[Stress-Echocardiography in Low-risk Acute Coronary Syndrome Without Persistent ST-segment Elevation Diagnostic Algorithm]

This review addresses the capabilities of stress EchoCG as a simple, non-invasive, non-radiation method for diagnosing occult disorders of coronary blood flow in patients with non-ST-elevation acute coronary syndrome on a low-risk electrocardiogram. The capabilities of the enhanced stress EchoCG protocol are based on supplementing the standard detection of transient disturbances of local contractility, generally associated with coronary artery obstruction, with an assessment of the heart rate reserve, coronary reserve and other parameters. This approach is considered promising for a more complete characterization of heart function during exercise and an accurate prognosis of the clinical case, which allows determining the tactics for patient management not limited to selection for myocardial revascularization.

Structural and Functional Disturbances of the Thoracic Aorta in Atherosclerosis of Various Gradations

Aim      To study global aortic circumferential strain in normal conditions and in atherosclerosis of various grades and to determine its role in prediction of structural and functional disorders of the thoracic aorta (TA) and coronary atherosclerosis using 2D speckle-tracking transesophageal echocardiography.Material and methods  182 patients with typical or probable angina were examined. The control group consisted of 11 healthy volunteers. TA was visualized along its entire length. The height of each atheroma was measured, and the total number of plaques in the TA was determined. Five stages of TA atherosclerosis were identified. In the descending TA, the global peak systolic circumferential strain (GCS, %) and the global peak systolic circumferential strain normalized to pulse arterial pressure (PAP) (GCS / PAP∙100) were calculated. All patients underwent coronary angiography. The number of coronary arteries (CAs) with >50 % stenosis was determined, and the SYNTAX Score was calculated.Results TA atherosclerosis was not detected in the control group. Among 182 patients, stage 1-5 TA atherosclerosis was found in 23 (12.6 %), 103 (56.6 %), 43 (23.6 %), 7 (3.8 %), and 6 (3.4 %) cases respectively. GCS and GCS / PAD decreased as the ultrasound stage of TA atherosclerosis increased as compared with the control group: 9.2 % and 15.3 for the control group; stage 1, 5.6 % and 8.9 (p<0.001); stage 2, 4.1 % and 5.9 (p<0.001); stage 3, 4 % and 5.8 (p<0.001); stage 4, 3.7 % and 4.9 (p<0.01); and stage 5, 2.6 % and 3.3 (p<0.01), respectively. ROC analysis showed that GCS ≥5.9 % (area under the curve, AUC, 0.94±0.03; p<0.001) and GCS / PAD ≥11.4 (AUC, 0.97±0.02; p <0.001) were predictors of intact TA. Also, GCS ≤4.85 % (AUC, 0.82±0.04; p<0.001) and GCS / PAD ≤8.06 (AUC, 0.87±0.03; p<0.001) were predictors of hemodynamically significant TA atherosclerosis (stages 3-5). GCS ≤4.05 % (AUC, 0.62±0.04; p=0.007) and GCS / PAD ≤5.95 (AUC, 0.61±0.04; p=0.018) were predictors of hemodynamically significant (>50 %) stenosing atherosclerosis of at least one CA. Furthermore, GCS ≤3.75 % (AUC, 0.67±0.07; p=0.039) and GCS / PAD ≤5.15 (AUC, 0.64±0.07; p=0.045) were predictors of severe and advanced coronary atherosclerosis (SYNTAX Score ≥22).Conclusion      GCS and GCS / PAD are new diagnostic markers of structural and functional disorders of TA in atherosclerosis of various grades. GCS and GCS / PAD are independent predictors of high-grade TA atherosclerosis (stages 3-5) with GCS / PAD demonstrating the highest level of significance. GCS and GCS / PAD are non-invasive predictors of severe and advanced CA atherosclerosis.

KATP channels are regulators of programmed cell death and targets for the creation of novel drugs against ischemia/reperfusion cardiac injury

BACKGROUND

The use of percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is associated with a mortality rate of 5%-7%. It is clear that there is an urgent need to develop new drugs that can effectively prevent cardiac reperfusion injury. ATP-sensitive K+ (KATP ) channel openers (KCOs) can be classified as such drugs.

RESULTS

KCOs prevent irreversible ischemia and reperfusion injury of the heart. KATP channel opening promotes inhibition of apoptosis, necroptosis, pyroptosis, and stimulation of autophagy. KCOs prevent the development of cardiac adverse remodeling and improve cardiac contractility in reperfusion. KCOs exhibit antiarrhythmic properties and prevent the appearance of the no-reflow phenomenon in animals with coronary artery occlusion and reperfusion. Diabetes mellitus and a cholesterol-enriched diet abolish the cardioprotective effect of KCOs. Nicorandil, a KCO, attenuates major adverse cardiovascular event and the no-reflow phenomenon, reduces infarct size, and decreases the incidence of ventricular arrhythmias in patients with acute myocardial infarction.

CONCLUSION

The cardioprotective effect of KCOs is mediated by the opening of mitochondrial KATP (mitoKATP ) and sarcolemmal KATP (sarcKATP ) channels, triggered free radicals' production, and kinase activation.

Intermediate Monocytes and Circulating Endothelial Cells: Interplay with Severity of Atherosclerosis in Patients with Coronary Artery Disease and Type 2 Diabetes Mellitus

The aim was to investigate the association of monocyte heterogeneity and presence of circulating endothelial cells with the severity of coronary atherosclerosis in patients with coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM). We recruited 62 patients with CAD, including 22 patients with DM2. The severity of atherosclerosis was evaluated using Gensini Score. Numbers of classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14+CD16++) monocyte subsets; circulating endothelial progenitor cells; and the presence of circulating endothelial cells were evaluated. Counts and frequencies of intermediate monocytes, but not glycaemia parameters, were associated with the severity of atherosclerosis in diabetic CAD patients (rs = 0.689; p = 0.001 and rs = 0.632; p = 0.002, respectively). Frequency of Tie2+ cells was lower in classical than in non-classical monocytes in CAD patients (p = 0.007), while in patients with association of CAD and T2DM, differences between Tie2+ monocytes subsets disappeared (p = 0.080). Circulating endothelial cells were determined in 100% of CAD+T2DM patients, and counts of CD14++CD16+ monocytes and concentration of TGF-β predicted the presence of circulating endothelial cells (sensitivity 92.3%; specificity 90.9%; AUC = 0.930). Thus, intermediate monocytes represent one of the key determinants of the appearance of circulating endothelial cells in all the patients with CAD, but are associated with the severity of atherosclerosis only in patients with association of CAD and T2DM.

A historical literature review of coronary microvascular obstruction and intra-myocardial hemorrhage as functional/structural phenomena

The analysis of experimental data demonstrates that platelets and neutrophils are involved in the no-reflow phenomenon, also known as microvascular obstruction (MVO). However, studies performed in the isolated perfused hearts subjected to ischemia/reperfusion (I/R) do not suggest the involvement of microembolization and microthrombi in this phenomenon. The intracoronary administration of alteplase has been found to have no effect on the occurrence of MVO in patients with acute myocardial infarction. Consequently, the major events preceding the appearance of MVO in coronary arteries are independent of microthrombi, platelets, and neutrophils. Endothelial cells appear to be the target where ischemia can disrupt the endothelium-dependent vasodilation of coronary arteries. However, reperfusion triggers more pronounced damage, possibly mediated by pyroptosis. MVO and intra-myocardial hemorrhage contribute to the adverse post-infarction myocardial remodeling. Therefore, pharmacological agents used to treat MVO should prevent endothelial injury and induce relaxation of smooth muscles. Ischemic conditioning protocols have been shown to prevent MVO, with L-type Ca ²⁺ channel blockers appearing the most effective in treating MVO.

