Portal Hypertension Flashcards
Portal hypertension is defined by
Portal hypertension is defined by a portal pressure gradient (the difference in pressure between the portal vein and the hepatic veins) greater than 5 mm Hg
collateral network
The collateral network through the coronary and short gastric veins to the azygos vein is clinically the most important because it results in the formation of esophagogastric varices.
other sites include a recanalized umbilical vein from the left portal vein to the epigastric venous system (caput medusae), retroperitoneal collateral vessels, and the hemorrhoidal venous plexus
splanchnic hyperemia
a major contributor to the maintenance of portal hypertension as portal systemic collaterals develop
The most common cause of prehepatic portal hypertension
portal vein thrombosis
Isolated splenic vein thrombosis (left-sided portal hypertension)
is usually secondary to pancreatic inflammation or neoplasm.
> gastrosplenic venous hypertension, with superior mesenteric and portal venous pressures remaining normal.
The left gastroepiploic vein becomes a major collateral vessel, and gastric rather than esophageal varices develop.
Tx Splenectomy
The most common cause of intrahepatic presinusoidal hypertension
is schistosomiasis.
alcoholic cirrhosis
the most common cause of portal hypertension in the United States, usually causes increased resistance to portal flow at the sinusoidal (secondary to deposition of collagen in the space of Disse) and postsinusoidal (secondary to regenerating nodules distorting small hepatic veins) levels.
Posthepatic or postsinusoidal causes of portal hypertension are rare
they include Budd-Chiari syndrome (hepatic vein thrombosis), constrictive pericarditis, and heart failure
Upper GIT Bleeding Tx
-securing the airway
- two large-bore intravenous [IV] lines
- fluid infusion
- type and crossmatch of blood
- judicious blood and products transfusion
- restrictive transfusion (transfusion when the hemoglobin levels fell below 7 g/dL) > better survival at 6 weeks and reduced risk of rebleeding.
- Endoscopic treatment (e.g., sclerosis or ligation)
- Balloon tamponade > lifesaving
Band ligation Vs Sclerotherapy , and When
band ligation is better than sclerotherapy in the initial control of bleeding and is associated with fewer complications
sclerotherapy > may increase portal pressures
Early endoscopy, preferably within 12 hours of admission
Pharmacotherapy
- antibiotic prophylaxis should be initiated.
- somatostatin and its longer-acting analogue octreotide
> for control of acute variceal bleeding
> adjunct to endoscopic therapy
In severe cases of hemorrhage
> vasopressin can be used to diminish splanchnic blood flow.
> nitroglycerin should be simultaneously infused and then titrated to achieve blood pressure control.
Sengstaken-Blakemore tube
- immediate cessation of bleeding in more than 85% of patients
disadvantages :
- recurrent hemorrhage in up to 50% of patients after balloon deflation
- considerable discomfort for the patient
- high incidence of serious complications when it is used incorrectly by an inexperienced healthcare provider
When to Use TIPS ?
- preferred treatment for acute variceal bleeding when pharmacotherapy and endoscopic treatment fail.
- With TIPS, a functional portacaval side-to-side shunt is established.
- TIPS is able to control bleeding in almost all patients. However, TIPS is associated with risk of encephalopathy.
When Early TIPS indicated ?
Use of TIPS in patients with multiorgan failure or in patients with decompensated liver disease is associated with high 30-day mortality. In such patients, early use of TIPS, rather than after failure of other therapies, may be associated with better outcomes.
PTFE or no ?
Use of polytetrafluoroethylene (PTFE)-covered stents has been a major step forward. PTFE stents have higher patency rates over time and reduced mortality rates.
Modified Sengstaken-Blakemore tube
See
Prevention of Recurrent Variceal Hemorrhage
- nonselective β-adrenergic blockade > decreases the recurrent hemorrhage and decreased mortality.
- The combination of a beta blocker and long-acting nitrate (e.g., isosorbide 5-mononitrate) more effective than variceal ligation
- variceal ligation and nonselective beta blockade is more effective than variceal ligation alone
major limitation of TIPS
high incidence (up to 50%) of shunt stenosis or shunt thrombosis within the first year
What causes Shunt stenosis
secondary to neointimal hyperplasia, is more common than thrombosis and can often be resolved by balloon dilation of the TIPS or, in some cases, by placement of a second shunt.
What is used to decrease the incidence of thrombosis or stenosis
TIPS stenosis and occlusion have become less frequent with the use of PTFE-covered stents.
