Hemodynamic Mechanisms in Portal Hypertension

Portal hypertension arises from an abnormally elevated pressure in the portal venous system, most commonly as a consequence of cirrhotic remodelling of the hepatic microcirculation. Increased intrahepatic vascular resistance occurs through a combination of sinusoidal capillarisation, activation of hepatic stellate cells and perisinusoidal fibrosis. This structural alteration, together with dynamic changes in endothelial function and heightened vasoconstrictive signalling within the hepatic circulation, precipitates a backlog in portal inflow. Compensatory splanchnic vasodilatation driven by nitric oxide and other mediators further exacerbates the volume of blood entering the portal vein. Over time, this high-flow state promotes the development of portosystemic collaterals and variceal channels, which carry systemic risks of bleeding and organ dysfunction. Recent mechanistic insights have uncovered the role of angiogenic pathways, microvascular thrombosis and neurohumoral regulators in modulating these events, providing potential targets for novel therapeutic approaches aimed at reducing vascular resistance and controlling portal venous inflow.

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Hemodynamic Mechanisms in Portal Hypertension publication trend

The graph below shows the total number of articles in hemodynamic mechanisms in portal hypertension across all publications each year (not limited to Nature Index journals).

Technical terms

Portal hypertension: Elevation of blood pressure within the portal venous system above normal physiological levels.

Hepatic venous pressure gradient (HVPG): The difference between wedged and free hepatic venous pressures, reflecting portal pressure indirectly.

Splanchnic circulation: The vascular network supplying abdominal organs, whose vasodilatation modulates portal inflow.

Vasoactive agents: Pharmacological compounds that alter vascular tone, used to decrease portal pressure.

Variceal pressure: The blood pressure within portosystemic collateral vessels, indicative of bleeding risk.

References

1. An obscure cause of gastrointestinal bleeding: Recurrent duodenal variceal hemorrhage treated with intramuscular octreotide in the absence of portal hypertension. JGH Open (2022).
2. Short-term vasoactive agent treatment driven by physicians’ preference in acute esophageal variceal bleeding in a tertiary center. PeerJ (2019).
3. Validation of an Endoscopic Fibre‐Optic Pressure Sensor for Noninvasive Measurement of Variceal Pressure. BioMed Research International (2016).