Complications of Transjugular Intrahepatic Portosystemic Shunt
Complications of Transjugular Intrahepatic Portosystemic Shunt
Procedural complications are generally seen in 10% or fewer patients after TIPS.Severe life-threatening bleeding has been reported in 1% to 2% of cases because of either puncture of the liver capsule with resulting hemoperitoneum or inadvertent puncture of the biliary tree with resulting hemobilia. Other major complications include contrast medium induced renal failure, heart failure, stent migration, fever, infection, transient arrhythmias, and inadvertent puncture of the gallbladder or other organs adjacent to the liver. Hemolysis, which is typically self-limited and mild, is not uncommon after TIPS.
Although procedural complications are relatively infrequent, hepatic encephalopathy is a common complication after TIPS, with a frequency in the range of 20% to 30%. This figure is not unexpected: TIPS represents a side-to-side portosystemic shunt that often results in complete diversion of portal flow, as well as a proportion of hepatic arterial blood flow, into the shunt (hepatofugal flow).
Related to post-TIPS encephalopathy, but much more ominous, is the development of accelerated liver failure after TIPS as a result of a critical loss of hepatic perfusion. A retrospective study at the University of California, San Francisco, noted clinically significant increases in serum bilirubin or alanine aminotransferase levels or prolongation of the prothrombin time in over one fourth of patients after TIPS.This deterioration in liver function is typically transient, but in a minority (about 5%) of patients progressive liver failure develops leading to expedited liver transplantation or death. Determining the natural history of liver function after TIPS will be an important challenge in the years to come and will be important for the understanding of the long-term utility of TIPS as well as for optimal patient selection.
The 30-day mortality rate after TIPS varies from 3% to 44% but is typically in the range of 10% to 15%.Appropriate patient selection is the key to reducing the mortality rate after TIPS. Death after TIPS is usually related to decompensated hepatic function and is caused by liver failure, infection, renal insufficiency, or multisystem organ failure. The paradox is that patients in whom TIPS is most clearly indicated for refractory bleeding or ascites often have advanced liver disease and are at greatest risk of dying after the procedure. Identification of specific prognostic factors that will help identify patients at greatest risk of death after TIPS has therefore been undertaken in a number of studies. Independent prognostic variables identified in these studies have been used to formulate models and nomograms that can be used to calculate risk scores and the probability of short-term mortality after TIPS.Although this approach is clearly valuable, none of the predictive models published to date has been validated independently and prospectively. They are best used currently to complement clinical judgment and to counsel patients and their families accordingly. Another major problem that has limited the utility of TIPS is occlusion or stenosis of the shunt. Narrowing or occlusion of TIPS stents may occur as an early event secondary to thrombosis or more chronically over a period of weeks or months as a result of pseudointimal hyperplasia. The latter occurrence is the much more common cause of significant shunt insufficiency after TIPS. From 30% to 50% of cases of shunt insufficiency present with recurrent variceal hemorrhage or ascites; the remainder are discovered during routine monitoring, a practice necessitated by the high frequency of shunt dysfunction.The actuarial frequency of shunt insufficiency ranges from 30% to 50% at 12 months and 47% to 68% at 24 months.[The higher frequencies of shunt insufficiency reported by some centers reflect, in part, a more aggressive approach to monitoring of TIPS patency with frequent venography, as well as classification of any narrowing as an abnormality. A more conservative and practical approach is to monitor shunt patency every 3 to 4 months by Doppler ultrasound, with venography performed when a suggestive ultrasonographic abnormality is found.Such abnormalities include a reduction in mean peak flow velocity in the TIPS below 0.5 m/second, reversal of previous hepatofugal flow to hepatopetal flow, and reversal of flow in the stented hepatic vein. Useful venographic criteria for shunt insufficiency include narrowing of the lumen by 75% or more or a pressure gradient across the shunt of 15 mm Hg or higher.
The development of strategies to prevent shunt stenosis is the focus of active research. Potential strategies include pharmacologic approaches to reduce shunt intimal hyperplasia, the primary cause of stenosis, and engineering and testing of stents covered by selectively permeable materials like polytetrafluoroethylene.
Although procedural complications are relatively infrequent, hepatic encephalopathy is a common complication after TIPS, with a frequency in the range of 20% to 30%. This figure is not unexpected: TIPS represents a side-to-side portosystemic shunt that often results in complete diversion of portal flow, as well as a proportion of hepatic arterial blood flow, into the shunt (hepatofugal flow).
Related to post-TIPS encephalopathy, but much more ominous, is the development of accelerated liver failure after TIPS as a result of a critical loss of hepatic perfusion. A retrospective study at the University of California, San Francisco, noted clinically significant increases in serum bilirubin or alanine aminotransferase levels or prolongation of the prothrombin time in over one fourth of patients after TIPS.This deterioration in liver function is typically transient, but in a minority (about 5%) of patients progressive liver failure develops leading to expedited liver transplantation or death. Determining the natural history of liver function after TIPS will be an important challenge in the years to come and will be important for the understanding of the long-term utility of TIPS as well as for optimal patient selection.
The 30-day mortality rate after TIPS varies from 3% to 44% but is typically in the range of 10% to 15%.Appropriate patient selection is the key to reducing the mortality rate after TIPS. Death after TIPS is usually related to decompensated hepatic function and is caused by liver failure, infection, renal insufficiency, or multisystem organ failure. The paradox is that patients in whom TIPS is most clearly indicated for refractory bleeding or ascites often have advanced liver disease and are at greatest risk of dying after the procedure. Identification of specific prognostic factors that will help identify patients at greatest risk of death after TIPS has therefore been undertaken in a number of studies. Independent prognostic variables identified in these studies have been used to formulate models and nomograms that can be used to calculate risk scores and the probability of short-term mortality after TIPS.Although this approach is clearly valuable, none of the predictive models published to date has been validated independently and prospectively. They are best used currently to complement clinical judgment and to counsel patients and their families accordingly. Another major problem that has limited the utility of TIPS is occlusion or stenosis of the shunt. Narrowing or occlusion of TIPS stents may occur as an early event secondary to thrombosis or more chronically over a period of weeks or months as a result of pseudointimal hyperplasia. The latter occurrence is the much more common cause of significant shunt insufficiency after TIPS. From 30% to 50% of cases of shunt insufficiency present with recurrent variceal hemorrhage or ascites; the remainder are discovered during routine monitoring, a practice necessitated by the high frequency of shunt dysfunction.The actuarial frequency of shunt insufficiency ranges from 30% to 50% at 12 months and 47% to 68% at 24 months.[The higher frequencies of shunt insufficiency reported by some centers reflect, in part, a more aggressive approach to monitoring of TIPS patency with frequent venography, as well as classification of any narrowing as an abnormality. A more conservative and practical approach is to monitor shunt patency every 3 to 4 months by Doppler ultrasound, with venography performed when a suggestive ultrasonographic abnormality is found.Such abnormalities include a reduction in mean peak flow velocity in the TIPS below 0.5 m/second, reversal of previous hepatofugal flow to hepatopetal flow, and reversal of flow in the stented hepatic vein. Useful venographic criteria for shunt insufficiency include narrowing of the lumen by 75% or more or a pressure gradient across the shunt of 15 mm Hg or higher.
The development of strategies to prevent shunt stenosis is the focus of active research. Potential strategies include pharmacologic approaches to reduce shunt intimal hyperplasia, the primary cause of stenosis, and engineering and testing of stents covered by selectively permeable materials like polytetrafluoroethylene.
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