Portal Hypertension - General Surgery PG Exam Theory

Definition

Portal Venous Anatomy (High-Yield)

• Portal vein carries ~75% of total hepatic blood flow and 72% of hepatic oxygen supply
• Flow: 1000-1500 mL/min in normal adults, significantly increased in cirrhosis
• No valves - drains spleen, pancreas, gallbladder, and abdominal alimentary tract
• Tributaries: Superior mesenteric vein + splenic vein form the portal vein behind the neck of the pancreas

Note: Hemorrhoids do NOT communicate with the portal system and are not increased in portal hypertension. Anorectal varices (present in ~45% of cirrhotics) must be distinguished from hemorrhoids.

Intra-abdominal venous pathways in portal hypertension (Schwartz's, Fig. 31-14)

Classification of Causes (Pre-sinusoidal / Sinusoidal / Post-sinusoidal)

Pre-sinusoidal

• Portal vein thrombosis
• Splenic vein thrombosis (pancreatitis, pancreatic tumour) - causes LEFT-SIDED (sinistral) portal hypertension
• Myelofibrosis, tropical splenomegaly, splenic arteriovenous fistula

• Schistosomiasis (most common cause worldwide)
• Congenital hepatic fibrosis
• Nodular regenerative hyperplasia, sarcoidosis, myeloproliferative disorders
• Veno-occlusive disease (sinusoidal obstruction syndrome), drugs/toxins, graft-vs-host disease

Sinusoidal (Intrahepatic)

• Cirrhosis (most common cause in the West/India)
• Alcohol-related liver disease, viral hepatitis (HBV/HCV)
• Primary biliary cholangitis, primary sclerosing cholangitis
• Autoimmune hepatitis, metabolic liver disease (NAFLD/NASH)

Post-sinusoidal

• Budd-Chiari syndrome (hepatic vein occlusion) - polycythemia vera, essential thrombocythemia, factor V Leiden, OCP use, IVC web
• Congestive cardiac failure / constrictive pericarditis
• Inferior vena caval web

Key exam point: In the West, cirrhosis accounts for the majority of portal hypertension. In India and developing nations, extrahepatic portal venous obstruction (EHPVO) and schistosomiasis are common non-cirrhotic causes.

Measurement of Portal Pressure

• Balloon catheter placed in hepatic vein via jugular approach
• FHVP (free hepatic venous pressure) = balloon deflated
• WHVP (wedged hepatic venous pressure) = balloon inflated
• HVPG = WHVP - FHVP
• Normal: <5 mmHg
• Portal hypertension: >5 mmHg
• Clinically significant: >10 mmHg
• Variceal bleeding threshold: >12 mmHg
• Severe (ascites): >12 mmHg

• Doppler ultrasound: best initial investigation - shows portal vein patency, thrombosis, direction of flow, collaterals
• CT/MRI angiography: detailed anatomy, patency
• Visceral angiography/venography: reserved for complex cases

Complications of Portal Hypertension

1. Ascites
2. Oesophageal/gastric varices
3. Portosystemic shunting (for problems not managed by other methods)
4. Left-sided portal hypertension and hypersplenism

1. Variceal Bleeding (Most Important)

• ~30% of compensated cirrhotics and 60% of decompensated cirrhotics have esophageal varices
• 1/3 of patients with varices will bleed
• Each episode: 20-30% mortality
• 70% of survivors will re-bleed within 2 years without treatment

2. Splenomegaly & Hypersplenism

• Causes leukopenia, thrombocytopenia, anemia
• Requires treatment if platelet count <50 × 10⁹/L or associated with variceal bleeding

3. Ascites

• Develops due to severe portal hypertension + hepatocyte dysfunction
• May develop spontaneous bacterial peritonitis (SBP)

4. Hepatic Encephalopathy

5. Hepatorenal Syndrome

Assessment of Liver Function - Scoring Systems (High-Yield PG Exam)

Child-Turcotte-Pugh (CTP) Score

• Originally developed to evaluate risk of portocaval shunt procedures
• Elective surgery generally NOT considered for Child B or C cirrhosis
• Limitation: includes subjective variables (ascites, encephalopathy); narrow range (5-15)

MELD Score (Model for End-Stage Liver Disease)

• Formula: 3.78[ln bilirubin (mg/dL)] + 11.2[ln INR] + 9.57[ln creatinine (mg/dL)] + 6.43
• Based on three objective values: INR, serum bilirubin, serum creatinine
• Originally developed to predict mortality after TIPS
• Now the primary method of liver transplant allocation
• MELD <16: lower postoperative mortality
• MELD-Na adds sodium as fourth variable (more accurate for ascites patients)
• Largely supplanted CTP for surgical risk stratification

Management of Variceal Bleeding

Management flowchart for complications of portal hypertension (Bailey & Love Fig. 69.12)

Step 1: Resuscitation (Immediate)

• Admit to ICU; large-bore IV access (two peripheral lines)
• Blood transfusion to Hb ~8 g/dL - avoid over-transfusion (raises portal pressure, worsens bleeding)
• IV Vitamin K 10 mg; FFP for coagulopathy; platelets if <50 × 10⁹/L
• Prophylactic antibiotics (ceftriaxone 1g/day IV) - reduces infection risk and increases survival
• Endotracheal intubation if encephalopathy present before endoscopy (airway protection)

Step 2: Vasoactive Drugs (Start immediately on clinical suspicion)

