To perform cardiac surgery in patients with mitral valve insufficiency, it is necessary to create optimal conditions for maintaining the stability of blood circulation, which, in particular, includes the maintenance of myocardial contractility. Despite the constant improvement of anesthesia and intensive care methods, which ensured low hospital mortality rates (0.4%-2.4%), the incidence of complications during cardiac surgery in patients with mitral heart disease remains significant. Intraoperative methods of myocardial protection and intraoperative methods of visualization of myocardi contractility have the greatest influence on the latter indicator. The purpose of our work was to study the initial state of intracardiac and central hemodynamics in patients with mitral valve insufficiency admitted for surgical correction. Material and methods. We examined 85 patients with mitral valve insufficiency at the age of 56.2 ± 4.5, who were admitted to the Heart Institute for surgical correction of the defect. All patients at the time of admission were divided using simple fixed randomization into 2 groups. All patients underwent an operation of mitral valve prosthetics and anesthetic management according to the traditional method, the difference was only in the cardioprotection method. Patients of the 1st group (n = 40) received therapy and surgery (mitral valve prosthetics) in accordance with the local intraoperative cardioprotection protocol, patients of the 2nd group (n = 45) received therapy and surgery (mitral valve prosthetics), where the local protocol of myocardial protection was implemented by applying electrical cardiac fibrillation and intermittent aortic clamping. We recorded the end-systolic, end-diastolic and stroke indices of the left ventricle, left ventricular ejection fraction, cardiac index, systolic pressure in the pulmonary artery and global longitudinal myocardial strain. Results and discussion. The results are explained by the presence of mitral valve insufficiency in the examined patients and the effect of this pathology on intracardiac hemodynamics. Global longitudinal myocardial strain in all examined patients was significantly lower in modulus than normal values. In 26 (65.0 ± 7.5%) patients of group 1 and in 30 (66.7 ± 7.5%) patients of group 2 the end-diastolic index exceeded 75 ml / m2, although there was no association of this indicator with global longitudinal myocardial strain. The end-systolic index > 35 ml / m2 was observed in 25 (62.5 ± 7.7%) patients in group 1 and in 26 (57.8 ± 7.8%) patients in group 2. This can be explained by a weak degree with global longitudinal myocardial strain. 17 (42.5 ± 7.8%) patients in group 1 and 23 (51.1 ± 7.5%) patients in group 2 had a stroke index <40 ml / m2; and ejection fraction <50% was observed in 13 (32.5 ± 7.4%) patients of group 1 and in 12 (26.7 ± 6.6%) of group 2. This indicator was associated with moderate-strength global longitudinal myocardial strain. All patients had cardiac index not less than 2.5 l / min ∙ m2 due to compensation with the help of heart rate, the degree of its connection with global longitudinal myocardial strain was weak. Systolic pressure in the pulmonary artery in all patients exceeded 30 mm Hg Art and closely correlated with ejection fraction, to a lesser extent it was with global longitudinal myocardial strain. Thus, the state of the intracardiac and central hemodynamics of the examined patients was due to the main pathology - mitral valve insufficiency. To the greatest extent, this pathology was reflected in such hemodynamic parameters as global longitudinal myocardial strain, systolic pressure in the pulmonary artery, ejection fraction, and stroke index, while the cardiac index level was compensated by the heart rate increase. Conclusions. The study showed that the insufficiency of the mitral valve in patients admitted for its surgical correction caused a number of significant shifts in intracardiac hemodynamics, the severity of which could be assessed by the degree of decrease in the modulus of global myocardial longitudinal strain. The greatest decrease in the modulus of global longitudinal myocardial strain affects the decrease in the left ventricular ejection fraction and the increase in systolic pressure in the pulmonary artery. Violations of intracardiac hemodynamics with mitral valve insufficiency are compensated primarily by increasing the heart rate, so that the central hemodynamics remains compensated.
Keywords: intracardiac and central hemodynamics, mitral valve insufficiency, global longitudinal myocardial strain
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