Massimo Primignani

Evidence of normal thrombin generation in cirrhosis despite abnormal conventional coagulation tests

The role played by coagulation defects in the occurrence of bleeding in cirrhosis is still unclear. This is partly due to the lack of tests that truly reflect the balance of procoagulant and anticoagulant factors in vivo. Conventional coagulation tests such as prothrombin time and activated partial thromboplastin time are inadequate to explore the physiological mechanism regulating thrombin, because they do not allow full activation of the main anticoagulant factor, protein C, whose levels are considerably reduced in cirrhosis. We used a thrombin generation test to investigate the coagulation function in patients with cirrhosis. Thrombin generation measured without thrombomodulin was impaired, which is consistent with the reduced levels of procoagulant factors typically found in cirrhosis. However, when the test was modified by adding thrombomodulin (i.e., the protein C activator operating in vivo), patients generated as much thrombin as controls. Hence, the reduction of procoagulant factors in patients with cirrhosis is compensated by the reduction of anticoagulant factors, thus leaving the coagulation balance unaltered. These findings help clarify the pathophysiology of hemostasis in cirrhosis, suggesting that bleeding is mainly due to the presence of hemodynamic alterations and that conventional coagulation tests are unlikely to reflect the coagulation status of these patients. In conclusion, generation of thrombin is normal in cirrhosis. For a clinical validation of these findings, a prospective clinical trial is warranted where the results of thrombin generation in the presence of thrombomodulin are related to the occurrence of bleeding. (HEPATOLOGY 2005;41:533–558.)

An Imbalance of Pro- vs Anti-Coagulation Factors in Plasma From Patients With Cirrhosis

BACKGROUND & AIMS Patients with cirrhosis have an increased tendency to develop thromboses despite the longer coagulation times of their plasma, compared with that of healthy individuals. We investigated whether plasma from cirrhotic patients has an imbalance of pro- vs anti-coagulation factors. METHODS We analyzed blood samples from 134 cirrhotic patients and 131 healthy subjects (controls) for levels of pro- and anti-coagulants and for thrombin generation in the presence or absence of thrombomodulin (the main physiologic activator of the protein C anticoagulant pathway). RESULTS The median ratio of thrombin generation (with/without thrombomodulin) was higher in patients (0.80; range, 0.51-1.06) than controls (0.66; range, 0.17-0.95), indicating that cirrhotic patients are resistant to the action of thrombomodulin. This resistance resulted in greater hypercoagulability of plasma from patients of Child-Pugh class C than of class A or B. The hypercoagulability of plasma from patients of Child-Pugh class C (0.86; range, 0.70-1.06) was slightly greater than that observed under the same conditions in patients with congenital protein C deficiency (0.76; range, 0.60-0.93). Levels of factor VIII, a potent pro-coagulant involved in thrombin generation, increased progressively with Child-Pugh score (from Child-Pugh class A to C). Levels of protein C, one of the most potent naturally occurring anti-coagulants, showed the opposite trend. CONCLUSIONS The hypercoagulability of plasma from patients with cirrhosis appears to result from increased levels of factor VIII and decreased levels of protein C-typical features of patients with cirrhosis. These findings might explain the risk for venous thromboembolism in patients with chronic liver disease.

