Transjugular intrahepatic portosystemic shunt for treatment of portal hypertension due to extramedullary hematopoiesis in idiopathic myelofibrosis

Patients with idiopathic myelofibrosis (IMF) present with variable clinical, as well histomorphologic, features. In the fibrotic stage of the disease, bone marrow fibrosis causes ineffective erythropoiesis, which leads to extramedullary hematopoiesis, mainly in the spleen and the liver.1,2 This could lead to intrahepatic portal hypertension with its associated problems of variceal bleeding or ascites refractory to medical therapy without development of liver cirrhosis.3 The transjugular intrahepatic portosystemic shunt (TIPS) is an effective and well-established radiologic procedure that involves the creation of a side-to-side portocaval shunt in patients with portal hypertension and cirrhosis of the liver, Budd Chiari syndrome, and veno-occlusive disease.4,5 It has good efficacy for the therapy of intractable ascites, and the shunt is associated with an acceptable risk and few serious interventional complications when implanted by an experienced operator.4 6 We report a case of IMF with intractable ascites and portal hypertension due to extramedullary hematopoiesis and its successful treatment with implantation of a GoreTex-coated TIPS endoprosthesis.

A 60-year-old man suffering from IMF for 12 years was referred from the hematology department because of intractable ascites. The patient presented with moderate anemia, normal liver enzymes, and normal liver synthetic function, and showed the abnormalities typical for IMF in his peripheral blood smear (leukoerythroblastic changes, teardrop-shaped cells). On examination, a distinct hepatomegaly, massive splenomegaly (20 × 12 × 30 cm), a dilated splenic vein (30 mm), a patent portal vein with orthograde blood-flow, massive ascites, oesophageal varices (grade III with red-color-signs), and varices of the cardia were found (Figure 1C).

The hepatic venous pressure gradient (HVPG) showed portal hypertension with a pressure gradient of 23 mmHg (upper limit of normal, 6 mmHg). A biopsy specimen of the liver showed noncirrhotic liver parenchyma with normal architecture, discrete portal fibrosis, and massive infiltration of the liver sinusoids with hematopoietic cells (Figure 1A).

Since sinusoidal obstruction by extramedullary blood-forming units is not very different from other forms of intrahepatic portal hypertension and conservative treatment (dietary sodium restriction and high-dose diuretic therapy were unsuccessful), we decided to implant a GoreTex-coated TIPS endoprosthesis (Viatorr, W. L. Gore and Associates, Flagstaff, AZ; diameter: 8 mm, length: 80 mm) (Figure 1B), which shows a much improved patency rate compared with previous uncoated TIPS models (80%-100%, versus 50%, at 1 year).7 The reduction of the HVPG to 14 mmHg was followed by a rapid and lasting relief of ascites and a marked regression of the oesophageal varices (Figure 1D). At 6 months after implantation, the patient was free of ascites but still required moderate doses of diuretics because of the residual portal hypertension (ideal HVPG after TIPS is below 12 mmHg).

In the absence of cirrhosis and portal or hepatic vein thrombosis, extramedullary hematopoiesis causing sinusoidal obstruction was likeliest in our patient. Between 90% and 100% of patients with IMF show varying degrees of extramedullary hematopoiesis in the liver,8 and HVPG was shown to be significantly higher in patients with IMF and hepatic lesions (infiltration of hematopoietic cells, fibrosis, or both) than in patients with normal livers.9 Collagenization of the space of Disse, transformation of perisinusoidal cells into fibroblastlike or myofibroblastlike cells, and fragmentary deposits of basement membranelike material are suggested to cause an increment in vascular resistance, too.10 Relief of intrahepatic portal hypertension in patients with IMF can be successfully accomplished by implantation of a TIPS. Such patients seem to be ideal candidates for TIPS implantation since they display normal liver synthetic function with little periinterventional risk.