Hyperdynamic performance of remote myocardium in acute infarction
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During and after myocardial infarction (MI), compensatory contractile and structural changes taking place in the remote uninvolved myocardial regions have been well described, in both experimental and clinical settings. However, quantitative information on the changes in perfusion in these regions in relation to their altered contractile function have not been available. This study was designed to assess the in vivo relationship between contractile function and perfusion in remote uninvolved hypercontractile myocardial regions, subtended by angiographically normal coronary arteries in patients with MI and single-vessel coronary artery disease. We utilized two-dimensional echocardiography and 15O-water positron emission tomography imaging to assess regional contractile function and myocardial blood flow, respectively. Measurements were performed in nine patients with single-vessel coronary artery disease and angiographically confirmed recanalization of the infarct-related artery, 1-2 days after MI (group A). Only patients demonstrating severely impaired wall motion of the infarcted area and reactive hypercontractility of the remote uninvolved regions were enrolled. Seven patients with previous non-reperfused MI (6-8 months post-MI) served as a control (group B). Systolic wall thickening and regional myocardial blood flow data sets were created for the remote myocardial segments perfused by angiographically detected patent coronary arteries by assigning regions on the tomograms to equivalent echocardiographic segments. In the remote regions, wall thickening and regional myocardial blood flow were higher in group A patients by 26% (43 +/- 6% vs 34 +/- 4%; P = 0.005) and 20% (1.06 +/- 0.15 vs 0.89 +/- 0.06 ml.g-1 per minute; P = 0.019), respectively. For both groups of patients, a significant correlation (r = 0.67; P = 0.004) between systolic wall thickening and regional myocardial blood flow was obtained. Infarcted regions in both groups showed no systolic wall thickening. In this selected group of patients these data demonstrate: (1) a proportionate increase in contractility and regional myocardial blood flow in uninvolved territories in patients with recent and old MI; (2) the in vivo relationship between contractile function and myocardial perfusion in man in these regions. When infarcted zones in both groups are equally affected, enhanced levels of catecholamines and sympathetic drive as well as different loading conditions may account for the hyperkinetic performance and consequently for the increased perfusion level in uninvolved segments in patients with recent MI.Keywords:
Coronary arteries
Objective:To reveal the direct sign of competitive blood flow between the Left Internal Mammary Artery(LIMA) graft and native Left Anterior Descending artery(LAD).To summarize the flow dynamics characteristics.To find the reason of competitive blood flow and clinical significance.Methods:75 patient who had undergone coronary artery bypass grafting(CABG) were examined by color Doppler of coronary flow imaging(CDCFI) and peripheral blood vessel ultrasound almost 1 week postoperatively.The proximal and distal of the LIMA graft,anastomosis,and proximal and distal LAD were examined.Results:7 patients have competitive blood flow after CABG.Both LAD and LIMA graft showed mainly antegrade flow by CDCFI.The proximal portion of the LIMA showed a dominant systolic flow pattern by Ultrasound.Conclusion:CDCFI could reveal the direct sign of competitive blood flow between LIMA graft and native LAD.It could provide the evi-dence of indication of CABG if Summed up the reason of competitive blood flow.
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Coronary arteries
Circumflex
Lumen (anatomy)
Left coronary artery
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Regional myocardial flow distributions in Langendorff rat hearts under Tyrode and blood perfusion were assessed by tracer digital radiography (100-microm resolution). Flow distributions during baseline and maximal hyperemia following a 60-s flow cessation were evaluated by the coefficient of variation of regional flows (CV; related to global flow heterogeneity) and the correlation between adjacent regional flows (CA; inversely related to local flow randomness). These values were obtained for the original images (64(2) pixels) and for coarse-grained images (32(2), 16(2), and 8(2) blocks of nearby pixels). At a given point in time during baseline, both CV and CA were higher in blood (n = 7) than in Tyrode perfusion (n = 7) over all pixel aggregates (P < 0.05, two-way ANOVA). During the maximal hyperemia, CV and CA were still significantly higher in blood (n = 7) than in Tyrode perfusion (n = 7); however, these values decreased substantially in blood perfusion and the CV and CA differences became smaller than those at baseline accordingly. During basal blood perfusion, the 60-s average flow distribution (n = 7) showed a smaller CV and CA than those at a given point in time (P < 0.05, two-way ANOVA). Coronary flow reserve was significantly higher in blood than in Tyrode perfusion. In conclusion, the flow heterogeneity and the local flow similarity are both higher in blood than in Tyrode perfusion, probably due to the different degree of coronary tone preservation and the presence or absence of blood corpuscles. Under blood perfusion, temporal flow fluctuations over 60-s order are largely involved in shaping microregional flow distributions.
