Perioperative observation and study of blood flow of different bypass form in right coronary artery bypass grafting
Authors: Zhao Zhou , Fu Chun , Zhang Li-xue , Zhang Guo-dong , Chen Yu 
Published: April 2020

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