Extreme theoretical pressure oscillations in coronary bypass

Pressure pulsation can cause strong pulsatile flow loads in both the internal and external portions of human blood systems, and thus can induce oscillatory motion in the enclosed blood. Stability, mode shape, and the maximum and minimum pressures are all influenced by the system characteristics and all these aspects should be analysed over the zone of typical excitations. More specifically, oscillatory behaviour is highly dependant on the length, diameter and elasticity of a bypass, the aging of the coronary system as well as of the characteristics of all the vessels around the heart. The analysis is based on a model of the vessels involved, and shows the essential effects in each component. It is found that even in the absence of a bypass graft, wave reflections from the narrowed coronary artery effect the pressure and flow both in the diseased vessel and in the bypass loop, and thus significantly change the response of even such a simplified system as presented here.