Selective embolization of the splenic vein for shunt-preserving disconnection of the portal and systemic circulation: report of two cases
This 70-year-old woman with chronic hepatitis due to hepatitis C virus infection had had recurrent episodes of hepatic encephalopathy despite protein restriction and the administration of lactulose and branched-chain amino acids. She was admitted with hepatic encephalopathy (West Haven Criteria stage 4). The liver function was Child-Pugh A (total bilirubin, 0.7 mg/dl; albumin, 3.2 g/dl; prothrombin time, 96%; no ascites) and the blood ammonia level 214 µg/dl. Contrast-enhanced CT scans were acquired with a 64-row multidetector scanner (Brilliance-64); 3D images revealed portosystemic shunts and a portal-hepatic vein shunt in the left lobe.\nThree-phase contrast-enhanced CT scans of the liver were acquired in the arterial, portal venous, and equilibrium phases in both patients. An automatic bolus-tracking program was used to time the start of scanning for each phase after contrast injection. Hepatic arterial, portal venous, and equilibrium phase scanning was started 18, 55, and 180 s after triggering. We used a bolus injection of 100 mL iopromide (Iopamiron 300; Nihon Beyer, Osaka, Japan) delivered at a rate of 3 mL/s. All images were obtained through the abdomen in a craniocaudal direction.\nFirst, under local anesthesia, superior mesenteric and celiac arteriography was performed to develop a treatment plan and to assess collateral circulations in both patients. DSA of the superior mesenteric artery and the celiac trunk was performed after the administration of 2.5 μg prostaglandin E1 (Liple; Mitsubishi Pharma Corp., Osaka, Japan), using a 4-Fr RC2 catheter (Medikit Co. Ltd., Tokyo, Japan) after injection of iomeprol (Iopamiron 300; Bayer, Osaka Japan) at a flow rate of 6 mL/s and 5 mL/s, respectively. In both cases, the venous phase of superior mesenteric arteriography demonstrated a spleno-renal and a spleno- retroperitoneal shunt, and an undetected portal vein trunk (Fig. ). There was enough distance to allow disconnecting the mesenteric-portal blood flow from the systemic circulation while preserving the shunt.\nStandard anesthesia consisted of 10 mL of 1% lidocaine injected locally; conscious sedation was with a continuous intravenous infusion of fentanyl (Phentanest, Sankyo, Tokyo, Japan) delivered at 100 μg/h during the procedure. Using a percutaneous transhepatic approach we performed ultrasonography-guided puncture of the portal vein, introduced a 6-Fr C-curved sheath (Medikit), and inserted a 5-Fr cobra catheter (Medikit) into the portal system to measure the pressure in the portal vein sequentially (23 mmHg). Splenic venography revealed a spleno-renal and a spleno-retroperitoneal shunt (Fig. ). We also inserted a 5-Fr catheter into the inferior mesenteric vein and identified the junction of the inferior mesenteric and the portal vein.\nBecause we use a balloon catheter as a flow control to prevent coil deviation, we used two 6-F balloon catheters with a 25-mm diameter balloon (Moiyan, Miyano, Osaka, Japan). One was inserted from the percutaneous transhepatic approach and wedged into the splenic vein during embolization, and the other from the right femoral vein wedged into the left adrenal vein.\nIn case 1, two coil anchors (Medikit) were placed in the proximal part of the splenic vein to prevent coil deviation. Embolization was performed with nine metallic coils (Vortex; Boston Scientific, Watertown, MA, USA) and 10 microcoils (interlocking detachable coils (IDC), Boston Scientific) using a 2.5-Fr microcatheter (Target, Boston Scientific) to prevent obstruction of the inferior mesenteric vein by coil migration. In case 2, one coil anchor (Medikit) was placed on the proximal part of the splenic vein to prevent coil deviation. Embolization was with one 3-dimensional Guglielmi detachable coil (GDC; Boston Scientific) and 11 IDCs (Boston Scientific) using a 2.5-Fr microcatheter (Target, Boston Scientific) to prevent inferior mesenteric vein obstruction by coil migration. In sequence, we then embolized the portal-hepatic vein shunt in the left lobe by introducing five IDCs (Boston Scientific) using a 2.5-Fr microcatheter (Target, Boston Scientific). This disconnected the mesenteric-portal blood flow from the systemic circulation while preserving the shunt.\nAfter successful embolization, the venous phase of superior mesenteric arteriography demonstrated a portal vein trunk toward the liver (Fig. ). There was enough distance to allow disconnection of the mesenteric-portal blood flow from the systemic circulation while preserving the shunt (Fig. a). The patients' encephalopathy resolved immediately and permanently and in the course of 30-month follow-up there was no evidence of ascites or esophageal varices. The pre- and postprocedure difference in portal pressure was 5 mmHg (from 18 to 23 mmHg, case 1) and 5 mmHg (from 11 to 16 mmHg, case 2). The blood ammonia level fell by 49 µg/dl from 333 µg/dl (case 1) and by 25 µg/dl from 214 µg/dl (case 2). Neither patient experienced episodes of hepatic coma during the follow-up period.