Advantages of TIPS
1- nonoperative approach
> short-term portal decompression
2- Liver transplantation candidates who fail to respond to endoscopic therapy or pharmacotherapy
3- advanced hepatic functional decompensation who are unlikely to survive long enough for the TIPS to malfunction.
4- Because it functions as a side-to-side portosystemic shunt, TIPS is also effective for the treatment of medically intractable ascites.
How to Do TIPS
- The inferior vena cava is accessed through right internal jugular vein.
- If the right internal jugular vein is unsuitable, the left internal jugular vein may also be used.
- 5F catheter is placed into the right hepatic vein and wedged into a peripheral branch.
- Wedged hepatic venography is then performed with CO2 gas to opacify the portal venous system.
- Using the wedged hepatic venogram image as a guide, a needle is advanced through the wall of the right hepatic vein and directed in an anteroinferior direction to access the right portal vein.
- Once the portal vein is cannulated, CO2 is injected into the parenchymal tract to exclude transgression of the bile duct or hepatic artery.
- Once proper placement is confirmed, TIPS endoprosthesis is deployed, which creates a shunt between the portal vein and the hepatic vein, thus decreasing resistance and decompressing varices
Nonselective shunts
- The end-to-side portacaval shunt is the prototype of nonselective shunts
- All the other nonselective shunts maintain continuity of the portal vein, thereby connecting the portal and systemic venous systems in a side-to-side fashion
- side-to-side portosystemic shunts are the most effective shunt procedures for relieving ascites as well as for preventing recurrent variceal bleeding.
Because they completely divert portal flow, like the end-to-side portacaval shunt, however, side-to-side shunts also accelerate hepatic failure and lead to frequent postshunt encephalopathy.
Major Disadvantage of Non selective Shunt
nonselective shunts effectively decompress varices. Because of complete portal flow diversion, however, they are complicated by frequent postoperative encephalopathy and accelerated hepatic failure.
When to use non selective Shunt
- rarely indicated.
- TIPS, also a nonselective shunt, is the preferred therapy for most situations in which nonselective shunts were previously used (e.g., patients with both variceal bleeding and medically intractable ascites).
- In general, a nonselective shunt is constructed only when a TIPS cannot be performed or when a TIPS fails.
Selective Shunts
The distal splenorenal shunt consists of anastomosis of the distal end of the splenic vein to the left renal vein and interruption of all collateral vessels (e.g., coronary vein and gastroepiploic veins) that connect the superior mesenteric vein and gastrosplenic components of the splanchnic venous circulation
> results in separation of the portal venous circulation into a decompressed gastrosplenic venous circuit and high-pressure superior mesenteric venous system that continues to perfuse the liver
Splenorenal Shunt ( Non Selective ) Proximal not distal
The conventional splenorenal shunt consists of anastomosis of the proximal splenic vein to the renal vein. Splenectomy is also performed.
Because the smaller proximal rather than the larger distal end of the splenic vein is used, shunt thrombosis is more common after this procedure than after the distal splenorenal shunt
Contraindications for Distal splenorenal Shunts
- distal splenorenal shunt tends to aggravate rather than to relieve ascites. Thus, patients with medically intractable ascites should not undergo this procedure
- Prior Splenectomy
- A splenic vein diameter less than 7 mm is a relative contraindication
Partial Shunt
- small-diameter interposition portacaval shunt using a PTFE graft, combined with ligation of the coronary vein and other collateral vessels
- When the prosthetic graft is 10 mm or less in diameter, hepatic portal perfusion is preserved in most patients, at least during the early postoperative interval.
- lower frequency of encephalopathy after the partial shunt but similar survival after both types of shunts ( Partial and nonselective )
- Early experience with this small-diameter prosthetic shunt is that less than 15% of shunts have thrombosed, and most of these have been successfully opened by interventional radiologic techniques.
after TIPS fails what to do
distal splenorenal shunt is likely to remain a more durable long-term solution and a reasonable alternative for TIPS failure.
Patients with medically intractable ascites in addition to variceal bleeding
Patients with medically intractable ascites in addition to variceal bleeding are best treated with TIPS when less invasive measures fail to control bleeding.
If the TIPS eventually fails, an open side-to-side shunt can then be constructed if the patient has reasonable hepatic function and is not a transplantation candidate.
Definitive Therapy Fig
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Definitive Therapy 2
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