Hepatopulmonary Syndrome (HPS) - Diagnosis and Management Summary
• Syndrome of intrapulmonary shunting through vasodilation/AVMs; mechanism unclear, possibly due to circulating NO
• Presentation: shunting tends to occur at lung bases → platypnea (dyspnea when upright, relieved when supine) & orthodeoxia (upright hypoxemia, PaO2 ↓ by 4 mmHg or ≥5%), clubbing, cyanosis, hypoxemia (↓PaO2 <70-80)
• Diagnosis: TTE with late bubbles (3-6 cardiac cycles after RA), ↑A-a gradient ≥15 (or >20 if age >64).
o 99mTc MAA scan is alternative to TTE but more invasive, less sensitive. May be useful in quantifying shunting if severe hypoxemia and coexistent intrinsic lung disease.
o Pulmonary angiography performed if severe hypoxemia poorly responsive to 100% O2 & areas amenable to embolization
o PFTs can be performed to evaluate for intrinsic lung disease; ↓DLCO in HPS
• Management: O2; no effective medical therapies; OLT can significantly improve (and reverse) HPS
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