Portopulmonary hypertension in liver transplant candidates

Table 1 Summary on assessment, grading and therapy for portopulmonary hypertension

TTDE in all patients prior to transplant surgery, systolic PAP ≥ 30 mmHg

RHC in selected cases, confirmation and grading of PoPHT:

Mild PoPHT: mPAP > 25 mmHg, PVR > 240 dynes/s per cm-5, PCWP ≤ 15 mmHg, allow LT

Moderate PoPHT: mPAP 35-45 mmHg, PVR > 240 dynes/s per cm-5, PCWP ≤ 15 mmHg if responder to vasodilator therapy, allow LT

Severe PoPHT: mPAP > 45 mmHg, PVR > 240 dynes/s per cm-5, PCWP ≤ 15 mmHg, medical therapy

PoPHT: Portopulmonary hypertension; TTDE: Transthoracic Doppler echocardiography; PAP: Pulmonary artery pressure; RHC: Right heart catheterization; PVR: Pulmonary vascular resistance; LT: Liver transplantation.

Table 2 Pulmonary arterial hypertension-specific therapy: A summary of agents used

Entothelin receptor antagonists

Agents used in PoPHT: bosentan, ambrisentan

Mechanism of action: blockade of endothelin receptors

Route of administration: oral

Effects: vasodilation, decrease in PVR and portal pressure

Adverse effects: hepatotoxicity

PDE-5 inhibitors

Agents used in PoPHT: sildenafil, tadalafil, vardenafil

Mechanism of action: inhibition of PDE-5 enzyme

Route of administration: oral

Effects: vasodilation, decrease in portal pressure

Adverse effects: hypotension

Prostacyclins

Agents used in PoPHT: epoprostenol, iloprost

Mechanism of action: prostaglandin analogue, increase in cAMP

Route of administration: epoprostenol IV, iloprost inhalation

Effects: vasodilation, antiaggregation

Adverse effects: flushing, headache, nausea, diarrhea. Problems with IV epoprostenol use: cost, infection, catheter thrombosis, and thrombocytopenia

PAH: Pulmonary arterial hypertension; PoPHT: Portopulmonary hypertension; PDE-5: Phosphodiesterase type 5 enzyme; PVR: Pulmonary vascular resistance; IV: Intravenous.