Distinct roles of tapered and uniform vessels in arterial trees revealed by viscoelastic analytical solutions

Abstract

Pulse wave propagation is intrinsically linked to both cardiovascular physiology and pathology. Although zero-dimensional (0D) and one-dimensional (1D) numerical models are widely used, they involve trade-offs among geometric fidelity, parameter uncertainty, and computational cost. Analytical approaches offer high computational efficiency but have traditionally been limited to uniform and elastic tubes, neglecting the critical effects of vessel tapering and wall viscoelasticity. In this study, a generalized frequency-domain analytical framework is proposed for geometrically heterogeneous arterial networks comprising both tapered and uniform vessels through a unified junction formulation. The framework is systematically validated against high-precision 1D numerical simulations using single-vessel and artery tree network geometries. The results demonstrate that tapered and uniform vessels play fundamentally different roles in arterial wave propagation. Geometric tapering introduces distributed wave reflections and substantially modifies input impedance, whereas wave propagation in uniform vessels is governed primarily by terminal impedance and blood viscosity. In complex arterial trees, proximal tapered arteries predominantly regulate central wave transmission, while distal uniform arteries mainly contribute to peripheral impedance and cumulative viscous dissipation. Under the conditions considered in this study, wall viscoelasticity primarily attenuates high-frequency waves but has little influence on the wave dynamics of uniform vessels. Furthermore, incorporating a resistance-based ( R 0 D ) correction effectively reduces errors in distal vessels. Overall, the proposed framework provides a computationally efficient platform for global wave propagation analysis and demonstrates particular utility for proximal pressure and impedance analysis. Following validation against patient-specific data, it may also provide a useful computational tool for future investigations of central aortic hemodynamics.