Do reactive oxygen species damage or protect the heart in ischemia and reperfusion? Analysis on experimental and clinical data

The role of reactive oxygen species (ROS) in ischemic and reperfusion (I/R) injury of the heart has been discussed for more than 40 years. It has been demonstrated that reperfusion triggers a multiple increase in free radical generation in the isolated heart. Antioxidants were found to have the ability to mitigate I/R injury of the heart. However, it is unclear whether their cardioprotective effect truly depends on the decrease of ROS levels in myocardial tissues. Since high doses and high concentrations of antioxidants were experimentally used, it is highly likely that the cardioprotective effect of antioxidants depends on their interaction not only with free radicals but also with other molecules. It has been demonstrated that the antioxidant N-2-mercaptopropionyl glycine or NDPH oxidase knockout abolished the cardioprotective effect of ischemic preconditioning. Consequently, there is evidence that ROS protect the heart against the I/R injury.

The Signaling Mechanism of Remote Postconditioning of the Heart: Prospects of the Use of Remote Postconditioning for the Treatment of Acute Myocardial Infarction

Acute myocardial infarction (AMI) remains the leading cause of mortality in the world, highlighting an urgent need for the development of novel, more effective approaches for the treatment of AMI. Remote postconditioning (RPost) of the heart could be a useful approach. It was demonstrated that RPost triggers infarct size reduction, improves contractile function of the heart in reperfusion, mitigates apoptosis, and stimulates autophagy in animals with coronary artery occlusion and reperfusion. Endogenous opioid peptides and adenosine could be involved in RPost. It was found that kinases and NO-synthase participate in RPost. KATP channels, MPT pore, and STAT3 could be hypothetical end-effectors of RPost. Metabolic syndrome and old age abolish the cardioprotective effect of RPost in rats. The data on the efficacy of RPost in clinical practice are inconsistent. These data are discussed in the review.

Regulation of autophagy of the heart in ischemia and reperfusion

Ischemia/reperfusion (I/R) of the heart leads to increased autophagic flux. Preconditioning stimulates autophagic flux by AMPK and PI3-kinase activation and mTOR inhibition. The cardioprotective effect of postconditioning is associated with activation of autophagy and increased activity of NO-synthase and AMPK. Oxidative stress stimulates autophagy in the heart during I/R. Superoxide radicals generated by NADPH-oxidase acts as a trigger for autophagy, possibly due to AMPK activation. There is reason to believe that AMPK, GSK-3β, PINK1, JNK, hexokinase II, MEK, PKCα, and ERK kinases stimulate autophagy, while mTOR, PKCδ, Akt, and PI3-kinase can inhibit autophagy in the heart during I/R. However, there is evidence that PI3-kinase could stimulate autophagy in ischemic preconditioning of the heart. It was found that transcription factors FoxO1, FoxO3, NF-κB, HIF-1α, TFEB, and Nrf-2 enhance autophagy in the heart in I/R. Transcriptional factors STAT1, STAT3, and p53 inhibit autophagy in I/R. MicroRNAs could stimulate and inhibit autophagy in the heart in I/R. Long noncoding RNAs regulate the viability and autophagy of cardiomyocytes in hypoxia/reoxygenation (H/R). Nitric oxide (NO) donors and endogenous NO could activate autophagy of cardiomyocytes. Activation of heme oxygenase-1 promotes cardiomyocyte tolerance to H/R and enhances autophagy. Hydrogen sulfide increases cardiac tolerance to I/R and inhibits apoptosis and autophagy via mTOR and PI3-kinase activation.

Association of Epicardial Adipose Tissue Adipocytes Hypertrophy with Biomarkers of Low-Grade Inflammation and Extracellular Matrix Remodeling in Patients with Coronary Artery Disease

The aim of the study was to compare the morphological features of epicardial adipose tissue (EAT) adipocyte with the circulating inflammatory biomarkers and parameters of extracellular matrix remodeling in patients with coronary artery disease (CAD). We recruited 42 patients with CAD (m/f 28/14) who were scheduled for coronary artery bypass graft surgery (CABG). EAT adipocytes were obtained by the enzymatic method from intraoperative adipose tissue samples. Concentrations of secreted and lipoprotein-associated phospholipase A2 (sPLA2 and LpPLA2), TNF-α, IL-1β, IL-6, IL-10, high-sensitive C-reactive protein (hsCRP), metalloproteinase-9 (MMP-9), MMP-2, C-terminal cross-linking telopeptide of type I collagen (CTX-I), and tissue inhibitor of metalloproteinase 1 (TIMP-1) were measured in blood serum. Patients were divided into two groups: group 1-with mean EAT adipocytes' size ≤ 87.32 μm; group 2-with mean EAT adipocytes' size > 87.32 μm. Patients of group 2 had higher concentrations of triglycerides, hsCRP, TNF-α, and sPLA2 and a lower concentration of CTX-I. A multiple logistic regression model was created (R_N² = 0.43, p = 0.0013). Concentrations of TNF-α, sPLA2 and CTX-I appeared to be independent determinants of the EAT adipocyte hypertrophy. ROC analysis revealed the 78% accuracy, 71% sensitivity, and 85% specificity of the model, AUC = 0.82. According to our results, chronic low-grade inflammation and extracellular matrix remodeling are closely associated with the development of hypertrophy of EAT adipocytes, with serum concentrations of TNF-α, sPLA2 and CTX-I being the key predictors, describing the variability of epicardial adipocytes' size.

Production of Reactive Oxygen Species by Epicardial Adipocytes Is Associated with an Increase in Postprandial Glycemia, Postprandial Insulin, and a Decrease in Serum Adiponectin in Patients with Severe Coronary Atherosclerosis

Purpose. This work investigates the relations between the production of reactive oxygen species (ROS) by epicardial adipose tissue (EAT) adipocytes and parameters of glucose/insulin metabolism, circulating adipokines levels, and severity of coronary atherosclerosis in patients with coronary artery disease (CAD); establishing significant determinants describing changes in ROS EAT in this category of patients. Material and methods. This study included 19 patients (14 men and 5 women, 53−72 y.o., 6 patients with diabetes mellitus type 2; 5 patients with prediabetes), with CAD, who underwent coronary artery bypass graft surgery. EAT adipocytes were isolated by the enzymatic method from intraoperative explants obtained during coronary artery bypass grafting. The size of EAT adipocytes and ROS level were determined. Results. The production of ROS by EAT adipocytes demonstrated a direct correlation with the level of postprandial glycemia (rs = 0.62, p < 0.05), and an inverse correlation with serum adiponectin (rs = −0.50, p = 0.026), but not with general and abdominal obesity, EAT thickness, and dyslipidemia. Regression analysis demonstrated that the increase in ROS of EAT adipocytes occurs due to the interaction of the following factors: postprandial glycemia (β = 0.95), postprandial insulin (β = 0.24), and reduced serum adiponectin (β = −0.20). EAT adipocytes in patients with diabetes and prediabetes manifested higher ROS production than in patients with normoglycemia. Although there was no correlation between the production of ROS by EAT adipocytes and Gensini score in the total group of patients, higher rates of oxidative stress were observed in EAT adipocytes from patients with a Gensini score greater than median Gensini score values (≥70.55 points, Gr.B), compared to patients with less severe coronary atherosclerosis (<70.55 points, Gr.A). Of note, the frequency of patients with diabetes and prediabetes was higher among the patients with the most severe coronary atherosclerosis (Gr.B) than in the Gr.A. Conclusions. Our data have demonstrated for the first time that systemic impairments of glucose/insulin metabolism and a decrease in serum adiponectin are significant independent determinants of oxidative stress intensity in EAT adipocytes in patients with severe coronary atherosclerosis. The possible input of the interplay between oxidative stress in EAT adipocytes and metabolic disturbances to the severity of coronary atherosclerosis requires further investigation.

