Activity of the right cardiac ventricle and metabolism in healthy persons during an orthostatic test after short term immobilization

A 15 minute orthostatic test was performed on healthy male volunteers under conditions of catheterization of the right ventricle of the heart and the radial (or brachial) artery before and after 5 day bedrest in an antiorthostatic position of the body (with the foot of the bed raised 4.5 degrees). The change to a vertical position after immobilization was attended by a more marked increase in the rate of cardiac contractions, an increase of max dp/dt pressure in the right ventricle, and a decrease of cardiac and stroke indices. The decrease of the cardiac index was compensated for, to a certain measure, by a further increase in the extraction and utilization of O2 by the tissues. The arterial blood pH did not change essentially, while the decrease in pCO2 and content of standard bicarbonate was more marked

СOrOnarY ParadOX

This work is a scientific and educational analytical review intended for practicing cardiologists. The purpose of the review is to draw physicians’ attention to the role of myocardial contractility in the regulation of coronary circulation. We consider the fundamental phenomenon of arterial compression (squeezing) in the left ventricular (LV) wall, creating an obstruction to blood flow during cardiac systole. This phenomenon formally resembles functional coronary artery stenosis. Based on a review of the literature, the positive role of arterial compression in coronary hemodynamics is interpreted. Understanding the mechanical relationship between the contractile and coronary systems in the cardiac wall may be useful for practicing physicians when choosing treatment tactics for patients, optimizing LV bypass during heart surgeries, and improving the efficiency of adaptation of the transplanted heart. © 2022 Russian Transplant Society. All rights reserved

Коронарный парадокс

This work is a scientific and educational analytical review intended for practicing cardiologists. The purpose of the review is to draw physicians’ attention to the role of myocardial contractility in the regulation of coronary circulation. We consider the fundamental phenomenon of arterial compression (squeezing) in the left ventricular (LV) wall, creating an obstruction to blood flow during cardiac systole. This phenomenon formally resembles functional coronary artery stenosis. Based on a review of the literature, the positive role of arterial compression in coronary hemodynamics is interpreted. Understanding the mechanical relationship between the contractile and coronary systems in the cardiac wall may be useful for practicing physicians when choosing treatment tactics for patients, optimizing LV bypass during heart surgeries, and improving the efficiency of adaptation of the transplanted heart.Работа представляет собой научно-образовательный аналитический обзор, предназначенный для практикующих кардиологов. Цель обзора – обратить внимание врачей на роль сократительной функции миокарда в регуляции коронарного кровотока. Рассмотрен фундаментальный феномен компрессии (сдавливания) артерий в стенке левого желудочка, создающий препятствие течению крови в систолическую часть сердечного цикла. Это явление формально напоминает функциональный стеноз коронарных артерий. На основе анализа литературы дано толкование позитивному вкладу компрессии артерий в коронарную гемодинамику. Понимание механических взаимоотношений сократительной и коронарной систем в сердечной стенке может быть полезно практикующим врачам при выборе тактики лечения пациентов, оптимизации левожелудочкового обхода при операциях на сердце, а также повышения эффективности адаптации трансплантированного сердца

Modeling of Local Hematocrit for Blood Flow in Stenotic Coronary Vessels

This mainly theoretical work is devoted to the study of the contribution of the cell-free layer (CFL) near the vessel wall to hemodynamics in a large coronary artery with stenosis to assess the relevance of CFL modeling to the needs of interventional cardiology. An Euler–Euler model considering blood as a two-component fluid with a discrete phase of erythrocytes and a liquid plasma phase was applied to a simple 2d vessel with 65% stenosis. It was found that both the CFL thickness and the local contribution of the CFL thickness to hemodynamics are inhomogeneous along the vessel. The effects of CFL on the velocity profiles, vortex formation, hematocrit, viscosity, and wall shear stresses in the area of stenosis were determined. To demonstrate the significance of CFL modeling for prognostic purposes, the same hemodynamic conditions, analyzed using a one-component model, were also considered. A comparison analysis showed that the existence of CFL resulted in a significant overestimation (up to over 100%) of the main hemodynamic characteristics of the flow obtained using the model based on the Carreau equation. © 2023 by the authors.Russian Science Foundation, RSF: 22-71-10071This study was supported by the Russian Science Foundation (project no. 22-71-10071)

Validity of ejection fraction as a measure of myocardial functional state: impact of asynchrony

Aims The goal of this study was to test whether peculiarities of left ventricular (LV) regional function place limits on the validity of ejection fraction (EF) as a measure of the myocardial functional state. Methods and results Transthoracic and transoesophageal data from patients with a variety of cardiac conditions were used for analysis of LV regional function. The focus was on the effects of mechanical asynchrony. Ejection fraction was calculated on the basis of LV end-diastolic volume and end-systolic volume obtained by two different ways: (i) end-systolic volume as a whole; and (ii) the sum of all regional end-systolic volumes (which may occur at different times). The relative difference, D-EF, between EFs obtained by (i) and (ii) was taken as the ‘merit ’ of EF. A value of zero is the highest merit. Irrespective of the examination method, we found that D-EF was always higher than zero, and that its value depended on the extent of mechanical asynchrony. Conclusions Ejection fraction is not the arithmetic average of regional EFs. An increase of asynchrony increases D-EF, i.e. it reduces the merit of EF as a measure of cardiac function

