Epiploic gonadal vein as a new bypass route for extrahepatic portal venous obstruction: report of a case

Patient

A 61-year-old male.

Chief complaint

Severe diarrhea and abdominal distention.

Past history

Bilateral common iliac artery stenting for the arteriosclerosis obliterans at the
age of 57.

Present illness

A 61-year-old male presented with severe diarrhea and abdominal distention. Computed
tomography (CT) showed EHPVO, and he was referred to our hospital for treatment. Although
laboratory test results showed a low albumin level of 2.7 g/dL and a decreased platelet
count of 9.8?×?10
⁴
/?L due to splenomegaly, liver function tests, including the serum ammonia level,
were normal. The protein C level (65 %) and protein S level (105 %) were normal. Further,
the patient had no previous history of abdominal surgery or trauma, and the cause
of EHPVO was suspected to be idiopathic. Upper gastrointestinal endoscopy revealed
linear varices without a red color sign from gastric cardia to the middle part of
the esophagus, and endoscopic injection sclerotherapy (EIS) was performed. He presented
6 months after the endoscopic treatment with massive hematemesis and was readmitted
to our hospital. Endoscopy showed bead-shaped moderate varices with a red color sign
and active bleeding from gastric varices. EIS was successfully performed. CT showed
an occluded extrahepatic portal vein and markedly dilated left gastric vein (LGV)
and mesenteric veins (Fig. 1). Cavernous transformation around the main portal vein and inferior vena cava (IVC)
was seen. Because the patient’s activity of daily life was severely impaired by frequent
diarrhea and abdominal distention and because the risk of rebleeding was high, gastric
devascularization and splenectomy concomitant with shunt surgery was planned. Before
the surgery, the markedly dilated LGV and IVC were the candidates for the proximal
and distal sites of the shunt, respectively, because the splenic vein (SpV) and LPV
had become constricted and were inadequate for anastomosis (Fig. 1).

Fig. 1. Schema of extrahepatic portal venous obstruction. Extrahepatic main portal vein (PV)
was occluded (between black arrows). The left portal vein was constricted, although it was perfused by cavernous transformation,
and the patient’s splenic vein (SpV) was also constricted. The left gastric vein (LVG)
and mesenteric vein (MV) were markedly dilated. SMV superior mesenteric vein

Surgical findings

Firstly, gastric devascularization and splenectomy were performed. However, the dilatation
of epiploic vein in the greater omentum got worse after the devascularization, and
shunt surgery was planned. Nets of collateral vessels were found circling the LGV
and IVC, and it was difficult to handle these vessels. Severe inflammation after EIS
was also seen around the LGV. The epiploic vein was markedly dilated, so it was chosen
as the proximal site of the bypass. Instead of using the IVC for the distal site of
the bypass, the left gonadal vein was chosen. The anastomosis was constructed end-to-end
with a single running suture using 6–0 Prolene (Fig. 2).

Fig. 2. Epiploic gonadal bypass. a Intraoperative photograph showing end-to-end anastomosis of the epiploic and left
gonadal veins. b, c Postoperative computed tomography showing patent and well-dilated epiploic vein (solid arrow) and left gonadal vein (dotted arrow)

Postoperative course

The postoperative course was uneventful, and the patient was discharged 14 days after
surgery. CT 3 months after the surgery showed disappearance of ascites and mesenteric
edema (Fig. 3). The dilatation of the mesenteric vein was also reduced. The bypass graft remains
patent 7 months after surgery, and the patient is in good health without any clinical
symptoms.

Fig. 3. Preoperative CT (a) and postoperative CT (b). CT 3 months after the surgery showed disappearance of ascites and mesenteric edema.
The dilatation of the mesenteric vein was reduced (white arrow)

Discussion

EHPVO causes portal hypertension, and up to 70 % of the etiological factors of this
disease remain idiopathic 1]–3]. Almost 90 % of children with EHPOV present with variceal bleeding, and the remaining
10 % present with splenomegaly 2]. Unlike patients with chronic liver disease, those with EHPVO have preserved liver
function. Therefore, mortality is mainly due to variceal bleeding, and endoscopic
therapy, either EIS or endoscopic variceal ligation, is indicated to treat the esophageal
varices 2]. Endoscopic therapy has been reported to be effective for controlling acute bleeding
from esophageal varices in 80–90 % of patients 1]. However, endoscopic therapy does not decrease the elevated portal venous pressure,
or, as in the current case, resolve other symptoms due to portal venous hypertension,
such as ascites and diarrhea. Therefore, in refractory or complicated cases, shunt
surgery is indicated. High long-term patency rates, ranging from 89 to 97 %, have
been reported 6]. To prevent the shunt thrombosis, low doses of heparin during the first week followed
by antiplatelet agents for 3–6 months is recommended 6]. A successful shunt decreases the portal venous pressure and improves most of the
clinical symptoms. Shunt surgery is classified as “selective” or “nonselective”. Selective
shunts are usually recommended because nonselective shunts, such as the mesocaval
shunt, have been associated with a significant risk of hepatic encephalopathy compared
with selective shunts 6]. Distal splenorenal shunt and MLPVB have been reported to be the representative selective
shunts 12], 13]. The distal splenorenal shunt, first described in 1967, has a lower incidence of
clinically significant post-shunt encephalopathy 13]. One problem with the splenorenal shunt is that it cannot be performed in almost
one-third of cases due to a small or blocked SpV 14], 15]. Another selective shunt, MLPVB, was first performed by de Ville de Goyet et al.
in 1992 in a 3-year-old patient with extrahepatic portal vein thrombosis after a partial
liver transplant 12]. This shunt restores mesenteric blood flow to the liver through the Rex recess, and
it is the most physiologic shunt. In the current case, however, preoperative CT showed
the SpV and LPV were narrowed. Further, during laparotomy, an enlarged LGV, which
was the first candidate for the proximal site of anastomosis, could not be handled
and mobilized because of severe inflammation and nets of collateral vessels around
it. Therefore, the epiploic and gonadal veins were chosen as anastomosis sites in
this case. These vessels were much easier to handle and mobilize than the LGV and
IVC. Autogenous epiploic and gonadal veins have not been used in shunt procedures
to date, and this is the first case report. Although MLPVB and distal splenorenal
shunts remain the first candidates for shunt surgery, epiploic gonadal vein bypass
might be an option, especially in cases with narrowed LPV and SpV.