The diagnostic value of SPECT CZT quantitative myocardial blood flow in high-risk patients

BACKGROUND

The objective of this study was to evaluate the accuracy of global MBF and MFR quantitation performed by myocardial perfusion scintigraphy (MPS) for the detection of multivessel coronary artery disease (CAD).

METHODS

52 CAD patients underwent CZT MPS, with the evaluation of MBF and MFR, followed by invasive coronary angiography (ICA). According to MPS and ICA results, all patients were divided into three groups: (1) non-obstructive CAD and normal MPS scan (control group) (n = 7), (2) one vessel disease (1VD) (n = 16), (3) multivessel disease (MVD) (n = 29).

RESULTS

Global absolute MBF and MFR were significantly reduced in MVD patients as compared to those with 1VD [0.93 (IQR 0.76; 1.39) vs 1.94 (1.37; 2.21) mL·min-1·g-1, P = .00012] and [1.4 (IQR 1.02; 1.85) vs 2.3 (1.8; 2.67), P = . 0 004], respectively. The Syntax score correlated with global stress MBF (ρ = - 0.64; P < .0001) and MFR (ρ = - 0.53; P = .0003). ROC analysis showed higher sensitivity and specificity for stress MBF and MFR compared with semiquantitative MPS stress evaluation. Multivariate regression analysis showed that only stress MBF [OR (95% CI) 0.59 (0.42-0.82); P < .0003] was an independent predictor of MVD.

CONCLUSIONS

Quantitative myocardial blood flow values assessed with the use of CZT camera may identify high-risk patients, such as those with multivessel disease.

Pharmacological Approaches to Limit Ischemic and Reperfusion Injuries of the Heart. Analysis of Experimental and Clinical Data on P2Y12 Receptor Antagonists

High mortality among people with acute myocardial infarction is one of the most urgent problems of modern cardiology. And in recent years, much attention has been paid to the search for pharmacological approaches to prevent heart damage. In this review, we tried to analyze data on the effect of P2Y₁₂ receptor antagonists on the ischemia/reperfusion tolerance of the heart.

Ischemic and reperfusion injuries of the heart underlie the pathogenesis of acute myocardial infarction (AMI) and sudden cardiac death. The mortality rate is still high and is 5–7% in patients with ST-segment elevation myocardial infarction. The review is devoted to pharmacological approaches to limitation of ischemic and reperfusion injuries of the heart. The article analyzes experimental evidence and the clinical data on the effects of P2Y₁₂ receptor antagonists on the heart’s tolerance to ischemia/reperfusion in animals with coronary artery occlusion and reperfusion and also in patients with AMI. Chronic administration of ticagrelor prevented adverse remodeling of the heart. There is evidence that sphingosine-1-phosphate is the molecule that mediates the infarct-reducing effect of P2Y₁₂ receptor antagonists. It was discussed a role of adenosine in the cardioprotective effect of ticagrelor.

Reperfusion Cardiac Injury: Receptors and the Signaling Mechanisms

It has been documented that Ca2+ overload and increased production of reactive oxygen species play a significant role in reperfusion injury (RI) of cardiomyocytes. Ischemia/reperfusion induces cell death as a result of necrosis, necroptosis, apoptosis, and possibly autophagy, pyroptosis and ferroptosis. It has also been demonstrated that the NLRP3 inflammasome is involved in RI of the heart. An increase in adrenergic system activity during the restoration of coronary perfusion negatively affected cardiac resistance to RI. Toll-like receptors are involved in RI of the heart. Angiotensin II and endothelin-1 aggravated ischemic/reperfusion injury of the heart. Activation of neutrophils, monocytes, CD4+ T-cells and platelets contributes to cardiac ischemia/reperfusion injury. Our review outlines the role of these factors in reperfusion cardiac injury.

[Focus ultrasound for cardiology practice. Russian consensus document]

This document is a consensus document of Russian Specialists in Heart Failure, Russian Society of Cardiology, Russian Association of Specialists in Ultrasound Diagnostics in Medicine and Russian Society for the Prevention of Noncommunicable Diseases. In the document a definition of focus ultrasound is stated and discussed when it can be used in cardiology practice in Russian Federation.

Absolute myocardial blood flows derived by dynamic CZT scan vs invasive fractional flow reserve: Correlation and accuracy

PURPOSE

To define the diagnostic power of absolute myocardial blood flow (MBF) evaluation on dynamic CZT imaging in intermediate risk patients in comparison with invasive coronary angiography (ICA) and fractional flow reserve (FFR).

METHODS

Twenty-three stable CAD patients underwent one-day dynamic rest-stress 99mTc-Sestamibi myocardial perfusion imaging by CZT camera. Stress and rest MBF values were calculated semi-automatically using a net retention model by Leppo. Coronary flow reserve (CFR) and flow difference (FD) [MBF stress - MBF rest] were also estimated. A total of 28 vessels were functionally quantified with FFR: 19 (68%) vessels with a stenosis ≥ 70% and 9 (32%) with < 70% stenotic lesions.

RESULTS

The mean global MBFs at rest and during stress were 0.36 (IQR 0.33-0.54) mL/min/g and 0.67 (IQR 0.55-0.81) mL/min/g, respectively, with an average CFR of 1.80 (IQR 1.35-2.24). Moderate correlations between stenosis severity and FFR (r = 0.45; P = .01), stress MBF (r = -0.46; P = .01) and FD (r = -0.37; P = .04) were detected. FFR abnormalities were best predicted by absolute stress MBF, CFR and FD with values of ≤ 0.54 mL/min/g (sensitivity 61.5%; specificity 93.3%), ≤ 1.48 (sensitivity 69.2%; specificity 93.3%) and ≤ 0.18 mL/min/g (sensitivity 69.2%; specificity 100%), respectively.

CONCLUSIONS

The values of stress MBF, CFR and FD obtained through dynamic CZT acquisitions compare well with invasive FFR. The clinical use of dynamic acquisition of myocardial perfusion imaging by CZT may help cardiologist in the detection of hemodynamically significant CAD.

Hypertrophy and Insulin Resistance of Epicardial Adipose Tissue Adipocytes: Association with the Coronary Artery Disease Severity

Changes in the structural and functional characteristics of the epicardial adipose tissue (EAT) are recognized as one of the factors in the development of cardiometabolic diseases. However, the generally accepted quantitative assessment of the accumulation of EAT does not reflect the size of adipocyte and presence of adipocyte hypertrophy in this fat depot. Overall contribution of adipocyte hypertrophy to the development and progression of coronary atherosclerosis remains unexplored. Objective: To compare the morphological characteristics of EAT adipocyte and its sensitivity to insulin with the CAD severity, as well as to identify potential factors involved in the realization of this relationship. The present study involved 24 patients (m/f 16/8) aged 53-72 years with stable CAD, who underwent coronary artery bypass graft surgery. Adipocytes were isolated enzymatically from EAT explants obtained during the operation. The severity of CAD was assessed by calculating the Gensini score according to selective coronary angiography. Insulin resistance of EAT adipocytes was evaluated by reactivity to insulin. In patients with an average size of EAT adipocytes equal to or exceeding the median (87 μm) the percentage of hypertrophic adipocytes was twice as high as in patients in whom the average size of adipocytes was less than 87 μm. This group of patients was also characterized by the higher rate of the Gensini score, lower adiponectin levels, and more severe violation of carbohydrate metabolism. We have revealed direct nonparametric correlation between the size of EAT adipocytes and the Gensini score (rs = 0.56, p = 0.00047). The number of hypertrophic EAT adipocytes showed a direct nonparametric correlation with the Gensini score (rs = 0.6, p = 0.002). Inverse nonparametric correlations were found between the serum adiponectin level and size (rs = -0.60, p = 0.001), hypertrophy of adipocytes (rs = -0.67, p = 0.00), and Gensini score (rs = -0.81, p = 0.00007). An inverse nonparametric correlation was found between the Gensini score and sensitivity of EAT adipocytes to insulin, estimated by the intracellular redox response (rs = -0.90, p = 0.037) and decrease in lipolysis rate upon insulin addition (rs = -0.40, p = 0.05). The intracellular redox response of adipocytes to insulin was directly correlated with fasting insulin and inversely with postprandial insulin. Our data indicate that the size and degree of hypertrophy of the epicardial adipocytes are related to the CAD severity. According to our results, insulin resistance of adipocytes may be considered as one of the factors mediating this relationship.

