Flow simulation of the intracoronary shunt tube for off-pump coronary artery bypass.

INTRODUCTION To simulate blood flow provided by the intracoronary shunt tube, and to clarify whether this method is actually suitable for Off-pump coronary artery bypass (OPCAB), we investigated the efficacy of the intracoronary shunt tube in a theoretical model on the basis of fluid dynamics. METHODS Fluid dynamics analysis was performed to simulate flow decrease after attachment on an intracoronary shunt model. RESULTS The flow ratio in the case of turbulent flow is in proportion to the ratio of the inner diameter to the third power, and that in the case of laminar flow is in proportion to the ratio of the inner diameter to the sixth power. When this analysis is applied to commercial shunt tubes, coronary flow was estimated as approximately 2-14% of pre-attachment flow in turbulent flow, and only less than 0.1% in laminar flow. CONCLUSIONS This result suggests that use of intracoronary shunt tubes in OPCAB may rarely contribute to maintenance of coronary flow, and they should be used carefully, especially in a jeopardized coronary artery.