Portopulmonary hypertension (PPHTN) is no longer an absolute contraindication to orthotopic liver transplantation (OLT).P ortopulmonary hypertension (PPHTN) is pathophysiologically distinct from hepatopulmonary syndrome. Whereas PPHTN is characterized by pulmonary vasoconstriction, hepatopulmonary syndrome is characterized by pulmonary vasodilation, shunting, and hypoxemia. 1 The early clinical recognition of PPHTN may be frustrated by nonspecific cardiopulmonary symptoms. Late PPHTN can be complicated by hemodynamic compromise and right heart failure.PPHTN is defined by a mean pulmonary arterial pressure (MPAP) greater than 25 mm Hg in a patient with a pulmonary capillary wedge pressure (PCWP) less than 15 mm Hg, portal hypertension, and no intrinsic or underlying lung disease. 2 PPHTN may be categorized further into mild (MPAP, 25 to 35 mm Hg), moderate (MPAP, 36 to 45 mm Hg), and severe (MPAP Ͼ 45 mm Hg). 3 Up to 12.5% of patients presenting for orthotopic liver transplantation (OLT) evaluation have PPHTN, 3-5 but 60% of these patients are asymptomatic at the time of diagnosis. 6 The prognosis for patients with PPHTN is dismal, with a mean and median survival after diagnosis of 15 months and 6 months, respectively. 6 The 6-month mortality rate is estimated to be approximately 50%. 6 In patients with severe PPHTN who proceed to OLT, perioperative mortality is very high. In 5 patients with severe PPHTN who underwent OLT at the University of Pittsburgh, PA, the perioperative mortality rate was reported at 80% and resulted primarily from right ventricular (RV) dysfunction. 7 It has been estimated that in patients who undergo OLT with an MPAP between 35 and 49 mm Hg and pulmonary vascular resistance (PVR) of 250 dynes ⅐ s ⅐ cm -5 or greater, the mortality rate is 50%. Patients with an MPAP of 50 mm Hg or greater have a cardiopulmonary mortality rate that approaches 100%. 2,8 It therefore has been recommended that moderate to severe PPHTN and significant RV dysfunction should be considered contraindications to OLT. 2 However, preoperative therapy to reduce pulmonary hypertension and RV dysfunction may improve clinical status and make OLT feasible. Continuous intravenous epoprostenol (prostacyclin, or prostaglandin I 2 ) is a potent vasodilator shown to improve exercise tolerance, reduce PVR, and improve mortality in patients with primary pulmonary hypertension. 9 Similar hemodynamic improvements have been achieved before OLT in patients with PPHTN. 10,11 Kuo et al 10 treated 4 patients with severe PPHTN (MPAP, 53 to 63 mm Hg) with 10 to 28 ng/kg/min of epoprostenol over 6 to 14 months and reported a 29% to 46% decrease in MPAP, a 22% to 71% decrease in PVR, and a 25% to 75% increase in cardiac output (CO).