The Role of Natriuretic Peptides in the Regulation of Cardiac Tolerance to Ischemia/Reperfusion and Postinfarction Heart Remodeling

In the past 10 years, mortality from acute myocardial infarction has not decreased despite the widespread introduction of percutaneous coronary intervention. The reason for this situation is the absence in clinical practice of drugs capable of preventing reperfusion injury of the heart with high efficiency. In this regard, noteworthy natriuretic peptides (NPs) which have the infarct-limiting effect, prevent reperfusion cardiac injury, prevent adverse post-infarction remodeling of the heart. Atrial natriuretic peptide does not have the infarct-reducing effect in rats with alloxan-induced diabetes mellitus. NPs have the anti-apoptotic and anti-inflammatory effects. There is indirect evidence that NPs inhibit pyroptosis and autophagy. Published data indicate that NPs inhibit reactive oxygen species production in cardiomyocytes, aorta, heart, kidney and the endothelial cells. NPs can suppress aldosterone, angiotensin II, endothelin-1 synthesize and secretion. NPs inhibit the effects aldosterone, angiotensin II on the post-receptor level through intracellular signaling events. NPs activate guanylyl cyclase, protein kinase G and protein kinase A, and reduce phosphodiesterase 3 activity. NO-synthase and soluble guanylyl cyclase are involved in the cardioprotective effect of NPs. The cardioprotective effect of natriuretic peptides is mediated via activation of kinases (AMPK, PKC, PI3 K, ERK1/2, p70s6 k, Akt) and inhibition of glycogen synthase kinase 3β. The cardioprotective effect of NPs is mediated via sarcolemmal K_ATP channel and mitochondrial K_ATP channel opening. The cardioprotective effect of brain natriuretic peptide is mediated via MPT pore closing. The anti-fibrotic effect of NPs may be mediated through inhibition TGF-β1 expression. Natriuretic peptides can inhibit NF-κB activity and activate GATA. Hemeoxygenase-1 and peroxisome proliferator-activated receptor γ may be involved in the infarct-reducing effect of NPs. NPs exhibit the infarct-limiting effect in patients with acute myocardial infarction. NPs prevent post-infarction remodeling of the heart. To finally resolve the question of the feasibility of using NPs in AMI, a multicenter, randomized, blind, placebo-controlled study is needed to assess the effect of NPs on the mortality of patients after AMI.

[Possibilities and limitations of three-dimensional transesophageal echocardiography in the diagnosis of thoracic aorta atherosclerosis]

OBJECTIVES

To compare the possibilities and limitations of the two-dimensional (2D) and three-dimensional (3D) multiplane transesophageal echocardiography (TEE) for the diagnosis of the thoracic aorta (TA) atherosclerosis stage, qualitative and quantitative assessment of aortic atheromas and coronary atherosclerosis prediction. Materials and methods. 2D and 3D multiplane TEE of the TA was performed in 180 consecutive CAD patients (104 men, 76 women, mean age 62,4±7,5 years) using Philips IE33 xMatrix system and a X7-2t multiplane probe. Ascending aorta, accessible parts of the arch and descending TA were visualized in 2D mode with standard protocol using Live xPlane mode. 3D study of TA was performed using Live 3D and Full Volume modes. 2D and 3D studies were recorded as video clips series on a system hard drive with subsequent off line processing on a QLab 10.8 (Philips) workstation. Qualitative and quantitative assessment of every atheroma was performed using 2D and 3D modes. The degree of severity and distribution of the TA atheromatosis was evaluated according to the classification of ASE and EACVI (2015): grade 0 - intimal-medial thickness ≤1 mm, 1 - intimal thickness ≤2 mm, 2 - focal or diffuse intimal thickening of 2-3 mm (small atheromas), 3 - atheromas &gt;3-5 mm (no mobile/ulcerated components), 4 - atheromas &gt; 5 mm (no mobile/ulcerated components), 5 - grade 2, 3, or 4 atheromas plus mobile or ulcerated components. After TEE all patients underwent digital coronary angiography. SYNTAX Score was calculated in 122 (67,7%) patients with no coronary stents and bypass grafts. Results. 620 atheromas were analysed: 109 (17,6%) in the ascending part, 8 (1,3%) in the arch and 503 (81,1%) in the descending part. On average 3,4±2,1 atheromas per patient were revealed. Atheromas height in 3D was significantly higher (p&lt;0,001), than in 2D, being 0,38±0,09 cm and 0,26±0,07 cm, respectively.  Averaged atheromas height increase in 3D was 0,12±0,06 cm. In 3D 87,7% of atheromas have shown irregular contours while in 2D only 35,4% of atheromas had rough countors. The mobile component in 6 (66,6%) out of 9 atheromas was revealed only in 3D. In 2D 1-5 stages of TA atheromatosis were revealed in 22 (12,2%), 103 (57,2%), 43 (23,9%), 7 (3,9%) and 4 (2,2%) cases, respectively. In 3D 1-5 stages of TA atheromatosis were revealed in 16 (8,9%), 25 (13,9%), 90 (50%), 38 (21,1%) and 10 (5,5%) cases, respectively. With 3D TEE 130 (72,2%) patients were found to have higher gradation of TA atheromatosis stage. TA atheromatosis was not detected in 1 (0,6%) patient. The direct Spearman's correlation between a stage of TA atheromatosis and SYNTAX Score which has been established for 2D rs =0,32 p&lt;0,001 and 3D rs =0,30, p&lt;0,01, respectively. Conclusion. A comparison between 2D and 3D TEE has shown, that 3D is more precise method of qualitative and quantitative assessment of aortic atheromas and diagnosis of TA atheromatosis stage which allows, ultimately, to change the stage of TA atheromatosis towards a higher gradation. 3D ultrasound stage of TA atheromatosis is a surrogate marker of the severity and prevalence of coronary atherosclerosis.

A Review of Humoral Factors in Remote Preconditioning of the Heart

A humoral mechanism of cardioprotection by remote ischemic preconditioning (RIP) has been clearly demonstrated in various models of ischemia-reperfusion including upper and lower extremities, liver, and the mesenteric and renal arteries. A wide range of humoral factors for RIP have been proposed including hydrophobic peptides, opioid peptides, adenosine, prostanoids, endovanilloids, endocannabinoids, calcitonin gene-related peptide, leukotrienes, noradrenaline, adrenomedullin, erythropoietin, apolipoprotein, A-I glucagon-like peptide-1, interleukin 10, stromal cell-derived factor 1, and microRNAs. Virtually, all of the components of ischemic preconditioning's signaling pathway such as nitric oxide synthase, protein kinase C, redox signaling, PI3-kinase/Akt, glycogen synthase kinase β, ERK1/2, mitoK_ATP channels, Connexin 43, and STAT were all found to play a role. The signaling pattern also depends on which remote vascular bed was subjected to ischemia and on the time between applying the rip and myocardial ischemia occurs. Because there is convincing evidence for many seemingly diverse humoral components in RIP, the most likely explanation is that the overall mechanism is complex like that seen in ischemic preconditioning where multiple components are both in series and in parallel and interact with each other. Inhibition of any single component in the right circumstance may block the resulting protective effect, and selectively activating that component may trigger the protection. Identifying the humoral factors responsible for RIP might be useful in developing drugs that confer RIP's protection in a more comfortable and reliable manner.

