Spectrum of hepatofugal collateral pathways in portal hypertension: an illustrated radiological review

Abstract

The purpose of this article is to describe the various portosystemic collateral pathways pertinent to portal hypertension on multi-detector row computed tomography (MDCT) and their clinical relevance, with special emphasis on the uncommon ones. The knowledge and understanding of the various patterns of portosystemic collateral channels has important implications both for the clinician and the interventionist. MDCT with its advanced post processing capabilities can exquisitely demonstrate these vascular pathways to help in therapeutic decision making.Teaching points• Portosystemic collaterals are an important cause of bleeding and hepatic encephalopathy.• Radiologists should be familiar with the imaging findings to effectively identify them.• Pre-operative knowledge of portosystemic collaterals is essential to avoid inadvertent vascular injury.

A Comprehensive Review of Portosystemic Collaterals in Cirrhosis: Historical Aspects, Anatomy, and Classifications

“…Portosystemic pathways are normally present embryonic channels that open up in presence of PHT [13]. The common and uncommon portosystemic pathways in cirrhosis and portal hypertension are shown in Table 1 [17–19]. In odd cases, tracheal and bronchial varices also form through efferents of esophageal varices that drain into the bronchial and pulmonary veins connected through bronchial plexus venous system [20].…”

“…(b) Classification based on the inflow pathway: Type 1 consists of single afferent vein for the varices; Type 2 has multiple afferent vessels contributing to the variceal formation; Type 3 is similar to Type 2 but with additional small collateral/shunts directly communicating with outflow tract. Modified and redrawn from [17]. …”

Restructuring of the vascular bed in response to hemodynamic disturbances in portal hypertension

“…It then turns backward and passes from left to right behind the omental bursa and drains into the portal vein. Anastomoses between the left and right gastric veins and the left and short gastric veins, respectively indicated by terms “coronary vein” and “posterior gastric vein”, have clinical significance only in portal hypertension, because they are involved in the formation of esophageal and related with them paraesophageal varices[34]. …”

Utility of cone-beam computed tomography in the assessment of the porto-spleno-mesenteric venous system

“…Collateralization aims to return blood to the liver via porto-portal collaterals or into systemic circulation via porto-systemic collaterals or both (15). There are a few common and several uncommon sites for these collaterals (16). In cases of intrahepatic resistance, the flow is hepatofugal via portosystemic collaterals.…”

“…In the splenic territory, this delay is short compared to the delay in the superior mesenteric vascular bed. When there is obstruction to venous outflow, the delay is longer, and the contrast sometimes takes one of many tortuous routes (16). Hence, this delay cannot be arbitrary and is not always predictable.…”