Transjugular Intrahepatic Portosystemic Shunt
From Radipedia
- Portal hypertension is defined as PV pressures > 12mmHg
- Two mechanisms for cause of PHTN
- Deposition of collagen between cells in the spaces of Disse and hepatocyte swelling, both of which increase the sinusoidal pressure and cause a relative resistance to blood flow into the hepatic sinusoids
- Hemodynamic factors, including intrahepatic endogenous vasoconstrictors and mesenteric vasodilators, which increase blood flow and pressure in the portal venous system.
- Indications: intractible ascites, bleeding varices which have failed endoscopic management
- Contraindications: right heart failure, encephalopathy, PV thrombus, active infection, hypervascular hepatic tumor
- Placed between right hepatic vein and right portal vein after CO2 portography via hepatic vein
Patients experiencing increased portal venous pressure can see a reversal of flow in the portal system, changing form hepatopetal (toward the liver), to hepatofugal (away from the liver).
Normal Post Precedure Doppler Findings
- Stent Flow 50-270 cm/sec
- Varies within shunt with means from 79 cm/sec preshunt to 131 cm/sec postshunt
- Main portal vein velocity 20-50 cm/sec
Criteria for Compromised TIPS Function
- Shunt velocity of <50cm/sec
- Change in shunt velocity of 50cm/sec from prior
- Focal region of increased velocity in shunt or hepatic vein
- Hepatopedal flow right and left portal vein branches
- Hepatofugal flow in main portal vein