Trigger, Signaling Mechanism and End Effector of Cardioprotective Effect of Remote Postconditioning of Heart

The hypothetical trigger of remote postconditioning (RPost) of the heart is the high-molecular weight hydrophobic peptide(s). Nitric oxide and adenosine serve as intermediaries between the peptide and intracellular structures. The role of the autonomic nervous system in RPost requires further study. In signaling mechanism RPost, kinases are involved: protein kinase C, PI3, Akt, JAK. The hypothetical end effector of RPost is aldehyde dehydrogenase-2, the transcription factors STAT, Nrf2, and also the BKCa channel.

Physiological and Pathological Role of TRPV1, TRPV2 and TRPV4 Channels in Heart

Transient receptor potential vanilloid channel 2 (TRPV2) is required for normal cardiac contractility. The stimulation of TRPV1 in isolated cardiomyocytes can aggravate the effect of hypoxia/ reoxygenation (H/R) on H9C2 cells. The knockout of the TRPV1 gene promotes increased tolerance of the isolated perfused heart to the impact of ischemia/reperfusion (I/R). However, activation of TRPV1 increases the resistance of the heart to I/R due to calcitonin gene-related peptide (CGRP) release from afferent nerve endings. It has been established that TRPV1 and TRPV2 are involved in the pathogenesis of myocardial infarction and, in all likelihood, ensure the cardiac tolerance to the ischemia/reperfusion. It has also been documented that the activation of TRPV4 negatively affects the stability of cardiomyocytes to the H/R. The blockade of TRPV4 can be considered as a new approach to the prevention of I/R injury of the heart. Studies also indicate that TRPV1 is involved in the pathogenesis of cardiac hypertrophy and that TRPV2 channels participate in the pathogenesis of dilated cardiomyopathy. Excessive expression of TRPV2 leads to chronic Ca2+- overload of cardiomyocytes, which may contribute to the development of cardiomyopathy.

Is oxidative stress of adipocytes a cause or a consequence of the metabolic syndrome?

Metabolic syndrome is accompanied by oxidative stress in animals and humans. The main source of ROS in experimental metabolic syndrome is NADPH oxidase and possibly adipocyte mitochondria. It is now documented that oxidative stress induces insulin resistance of adipocytes and increases secretion of leptin, MCP-1, IL-6, and TNF-α by adipocytes. It was established that oxidative stress induces a decrease in adiponectin production by adipocytes. It has also been shown that obesity itself can induce oxidative stress. Oxidative stress can cause an alteration of intracellular signaling in adipocytes that apparently leads to the formation of insulin resistance of adipocytes. Chronic stress, glucocorticoids, mineralocorticoids, angiotensin-II, TNF-α also play an important role in the pathogenesis of oxidative stress of adipocytes. Oxidative stress is not only a consequence of metabolic syndrome, but also a reason and a foundational link in the pathogenesis of the metabolic syndrome.

Reactive Oxygen Species as Intracellular Signaling Molecules in the Cardiovascular System

BACKGROUND

Redox signaling plays an important role in the lives of cells. This signaling not only becomes apparent in pathologies but is also thought to be involved in maintaining physiological homeostasis. Reactive Oxygen Species (ROS) can activate protein kinases: CaMKII, PKG, PKA, ERK, PI3K, Akt, PKC, PDK, JNK, p38. It is unclear whether it is a direct interaction of ROS with these kinases or whether their activation is a consequence of inhibition of phosphatases. ROS have a biphasic effect on the transport of Ca2+ in the cell: on one hand, they activate the sarcoplasmic reticulum Ca2+-ATPase, which can reduce the level of Ca2+ in the cell, and on the other hand, they can inactivate Ca2+-ATPase of the plasma membrane and open the cation channels TRPM2, which promote Ca2+-loading and subsequent apoptosis. ROS inhibit the enzyme PHD2, which leads to the stabilization of HIF-α and the formation of the active transcription factor HIF.

CONCLUSION

Activation of STAT3 and STAT5, induced by cytokines or growth factors, may include activation of NADPH oxidase and enhancement of ROS production. Normal physiological production of ROS under the action of cytokines activates the JAK/STAT while excessive ROS production leads to their inhibition. ROS cause the activation of the transcription factor NF-κB. Physiological levels of ROS control cell proliferation and angiogenesis. ROS signaling is also involved in beneficial adaptations to survive ischemia and hypoxia, while further increases in ROS can trigger programmed cell death by the mechanism of apoptosis or autophagy. ROS formation in the myocardium can be reduced by moderate exercise.

[Serial Assessment of Transthoracic Coronary Flow Reserve as Method of Assessing Efficacy of Intracoronary Intervention in the Left Anterior and Posterior Descending Arteries]

Transthoracic echocardiography (TTE) has been described as an accurate technique for noninvasive evaluation of coronary flow reserve (CFR) of the left anterior descending artery (LAD) and posterior descending artery (PDA). Aim of this study was to find out whether serial measurement of CFR in LAD and PDA using TTE allows detection of stenosis elimination after intracoronary intervention and is a marker of successful procedure.

METHODS

The study group comprised 14 patients with single-vessel coronary disease (stenosis 82+/-14%) of the LAD (9 patients) or right coronary artery (RCA, 5 patients) scheduled for stent implantation. All patients underwent dipyridamole stress echo with CFR evaluation of either distal LAD or PDA 1 day before and 6-9 days after successful stent implantation. CFR was calculated as the ratio of hyperemic to basal peak diastolic velocity. A CFR value of <2.0 was considered abnormal.

RESULTS

Adequate Doppler signals to measure CFR were obtained in 13 patients (93%). Abnormal pre-procedure CFR value was revealed in 12 assessed patients (92%). Significant increase of CFR due to a decrease of coronary flow velocity at rest and its more pronounced hyperemic rise was found in all patients after stent implantation (CFR: 1.28+/-0.52 before and 2.53+/-0.37 after stenting; p<0.001). Using a cut-off value of CFR more or equal 2.0 to identify absence of significant coronary artery disease, TTE detected successful stent implantation with a sensitivity of 91.7% and specificity of 100% for both LAD and RCA. CFR was still abnormal in only 1 patient with pre-procedure>90% LAD stenosis.

CONCLUSION

TTE is a feasible technique for serial CFR evaluation in LAD and PDA. Cut-off CFR value more or equal 2.0 is a sensitive and specific criterion of successful stent implantation in LAD and RCA.

[Coronary Flow Reserve in the Left Anterior and Posterior Descending Arteries as an Additional Option to Dipyridamole Stress Echocardiography for Detection of Stenosis]

AIM

to assess additive diagnostic value of simultaneous evaluation of coronary flow reserve (CFR) in the left anterior descending (LAD) artery and posterior descending artery (PDA) during dipyridamole stress echocardiography (stress-Echo) for detection of LAD and PDA stenoses >50%.

METHODS

108 in-patients (mean age 50+/-11 years) with cardiac chest pain underwent dipyridamole stress-Echo with ECG-analysis, wall motion analysis by 2-dimentional imaging (2D) and coronary flow reserve (CFR) evaluation in both LAD and PDA by pulse-wave Doppler. The 2D test was considered positive when more or equal 2 segments demonstrated wall motion abnormalities. CFR was calculated as ratio of hyperemic to basal peak diastolic blood flow velocity. CFR <2.0 was considered reduced. Coronary angiography was performed within one week after stress-Echo.

