joint with a reliable probability, without the use of invasive research methods.

Literature

1. Chamaidi A, Gatzoulis MA. Heart disease and pregnancy Hellenic J Cardiol 2006; 47: 275-91.

2. Clinical guidelines for ultrasound diagnostics. / Ed. V.V. Mitkova. IV volume - M .: Vidar, 1997 .-- 388 p. - il.

3. Ultrasound diagnosis in abdominal and vascular surgery./ Ed. G.I. Kuntsevich. - Mn .: Cavalier Publisher, 1999 .-- 256 p .: ill.

4. Shipov O.Yu., Zubarev A.V., Gazhonova V.E., Ivanikov I.O. Modern ultrasound diagnosis of portal vein obstruction. Materials of a scientific and practical conference dedicated to the 400th anniversary of Kremlin medicine. M. - 2000.S. 333-335.

Claims (5)

A non-invasive method for determining the pressure in the lower cavopulmonary joint in children with a functionally single ventricle of the heart after the operation of the total cavopulmonary joint, characterized in that the peak linear blood flow velocity in the hepatic vein is determined in a pulse-wave mode on expiration (HV1) and on inspiration (HV2), at a distance of 3-5 cm from the place where the hepatic vein flows into the inferior vena cava, for which they use an ultrasound system with a convex sensor, the control volume of which is 1/3 of the average diameter th hepatic vein, while the pressure in the lower cavopulmonary joint is determined by the formula: FP = 5.408 + 0.25128 × ([HV1] - [HV2]), where FP - pressure in the lower cavopulmonary joint, mm Hg; HV1 - peak linear blood flow velocity in the hepatic vein on exhalation, cm / s; HV2 - peak linear blood flow velocity in the hepatic vein on inspiration, cm / s.