What is the expected change in flow direction of the hepatic veins during expiration in cases of constrictive pericarditis?

In constrictive pericarditis, the pericardial sac becomes thickened and fibrous, leading to impaired filling of the heart chambers during diastole. This results in elevated central venous pressures and altered hemodynamics, specifically affecting the systemic venous return. During expiration, there is an expected increase in intrathoracic pressure which causes a decrease in venous return to the heart.

In patients with constrictive pericarditis, the hepatic veins can demonstrate a notable flow reversal during expiration due to the increased pressure in the right atrium and the heart being unable to accommodate increased venous return. This elevated pressure can exceed that of the systemic venous pressure, leading to a situation where hepatic venous blood flow temporarily reverses, highlighting the significant hemodynamic consequences of the condition.

Thus, the expected change in flow direction of the hepatic veins during expiration in cases of constrictive pericarditis is indeed a reverse flow direction, which indicates the severe impact of the disease on vascular dynamics.