RESULTS

34 of 97 patients with CFR in the LAD and wall motion in the LAD territory had LAD stenosis >50%, and 22 of 90 patients with evaluated CFR in the PDA and wall motion in the RCA territory had RCA stenosis >50%. Thus stenosis >50% was detected in 56 of 187 evaluated LAD and RCA. The 2D test and ECG results were positive for 35 arterial territories, reduced CFR - for 48 arteries. With combined evaluation of ECG, 2D test and CFR, accuracy was not significantly higher (80% for ECG+2D test, 82% for CFR and 80% for combined test) but sensitivity and negative predictive value increased (sensitivity: 63% for ECG+2D test, 86% for CFR and 91% for combined test; negative predictive value: 85% for ECG+2D test, 93% for CFR and 95% for combined test).

CONCLUSION

Assessment of CFR in both LAD and PDA is feasible for majority of patients and can increase sensitivity and negative predictive value of dipyridamole stress-Echo for the detection.

[Transthoracic dopllerographic assessment of the relative coronary reserve in the norm and in the presence of isolated hemodynamically significant stenoses of the left anterior descending coronary artery]

Comparison of velocity parameters of blood flow and absolute coronary reserve (absCR) in the left anterior descending and posterior interventricular coronary arteries (ADCA and PICA) with calculation of relative coronary reserve (relCR) and determination of its normative values was carried out with the help of transthoracic echocardiography in 29 healthy volunteers (mean age 40+/-13 years). Assessment of the role of absCR and relCR in ADCA in diagnostics of hemodynamically significant stenoses of this vessel was performed in 88 patients with syndrome of cardiac pain (mean age 40+/-12 years). Coronary angiography was used as a reference method. Coronary blood flow in distal segments of ADCA and PICA was measured at baseline and during infusion of a vasodilator (dipyridamole up to 0.84 mg/kg as intravenous infusion). AbsCR for each of these arteries was determined as ratio of hyperemic peak diastolic blood flow velocity and its baseline value. Lowering of absCR was diagnosed at its level &lt;2.0). RelCR was calculated only for ADCA as ratio of absCR of ADCA and PICA. It was established that parameters of coronary blood flow and absCR level in healthy volunteers in ADA and PICA had no significant differences. Therefore these vessels were considered referent for each other. In the norm relCR in ADA was 1.09+/-0.36 (95% confidence interval from 0.95 to 1.23). We proved that ADA abs CR in &lt;2.0 served as predictor of ADA stenosis &gt;50% with sensitivity 89% and specificity 85%. However 22% of subjects with lowering of absCR had ADA stenoses &lt;50%, microvascular involvement, or belonged to the group of healthy volunteers. It was established that ADA relCR &lt;0.80 in patients with ADA absCR &lt;2.0 was a sensitive and specific sign of isolated ADA stenosis &gt;50%.

[The role of coronary reserve in diagnosis of hemodynamically significant stenoses in anterior descending and right coronary arteries: transthoracic ultrasound study]

Analysis of possibilities of transthoracic echocardiography (TTEchoCG) diagnosis of hemodynamically significant stenoses of anterior descending and right coronary arteries (ADCA and RCA) based on Doppler assessment of coronary reserve (CR) was carried out in 73 patients with cardiac pain syndrome (mean age 48+/-7 years, 60 men, 13 women). As a referent method we used coronary angiography. Coronary blood flow at baseline and during administration of a vasodilator (dipyridamole up to 0.84 mg/kg) was assessed by broadband ultrasound transducer in the mode of noncontrast tissue second harmonic imaging in distal segments of ADCA and posterior interventricular artery (PIVA). CR was calculated as ratio of peak hyperemic to baseline diastolic coronary blood flow velocity. CR &lt;2.0 was diagnosed as lowered. We found that TTEchoCG was simple noninvasive method of assessment of CR in distal thirds of ADCA and PIVA, which can be fulfilled in 90 and 86%of patients, respectively. We also revealed that hemodynamically significant stenoses of ADCA and PIVA caused CR lowering distally to zone of stenosis and that degree of CR lowering depended on severity of vascular narrowing. We found that CR&lt;2.0 in distal third of ADCA was a predictor of its &gt;50% narrowing with sensitivity 78%, specificity 85%, positive predictive value (PPV) 67%, and negative predictive value (NPV) 90%. In the presence of &gt;70% ADCA stenosis sensitivity and NPV of the parameter reached 100%. We revealed that CR&lt;2.0 in PIVA served as a marker of &gt;50% RCA stenosis with sensitivity 88%, specificity 86%, PPV 68%, and NPV 95%. In the presence of &gt;70% RCA stenosis sensitivity and NPV of the parameter rose up to 92 and 97%, respectively.

Transthoracic echocardiography in the detection of chronic total coronary artery occlusion

AIMS

The aim of our study was to detect chronic total occlusion of the left anterior descending coronary artery (LAD), circumflex coronary artery (Cx), and right coronary artery (RCA) using transthoracic echocardiography (TTE) in 110 consecutive patients who underwent coronary angiography for investigation of angina.

METHODS AND RESULTS

Coronary blood flow direction was assessed in the epicardial collaterals [distal LAD (dLAD), obtuse marginal branches and right posterior descending artery (PDA)] and intramyocardial collaterals [LAD septal branch (SB LAD) and RCA septal branch (SB RCA)]. The sensitivity and specificity of retrograde flow for identification of the occluded LAD by TTE in the dLAD only were 78 and 96%, respectively, and those in both dLAD and SB LAD were 89 and 96%, respectively. The retrograde SB LAD flow detects proximal LAD occlusion with 88% sensitivity and 75% specificity. The sensitivity and specificity of retrograde flow for identification of the occluded RCA by TTE in the PDA only were 79 and 97%, respectively, and those in both PDA and SB RCA were 89 and 97%, respectively. The retrograde SB RCA flow does not allow us to differentiate between proximal and non-proximal RCA occlusion. Transthoracic echocardiography is not a method for diagnosing Cx occlusions as the success in visualizing the Cx epicardial collaterals was achieved in 31% of cases only.

CONCLUSION

TTE is a sensitive and highly specific non-invasive method for diagnosis of LAD and RCA occlusions, based on the detection of the coronary blood flow direction in the epicardial and intramyocardial collaterals.

[High frequency transthoracic echocardiography in diagnosis of chronic occlusions of major coronary arteries]

Comparative analysis of possibilities of transthoracic echocardiography (TTE) and coronary angiography in diagnosis of chronic occlusions of anterior descending (ADA), circumflex (CA), and right coronary (RA) arteries was carried out in 100 patients (90 men, 10 women, mean age 51 +/- 11 years). With the help of TTE we analyzed direction, structural and temporal parameters of coronary blood flow in zones of potential epicardial and intramyocardial collateral filling: for ADA - in distal segment (dADA) and septal branches (SBADA), for CA - in obtuse marginal branches (OMB), for RCA - in posterior interventricular artery (PIA) and septal branches (SBRCA). We found that TTE was a sensitive and highly specific method of diagnosis of ADA and RCA occlusions, but did not allow to diagnose adequately occlusions of CA. We proved that main criterion of ADA occlusion was registration of retrograde or retroanterograde collateral blood flow in dADA or SBADA. Sensitivity of detection of inverted blood flow in dADA without consideration of direction of blood flow in SBADA in diagnosis of ADA occlusions was 77%, with consideration of SBRCA - 85%, specificity - 97%. Detection of retrograde or retroanterograde blood flow in SBADA was indicative of proximal level of artery lesion with sensitivity 100% and specificity 75%. Detection of retrograde or collateral flow in PIA or SBRCA was found to be main criterion of RCA occlusion. Sensitivity of detection of inverted blood flow in PIA without taking into account direction of blood flow in SBRCA in diagnosis of RCA occlusions was 77%, with consideration of SBRCA - 88%, specificity - 98%. The study of lat flow in SBRCA did not allow to determine accurately the level of artery lesion.

