Surgery for Portal Hypertension in Children and Adults



Surgery for Portal Hypertension in Children and Adults


Michael J. Englesbe

Amit K. Mathur





DEFINITION



  • Portal vein (including splenic and superior mesenteric vein) pressure ranges between 1 and 4 mmHg higher than the hepatic vein free pressure and not more than 6 mmHg greater than central venous pressures (CVPs). Pressures that exceed these limits define portal hypertension. More commonly, portal hypertension is used to define a constellation of symptoms related to elevated mesenteric venous pressures, including ascites, gastrointestinal bleed due to varices, and the development of mesenteric venous collaterals. Portal hypertension may be caused by liver disease or prehepatic or posthepatic venous obstruction.


PATIENT HISTORY AND PHYSICAL FINDINGS



  • The first step in the management of a patient with portal hypertension is to assess liver function. Most children and adults with portal hypertension have cirrhosis. Complete an extensive history to investigate for risk factors of liver disease. In children, neonatal history is important including exposure to umbilical catheterization.


  • Patients with noncirrhotic portal hypertension usually present with a variceal hemorrhage. Many patients have chronic abdominal pain, especially in the left upper quadrant.


  • Assess for signs of liver disease and portal hypertension on physical examination. Measure the spleen relative to the costal margin and umbilicus.


  • Malnutrition, jaundice, encephalopathy, frailty, or coagulopathy are signs of decompensated liver disease. Patients with noncirrhotic portal hypertension usually have only splenomegaly.


IMAGING AND OTHER DIAGNOSTIC STUDIES



  • Assessment should include blood tests and serologies. Attention to synthetic liver function and platelet count is important. A complete hypercoagulable workup is needed. Results should be interpreted with care; many patients with abnormal liver function will have abnormal levels, such as protein C and protein S.


  • Complete a liver ultrasound to assess the patency of the vasculature in the right upper quadrant and liver morphology. Importantly, a recanalized, thrombosed portal vein may be mistakenly appreciated as “normal” on ultrasound.


  • Arterial and venous phase magnetic resonance imaging (MRI) or computed tomography (CT) scan (both require intravenous contrast) provides an excellent anatomic assessment.


  • Do an endoscopy to assess for varices, with particular attention to gastric varices.


  • Assess for liver pathology with a liver biopsy. This can be done via the transjugular approach. At the same time, an assessment can be made of pressures within the right atrium, inferior vena cava, hepatic veins, and wedged portal pressures. Patients with mesenteric veno-occlusive disease (such as portal vein thrombosis) and portal hypertension usually have normal wedged hepatic vein pressures.


  • Complex patients will merit a comprehensive angiographic assessment, which may include imaging of the inferior vena cava, abdominal arterial system, and mesenteric venous system with or without direct access to these veins.


  • Patients with severe portal hypertensive complications and a portal to systemic gradient of greater than 12 mmHg merit intervention.


SURGICAL MANAGEMENT


Preoperative Planning



  • Patients with cirrhosis and portal hypertension-related complications should have a transjugular intrahepatic portosystemic shunt (TIPS) procedure unless contraindicated.


  • A multidisciplinary committee should review all complex cases. The committee must include pediatric and adult hepatologists, pediatric and adult radiologists, interventional radiologists, and surgeons.


  • Endovascular procedures (including TIPS) can provide durable management of portal hypertension. These percutaneous interventions to shunt and/or recanalize are the first-line therapy. Percutaneous procedures to embolize the spleen are poorly tolerated by most patients, although occasionally, splenic embolization is the best option.


  • Indications for surgery in adults are the following:



    • At least one life-threatening complication of portal hypertension. This usually includes a large gastrointestinal bleed.


    • Adults with complications of portal hypertension related to decompensated cirrhosis should have a liver transplant or TIPS procedure; shunt surgery is rarely indicated in these patients.


    • Severe and long-standing thrombocytopenia


    • Severe and disabling abdominal pain. This is usually from massive splenomegaly. Many patients with mesenteric veno-occlusive disease will have abdominal pain and no other complications; few of these patients should have surgery.


    • Massive splenomegaly affecting lifestyle. The spleen crosses the abdominal midline and occupies much of the pelvis.


  • Indications for surgery in children are the following:



    • Two life-threatening complications of portal hypertension.


    • Massive splenomegaly or severe thrombocytopenia affecting lifestyle.


    • No viable or durable endovascular procedure available.


    • Children with complications of portal hypertension related to decompensated cirrhosis should have a liver transplant and not shunt surgery.


  • All patients having surgery should have immunizations for pneumococcus, meningococcus, and Haemophilus influenzae.



Positioning



  • The patient is placed in the supine position on the operating table with arms at sides for smaller children. Operative exposure to the neck and/or groin for vein procurement is needed in many cases.


  • An arterial line and central line should be placed in most cases. The central line will be used to assess the CVP in calculations of the portal-systemic pressure gradient. Additional tubing and anesthesia equipment will be needed for intraoperative mesenteric venous pressure measurements.


  • All members of the operative team (surgical, nursing, and anesthesia) should be prepared for significant intraoperative bleeding, as is frequently experienced during liver transplantation or open abdominal vascular surgery. Overresuscitation will worsen this bleeding; the goal CVP during the dissection should be 5 mmHg. This requires frequent communication between the anesthesiologists and surgeons.


