This is a paper written by a group of reconstructive surgeons and school of computing. This study used computational fluid dynamics to model blood flow through ‘idealised sutured and coupled’ vessels. They investigate if the anastomotic technique affects intra vascular blood flow. They used computer aided three dimensional interactive application (CATIA) and computer aided design (CAD) and a microvascular anastomotic coupling (MAC) device to obtain results of a simulated anastomoses. They demonstrate the flow patterns in the two different anastomoses vary to produce different physical properties at the anastomotic site. Based purely on the simulated data gathered, it appears clot formation may be more likely using the sutured technique. I think this is an excellent use of modern computers and simulations techniques to try and get an informed answer re the above technique. This paper does, however, support the usual basic knowledge of all microvascular surgeons. Namely a sutured anastomosis should be done with the minimum number of sutures that is compatible with a well sealed anastomosis. It would suggest the coupled anastomosis has less thrombogenic potential.