Association of coronary microvascular dysfunction and cardiac muscle injury in acute myocardial infarction: results of comparison of dynamic SPECT and cardiac MRI.

Aim      To study the interrelation of changes in coronary microcirculation by data of dynamic single photon emission computed tomography (SPECT) and myocardial injury by data of magnetic resonance imaging (MRI) in patients with acute myocardial infarction (AMI).Material and methods  The study included patients admitted to the emergency cardiology department with new-onset AMI. Contrast-enhanced cardiac MRI was performed for all patients on day 2-7 of admission. Dynamic SPECT of the myocardium with evaluation of semiquantitative and quantitative parameters of perfusion was performed on day 7-10.Results All patients were divided into two groups based on the type of MR contrast agent accumulation: 1) patients with the ischemic type of contrast enhancement (n=34; 62 %); 2) patients with the non-ischemic type of contrast enhancement (n=21; 38 %). According to data of myocardial perfusion scintigraphy (MPS), the group of ischemic MR pattern had larger perfusion defects at rest and during a stress test. Moreover, this group was characterized by lower global stress-induced blood flow and absolute and relative myocardial flow reserve (MFR). When the study group was divided into patients with transmural (n=32; 58 %) and non-transmural (n=23; 42 %) accumulation of the MR-contrast agent, lower values of global stress-induced blood flow and of absolute and relative MFR were observed in the group of transmural MR-enhancement pattern. A moderate inverse correlation was found between the stress-induced myocardial blood flow and the volume of myocardial edema (r= -0.47), infarct area (r= -0.48) and microvascular obstruction area (r= -0.38).Conclusion      The variables of dynamic SPECT characterizing microcirculatory disorders that are independent on or due to injuries of the epicardial coronary vasculature reflect the severity and depth of structural changes of the myocardium in AMI. In this process, quantitative variables of myocardial perfusion are interrelated with the myocardial injury more closely than semiquantitative MPS indexes. The findings of the present study can also contribute to the heterogenicity of a patient group with acute coronary syndrome and AMI. Further study is required for understanding the prognostic significance of dynamic SPECT parameters.

[State of the art mathematical methods of the coronary blood flow modelling: background and clinical value].

X-ray computed tomography coronary angiography (CTCA) is a current method for diagnosing ischemic heart disease. Although this method has a high specificity and a negative predictive value in diagnosing coronary obstructions, there are limitations in determining the hemodynamic significance of the stenosis. Extensive use of noninvasive methods for evaluation of coronary hemodynamics, specifically evaluation of the fractional flow reserve (FFR) is limited due to its high cost and risks of complications. Mathematical modeling of coronary circulation and its reserve based on CTCA data is an up-to-date method that has been experimentally confirmed and clinically validated. This method showed a high diagnostic efficacy in several large studies that used the invasive determination of FFR as a "gold standard". This review addresses the current state of studies on mathematical modeling for fractional coronary reserve in patients with ischemic heart disease, as well as the limitations and prospects of this method.

Ex Vivo Analysis of an Association of Mechanical Strength of Dilated Ascending Aorta with Tissue Matrix Metalloproteinases and Cytokines.

We analyzed the associations of the mechanical strength of dilated ascending aorta wall (intraoperative samples from 30 patients with non-syndromic aneurysms) with tissue MMPs and the cytokine system. Some samples were stretched to break on an Instron 3343 testing machine and the tensile strength was calculated; others were homogenized and the concentrations of MMP-1, MMP-2, MMP-7, their inhibitors (TIMP-1 and TIMP-2), and pro- and anti-inflammatory cytokines were determined by ELISA. Direct correlations between aortic tensile strength and concentrations of IL-10 (r=0.46), TNFα (r=0.60), and vessel diameter (r=0.67) and an inverse correlation with patient's age (r=-0.59) were revealed. Compensatory mechanisms supporting the strength of the ascending aortic aneurysm are possible. No associations of MMP-1, MMP-7, TIMP-1, and TIMP-2 with tensile strength and aortic diameter were found.

[Brain-derived neurotrophic factor in multiple sclerosis]. / Mozgovoi neirotroficheskii faktor pri rasseiannom skleroze.

The review presents data on brain-derived neurotrophic factor (BDNF), its structure and functions, the effect on the pathogenesis of experimental autoimmune encephalomyelitis and multiple sclerosis (MS). The correlation of BDNF level with clinical manifestations of MS and the changes of its level during disease-modifying therapy is considered.