8MM Interposition Portacaval Shunt
Alexander S. Rosemurgy II, Dimitris P. Korkolis
Indications and Contraindications
Indications
■Control of acute hemorrhage from esophageal varices not amenable to or failing medical therapy, e.g., pharmacotherapy, balloon tamponade, endoscopic variceal sclerotherapy, in patients with liver cirrhosis and portal hypertension
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Control of bleeding gastric or intestinal varices
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Prevention of recurrent variceal bleeding after initial control
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Complicated Budd-Chiari syndrome
Contraindications
■Portal vein thrombosis, even with recanalization (cavernomatous transformation)
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Inferior vena cava thrombosis
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Extensive adhesions from previous operative procedures in the right upper quadrant (relative contraindication)
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Severe medical comorbidities (e.g., mitral regurgitation, severe aortic stenosis, etc.)
Preoperative Investigation and Preparation for the Procedure
History: Alcohol consumption and alcohol withdrawal syndromes, hepatitis and hepatotoxic medications
Clinical evaluation: Variceal bleeding, ascites, hypersplenism, hepatic
encephalopathy, jaundice, nutritional status, signs of portal hypertension (e.g., caput medusa)
Laboratory tests: ALT, AST, bilirubin, alkaline phosphatase, albumin, coagula- tion profile (PT, INR, platelets), tumor markers and serologies (e.g., hepatitis), when indicated. Electrolyte and acid-base profile
Color-flow Doppler Assessment of portasplanchnic patency, as well as patency ultrasound and of the inferior vena cava
visceral angiography:
Determination of Child-Pugh score
Procedure
Positioning, Access and Mobilization
Initially, the patient is positioned supine on the operating table. A nasogastric tube is placed only if gastric distension requires it. Neither vasopressin nor octreotide need to be given perioperatively, unless active bleeding is occurring. Otherwise, the operation can be undertaken with minimal blood loss and almost always without blood transfu- sion. The patient is then rolled into a 30-degree left lateral decubitus position by means of a bed sheet rolled tightly and placed just to the right of the spine.
The patient is operated on through a right transverse upper abdominal incision.
The exact placement of this incision depends on the size of the liver, which is often palpable below the right costal margin. The incision is placed over the liver edge.
It does not generally cross the midline and includes only a small portion of the muscu- lature lateral to the rectus muscle.
If the falciform ligament is divided during the incision, it should be divided carefully, as it may contain large collateral vessels. Suture ligation of the falciform ligament at the time of the division is usually undertaken.
STEP 1 Kocherization and preparation of the vena cava
Optimum exposure of the right upper quadrant of the peritoneal cavity should be achieved, with as little dissection as possible. The foramen of Winslow is the key land- mark. A limited Kocher maneuver is undertaken, always maintaining orientation with the foramen of Winslow. Visible venous collaterals, as well as large lymphatic channels, should be ligated before division. Cautery is liberally applied. The Kocher maneuver does not need to be extensive but just enough to adequately expose 5cm of the sub- hepatic inferior vena cava and enable the placement of a side-biting vascular clamp.
The exposed segment of the inferior vena cava should include the portion that forms
the dorsal border of the foramen of Winslow. The cephalad area of this segment of
the cava may lie dorsal to the inferior tip of the caudate lobe of the liver. If necessary,
this portion of the caudate lobe should be excised with electrocautery.
STEP 2 Exposure of portal vein
It is very important that the inferior vena cava is well exposed medially and laterally so a vascular clamp can be placed. Exposure of at least one-half circumference of the 4- to 5-cm segment of the inferior vena cava is usually necessary to facilitate secure clamp placement and anastomosis. After the inferior vena cava is adequately exposed, one or two traction sutures are placed into the loose tissue adjacent to the right side of the cava.
These sutures are further placed into the lateral abdominal wall to retract laterally and optimize exposure.
The gallbladder is retracted toward the patient’s left shoulder. This lifts and rotates
the gallbladder and the common bile duct ventrally and medially. The hepatoduodenal
ligament is then dissected posteriorly and laterally, along its whole length with attention
to minimize chances of duct injury, as well as injury to an accessory or replaced right
hepatic artery, if present. The common bile duct should be retracted ventrally and
medially with a vein retractor to facilitate exposure of the portal vein. As the portal
vein comes into view, a Russian forceps is used to grasp it and a plastic Yankauer sucker
is utilized for circumferential dissection of the vein. The portal vein is then controlled
by a vessel loop. This vessel loop may be helpful if bleeding develops because it can
provide secure control of the portal vein.
STEP 3 Caval anastomosis
A segment of 8mm externally reinforced polytetrafluoroethylene (PTFE) graft is used for the portacaval shunt. The graft is 3cm long from toe to toe and 1.5cm from heel to heel. The bevels of the graft are oriented at 90degrees to each other because the portal vein is not parallel to but rather oriented approximately 60degrees to the inferior vena cava.
The graft is placed in heparinized saline and negative pressure is applied in order to remove any air bubbles. A side-biting Satinsky clamp is then securely placed on the anterior surface of the vena cava. Hypotension is virtually never a problem because of this clamping. A window must then be cut in the vena cava so that outflow from the graft is adequate; merely opening the cava is not sufficient. When the vena cava is opened, the ex vivo portion of the vein should be approximately 4mm long and 1–2mm wide. This will provide an adequate opening in the vena cava.
