[Mathematical modeling of high-flow extra-intracranial bypass in the treatment of a complex cerebral aneurysm]. / Matematicheskoe modelirovanie obkhodnogo vysokopotochnogo ekstra-intrakranial'nogo shuntirovaniya pri lechenii slozhnoi tserebral'noi anevrizmy.

BACKGROUND: Intracranial aneurysms (IAs) pose a high risk of spontaneous subarachnoid hemorrhage. In the most complex cases, the only way to exclude the aneurysm from the circulation is to perform a high-flow extracranial-to-intracranial bypass, thus creating a new bloodstream. This avoids severe ischemic complications; however, it requires careful consideration of individual anatomy and hemodynamic parameters. Computational fluid dynamics (CFD) can be of great help in planning such a surgery by creating 3D patient-specific models of cerebral circulation. OBJECTIVE: Assessment of the perspectivity of high-flow extracranial-to-intracranial bypass planning using computational modeling. MATERIAL AND METHODS: In this research work, we have applied the CFD methods to a patient with a giant thrombosed IA of the internal carotid artery (ICA). Preoperative CTA images and Gamma Multivox workstation were used to create a 3D model with current geometry and three additional models: Normal anatomy (no IA), Occlusion (with ligated ICA), Virtual bypass (with bypass and ligated ICA). The postoperative data were also available. Boundary conditions were based on PC-MRI measurements. Calculation of hemodynamics was conducted with a finite element package ANSYS Workbench 19. RESULTS: The results demonstrated an increase in the blood flow on the affected side by more than 70% after the virtual surgery and uniformity of flow distribution between the affected and contralateral sides, indicating that the treatment is likely to be efficient. Later, postoperative data confirmed that. CONCLUSION: The study showed that virtual preoperative CFD modeling could significantly simplify and improve surgical planning.

Evaluation of the Fractional Flow Reserve by Computer Tomography Data: Comparison of the Calculated Parameters with the Results of Invasive Measurements.

Aim      To create a three-dimensional mathematical model of coronary flow in patients with ischemic heart disease based on findings of computed tomography angiography (CTA) with subsequent calculation of the fractional flow reserve (FFRCTA) and comparison of estimated FFRCTA with FFR reference values measured by coronary angiography (CAG).Material and methods  The study included 10 patients with borderline stenosis (50-75 %) as determined by CTA performed with a 640­slice CT-scanner. Based on CTA findings, three-dimensional mathematical models were constructed for further calculation of FFRCTA. Later, an invasive measurement of FFR (FFRINV) was performed for all patients. FFR values <0.8 indicated the hemodynamic significance of stenosis.Results FFRCTA and FFRINV values differed insignificantly in most cases (n=9) and exceeded 5% in only one case. The regression analysis showed a close correlation between estimated and invasively measured FFR values.Conclusion      Preliminary results showed a good consistency of calculated and measured FFR values. Therefore, further development of the method for mathematical modeling of three-dimensional blood flow by CTA findings is promising. Noninvasive evaluation of FFR is particularly relevant for analysis of hemodynamic significance of borderline (50-75 %) coronary stenoses.

[Analysis of local hemodynamics in complex aneurysms: an effect of the vessel arising from the dome or the neck]. / Issledovanie lokal'noi gemodinamiki v slozhnykh anevrizmakh: vliyanie sosuda, otkhodyashchego ot kupola ili sheiki.