• Terlipressin (vasopressin analogue) - first choice; reduces splanchnic blood flow
• Octreotide / Somatostatin (somatostatin analogue) - preferred in many centres; can be given for 5 days; fewer systemic side effects than vasopressin
• Vasopressin - most potent vasoconstrictor; limited by side effects (hypertension, myocardial ischemia, arrhythmias, limb gangrene)
• Non-selective beta-blockers (propranolol/nadolol): reduce index bleed by 45%, bleeding mortality by 50% - used for PRIMARY PROPHYLAXIS, not acute bleeding

Step 3: Endoscopy (as soon as stable)

• Confirms source in 70% (30% will have non-variceal source)
• Oesophageal varices: Endoscopic band ligation (EBL) preferred over sclerotherapy - lower rebleeding rate
• Fundal/gastric varices: Cyanoacrylate (tissue glue) injection; thrombin injection

Management algorithm for variceal bleeding (Bailey & Love Fig. 69.13)

Step 4: Balloon Tamponade (Bridge therapy only)

• Used when endoscopic + pharmacological therapy fails
• Sengstaken-Blakemore (SB) tube - gastric and esophageal balloons
• Minnesota tube - adds a fourth port for esophageal suction
• Controls bleeding in up to 90%, but only temporary bridge
• Complications: aspiration, airway obstruction, esophageal perforation
• CONTRAINDICATION: hiatal hernia, recent esophageal surgery
• Should be replaced within 24-48 hours; max 24 hours recommended

Step 5: TIPSS (Transjugular Intrahepatic Portosystemic Stent Shunt)

• Has replaced surgical portocaval shunt as preferred method for refractory portal hypertension
• First described in 1969; widely available since 1985 with endovascular stents
• Technique: Via internal jugular vein → superior vena cava → hepatic vein → guidewire through hepatic parenchyma into portal vein branch → tract dilated → metallic stent inserted
• Creates a channel between portal vein and hepatic vein
• Performed under local anaesthetic with fluoroscopic + US guidance
• Complications:
  • Early: liver capsule perforation with fatal intraperitoneal haemorrhage
  • Stent occlusion (more common with good hepatic synthetic function)
  • Post-TIPSS encephalopathy in 40% (comparable to surgical shunts) - due to portal blood bypassing hepatic detoxification
• If severe encephalopathy: flow in stent is reduced (flow-restricting device inserted)
• Preferred over surgical shunts in transplant candidates (easier subsequent transplant)

Step 6: Surgery

• Failure to control bleeding with medical management: 10-20% of cases
• Options: portosystemic shunts, devascularisation procedures

Surgical Portosystemic Shunts (High-Yield)

Types of portosystemic shunts: A. Normal anatomy, B. Side-to-side portacaval, C. End-to-side portacaval, D. Mesocaval shunt, E. Distal splenorenal (Warren) shunt (Schwartz's Fig. 31-15)

Classification of Shunts

• Selective shunts (Warren) - lower incidence of encephalopathy; preserve hepatic blood flow
• No evidence prophylactic shunting is beneficial
• Previous surgical shunts increase complexity and morbidity of liver transplantation
• TIPSS should be preferred over surgical shunts in transplant candidates

Devascularisation Procedures

Sugiura Procedure (for refractory esophageal varices)

• Combines splenectomy with oesophagogastric devascularisation
• Permanently interrupts intraoesophageal portacaval shunt while preserving perioesophageal varices
• Devascularisation of both lesser and greater curves of upper stomach
• 8-10 cm of oesophagus cleared
• Oesophageal transection with large stapler just above cardia
• Preserves collateral channels and vagus nerve

Management of Ascites in Portal Hypertension

• CT confirms aetiology (irregular shrunken cirrhotic liver, portal hypertension, splenomegaly)
• IV contrast demonstrates abdominal varices and portal vein patency
• SAAG (Serum-Ascites Albumin Gradient) >1.1 g/dL = portal hypertension
• Protein content distinguishes causes: cardiac ascites (high protein) vs cirrhotic (low protein)

1. Salt restriction + diuretics (spironolactone ± furosemide)
2. Therapeutic paracentesis + albumin replacement
3. Refractory ascites: Peritoneovenous shunt (LeVeen shunt) or TIPSS (if transplant candidate)
4. Ultimately: Liver transplantation

Budd-Chiari Syndrome (Post-sinusoidal Portal Hypertension)

• Hepatic vein obstruction → hepatomegaly, liver congestion, RUQ pain
• Causes: Polycythemia vera (35-50% of primary cases), essential thrombocythemia, factor V Leiden (25%), anticardiolipin antibodies, oral contraceptives, hyperhomocysteinemia
• Caudate lobe hypertrophy in ~50% (direct venous drainage into IVC is preserved)
• 70% have centrilobular necrosis on biopsy
• Diagnosis: Abdominal US + Doppler first; CT/MRI; definitive = hepatic venography
• Treatment: Anticoagulation + treat underlying condition → angioplasty/TIPS + thrombolytics → surgical shunt → liver transplantation

Primary Prophylaxis of Variceal Bleeding

• Non-selective β-blockers (propranolol/nadolol): reduce index bleed by 45%, mortality by 50%
• ~20% do not respond; ~20% cannot tolerate
• Endoscopic band ligation (EBL): recommended for medium-to-large varices
  • Every 1-2 weeks until obliteration
  • EGD 1-3 months later, then surveillance every 6 months

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