Etiology, management, and outcome of the Budd-Chiari syndrome

BACKGROUND The Budd-Chiari syndrome (BCS) is hepatic venous outflow obstruction. What is known about the syndrome is based on small studies of prevalent cases. OBJECTIVE To characterize the causes and treatment of incident BCS. DESIGN Consecutive case series of patients with incident BCS, enrolled from October 2003 to October 2005 and followed until May 2006. SETTING Academic and nonacademic hospitals in France, Spain, Italy, Great Britain, Germany, Belgium, the Netherlands, Portugal, and Switzerland. PATIENTS Persons older than 16 years with definite hepatic outflow obstruction diagnosed by imaging. Persons with hepatic outflow obstruction due to heart failure, sinusoidal obstruction syndrome, cancer, or liver transplantation were excluded. MEASUREMENTS Signs and symptoms; laboratory and imaging findings; diagnosis; treatment; and overall, transplantation-free, and intervention-free survival. RESULTS 163 incident cases of BCS were identified. Median follow-up was 17 months (range, 0.1 to 31 months). Most patients (84%) had at least 1 thrombotic risk factor, and many (46%) had more than 1; the most common was myeloproliferative disorders (49% of 103 tested patients). Patients were mainly treated with anticoagulation (140 patients [86%]), transjugular intrahepatic portosystemic shunting (56 patients [34%]), or liver transplantation (20 patients [12%]), and 80 patients (49%) were managed noninvasively. Only 3 patients underwent surgical shunting. The survival rate was 87% (95% CI, 82% to 93%) at 1 year and 82% (CI, 75% to 88%) at 2 years. LIMITATION Treatment was not standardized across all centers, and data on important clinical variables were missing for some patients. CONCLUSION Most patients with BCS have at least 1 thrombotic risk factor, and many have more than 1; myeloproliferative disorders are most common. One- and 2-year survival rates are good with contemporary management, which includes noninvasive therapies (anticoagulation and diuretics) and invasive techniques. Transjugular intrahepatic portosystemic shunting seems to have replaced surgical shunting as the most common invasive therapeutic procedure. PRIMARY FUNDING SOURCE Fifth Framework Programme of the European Commission.

Acute portal vein thrombosis unrelated to cirrhosis: a prospective multicenter follow-up study.

Current recommendations for early anticoagulation in acute portal vein thrombosis unrelated to cirrhosis or malignancy are based on limited evidence. The aim of this study was to prospectively assess the risk factors, outcome, and prognosis in patients managed according to these recommendations. We enrolled 102 patients with acute thrombosis of the portal vein, or its left or right branch. Laboratory investigations for prothrombotic factors were centralized. Thrombus extension and recanalization were assessed by expert radiologists. A local risk factor was identified in 21% of patients, and one or several general prothrombotic conditions in 52%. Anticoagulation was given to 95 patients. After a median of 234 days, the portal vein and its left or right branch were patent in 39% of anticoagulated patients (versus 13% initially), the splenic vein in 80% (versus 57% initially), and the superior mesenteric vein in 73% (versus 42% initially). Failure to recanalize the portal vein was independently related to the presence of ascites (hazard ratio 3.8, 95% confidence interval 1.3‐11.1) and an occluded splenic vein (hazard ratio 3.5, 95% confidence interval 1.4–8.9). Gastrointestinal bleeding and intestinal infarction occurred in nine and two patients, respectively. Two patients died from causes unrelated to thrombosis or anticoagulation therapy. Conclusion: Recanalization occurs in one‐third of patients receiving early anticoagulation for acute portal vein thrombosis, whereas thrombus extension, intestinal infarction, severe bleeding, and death are rare. Alternative therapy should be considered when ascites and splenic vein obstruction are present. (HEPATOLOGY 2009.)

NATURAL HISTORY OF PORTAL HYPERTENSION IN PATIENTS WITH CIRRHOSIS

All patients with cirrhosis will eventually develop portal hypertension and esophagogastric varices. Bleeding from ruptured esophagogastric varices is the most severe complication of cirrhosis and is the cause of death in about one third of patients. The rate of development and growth of esophageal varices is poorly defined but in general seem to be related to the degree of liver dysfunction. Once varices have formed, they tend to increase in size and eventually to bleed. In unselected patients, the incidence of variceal bleeding is about 20% to 30% at 2 years. Variceal size is the single most important predictor of a first variceal bleeding episode. Several prognostic indexes based on endoscopic and clinical parameters have been developed to predict the risk of bleeding; however, their degree of accuracy is unsatisfactory. Death caused by uncontrolled bleeding occurs in about 6% to 8% of patients; the 6-week mortality rate after a variceal hemorrhage is 25% to 30%. There are no good prognostic indicators of death caused by uncontrolled bleeding or death within 6 weeks. Untreated patients surviving a variceal hemorrhage have a 1- to 2-year risk of rebleeding of about 60% and a risk of death of about 40% to 50%. The risk of bleeding is greatest in the first days after a bleeding episode and slowly declines thereafter. All patients surviving a variceal hemorrhage must be treated to prevent rebleeding. Varices can also be found in the stomach of cirrhotic patients, alone or in association with esophageal varices. Gastric varices bleed less frequently but more severely than esophageal varices. Portal hypertensive gastropathy is a common feature of cirrhosis, and its prevalence parallels the severity of portal hypertension and liver dysfunction. Portal hypertensive gastropathy can progress from mild to severe and vice-versa or even disappear completely. Acute bleeding from portal hypertensive gastropathy seems to be relatively uncommon, and less severe than bleeding from varices.