[Current methods of noninvasive imaging of coronary arteries in the diagnosis of coronary atherosclerosis]

The lecture contains: presentation of possibilities of ultrasound and tomographic methods of investigation in visualization of major coronary arteries; consideration in a comparative aspect of main advantages, disadvantages and limitations of these methods in diagnostics of coronary atherosclerosis; analysis of indications for application and perspectives of their use in everyday clinical practice in patients with a diagnosis of possible or verified ischemic heart disease.

[Revascularization interventions in the left coronary artery system: transesophageal Doppler ultrasound study]

AIM

To elucidate the role of evaluation of coronary reserve in coronary sinus by transesophageal doppler for assessment of efficacy of various revascularization interventions.

MATERIAL AND METHODS

Patients with isolated stenoses of either left anterior descending or circumflex coronary artery subjected to stenting (n=14) and with two vessel disease subjected to bypass surgery (n=20). Dipyridamole was used as a stress agent. Coronary reserve was calculated as ratio of peak hyperemic to baseline antegrade coronary sinus blood flow velocity (CR(P)) and as ratio of hyperemic to baseline antegrade coronary sinus volume blood flow (CR(VBF)).

RESULTS

In patients with atherosclerotic lesions in the system of left coronary artery normalization of CR(P) after stenting of single vessel stenoses and of CR(VBF) after bypass surgery in two vessel disease were markers of efficacy of revascularization with sensitivity 75 and 71%, respectively.

[Transesophageal and transthoracic ultrasound study of coronary arteries in diagnosis of atherosclerosis and assessment of coronary reserve]

The lecture deals with methodological aspects and diagnostic potential of the use of novel ultrasound technologies -- transesophageal and transthoracic doppler ultrasonography of coronary arteries for noninvasive assessment of coronary blood flow and coronary reserve. It contains detailed description of technique of visualization of coronary arteries from transesophageal and from transthoracic approaches and interpretation of dopplero-graphic parameters of laminar and turbulent coronary flows. Diagnostic role of the use of contrast echo imaging of coronary arteries is also discussed and dopplero-graphic criteria of occlusion and hemodynamically significant coronary artery stenosis as well as characteristics of normal and lowered coronary reserve are presented.

Reduced coronary flow reserve in the coronary sinus is a predictor of hemodynamically significant stenoses of the left coronary artery territory

AIM AND METHODS

The role of transesophageal Doppler assessment of coronary flow reserve (CFR) in the coronary sinus (CS) in the diagnostics of significant left coronary artery (LCA) stenoses was studied in 65 CAD patients with angiographically proven >50% stenotic atherosclerosis of the LCA territory (38--with isolated left anterior descending artery (LAD) or left circumflex artery (Cx) stenosis; 27--with both LAD and Cx stenoses) and 31 healthy volunteers (all men). Dipyridamole was used as a stress agent. The antegrade phase of coronary flow in the CS moving into the right atrium was analysed. CFR in the CS was calculated in two ways: (1) as ratio of hyperemic to baseline peak antegrade flow velocity (CFRp); (2) as ratio of hyperemic to baseline volumetric blood flow velocity (CFRv). The level of CFR <2.0 in both ways of calculation was diagnosed as reduced.

RESULTS

CAD patients compared with healthy volunteers had significantly lower CFRp (1.51+/-0.44 and 2.57+/-0.79; p<0.001) and CFRv (2.21+/-1.18 and 5.43+/-2.83; p < 0.001) in the CS. CFRp <2.0 in the CS was a predictor of significant stenoses of the LCA with sensitivity of 89% and specificity of 76%, while CFRv <2.0 was a predictor of significant stenoses of the LCA with sensitivity of 49% and specificity of 97%. CFRp <2.0 in the CS was registered in 96% of CAD patients with two-vessel lesion and in 84% of CAD patients with one-vessel lesion, while CFRv <2.0 in the CS was revealed in 85% of CAD patients with two-vessel lesion and only in 26% of CAD patients with one-vessel lesion. Sensitivity and specificity of CFRv <2.0 in the CS in the diagnostics of significant two-vessel lesion of the LCA were 85% and 84%, respectively.

CONCLUSIONS

Thus, the reduced CFR in the CS is a sensitive and specific predictor of LCA stenoses. A decrease of both CFRp <2 and CFRv <2.0 in the CS is a predictor of significant two-vessel lesion of the LCA, while a decrease of only CFRp <2.0 in the CS is a predictor of significant one-vessel lesion of the LCA.

Simultaneous transesophageal Doppler assessment of coronary flow reserve in the left anterior descending artery and coronary sinus allows differentiation between proximal and non-proximal left anterior descending artery stenoses

AIM AND METHODS

The role of simultaneous transesophageal Doppler assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) and coronary sinus (CS) in the diagnostics of hemodynamically significant LAD stenoses of various localization was studied in 16 CAD patients with angiographically proven >50% stenotic atherosclerosis of the LAD (nine--in the proximal third, seven--in the mid and/or distal third) and 23 healthy volunteers (all men). Dipyridamole was used as a stress agent. The diastolic phase of coronary flow in the LAD and the antegrade phase of coronary flow in the CS were analyzed. CFR in the LAD and CS was calculated in two ways: one--as ratio of peak hyperemic flow velocity to the peak baseline blood flow velocity (CFR by Vp); two--as ratio of volume hyperemic blood flow velocity to the volume baseline blood flow velocity (CFR by VBF). The level of the CFR <2 in both ways of calculation was diagnosed as reduced.

RESULTS

It was found that in CAD patients with LAD proximal stenosis the values of CFR in the LAD were significantly lower than those in healthy individuals by both Vp (1.87 +/- 0.43 and 3.54 +/- 0.82; P<0.001) and VBF (1.79 +/- 0.77 and 3.85 +/- 1.25; P<0.01). In proximal stenosis CFR in the LAD by Vp was significantly lower than that in non-proximal stenosis (1.87 +/- 0.43 and 3.31 +/- 1.44; P<0.05). Sensitivity and specificity of CFR <2 in the LAD by Vp in the diagnostics of LAD proximal stenosis were 56% and 97%, respectively; and CFR <2 in the LAD by VBF--89% and 93%, respectively. In CAD patients with both proximal and non-proximal LAD stenoses CFR in the CS by Vp was significantly lower than that in healthy volunteers and was 1.74 +/- 0.53, 1.63 +/- 0.30 and 2.56 +/- 0.87; P<0.05, respectively. Sensitivity and specificity of CFR <2 in the CS by Vp in the diagnostics of hemodynamically significant LAD stenoses were 75% and 70%, respectively. The values of CFR in the CS by VBF in CAD patients and healthy volunteers did not differ significantly.

CONCLUSIONS

Thus, simultaneous evaluation of CFR in the LAD and CS makes it possible to diagnose hemodynamically significant LAD stenoses and to differentiate between proximal and non-proximal impairments.

[Propranolol treatment of effort angina in patients with arterial hypotension]

AIM

To compare antianginal efficacy and tolerability of propranolol therapy in patients with stable angina pectoris and chronic hypotension (Hpts) and normotensive patients with angina of effort (Npts).

MATERIAL AND METHODS

A randomized, single-blind, placebo-controlled study was made in 35 Hpts and 38 Npts was made using bicycle exercise tests, echocardiography, stress myocardial scintigraphy with 77-199.

