Dual and context-dependent roles of blood viscosity in cirrhotic portal hypertension

Caiyi He1, Zhongjie Hu^2*

¹Clinical Medical College of Qinghai University, Xining 810000, China.

²Beijing You’an Hospital, Capital Medical University, Beijing 100069, China.

*Correspondence:

Zhongjie Hu; Email: yfcyt@139.com

Abstract

Portal hypertension is a major complication of cirrhosis characterized by increased intrahepatic resistance and hyperdynamic circulation. Emerging evidence suggests that hemorheological alterations may play a context-dependent dual role in this process. Increased sinusoidal blood viscosity may aggravate intrahepatic resistance, whereas decreased peripheral viscosity may facilitate splanchnic inflow and help sustain hyperdynamic circulation under specific clinical conditions. However, current evidence primarily stems from theoretical models, experimental studies, and a limited number of clinical observations, and it has not yet been established that blood viscosity is an independent upstream determinant of portal vein pressure. Therefore, this review synthesizes the existing evidence regarding the mechanistic link between blood viscosity and portal hypertension and proposes that blood viscosity be interpreted as a context-dependent modulator and amplifier of portal hypertensive pathophysiology in cirrhosis. We also discuss unresolved controversies, implications for different disease stages and specific clinical contexts, and potential directions for translational research.

Keywords: liver cirrhosis, portal hypertension, blood viscosity, hemorheology, hemodynamics