Role of the JAK2 mutation in the diagnosis of chronic myeloproliferative disorders in splanchnic vein thrombosis

The diagnosis of an underlying chronic myeloproliferative disorder (CMPD) is often problematic in patients with primary extrahepatic portal vein obstruction (EHPVO) or Budd‐Chiari syndrome (BCS); indeed, conventional clinical and hematological parameters usually yield insufficient information. To assess the diagnostic contribution of the gain‐of‐function mutation V617F of the JAK2 gene, 93 patients with EHPVO or BCS were investigated. JAK2 V617F was identified in 35.6% of 73 patients with EHPVO and in 40% of 20 patients with BCS. Taking the JAK2 mutation as a test with the highest positive predictive value for the diagnosis of CMPD, conventional clinical‐hematological parameters had a sensitivity for CMPD lower than 48%. Bone marrow (BM) histology provided a diagnosis of CMPD in 41/74 (55.4%) patients, with a sensitivity of 93.5%. Clonality of hematopoiesis as assessed by granulocyte X‐chromosome inactivation was present in 65.1% of 43 informative female patients, with a sensitivity of 86.6%. By resolving the sensitivity bias of the JAK2 mutation with the results of BM histology and clonality assay, CMPD was diagnosed in 53% of patients with EHPVO or BCS. In conclusion, CMPD is the major cause of primary EHPVO or BCS. JAK2 V617F is a very reliable and noninvasive molecular marker for CMPD and should be used as a first test for diagnosis. (HEPATOLOGY 2006;44:1528–1534.)

TIPS for Budd-Chiari syndrome: long-term results and prognostics factors in 124 patients.

BACKGROUND & AIMS Budd-Chiari syndrome (BCS) is a rare and life-threatening disorder secondary to hepatic venous outflow obstruction. Small series of BCS patients indicate that transjugular intrahepatic portosystemic shunt (TIPS) may be useful. However, the influence of TIPS on patient survival and factors that predict the outcome of TIPS in BCS patients remain unknown. METHODS One hundred twenty-four consecutive BCS patients treated with TIPS in 6 European centers between July 1993 and March 2006 were followed until death, orthotopic liver transplantation (OLT), or last clinical evaluation. RESULTS Prior to treatment with TIPS, BCS patients had a high Model of End Stage Liver Disease and high Rotterdam BCS prognostic index (98% of patients at intermediate or high risk) indicating severity of liver dysfunction. However, 1- and 5-year OLT-free survival were 88% and 78%, respectively. In the high-risk patients, 5-year OLT-free survival was much better than that estimated by the Rotterdam BCS index (71% vs 42%, respectively). In the whole population, bilirubin, age, and international normalized ratio for prothrombin time independently predicted 1-year OLT-free survival. A prognostic score with a good discriminative capacity (area under the curve, 0.86) was developed from these variables. Seven out of 8 patients with a score >7 died or underwent transplantation vs 5 out of 114 patients with a score <7. CONCLUSIONS Long-term outcome for patients with severe BCS treated with TIPS is excellent even in high-risk patients, suggesting that TIPS may improve survival. Furthermore, we identified a small subgroup of BCS patients with poor prognosis despite TIPS who might benefit from early OLT.