The graft is placed on the vena cava so that its bevel allows it to lean cephalad. The
anastomosis is undertaken with 5-0Prolene in a running fashion. This anastomosis is
initiated with a horizontal mattress suture so that sewing is always from “inside-out” on
the vein and “outside-in” on the graft (Figure 3). The back wall is completed first. Before
the knot is tied, a suture is reversed so that the knot is secured across the anastomosis.
STEP 4 Testing the caval anastomosis
Once the anastomosis has been completed and the knot tied, a right-angled clamp is placed across the graft, and the side-biting clamp is removed. This tests the anastomosis;
it should not leak and it should only bleed at needle holes and then only minimally
(Figure 4). The Satinsky clamp is repositioned on the vena cava and the right-angled
clamp removed from the graft. The graft is then vigorously irrigated with heparinized
saline through an 18-gauge angiocatheter.
STEP 5 Exposure of the portal vein
The portal vein anastomosis is now constructed. The common bile duct and accessory
right hepatic artery, if present, are retracted ventrally and medially, exposing the
dissected portal vein. The bevel of the portal vein end of the graft is at 90° to the IVC
level as shown here.
STEP 6 Preparation of the portal anastomosis
A right-angled side-biting clamp is then placed across the portal vein. This clamp does not have to occlude all the portal flow, but it must be placed securely enough to prevent bleeding once the vein is opened. Once the Satinsky clamp is placed, the posterolateral surface of the portal vein is incised with a No. 11 knife blade. Potts scissors are then used to lengthen the opening in order to accommodate the placement of the graft. In contrast to the inferior vena cava, a window does not usually need to be cut in the portal vein.
A 5-0 Prolene suture is placed in the ventral edge of the opening in the portal vein to act
as a retraction suture, so as to “open up” the hole in the vein.
STEP 7 Portal anastomosis
With this exposure, the posterior wall of the portal vein is then sewn to the graft with a 5-0 Prolene suture. The anastomosis is initiated by placing a horizontal mattress suture in the midportion of the posterior wall of the portal vein. Thereafter, all sewing of this anastomosis is “inside-out” on the portal vein and “outside-in” on the graft. As sewing is carried around both the cephalad and caudad corners of the anastomosis, the sutures along the back wall are drawn taut with a nerve hook. As the sewing continues toward the middle of the anterior portion of the anastomosis, the clamp on the portal vein is momentarily opened so that clot and debris within the vein will be blown out.
Heparinized saline is again applied liberally through the anterior defect of the
anastomosis into the graft.
STEP 8 Completing the anastomosis
The anastomosis is then completed, with one of the sutures reversed so that the knot is
tied across the anastomosis. The clamp on the vena cava is released first, and then the
clamp on the portal vein is removed. There should be a thrill in the vena cava, just
cephalad to the anastomosis.
Postoperative Tests
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Postoperative surveillance in an appropriate hospital setting.
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Remove nasogastric tube, if present, as soon as possible.
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Attention should be given to avoid dehydration. Low urinary output during the first 24–48h predisposes to graft thrombosis.
If hypovolemia is diagnosed, rehydration with normal saline and use of intravenous mannitol are recommended.
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Liver function tests (including SGOT), coagulation parameters, and hemoglobin should be checked for at least 48h, postoperatively.
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Daily assessment of clinical signs of liver failure, such as jaundice and encephalopathy.
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Ascites can be controlled with fluid and salt restriction, as well as with judicious use of diuretics.
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The shunt should be evaluated with transfemoral cannulation, in order to document patency and to measure the portal vein-inferior vena cava pressure gradients at 3–6days postoperatively.
Complications
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Intra-abdominal bleeding
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Recurrence of gastrointestinal hemorrhage due to shunt thrombosis
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Hepatic failure
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Changes in cardiopulmonary dynamics (increased cardiac index)
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Ascites
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Portal-systemic encephalopathy
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Bile duct injury
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Injury to an accessory right hepatic artery
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Wound infection
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Shunt failure
Summary
Pressures within the portal vein and inferior vena cava are measured early in the opera- tion, before the vessels are clamped. These pressures can be recorded with a 25-gauge needle and a pressure-transducing setup. A portal-caval pressure gradient is determined.
On completion of the shunt, pressures are measured again. In a satisfactorily completed shunting, we look for a decrease in portal pressure of ≥10mmHg and a gradient between the portal vein and the inferior vena cava of less than 10mmHg.
The vena cava-graft anastomosis is marked with large Hemoclips placed on tissue adherent to the cava and secured both cephalad and caudad to the anastomosis. These clips allow the radiologist to identify and cannulate the inferior vena cava-graft anasto- mosis during the routine postoperative assessment of the shunt.
After copious irrigation of the operative field, the wound is closed along anatomic
layers using #2 Prolene suture. The skin is reapproximated with a running nylon suture,
in order to minimize any postoperative ascitic leak.
Tricks of the Senior Surgeon
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Identify the foramen of Winslow. The Kocher maneuver should be limited.
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Cut a window in the inferior vena cava.
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Begin each anastomosis with a horizontal mattress suture.
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Check the graft-inferior vena cava anastomosis before proceeding with the portal vein-graft anastomosis.
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If there is significant bleeding when a portion of the caudate lobe is removed, apply pressure and most of the bleeding will drop within minutes.
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