BACKGROUND: Assessment of rupture risk for intracranial aneurysms (IA) is a particular challenge in cases of so-called complex aneurysms due to their variable morphometric characteristics. Arterial branch arising from the dome or the neck of IA is one of the least explored features of complex aneurysms. The methods of computational fluid dynamics may be valuable to determine the influence of arterial branches of IA on local hemodynamics. OBJECTIVE: To analyze local hemodynamics in IA with arterial branch arising from the cupola or the neck depending on the structure of the aneurysm and blood flow rate in the parent vessel. MATERIAL AND METHODS: CT angiography data of 4 patients with IA were estimated in this study. Modifications of the baseline 3D models of the aneurysms resulted 12 patient-specific models included into analysis. Hemodynamic calculations were made by using of ANSYS Workbench 19 software package. RESULTS: Wall shear stress (WSS) was characterized by the most significant variability, especially in case of sidewall aneurysms. Small cross-sectional area of additional branch in relation to the neck of IA was not followed by considerable changes of blood flow patterns inside IA after «virtual¼ removal of the vessel. Otherwise, the intensity of flows was drastically reduced. Simulation of high inlet flows demonstrated substantial variation of WSS in the area of jet. CONCLUSION: Additional arterial branch arising from the dome or the neck of IA significantly influences local hemodynamics. This influence depends on the localization of IA in relation to the parent vessel and the diameter of additional arterial branch.

[Echocardiography in the Assessment of Intraventricular Flows and Pressure Gradients in Obstructive Hypertrophic Cardiomyopathy].

Aim      To evaluate results of myomectomy by intraventricular pressure gradients (IVPG) and blood flows in patients with obstructive hypertrophic cardiomyopathy (OHCMP).Material and methods  The study included a total of 76 subjects, 42 patients with OHCMP (mean age, 39±7 years) and 34 healthy volunteers (mean age, 41±3 years). Prior to and after myomectomy, transthoracic echocardiography was performed and followed by digital image processing and calculation of IVPG and left ventricular (LV) vortex flows. Vector analysis was used to estimate the myocardial displacement rate (V), vortex flows, and LV apex-to-base pressure gradients.Results The study showed a dynamic decrease in the LV apex-to-outflow IVPG by more than 50% and recovery of myocardial contraction velocity in the septal area (р<0.001). The decrease in LV cavity pressure gradient serves as an index for evaluating the effectiveness of OHCMP correction. Myomectomy reduces the load on the myocardium and abolishes mitral valve regurgitation with improvement of LV blood flows as also evidenced by the dynamics of long axis velocity change during the cardiac cycle (dL / dt) and the myocardial contraction velocity (V).Conclusion      Effectiveness of the surgical correction of OHCMP is based on the dynamics of myocardial contraction velocities, vortex blood flows, and a decrease in LV apex-to-base IVPG.

[Vector mapping of deformation and blood flows in patients with ascending aortic aneurysm]. / Vektornoe kartirovanie deformatsii i potokov krovi u patsientov s anevrizmoi voskhodiashchei aorty.

The authors performed clinical studies based on modelling of an ascending aortic aneurysm in 37 patients and 10 apparently healthy subjects. Echocardiography was carried out in the B-mode using the Vivid E9 device (USA, GE). The linear dimensions of the aorta were assessed at three points - in the immediate vicinity of the valves, in the area of the maximum dilatation and in the area of decreased dilatation with registration of blood flow velocity in the aorta. The aortic walls were contoured with the division of equal intervals into 4 portions in order to obtain longitudinal shear deformation velocity during the cardiac cycle. We worked out a system of assessing the velocity vector fields with the help of transthoracic echocardiography in patients with an ascending aortic aneurysm, based on registration of blood flows, which made it possible to obtain the components of velocity. We also determined an optimal method of assessing turbulence in the aorta taking into account the direction of the vectors. Obtained were the numerical data of aortic wall deformation velocity in the longitudinal direction and calculation of the weighting function with the distinction between pathology and the norm. Based on the deformation, the distance between the registered points, and the movement of the vascular wall, we determined the reference values of blood flow velocity inside the aorta and immediately close to its walls.

[Phenomenological Regularities of Assessment of Left Ventricle Function in Mitral Valve Insufficiency].