TECHNIQUES


INCISION AND RETRACTION



  • Do a midline incision.


  • Retract aggressively in the superior direction to facilitate access to the short gastric veins in the upper abdomen. This is best achieved with an Omni™ or Thompson™ retractor.


OPERATIVE DECISION MAKING



  • The final surgical approach to manage severe portal hypertension is determined by operative findings. The surgeon must understand the patient’s physiology and how to best assure long-term management of portal hypertension with reasonable operative risks. Consideration must be made for future options for management if the current surgical procedure fails.


  • Prosthetic graft material or cryopreserved vein should be reserved for patients in severe extremis from acute portal hypertensive complications.


  • Assessment of portal pressures. Ask the anesthesiologist to hand pressure tubing onto the field. Select a vein that will be easy to ligate following cannulation; omental branches work well for this. Cannulate the vein with an angiocatheter and measure pressures (FIG 1). Pressures are low and variations in transducer location can have marked effects on pressures. Fix the transducer in a location so that subsequent measures can be reliably compared to this baseline measure.






FIG 1 • Measurement of mesenteric vein pressures. Select a vein that will be easy to ligate following cannulation. Cannulate the vein with an angiocatheter and measure pressures with the assistance of the anesthesia team.


SPLENECTOMY WITH PROXIMAL SPLENIC ARTERY LIGATION AND ESOPHAGOGASTRIC DEVASCULARIZATION



  • The indications for this procedure include patients with a life-threatening complication from portal hypertension and complex mesenteric veno-occlusive disease or poor venous drainage of the spleen (left-sided portal hypertensive physiology) (FIG 2).



    • Patients with long-standing thrombocytopenia (platelets <35,000/µL) and massive splenomegaly needs a splenectomy. The spleen is fibrotic and will remain large (and platelet counts will remain low) following shunt surgery alone. Also, a massive spleen will make many portal hypertension surgical procedures impossible and, as a result, splenectomy is the first portion of the procedure (FIG 3).






    FIG 2 • Complex mesenteric veno-occlusive disease. These patients can usually be managed with splenectomy.







    FIG 3 • Massive splenomegaly with the spleen crossing the midline.


  • The procedure can be done with a laparoscope. If there is significant portal hypertension and collaterals, preoperative splenic embolization should be done immediately prior to the procedure. If done more than a few hours before the splenectomy, the patient will have significant adverse symptoms and the spleen will become soft and easy to injure during surgery. The size of the spleen and the severity of the portal hypertension usually favor an open procedure.


  • Key steps include the following:



    • Exposure above the spleen with generous retraction of the abdominal wall superiorly


    • Keep dissection to a minimum. Use hands instead of metal retractors for operative exposure. Collateral veins are best ligated using a “no-touch” technique and either surgical clips or an electrosurgical device (such as a LigaSure or Harmonic scalpel) (FIG 4).


    • Divide enough short gastric vessels to expose the splenic vein.


    • Ligate the splenic artery with surgical clips. Identify the splenic artery proximally, but more importantly, in a location that is easy to dissect. Do not circumferentially dissect the splenic artery; the splenic vein and branches are posterior to the artery and injury to these veins can be extremely difficult to manage. Ligation of the artery will decompress the spleen, lower portal pressures, and profoundly reduce bleeding.






      FIG 4 • Large collateral veins are best managed with the LigaSure device and clips. Use of surgical instruments to pick up and dissect out tissues should be kept to a minimum.


    • Mobilize the spleen by taking down collaterals to the retroperitoneum with the LigaSure device and clips.


    • Use the argon beam coagulator to mobilize the planes around the spleen. This effectively manages the innumerable small collaterals.


    • Leave the short gastric vessels at the upper pole of the spleen to the end of the procedure after the hilum has been divided.


    • Achieve circumferential control of the splenic hilum as close to the spleen as possible. Advance a surgical stapler across the hilum. Make sure the stapler is designed to traverse thick tissue loads. Fire the stapler after assuring no pancreas tissue will be transected with the stapler.


    • Once the hilum is transected, divide the remaining short gastric veins either with the stapler or surgical clips (FIG 5).


    • Place clips on the splenic artery close to the celiac artery. Once again, circumferential dissection of the artery should not be done.


    • Complete the esophagogastric devascularization. Identify any collateral vessels behind the stomach and in the gastrohepatic ligament. Ligate these veins with clips (FIG 6).


    • Repeat portal pressure measurements to determine whether a shunt is needed. Cannulate collateral veins prior to ligation. Direct pressure measurements of the splenic vein may be necessary. Multiple measurements may be needed.


    • A shunt should be done if there is a viable target for mesenteric venous inflow and central venous outflow and a postsplenectomy mesenteric-systemic gradient of 12 mmHg.







FIG 5 • Use a stapler designed for thick tissue loads. Staple across the hilum close to the spleen. Take the upper pole collaterals last with a stapler.






FIG 6 • Ligate esophagogastric collaterals with clips.


PROXIMAL SPLENORENAL SHUNT

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Jul 24, 2016 | Posted by in Aesthetic plastic surgery | Comments Off on Surgery for Portal Hypertension in Children and Adults

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