Overview
Definition:
Portal vein reconstruction with autologous vein is a surgical procedure aimed at restoring continuity and patency of the portal venous system, typically using a graft fashioned from the patient's own vein
This is often performed in cases of trauma, tumor involvement, or congenital anomalies leading to portal vein stenosis or occlusion.
Epidemiology:
Incidence is rare and typically associated with specific etiologies like blunt abdominal trauma, operative injuries during pancreaticoduodenectomy or liver transplantation, and advanced hepatocellular carcinoma with portal vein tumor thrombus
Patient demographics vary widely based on the underlying cause.
Clinical Significance:
Successful portal vein reconstruction is crucial for maintaining adequate blood flow to the liver, preventing or managing portal hypertension, and enabling definitive treatment for underlying conditions such as malignant tumors
It impacts patient survival and quality of life significantly.
Indications
Indications For Reconstruction:
Acute or chronic portal vein thrombosis (non-neoplastic)
Portal vein stenosis secondary to pancreatitis or surgery
Trauma to the portal vein requiring repair
Portal vein tumor thrombus amenable to resection and reconstruction
Congenital abnormalities of the portal vein.
Contraindications:
Irresectable portal vein tumor thrombus
Uncontrolled coagulopathy
Severe underlying liver disease (decompensated cirrhosis)
Extensive intra-abdominal infection
Patient's inability to tolerate major surgery.
Patient Selection:
Careful patient selection is paramount, involving thorough assessment of liver function, extent of thrombosis or tumor involvement, and overall physiological status
Multidisciplinary team discussion is often beneficial.
Preoperative Preparation
Imaging Studies:
Contrast-enhanced computed tomography (CECT) scan for detailed anatomical assessment and extent of involvement
Magnetic resonance venography (MRV) or conventional angiography may also be used
Doppler ultrasonography for initial assessment of flow.
Laboratory Investigations:
Complete blood count (CBC), coagulation profile (PT/INR, aPTT), liver function tests (LFTs), renal function tests (RFTs), electrolyte panel
Blood typing and cross-matching are essential due to potential for significant blood loss.
Anesthesia Considerations:
General anesthesia is typically required
Careful hemodynamic monitoring is essential due to the large vascular nature of the surgery
Fluid management and blood product availability are critical.
Donor Vein Assessment:
Assessment for suitable autologous vein graft: saphenous vein (long or short saphenous) is most common
Other options include cephalic vein or femoral vein segments, depending on availability and length required.
Surgical Procedure Steps
Surgical Approach:
Laparotomy (midline or subcostal incision) or laparoscopic approach depending on surgeon preference and patient condition
Median laparotomy provides excellent exposure of the entire portal venous system and surrounding structures.
Mobilization And Exposure:
Careful dissection and mobilization of the portal vein, superior mesenteric vein (SMV), and splenic vein
Identification of patent proximal and distal ends of the portal vein for anastomosis
Excision of diseased or thrombosed segment if necessary.
Graft Harvesting:
Harvesting of the autologous saphenous vein graft
The graft is typically prepared by flushing with heparinized saline and sometimes distending to ensure patency
Intraluminal conduits may be used to prevent endothelial damage during preparation.
Anastomosis Technique:
End-to-end or end-to-side anastomosis
The portal vein is typically ligated distally if occluded or involved by tumor
The proximal and distal ends of the portal vein are prepared for anastomosis
The autologous vein graft is then anastomosed to the portal vein using fine monofilament sutures (e.g., 6-0 or 7-0 Prolene)
The orientation of the graft is crucial to avoid kinking or flow obstruction.
Confirmation Of Patency:
Assessment of graft patency by direct visualization of pulsatile flow or Doppler ultrasound
Intraoperative angiography may be performed if there is any doubt about the patency.
Postoperative Care
Monitoring:
Intensive care unit (ICU) monitoring is typically required
Close monitoring of vital signs, urine output, and fluid balance
Serial abdominal examinations for signs of bleeding or bowel ischemia.
Anticoagulation:
Postoperative anticoagulation is often initiated to prevent graft thrombosis
Options include continuous heparin infusion, followed by oral anticoagulants (warfarin) or direct oral anticoagulants (DOACs)
Duration and specific agent depend on surgeon's protocol and patient's risk factors.
Pain Management:
Adequate analgesia to ensure patient comfort and facilitate early mobilization
Epidural analgesia or patient-controlled analgesia (PCA) may be utilized.
Nutritional Support:
Early enteral nutrition is preferred to maintain gut integrity
If oral intake is not possible, parenteral nutrition may be required
Assessment of pancreatic exocrine and endocrine function may be necessary postoperatively.
Complications
Early Complications:
Graft thrombosis is the most feared early complication, leading to re-occlusion and recurrence of portal hypertension
Hemorrhage from the anastomosis site
Bowel ischemia secondary to inadequate flow or venous congestion
Wound infection
Anastomotic leak.
Late Complications:
Graft stenosis or pseudoaneurysm formation
Recurrent portal vein thrombosis
Development or worsening of ascites
Hepatic encephalopathy
Increased risk of hepatic decompensation.
Prevention Strategies:
Meticulous surgical technique to ensure tension-free and widely patent anastomoses
Optimal anticoagulation management postoperatively
Careful selection of graft length and orientation to avoid kinking
Aggressive management of ascites and hepatic encephalopathy.
Prognosis
Factors Affecting Prognosis:
The presence and extent of underlying malignancy are major determinants of long-term survival
Successful restoration of portal venous flow is critical
The functional status of the native liver and the development of complications significantly impact outcomes.
Outcomes:
Successful reconstruction can alleviate symptoms of portal hypertension and facilitate curative treatment for malignancy
Long-term patency rates vary, with some studies reporting good outcomes, while others highlight the risk of thrombosis
Survival is largely dependent on the underlying pathology.
Follow Up:
Regular follow-up with serial Doppler ultrasonography or CECT scans to assess graft patency and monitor for recurrence of thrombosis or stenosis
Liver function tests and assessment for ascites and encephalopathy are also crucial
Lifelong anticoagulation may be considered in selected patients.
Key Points
Exam Focus:
Indications for portal vein reconstruction, choice of graft (autologous vs
synthetic/cadaveric), common anastomotic techniques (end-to-end vs
end-to-side), critical importance of anticoagulation postoperatively, most common early complication (graft thrombosis), role in managing portal vein tumor thrombus.
Clinical Pearls:
Ensure adequate length and appropriate orientation of the autologous graft to prevent kinking
Meticulous hemostasis during anastomosis is vital
Consider early commencement of anticoagulation in the OR
Recognize the importance of assessing liver reserve preoperatively.
Common Mistakes:
Inadequate graft preparation leading to thrombosis
Improper graft orientation causing stenosis or kinking
Insufficient anticoagulation postoperatively
Failure to adequately assess liver function pre-empting poor outcomes
Misjudgment of tumor resectability in cases of portal vein tumor thrombus.