Hepatopulmonary Syndrome and Portopulmonary Hypertension

Abstract

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are pulmonary vascular complications of portal hypertension with or without cirrhosis. The prevalence among liver transplant candidates is roughly 5-32 % for HPS and approximately 6 % for POPH. Although these two conditions may initially present with dyspnea and are pathologically linked by the presence of portal hypertension, their pathophysiologic mechanisms are significantly different. HPS is characterized by low pulmonary vascular resistance secondary to intrapulmonary vascular dilatations and hypoxemia; on the other hand, POPH features elevated pulmonary vascular resistance and constriction of the pulmonary vasculature. Medical treatment for HPS has been disappointing overall. POPH patients can be treated with pulmonary artery-specific vasodilatory therapy. Whereas liver transplantation (LT) results in the resolution of HPS and is an indication per se for LT, its effect on POPH is highly unpredictable. LT poses a high risk of death in those with significant POPH, where pulmonary artery-specific vasodilatory therapy may improve functional status and allow successful LT in a small number of select patients. Modern strategies in managing HPS and POPH rely on a thorough screening and grading of the disease's severity, in order to tailor the appropriate therapy and select only the patients who will benefit from LT.

Cardiac diseases among liver transplant candidates

“…55 60 Circulating vasodilation factors cause pulmonary endothelial smooth muscle proliferation, leading to pulmonary blood flow obstruction and pulmonary arterial hypertension. 61,62 Risk factors include female sex, autoimmune liver disorders, and an increase in preload associated with a portosystemic shunt. 61,62 Often asymptomatic, patients present most commonly with dyspnea on exertion.…”

“…61,62 Risk factors include female sex, autoimmune liver disorders, and an increase in preload associated with a portosystemic shunt. 61,62 Often asymptomatic, patients present most commonly with dyspnea on exertion. 62 When POPH is severe, patients may show signs of right HF with peripheral edema, jugular venous distention, or a systolic murmur of tricuspid regurgitation.…”

“…61,62 Often asymptomatic, patients present most commonly with dyspnea on exertion. 62 When POPH is severe, patients may show signs of right HF with peripheral edema, jugular venous distention, or a systolic murmur of tricuspid regurgitation. 59,62 Echocardiography can show increased pulmonary arterial systolic pressure, tricuspid regurgitation, right ventricular dilatation, or right ventricular dysfunction, or a combination.…”

“…Mean pulmonary arterial pressure (mPAP) >25 mm Hg accompanied by pulmonary arterial occlusion pressure <15 mm Hg, pulmonary vascular resistance (PVR) >240 dynes*s/cm, 5 and transpulmonary gradient >12 mm Hg confirm the diagnosis of POPH. 59,62 Pharmacologic therapy is initiated at mPAP >35 mm Hg and PVR > 240 dynes*s/cm 5 , 58 including prostaglandin analogs, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors. 62 If untreated, long-term survival is 2%-14%, but with prostacyclin therapy, 5-year survival can be as good as 40%-68%.…”

“…59,62 Pharmacologic therapy is initiated at mPAP >35 mm Hg and PVR > 240 dynes*s/cm 5 , 58 including prostaglandin analogs, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors. 62 If untreated, long-term survival is 2%-14%, but with prostacyclin therapy, 5-year survival can be as good as 40%-68%. 63 Outcomes are not predictable, and the possibility of intraoperative right HF continues.…”