ABSTRACT
The aorta is the major blood vessel with spiral shaped geometry where the flow pattern is swirling in late systole. The swirling blood flow may have a positive physiological role in preventing cardiovascular diseases by reducing turbulent flow and enhancing mass transport. Several factors have shown to contribute to the formation of the swirling flow in the aorta such as the ventricular twisting, the 3D spiral shaped aorta, the pulsatile blood flow in the aorta and the motion of ascending aorta. Inspired by the above basic researches, the swirling flow mechanism has been applied to the vascular interventional therapies and the design of cardiovascular interventional devices. In the present review, the observation of swirling patterns in the aorta, its physiological significance, the factors contributing to its formation and its potential clinical application are summarized.
ABSTRACT
Objective To apply the swirling flow mechanism to the design of arterial prostheses with small diameters and the arterial bypass surgery to resolve the acute thrombus in small diameter prostheses after implantation, and lessen the restenosis of bypassed arteries due to the formation of internal hyperplasia. Method The computational fluid dynamics (CFD) method was used to investigate the flow field and wall shear stress distribution of a new graft, an S type bypass and an axis deviated arterial bypass, which all had the swirling flow. In addition, the platelet adhesion under swirling flow and internal hyperplasia in S-type bypass were measured. Results The swirling flow can apparently enhance the wall shear stress (WSS) and suppress the platelet adhesion and internal hyperplasia. Conclusions The swirling flow can significantly improve the flow field in arterial graft and bypass to inhibit the acute thrombus in small diameter prostheses and internal hyperplasia after bypass surgery.