Risk factors for thrombophilia in extrahepatic portal vein obstruction

Scant information exists on the role of thrombophilia in extrahepatic portal vein obstruction (EHPVO). We studied 65 patients with EHPVO, 500 with deep vein thrombosis (DVT) of the lower limbs, and 700 healthy controls referred for thrombophilia screening, including the search for gain‐of‐function mutations in genes encoding coagulation factor V (factor V Leiden) and prothrombin (prothrombin G20210A); antithrombin, protein C, and protein S deficiency; and hyperhomocysteinemia. At least one abnormality in the thrombophilia screening was found in 40% of patients with either EHPVO or lower limb DVT and in 13% of controls, for odds ratios of 4.0 (95% CI, 2.3–7.0) and 4.4 (95% CI, 3.3–5.9), respectively. Statistically significant associations with EHPVO were observed for the prothrombin G20210A mutation (odds ratio, 8.1; 95% CI, 3.8–17.5) and the deficiencies of antithrombin, protein C, or protein S taken together (odds ratio, 4.5; 95% CI, 1.1–18.0). The odds ratio for the prothrombin G20210A was approximately twice that for lower limb DVT. Patients with factor V Leiden had an odds ratio for EHPVO of 0.8 (95% CI, 0.1–6.4) and for lower limb DVT of 7.5 (95% CI, 4.4–13.0). The odds ratio for EHPVO in patients with hyperhomocysteinemia was 2.0 (95% CI, 0.9–4.9). At variance with lower limb DVT, oral contraceptive use was not associated with an increased risk of EHPVO. Myeloproliferative disorders were diagnosed in 35% of patients with EHPVO. In conclusion, the risk for EHPVO is increased in the presence of thrombophilia resulting from the prothrombin G20210A mutation and from the deficiencies of the naturally occurring anticoagulant proteins, but not from factor V Leiden. (HEPATOLOGY 2005;41:603–608.)

The international normalized ratio calibrated for cirrhosis (INRliver) normalizes prothrombin time results for model for end‐stage liver disease calculation

The model for end‐stage‐liver‐disease (MELD) is a mathematical score used to prioritize patients for liver transplantation and includes results for creatinine, bilirubin, and prothrombin time (PT) expressed as international normalized ratio (INR). The rationale of using the MELD rests on the assumption that the score would be the same across the country if the methods used to measure the variables yield the same numerical results regardless of the testing laboratory. Evidence was provided that specific methodologies may influence the MELD, and the PT‐INR was identified as the most important. This study was designed to provide information on the between‐thromboplastin variability and to explore alternatives to obviate such variability. Fifty‐seven patients with cirrhosis were selected, and their PTs were measured with 7 thromboplastins. The thromboplastins were previously calibrated by testing plasmas from patients on vitamin K antagonists and healthy subjects to assign the international sensitivity index (ISIvka) needed to convert PT into INR. Each of the thromboplastins was also assigned an ISIliver by substituting in the calibration the plasmas from vitamin K antagonist patients with plasmas from patients with cirrhosis. INR and MELD values for individual patients were calculated by using the ISIvka or the ISIliver. The mean INRvka obtained with the 7 thromboplastins were significantly different (P < 0.001). Conversely, the mean INRliver were not. Similarly, the mean MELDvka were significantly different (P < 0.001), but those differences were abrogated for the MELDliver. Conclusion: The alternative thromboplastin calibration using plasmas from patients with cirrhosis instead of from vitamin K antagonist patients is feasible and may resolve the variability of the MELD to prioritize patients for transplantation. (HEPATOLOGY 2007.)

Good long-term outcome of Budd-Chiari syndrome with a step-wise management

Budd‐Chiari syndrome (BCS) is a rare, life‐threatening disease caused by obstruction of hepatic venous outflow. The aim of the study was to assess long‐term outcome and identify prognostic factors in BCS patients managed by a step‐wise approach using anticoagulation, angioplasty/thrombolysis, transjugular intrahepatic portosystemic shunting (TIPS), and orthotopic liver transplantation (OLT). We reviewed long‐term data on 157 patients previously included by the European Network for Vascular Disorders of the Liver, a multicenter prospective study of newly diagnosed BCS patients in nine European countries. Patients were followed for a median of 50 months (range, 0.1‐74.0). During the study, 88 patients (56%) received at least one invasive intervention (22 patients angioplasty/thrombolysis, 62 TIPS, and 20 OLT) and 36 (22.9%) died. Most interventions and/or deaths occurred in the first 2 years after diagnosis. The Rotterdam score was excellent in predicting intervention‐free survival, and no other variable could significantly improve its prognostic ability. Moreover, BCS‐TIPS prognostic index (PI) score (based on international normalized ratio, bilirubin, and age) was strongly associated with survival and had a discriminative capacity, which was superior to the Rotterdam score. Conclusions: The current study confirms, in a large cohort of patients with BCS recruited over a short period, that a step‐wise treatment approach provides good long‐term survival. In addition, the study validates the Rotterdam score for predicting intervention‐free survival and the BCS‐TIPS PI score for predicting survival. (HEPATOLOGY 2013;)