Multiscale Modelling of the cardiovascular system: application to the study of pulmonary and coronary perfusions in univentricular circulation

The objective of this studyis to compare the coronaryand pulmonaryblood flow dynamics resulting from two configurations of systemic-to-pulmonary artery shunts currently utilized during the Norwood procedure: the central (CS) and modified Blalock Taussig (MBTS) shunts. A lumped parameter model of the neonatal cardiovascular circulation and detailed 3-D models of the shunt based on the finite volume method were constructed. Shunt sizes of 3, 3.5 and 4mm were considered. A multiscale approach was adopted to prescribe appropriate and realistic boundaryconditions for the 3-D models of the Norwood circulation. Results showed that the average shunt flow rate is higher for the CS option than for the MBTS and that pulmonaryflow increases with shunt size for both options. Cardiac output is higher for the CS option for all shunt sizes. Flow distribution between the left and the right pulmonaryarteries is not completely balanced, although for the CS option the discrepancyis low (50–51% of the pulmonaryflow to the right lung) while for the MBTS it is more pronounced with larger shunt sizes (51–54% to the left lung). The CS option favors perfusion to the right lung while the MBTS favors the left. In the CS option, a smaller percentage of aortic flow is distributed to the coronarycirculation, while that percentage rises for the MBTS. These findings mayhave important implications for coronaryblood flow and ventricular function.