РЕЗУЛЬТАТЫ ГИБРИДНОГО МЕТОДА ЛЕЧЕНИЯ СОЧЕТАННОЙ ПАТОЛОГИИ (ПОРОКИ СЕРДЦА И ИБС) У БОЛЬНЫХ С ВЫСОКИМ УРОВНЕМ ОПЕРАЦИОННОГО РИСКА

The analysis of results of hybrid treatment of complex combined coronary and valve disease at patients with high level of operational risk between January 2005 and December 2010. The hybrid treatment of complex combined coronary and valve disease, provides performance of percutaneous coronary interventions (PCI) in a combinati- on valve surgery. 118 patients, with a median age 64.4 ± 8.9 years, are included in research. 2 approaches of a hy- brid method of treatment – 2-Staged (n = 86) and a method «1-stop» (n = 32) are applied. The оperative mortality has made 4.2%. On the basis of the received results were the conclusion is drawn that at high-risk patients with complex combined coronary and valve disease the hybrid method of treatment allows to lower risk of operation. Представлен анализ результатов гибридного лечения сочетанной патологии (ИБС и пороки сердца) у больных с высоким уровнем операционного риска за период с января 2005 г. по декабрь 2010 г. Гибридный метод лечения сочетанной патологии предусматривает выполнение баллонной ангиопластики (БАП) коронарных артерий в сочетании с протезированием клапанов сердца. В исследование включены 118 пациентов, средний возраст которых – 64,4 ± 8,9 года. Применено 2 подхода гибридного метода лечения – 2-этапный (n = 86) и метод «1-stop» (n = 32). Госпитальная летальность составила 4,2%. На основании полученных результатов был сделан вывод, что у тяжелых больных с сочетанной коронарной и клапанной патологией гибридный метод лечения позволяет снизить риск операции.

DONOR-TRANSMITTED CORONARY ATHEROSCLEROSIS

Aim. To estimate opportunities, prospects and safety of using heart transplants from aged donors who are at high risk of coronary atherosclerosis.Materials and methods. Over the period from March 1987 to May 2014450 heart transplantations (HTx) were performed in V.I.Shumakov Federal Research Center of Transplantology and Artifi cial Organs. During the fi rst month after HTx coronarography was made to 152 (37,8%) recipients inorder to exclude/confi rm donor-transmitted coronary atherosclerosis (DTCA) and to identify tactics of treatment. Coronary atherosclerosis was detected among 16 patients (3,6% of total number of HTx), 15 (93,8%) men and 1 (6,2%) women. Mean age of recipients with DTCA at the moment of HTx was 48,3 ± 13,1 years.Results. Hemodynamically relevant coronary atherosclerosis was not detected and percutaneous coronary intervention (PCI) was not made in the group of patients with the mean age of 42,24 ± 8,91 years. Using heart transplants from aged donors is connected with increasing risk of DTCA among the recipients. DTCA-dependent PCI is not connected with coronary mortality. Actuarial survival rate of patients who underwent PCI is comparable with the same one in the total population of HTx recipients and is equal to 87,5% at 5 years and less.Conclusion. Hearts from aged donors (older than 50 years) may be used for HTx with suffi cient level of safety. Due to high level of DTCA using of hearts from such donors is preferable for completing urgent HTx to recipients 1А–В UNOS

Cell cycle-dependent acetylation of Rb2/p130 in NIH3T3 cells

The retinoblastoma protein (pRb) and the pRb-related proteins, p130 and p107, form the ‘pocket protein' family of cell cycle regulatory factors. A well characterized function of these proteins is the cell cycle-dependent regulation of E2F-responsive genes. The biological activity of pocket proteins is regulated by phosphorylation and for the founding member pRb it has been shown that acetylation also has an important role in modulating its function during the cell cycle. Here, we show that hyperphosphorylated retinoblastoma 2 (Rb2)/p130 also exists in an acetylated form in NIH3T3 cells. Acetylated p130 is present in the nucleus but not in the cytoplasm. Acetylation is cell cycle dependent, starting in S-phase and persisting until late G2-period. Using recombinant p130 and truncated forms for in vitro acetylation by the acetyltransferase p300, we could identify K1079 in the C-terminal part as the major acetylation site by mass spectrometry. Minor acetylation sites were pinpointed to K1068 and K1111 in the C-terminus, and K128 and K130 in the N-terminus. The human papilloma virus 16 protein-E7 preferentially binds to acetylated p130 and significantly increases in vitro p130 acetylation by p300