Key result
Sequential venous grafts had a similar failure rate to normal grafts (36.8% vs 36.5%), despite significant differences in underlying hemodynamic mechanisms such as flow rate and wall shear stress.
Why the study?
In CABG, the patency of venous sequential grafts remains controversial, and hemodynamic factors are known to influence graft patency.
Does venous sequential grafting compared to normal grafting improve hemodynamic parameters and graft patency in patients undergoing CABG?
Does venous sequential grafting compared to normal grafting improve hemodynamic parameters and graft patency in patients undergoing CABG?
Computational modeling reveals that while sequential and normal venous grafts have similar failure rates, sequential grafts exhibit higher flow rates and wall shear stress but also regions of high oscillatory shear index.
Similar patency rates do not support preferring sequential grafts in CABG; leaves open whether hemodynamic differences influence long-term outcomes.
Background: In coronary artery bypass grafting (CABG), the patency of venous sequential graft remains controversial. Hemodynamic factors have been proved to be the important factors influencing graft patency. The objective of this study is to compare the patency of sequential grafts and normal grafts by hemodynamic environment. Methods: This study used a patient’s clinical data to construct a 0D/3D coupled multi-scale model, and used this model to calculate graft’s hemodynamics under two grafting methods. Meanwhile, CABG ideal models were constructed based on grafts’ flow data of 60 patients (63 normal grafts, 19 sequential grafts) to calculate grafts’ hemodynamics. Results: Based on the multi-scale model, it was found that the sequential graft flow and time average wall shear stress (TAWSS) were higher than normal graft, which was good for graft patency. But there were a flow separation region, some regions of high oscillatory shear index (OSI) and relative residence time (RRT) in sequential graft, which could lead to intimal hyperplasia. Based on ideal CABG models, it was known that failure rate of sequential and normal grafts were 36.8% and 36.5%, and there were significant differences between them in flow rate, TAWSS and OSI (sequential versus normal: flow rate (ml/min): [Formula: see text] versus [Formula: see text], TAWSS (Pa): [Formula: see text] versus [Formula: see text], OSI: 0.[Formula: see text] versus [Formula: see text]). Conclusion: For saphenous venous graft (SVG), although the normal graft has similar patency with the sequential graft, the hemodynamic mechanism behind it is different. In flow rate and WSS, sequential grafts have an advantage over normal grafts. But there are high OSI and RRT regions in sequential grafts.
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Mao et al. (2020) studied Coronary artery bypass grafting (CABG) (n=60). Sequential venous graft vs. Normal venous graft was evaluated on Graft failure rate. Sequential venous grafts had a similar failure rate to normal grafts (36.8% vs 36.5%), despite significant differences in underlying hemodynamic mechanisms such as flow rate and wall shear stress.
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