How do you diagnose portal hypertension?

How to Test for Portal Hypertension

Hepatic venous pressure gradient (HVPG) measurement via hepatic vein catheterization is the gold standard for diagnosing and quantifying portal hypertension, with HVPG ≥10 mm Hg defining clinically significant portal hypertension (CSPH). 1, 2

Gold Standard: Invasive Measurement

• HVPG measurement remains the reference standard for assessing portal pressure severity, with portal hypertension defined as HVPG >5 mm Hg and CSPH as HVPG ≥10 mm Hg 1
• HVPG ≥10 mm Hg predicts risk of clinical decompensation, while HVPG ≥16 mm Hg is strongly associated with death 1
• This invasive test is limited by availability and technical requirements, making it impractical for routine screening 1

First-Line Noninvasive Approach: Imaging

Ultrasound with Doppler (Initial Test)

The presence of portosystemic collaterals or flow reversal in the portal system on ultrasound is 100% specific for CSPH and confirms the diagnosis. 3, 4

• Look for portosystemic collaterals (recanalized umbilical vein, splenorenal shunts, gastric varices) - 100% specific for CSPH 3
• Assess for portal vein flow reversal (hepatofugal flow) - 100% specific for CSPH 3
• Measure splenomegaly - sensitive but nonspecific when used alone; valuable when combined with other parameters 3
• Evaluate portal vein diameter (≥13 mm suggests portal hypertension) and reduced portal vein velocity (<12-20 cm/s) 5

Upper Endoscopy

• Perform esophagogastroduodenoscopy to assess for gastroesophageal varices, which indicate the presence of portal hypertension 6, 2
• Varices on endoscopy directly indicate clinically significant portal hypertension 2

Second-Line Noninvasive Assessment: Liver Stiffness Measurement

Transient elastography (TE) with liver stiffness measurement (LSM) is the best available noninvasive test for detecting CSPH when direct signs are absent. 1

Interpretation of LSM Values

• LSM ≤15 kPa: CSPH is highly unlikely (sensitivity 90-96% at this cutoff) 1
• LSM 15-25 kPa: Intermediate zone requiring additional assessment 1
• LSM ≥25 kPa: CSPH is likely present (specificity 82-93% at this cutoff) 1
• LSM >20-25 kPa: European guidelines recommend this cutoff to diagnose CSPH in compensated advanced chronic liver disease 3

Important Caveats for LSM

• Substantial variation exists in cutoff values across different liver disease etiologies 1
• Accuracy is modest at best, with sensitivity and specificity varying significantly based on the cutoff used 1
• Results should be interpreted in context of the specific liver disease etiology 1

Third-Line: Blood-Based Tests (Limited Utility)

Blood-based tests have poor accuracy and should not be used alone to diagnose portal hypertension. 1

• Platelet count <100,000/mcL: Sensitivity only 78% for CSPH, specificity <50% 1
• APRI score: 56% sensitivity and 68% specificity for CSPH 1
• FIB-4 score: 54% sensitivity and 73% specificity for CSPH 1
• These tests are too inaccurate for clinical decision-making regarding portal hypertension 1

Combined Scoring Systems (Investigational)

• Liver stiffness-spleen diameter to platelet ratio score (LSPS): Formula = LSM × spleen diameter (mm)/platelet count; cutoff >2.06 has 90% specificity 3
• At LSPS cutoff 0.927 kPa: 99% sensitivity, 54% specificity for CSPH 1
• At LSPS cutoff 3.75 kPa: 52% sensitivity, 97% specificity for CSPH 1
• Platelet/spleen ratio: Limited utility with highly variable sensitivity and specificity 1

Practical Diagnostic Algorithm

1. Start with Doppler ultrasound looking for portosystemic collaterals and flow reversal - if present, CSPH is confirmed 3, 4

2. Perform upper endoscopy to assess for varices - their presence indicates portal hypertension 6, 2

3. If ultrasound and endoscopy are negative or equivocal, obtain transient elastography (LSM): 1

   • LSM ≤15 kPa: CSPH unlikely, consider alternative diagnoses
   • LSM ≥25 kPa: CSPH likely present
   • LSM 15-25 kPa: Consider HVPG measurement for definitive diagnosis

4. Reserve HVPG measurement for cases requiring definitive diagnosis, therapeutic decision-making, or monitoring response to portal pressure-lowering therapy 1, 6

Key Clinical Pitfalls

• Do not rely on blood tests alone (platelets, APRI, FIB-4) - they lack sufficient accuracy for clinical decision-making 1
• Splenomegaly is nonspecific - it supports the diagnosis but cannot confirm portal hypertension without other findings 3, 5
• LSM cutoffs vary by etiology - apply disease-specific thresholds when available 1
• Normal portal vein diameter does not exclude portal hypertension - other findings must be assessed 5