RESULTS

Acute bicycle exercise tests showed high anti-ischemic activity of propranolol in 86% Hpts and 65% Npts. Stable antianginal propranolol effect in 57% Hpts was accompanied with a decrease of myocardial perfusion defect. Secondary resistance or pseudotolerance to an antianginal effect of propranolol was observed in 43% Hpts in 4-12 weeks (vs 0 of Npts; p < 0.01) as evidenced by T-199 stress myocardial scintigraphy. Hpts with secondary resistance and pseudotolerance to propranolol had lower control hypotension and bradicardia (p < 0.05), more anginal attacks (p < 0.001).

CONCLUSION

Hpts had rapidly developing secondary resistance and pseudotolerance to propranolol antianginal effect, bad tolerability of the drug.

[Stress-ultrasound study of hemodynamic reserve of aortic compression chamber in atherosclerosis: effect on coronary blood flow]

AIM

To study the role of hemodynamic reserve of aortic compression chamber (ACC) in compensation of coronary blood flow during stress.

MATERIAL

Ninety three subjects (78 men and 15 women) including 74 patients with chronic ischemic heart disease (mean age 50-/+7 years) and 19 healthy volunteers (mean age 45-/+5 years).

METHODS

Hemodynamic reserve of ACC was defined as volume of blood deposited in walls of ascending aorta at the end of systole. M-mode cross-section of ascending aorta was obtained during transesophageal pacing with long-axis view from parasternal approach. Antegrade and retrograde blood flow in the ascending aorta was registered through suprasternal approach with wave-impulse doppler. Movements of left ventricular walls were assessed via apical approach with the use of 12-segment model. The following factors were directly determined or calculated: morphometrical parameters, elasticity and rigidity of aorta, temporal and amplitudal characteristics of antegrade and retrograde flow in ascending aorta, stroke volume, cardiac output, coronary fraction of stroke volume, coronary blood flow. Results. During transesophageal pacing in healthy subjects elastic ACC despite increasing limit of diastole duration accumulated energy, pressure and part of volume of moving blood, providing sufficient flow in the coronary circulation. In patients with ischemic heart disease rigid ACC functioned as hydrodynamically inert tube being the cause of progressive diminishment of coronary flow.

CONCLUSION

Decreased capacitance and functional reserves of ACC in atherosclerosis constituted the first hemodynamic barrier determining deficit of coronary blood flow during stress.

[Stress echocardiography with the use of impulse wave tissue Doppler technology in diagnosis and quantitative evaluation of concealed myocardial ischemia]

AIM

To elucidate the role of the use of impulse-wave tissue doppler technology during stress echocardiography with transesophageal atrial pacing for diagnosis and evaluation of concealed myocardial ischemia.

MATERIAL

Patients (n=82, 72 men, 10 women, mean age 43+/-10 years) with syndrome of cardiac pain of obscure etiology.

METHODS

Regional contractility of left ventricular wall was studied through apical approach with the use of 12-segment model. Peak systolic velocity of myocardial segments (S, cm/s), its acceleration (Asl, cm/s(2)), duration of period of preejection (PEP, ms) and isovolumic relaxation time (IVRT, ms) of each segment were calculated at rest, and during subthreshold and threshold pacing.

RESULTS

Concealed myocardial ischemia was revealed by stress echo in 44 patients. Total number of analyzed segments was 984 and parameters of impulse-wave tissue doppler could be measured in 959 (97%) segments. At peak pacing rate during stress test 789 (82%) segments were normokinetic, 142 (15%) - hypokinetic, 20 (2%) - akinetic, and 8 (1%) - dyskinetic. Absence of increase or decrease of S and prolongation of PEP by 10% or more from baseline during stress test were found to be predictors of myocardial ischemia (sensitivity 35 and 75%, respectively, specificity 37 and 81%, respectively), and criteria of objectification of zones of left ventricular wall with impaired contractility (sensitivity 51 and 75%, respectively, specificity 52 and 76%, respectively). During stress echocardiography only dynamics of myocardial IVRT reflected the state of regional left ventricular diastolic function.

CONCLUSION

Stress echocardiography with transesophageal atrial pacing combined with impulse-wave tissue doppler imaging is a highly informative method of diagnosis and quantitative assessment of concealed myocardial ischemia.

[The role of transesophageal dopplerographical assessment of coronary reserve in coronary sinus in diagnosis of hemodynamically significant left coronary artery stenoses]

AIM

To assess the role of estimation of coronary reserve in coronary sinus by transesophageal doppler during dipyridamole stress test for diagnosis of hemodynamically significant left coronary artery stenoses.

MATERIAL

Patients with angiographically proven left coronary artery stenoses (n=29) and 25 healthy volunteers.

METHODS

Coronary reserve was calculated as 1) ratio of peak to basal diastolic coronary flow velocity (V(p)CR), and 2) ratio of volume coronary blood flow velocity before and during hyperemia (VBF CR). Coronary reserve <2 was considered decreased.

RESULTS

Compared with healthy subjects patients with coronary heart desease had significantly lower V(p)CR (1.67+/-0.44 and 2.56+/-0.87, respectively, p<0.001) and VBF CR (2.42+/-1.37 and 5.53+/-3.65, respectively, p<0.001). Sensitivity and specificity of coronary reserve below 2 for diagnosis of left coronary artery stenoses was 72 and 72%, respectively, for V(p)CR, and 49 and 96%, respectively, for VBF CR. VBF CR below 2 was a marker of severe double vessel left coronary artery disease. V(p)CR <2 was associated with single vessel stenoses within left coronary artery system.

CONCLUSION

The use of evaluation of coronary reserve by transesophageal dopplerography for diagnosis of left coronary artery stenoses is methodologically correct. Level of coronary reserve in coronary sinus can be considered an integral parameter characterizing total left coronary artery atherosclerotic damage.

Diagnostics of main coronary artery stenoses and occlusions: multiplane transoesophageal Doppler echocardiographic assessment

AIM AND METHODS

The possibility of using multiplane transoesophageal echocardiography (TEE) and quantitative coronary angiography (QCA) in the diagnostics of stenotic atherosclerosis of the main coronary arteries in a comparative aspect were studied in 94 patients with coronary artery disease (men, mean age 52 +/- 7 years). Coronary arteries stenoses were calculated with Doppler echocardiography using a modified continuity equation: stenosis (%)=100 x(1-prestenotic VTI(d)/stenotic VTI(d)) where prestenotic VTI(d), (cm)=diastolic velocity integral in the prestenotic zone, and stenotic VTI(d), (cm)=in the trans-stenotic zone.

RESULTS

High sensitivity and specificity of TEE in the diagnostics of stenotic and occlusive atherosclerosis of coronary arteries were revealed. They measured 88% and 98% for the left main coronary artery (LMCA), 97% and 67% for the left descending artery (LDA), 95% and 92% for the circumflex artery (CX), 83% and 97% for the right coronary artery (RCA), respectively. A high correlation was found between the results of TEE and QCA in the diagnostics of coronary stenoses which were made for the LMCA (r=0.82P <0.001), LDA (r=0.84, P<0.001), CX (r=0.85,P <0.001), and RCA (r=0.84, P<0.001). We developed Doppler echocardiography criteria for haemodynamically significant stenoses of coronary arteries (>50%) according to a peak diastolic velocity of the coronary blood flow, calculated as 1.4m.s(-1)for the LMCA, 0.9m.s(-1)for the LDA, and 1.1m.s(-1)for the CX. We determined Doppler echocardiography criteria of coronary arteries occlusions such as a 'break' of colour mapping, absence of Doppler spectrum and retrograde blood flow during late diastole.

CONCLUSION

Transoesophageal Doppler evaluation of coronary blood flow with application of a modified continuity equation is an accurate, non-invasive method of coronary arteries stenoses diagnostics.