PHASIC BLOOD FLOW AND ITS DETERMINANTS IN THE RIGHT CORONARY ARTERY

1937 ◽  
Vol 119 (3) ◽  
pp. 580-588 ◽  
Author(s):  
Donald E. Gregg
2020 ◽  
Author(s):  
Zhou Zhao ◽  
Chun Fu ◽  
Li-xue Zhang ◽  
Guo-dong Zhang ◽  
Yu Chen

Abstract Background: With the ageing of China's population, the incidence and mortality of coronary atherosclerotic heart disease (CAD) is increasing year by year, which brings a heavy burden to the family and society [1]. We aimed to analyse the strategy of coronary artery bypass grafting (CABG) in the right coronary artery and to compare the haemodynamic characteristics of the sequential grafts with those of single grafts and to observe the patency rate of those grafts for one week after the operation.Methods: A total of 242 patients (178 men, mean age 62.6±8.8 years) underwent right coronary artery bypass grafting in our hospital from October 2016 to January 2019. The blood flow (Q, ml/min), pulsatility index (PI) and related parameters of the grafts were measured and recorded by TTFM during the CABG. The patency of the grafts was evaluated by coronary computed tomography (CT) for one week after the operation. Results: The most common material used for the graft in the right coronary system of CABG is the greater saphenous vein (92.3%), followed by the radial artery (5.5%) and the internal mammary artery (1.9%). The highest frequency target of the right coronary artery is the posterior descending artery (PDA) (47.6%), followed by the right main coronary artery (RCA) (29.1%) and the posterior branch of the left ventricle (PL) (23.3%). The proportion of single grafts was the highest for the right coronary artery in CABG (178 cases, 67.9%), followed by a graft of the PDA-PL (42 cases, 16.0%) and other sequential grafts among the different coronary artery systems (including the system of the left anterior descending artery (LAD) and the left circumflex (LCX)). Whether there were sequential grafts of the PDA-PL or other sequential grafts among the different systems of the coronary artery, the instantaneous flow of a group of sequential grafts was higher than that of a single graft, and the difference had statistical significance (P < 0.01). However, there were no significant differences in the flow between the groups of sequential grafts (P = 0.410). Diastolic flow (DF) in the group of sequential grafts of the right coronary system was better than that in the non-sequential group (P < 0.001), and the difference had statistical significance. There was no significant difference between the DF of the groups of the other system of sequential grafts and that of the right coronary sequential grafts. Coronary artery CT suggested that there were 11 cases of poorly developing grafts or stenosis and occlusion a week after the operation, and those phenomenon mainly occurred in the group with a single graft. There was only one case that was occluded in the group of other systems of sequential grafts, and statistically significant differences existed between the two groups (P < 0.01).Conclusions: In our centre, the most common form of CABG in the right coronary artery system is a non-sequential vein bridge to the PDA. Whether there are sequential grafts of the PDA-PL or other sequential grafts among the different coronary artery systems, the instantaneous flow of a group of sequential grafts is higher than that of a single graft. DF in the group of sequential grafts of the right coronary system was better than that in the non-sequential group.


2008 ◽  
Vol 08 (03) ◽  
pp. 293-315 ◽  
Author(s):  
M. SINGH ◽  
D. LIEPSCH ◽  
JOYCE McLEAN ◽  
G. PALLOTTI

It is well known from fundamental fluid mechanics that separation regions occur at bends and bifurcations of blood vessels. In addition to this, a secondary flow is also created. This means that the flow is moving forward like a vortical plait. Vortices are created that move counterclockwise to each other perpendicular to the mainstream direction. Three-dimensional flow exists, which is totally different to the well-known parabolic flow in straight pipes under laminar flow conditions. Therefore, a short fundamental introduction to biofluid mechanics is presented in this paper. A coronary artery model with different bypasses is shown as an example. The coronary artery is a prominent cardiac vessel often affected by the atherosclerosis process, which can lead to its full blockage. Blood flow is restored by the construction of a bypass performed by implanting part of the saphenous vein. This bypass is subjected to varying flow conditions during the various phases of pulsatile blood flow. For precise location of the regions associated with flow abnormalities, flow visualization through the complete bypass, covering the arterial and bypass sections, is required. This forms the objective of the present work: to visualize flow changes in bypass models of the right coronary artery prior to its bifurcation under pulsatile flow conditions.


1994 ◽  
Vol 24 (4) ◽  
pp. 1012-1017 ◽  
Author(s):  
Louis I. Heller ◽  
Kevin H. Silver ◽  
Bernard J. Villegas ◽  
Sharon J. Balcom ◽  
Bonnie H. Weiner

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