Coronary bridgings  Velocity fields and parietal friction   The analysis of the velocities fields puts several major phenomena into light. The phase-shift between the two intake flows (1st case) can change the flow configurations. The recirculation zone nearby the higher lining is amplified by a backward flow from the graft in the receiving artery. This provokes the jet deflection towards the lower lining, while for two flows with a diastolic component (case 2), the jet is deviated towards the higher lining. Secondary flows are perturbed by the post-stenotic jet. The star shaped flow usually observed downstream from constriction, is sooner asymmetric during the cardiac cycle for case 1 compared to case 2. Furthermore, downstream from anastomosis, the secondary motions initiated by the opposition between the pressure transverse gradient and the centrifugal forces are also influence by the post-stenotic jet. The contrarotating structures which occupy the entire transverse section in the obstruct case (3), remained confined nearby the upper lining as soon as a remaining flow occurs in the sick artery. Emitting lines and secondary flows in transverse plans for three bridging models at various instants of the cardiac cycle Taking the stenosis into account generates downstream from it values of parietal shearing which are, considering their average, , are lower than those admitted in an artery (between 10 and 15 dyn/cm2, according to some authors), at the heel and suture line level. The friction values fluctuate in time and in the space limiting the high-risk areas, which are different from the occlusive case which is described in the literature. In addition to the negative effect of the suture and the non-concordance of the mechanical properties of the graft and the receiving artery, the site of junction seems to be one of the most favorable site for neointimous proliferation. Fluctuations at the resticking point can be also added as other damaging event. Moreover, these results are confirmed by the point of view of Reininger et al. (1994) : if it is considered that the thrombus growth due to the deposit of fibrine is correlated to the increased time of resting in the recirculation zone rather than to a strong or reduced parietal friction. An "intermediate" distance of bridging equivalent to three diameters could thus constitute a good compromise, as on the one hand, the recirculation zone does not expands as far as the heel during most of the cycle. On the other hand, the jets manage to preserve a non neglectable influence downstream from the junction, which minimizes the stasis zone at the point.