OBJECTIVE: to examine relationship between anatomical changes of the left ventricle (LV), dynamics of velocity of its volume modification, and blood flows in the LV in patients with mitral regurgitation (MR) before and after surgical treatment. MATERIALS AND METHODS: We included into this study 58 patients with severe 3-4 degree MR (38 men, 20 women aged 24-69 [mean age 51±9] years) in sinus rhythm (96 %) or atrial fibrillation (4 %). The control group included 86 healthy volunteers, mean age 39±7 years. Transthoracic echocardiographic studies were performed in both groups by standard technique at rest using a high-quality echocardiograph Vivid E9, equipped with a 3.5-4.6 MHz multi frequency transducer (in patients before and after surgical repair - mitral valve [MV] replacement and MV reconstruction with annuloplasty ring). The analysis of files recorded was performed off-line by vector analysis technique including estimation of myocardial deformation velocities and dynamics of LV volume modification, construction of "flow-volume" diagram, calculation of the expended kinetic energy, and registration of intraventricular blood flows. RESULTS: End diastolic volume (EDV), end systolic volume (ESV) and total stroke volume (TSV) (effective + retrograde) were significantly increased in patients with severe LV volume overload before surgery in comparison with the control group (p.

[Modeling of hemodynamic changes in the aneurysm of the middle cerebral artery depending on the pathology of the parent artery].

OBJECTIVE: To examine the influence of the parent artery pathology on the local hemodynamics on the level of aneurysm. MATERIAL AND METHODS: Mathematical models of the arteriovenous malformation (AVM) were built on the CT-angiography data of real patients. To simulate the thrombosis, the parent artery and its branches were sequentially turned off in the model 1. In the model 2, the simulation of embolization of AVM was achieved by cutting off the exactly section of the parent artery that was involved in the arteriovenous formation. RESULTS AND CONCLUSION: Model 1 showed that the flow redistribution did not significantly impact on the risk of rupture after the parent artery was turned off and blood pressure was increased in both aneurysms by 3 mm Hg. Model 2, in which the aneurysms were combined with a direct arteriovenous drainage with low peripheral resistance, showed that turning off the parent artery and pathological drainage led to the serious reduction in the venous drainage flow and it's increasing in the parent artery by about 60% that significantly increased the risk of rupture.

[ASSESSMENT OF EXTRAVASCULAR LUNG WATER BY QUANTITATIVE COMPUTER IMAGE ANALYSIS IN PATIENTS WITH ACUTE RESPIRATORY DISTRESS SYNDROME].

PURPOSE: To evaluate the possibility of quantitative computed tomography (CT) of the lungs in patients with acute respiratory distress syndrome (ARDS) for assessment of the severity of the condition and the effectiveness of treatment. MATERIALS AND METHODS: The study included 29 patients with ARDS and 22 with no signs of lung disease (control group). We measured extravascular lung water (EVLW) by transpulmonary thermodilution (TTD) and analysed CT of the lungs in patients with ARDS. Patients in the control group underwent CT of the lungs only. CT images were processed using the "Gamma Multivoks". RESULTS: According to CT poorly ventilated lung areas accounted for 2% of the total in the control group. Normally ventilated and hyper-ventilated lung areas prevailed in these patients. In the group of ARDS hyper-ventilated areas almost were not identified and normality and poorly ventilated areas we found. In patients with ARDS total lung volume was 1.5 times less than in the control group (median volume of 3393 and 4955 mL respectively). Pulmonary weight in ARDS group was bigger than in controls (median weight of the lungs 1233 and 812 g respectively). Effects of treatment according to quantitative CT evaluated in 14 survived patients. Notes the increase in lung volume (median 4656.5 ml) (p = 0.0001) and a decrease in lung weight (median 862 g) (p = 0.0012). The weight and volume of the lungs, the ratio of hyper, normal and poorly ventilated areas of the lung in patients with acute respiratoy distress syndrome after treatment did not differ from those in the control group. CONCLUSIONS: Quantitative analysis of CT reveals changes in the mass and volume of the lungs and can be used to diagnose and evaluate the effectiveness of the treatment. Pulmonary weight calculated by CT correlates with EVLW determined by TTD.

