Portopulmonary Hypertension

Portopulmonary hypertension (PoPH) is pulmonary arterial hypertension (WHO group 1) in patients with portal hypertension, with or without cirrhosis.

Prevalence 2 to 6% in patients evaluated for liver transplant; risk not correlated with severity of liver disease; female sex and autoimmune hepatitis are risk factors.

Pathogenesis: vasoconstriction (endothelin), proliferation, in situ thrombosis, plexiform lesions, high output hyperdynamic state with shear stress.

Haemodynamic definition: mean PAP over 20 mmHg, PAWP 15 mmHg or less, PVR over 2 WU, portal hypertension.

Perioperative mortality for liver transplant is prohibitive when mean PAP over 50 mmHg (100% mortality) or 35 to 50 mmHg with PVR over 3 WU.

• Exertional dyspnoea, fatigue, syncope, chest pain, peripheral oedema; often asymptomatic and found during transplant evaluation.
• Loud P2, tricuspid regurgitation murmur, right ventricular heave, signs of cirrhosis.

• Screening transthoracic echocardiography in all liver transplant candidates (right ventricular systolic pressure over 45 to 50 mmHg prompts catheterisation).
• Right heart catheterisation: confirm PAP, wedge, PVR; exclude high output state and volume overload (wedge over 15 mmHg).
• Exclude other causes: V/Q scan, pulmonary function tests, CT.
• NT proBNP, liver evaluation (MELD, portal hypertension features).

• Pulmonary vasodilator therapy pre transplantation to lower mean PAP below 35 and PVR below 4 to 5 WU (then proceed with liver transplantation, MELD exception points):
  • Sildenafil 20 to 40 mg three times daily or tadalafil 40 mg daily.
  • Ambrisentan 5 to 10 mg or macitentan 10 mg (monitor liver tests; bosentan avoided).
  • IV epoprostenol or treprostinil (SC/IV) for severe disease; inhaled iloprost.
  • Avoid riociguat uncertain data; sotatercept limited experience.
• Beta blockers for varices may need review (can reduce cardiac output).
• Diuretics for volume overload; oxygen as needed; avoid anticoagulation unless indicated (bleeding risk).
• Liver transplantation if response adequate; combined heart/lung/liver rarely.
• Follow up with echo and catheterisation; reassess perioperative risk.
• Poor prognosis untreated (median survival 6 to 15 months); better with treatment and transplantation (5 year survival about 65%).