Coronary circulation
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128 human hearts including 70 males and 58 females in all age groups were used for the present study. Coronary arteries were dissected out from all the human hearts. The luminal diameter was studied in all the four major coronary arteries, namely, right coronary artery (RCA), left coronary artery (LCA), left anterior descending artery (LAD) and left circumflex coronary artery (LCX) in both the sexes. The histological sections were stained with H & E stain and the diameter was measured with the help of ocular micrometer. Among the four major coronary arteries luminal diameter is found to be more in LCA followed by LAD, RCA and LCX. Luminal diameter was found to be more in males as compared to females in all the four major coronary arteries. The data of present study can be useful for doing any instrumentation of coronary artery.
Coronary arteries
Circumflex
Left coronary artery
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The review covers possibilities of modern techniques of computer tomography (CT) of coronary arteries: electron beam tomography and 4-, 16-, 64-slice multi-spiral CT. Main studies conducted in this area are analyzed. Results of these studies (values of sensitivity and specificity, numbers of included patients, numbers of segments of coronary arteries which were excluded from analysis because of poor quality of images) are presented and compared. Problems of further development of CT of coronary arteries are also considered.
Coronary arteries
Spiral computed tomography
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The heart is covered with arteries that also known as the coronary artery which in blood vessel the oxygenated blood from the lungs is being transferred to the heart. The blood flow in human arterial system can be considered as a fluid dynamics problem. Simulation of blood flow in the coronary artery will provide a better understanding of the physiology of human body. The simulation also gives the doctors to predict the behaviour of the coronary artery blood flow to avoid any unwanted problems. The main objective of the project was to demonstrate and stimulate the blood flow in the coronary artery by using a Computational Fluid Dynamic (CFD) modelling approach. The simulation used software ANSYS Fluent 18.2 which provide us with the details of the behaviour of the blood flow. The steps of achieving the simulation will be shown in the report and also the parameters used for the simulation such as density of blood, viscosity of blood and the shear stress on the wall of the vessel. The project aims to see the effect of coronary artery bypass graft (CABG) with length 9mm and 10.5 mm towards the right coronary artery with plaque blocked within the artery simulation. The project will be stimulated the changes of velocity of the blood flow in the RCA.
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It is known that regional perfusion with hyper-thermal perfusate (42d`C) has a better effect than normother-mal perfusate in the treatment of malignant melanoma. This could be an effect of a greater skin blood flow during hyper-thermal perfusion. In the following article, the relation between skin/muscle blood flow during hyperthermal perfusion was studied using a strain-gauge plethysmograph. The relation between skin/muscle blood flow was the same throughout the perfusion. The better effect of hyperthermal perfusion than normothermal in treatment of malignant melanoma is not an effect of a better skin blood flow.A satisfactory circulation and passage of blood in a regionally isolated area is a prerequisite for the successful treatment of malignant tumours with cytostatic perfusion. In the case of malignant skin tumours, it is desirable to obtain as large a skin blood flow as possible, while maintaining only a slight blood flow to the underlying tissues. It is a well-known fact that an increase in the body temperature results in an increase in the blood flow to the skin. In the following experimental series, we investigated the value of hyperthermal perfusion (42d`C) and its effect on the relation, skin blood flow: muscle blood flow.We studied the blood flow in the lower extremities during perfusion with the aid of venous occlusion plethysmography using the strain-gauge technique.
Plethysmograph
Blood circulation
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The lack of reliable mechanical data on coronary arteries and, more specifically, on their wall strength hampers the application of numerical models and simulations to vascular problems, and precludes physicians from knowing in advance the response of coronary arteries to the different interventions. Studies of the mechanical properties of coronary arteries have been carried out almost exclusively on animals. Only a few studies have tried to characterize the in vivo behavior of human coronaries through tests under physiological conditions. In this work, the mechanical properties of human coronary arteries have been characterized. Whole samples from human right (RC) and left anterior descending (LAD) coronary arteries aged between 23 and 83 years have been studied by means of in-vitro tensile testing up to failure.
Coronary arteries
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Suction type stabilizers are popular for off-pump coronary artery bypass. However, arteries running deeply underneath fatty tissue are not stabilized well because the soft tissues act as cushions between the coronary artery and the stabilizer. We propose a simple method to stabilize and visualize intra fat coronary arteries. After dissection of target arteries, 5-0 polypropylene continuous over-and-over sutures are placed on the fat tissues along both sides of the coronary artery. These sutures are pulled laterally, and a suction stabilizer is placed so that the sutures lie under the legs of the stabilizer. Sutures fixed to the stabilizer legs with suction force reduce motion of the target vessel. Visualization of the coronary arteries is also improved because the banks of fat tissue become flat by pulling the sutures laterally.
Coronary arteries
Stabilizer (aeronautics)
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