[Assessment of velocity of deformation of abdominal aorta wall with the help of the multivox working station].

Most frequent cause of abnormalities of elastic properties of walls of abdominal aorta is development of atherosclerosis resulting in replacement of elastin by simpler fibrillar proteins and collagen. This subsequently leads to dilation of the aorta and formation of aneurism. Increase of collagen content in the aortic wall correlates with growth of aneurism dimensions. Main method of treatment of aneurisms is implantation of abdominal aortic prosthesis. Detailed preoperative assessment of functional state of the aortic wall is necessary in preoperative period but none of modern imaging instrumental methods including ultrasound study allows to realize this assessment. In this article we present first experience of assessment of aortic wall deformation velocity analyzing results of ultrasound study with the help of the Multivox working station in 36 patients 16 of whom were operated because of aneurism of abdominal aorta.

[Risk assessment of respiratory diseases in industrial workers].

The paper assesses a dust factor and establishes its etiological proportion in the development of respiratory diseases in workers from mining enterprises in different regions of Russia. Service-length groups at risk for upper tract diseases, criteria for early diagnosis, and a risk for occupational respiratory tract diseases were identified in miners. Trends in humoral factors of immunity were revealed in the workers without bronchopulmonary abnormalities. The efficiency of a scientifically grounded management system for an occupational risk of respiratory tract diseases was evaluated in miners.

[Myocardial biomechanics in patients with coronary circulatory insufficiency].

The paper analyzes a new approach to evaluating myocardial systolic and diastolic function, which is based on recording of the rate of myocardial displacement in different phases of a cardiac cycle. Changes in the rate of vector movements in a period of isovolumic contraction and relaxation are shown on ample clinical materials in both healthy individuals and patients with coronary heart disease. There is evidence for a significant difference in the performance of a stress test by healthy individuals and patients with a low coronary circulatory reserve.

[Late consequences of hemorrhagic fever with renal syndrome in a woman who had it during pregnancy].

The authors adduce a brief description of the features and outcomes of hemorrhagic fever with renal syndrome (HFRS) in 8 pregnant women. The results of the examination of a 54-year-old woman and her son, who suffered from a severe form of HERS 28 years ago during the 31st week of pregnancy, are presented in detail. Antibodies to Hantaan virus 1:32 were found; magnetic resonance tomography of the skull revealed sequelae of hypophysial hemorrhage with the formation of "partly empty ephippium". The antibodies were not found in the son; hydrocephalus, forehead cortex atrophy, and lateral ventricular asymmetry were revealed.

[A familial case of severe hemorrhagic fever with renal syndrome].

The authors describe two lethal outcomes of severe hemorrhagic fever with renal syndrome in spouses aged 50 and 44. A detailed description of clinical symptoms, the results of laboratory and instrumental tests, and possible mechanisms of contamination is given. Cross-sectional photographs of kidneys and hypophyseal hemorrhage, as well as radiograms of renal arteries and right pulmonary blood vessels after post-mortem filling with radiopaque mass are presented.

[Infrastructure of information support to clinical medicine]. / Ob infrastrukture informatsionnoi podderzhki klinicheskoi meditsiny.

Issues are discussed related with designing an effective infrastructure of the information-and-computer support to clinical medicine with regard for the recent achievements in informatics, automated systems, medical equipment and robotics. It is suggested to focus on creating a module-type infrastructure meeting evenly both the trends towards integration and towards autonomy. A scheme of an information infrastructure constructed for Bakulev's National Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences is described.

[Clonorchiasis in the Upper Amur region: biology, epidemiology, clinical presentation]. / Klonorkhoz v regione verkhnego Priamur'ia (biologia, épidemiologia, klinika).

Results of studies of clonorchiasis in the region of the Upper Amur and its tributaries are presented. Biological features of the pathogen and its epidemiology are outlined. Clinical symptoms were studied in 112 patients. In case of death, a pathoanatomic picture is given.