CON: Anticoagulation for Portal Vein Thrombosis in Advanced Cirrhosis

Nonmalignant portal vein thrombi in patients with cirrhosis consist of intimal fibrosis with or without a fibrin-rich thrombus

BACKGROUND AND AIM

Portal vein thrombosis (PVT) is a common complication of cirrhosis. The exact pathophysiology remains largely unknown, and treatment with anticoagulants does not lead to recanalization of the portal vein in all patients. A better insight into the structure and composition of portal vein thrombi may assist in developing strategies for the prevention and treatment of PVT.

APPROACH AND RESULTS

Sixteen prospectively and 63 retrospectively collected nonmalignant portal vein thrombi from patients with cirrhosis who underwent liver transplantation were included. Histology, immunohistochemistry, and scanning electron microscopy were used to assess structure and composition of the thrombi. Most recent CT scans were reanalyzed for thrombus characteristics. Clinical characteristics were related to histological and radiological findings. All samples showed a thickened, fibrotic tunica intima. Fibrin-rich thrombi were present on top of the fibrotic intima in 9/16 prospective cases and in 21/63 retrospective cases. A minority of the fibrotic areas stained focally positive for fibrin/fibrinogen (16% of cases), von Willebrand factor (VWF; 10%), and CD61 (platelets, 21%), while most of the fibrin-rich areas stained positive for those markers (fibrin/fibrinogen, 100%; VWF, 77%; CD61, 100%). No associations were found between clinical characteristics including estimated thrombus age and use of anticoagulants and presence of fibrin-rich thrombi.

CONCLUSION

We demonstrate that PVT in patients with cirrhosis consists of intimal fibrosis with an additional fibrin-rich thrombus in only one-third of cases. We hypothesize that our observations may explain why not all portal vein thrombi in patients with cirrhosis recanalize by anticoagulant therapy.

Safety, Efficacy, and Long-Term Outcomes of Anticoagulation in Cirrhotic Portal Vein Thrombosis

BACKGROUND

The role of anticoagulation (AC) in the management of cirrhotic patients with portal vein thrombosis (PVT) remains unclear.

AIMS

We conducted a retrospective study of cirrhotic patients diagnosed with PVT from 1/1/2000 through 2/1/2019, comparing those who received AC to those who did not.

METHODS

Outcomes included rate of complete radiographic resolution (CRR) of PVT, recanalization of occlusive PVT (RCO), PVT extension, major bleeding, and overall survival (OS). The log-rank test was used to compare Kaplan-Meier distributions of time-to-event outcomes. Multivariable Cox-proportional-hazards modeling was used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals.

RESULTS

A total of 214 patients were followed for a median 27 months (IQR 12-48). Eighty-six patients (39%) received AC. AC was associated with significantly greater CRR (48% vs. 27%, p = 0.0007), (multivariable HR for CRR with AC; 2.49 (1.54-4.04, p = 0.0002)). AC was also associated with significantly greater RCO (69% vs. 28%, p = 0.0013), (multivariable HR for RCO with AC; 4.86 (1.91-12.37, p = 0.0009)). Rates of major bleeding were similar with and without AC (20% vs. 17%, p = 0.5207), multivariable HR for major bleeding with AC; 1.29 (0.68-2.46, p = 0.4423)). OS rates in the AC and no-AC groups were 83% and 70%, respectively (p = 0.1362), (HR for death with AC; 0.69 (0.38-1.28, p = 0.2441)). Among 75 patients who had CRR, 10 (13%) experienced recurrent PVT during follow-up (none were receiving AC at the time of recurrence).

CONCLUSIONS

AC appears safe and effective for the treatment of cirrhotic PVT; however, prospective studies to confirm these findings and evaluate additional outcomes are needed.

Venous thrombosis of the liver: current and emerging concepts in management

Venous thrombosis within the hepatic vasculature is associated with a distinct array of risk factors, characteristics, and potential complication. As such, it entails unique management considerations and strategies relative to the more common categories of venous thromboembolic disease. Although broadly divided into thrombosis of the afferent vasculature (the portal venous system) and efferent vasculature (the hepatic venous system), presentations and management strategies within these groupings are heterogeneous. Management decisions are influenced by a variety of factors including the chronicity, extent, and etiology of thrombosis. In this review we examine both portal vein thrombosis and hepatic vein thrombosis (and the associated Budd-Chiari Syndrome). We consider those factors which most impact presentation and most influence treatment. In so doing, we see how the particulars of specific cases introduce nuance into clinical decisions. At the same time we attempt to organize our understanding of such cases to help facilitate a more systematic approach. Critically, we must recognize that although increasing evidence is emerging to help guide our management strategies, the available data remain limited and largely retrospective. Indeed, current paradigms are based largely on observational experiences and expert consensus. As new and more rigorous studies emerge, treatment strategies are likely to be continually refined, and paradigm shifts are sure to occur.