Efficacy of Pentoxifylline and Rifaximin Combination in Pentoxifylline Refractory Clinical and Subclinical Hepatopulmonary Syndrome

Inclusion Criteria: 1. Evidence of portal hypertension (esophagogastric varices or portal hypertensive gastropathy identified on esophagogastroduodenoscopy, and/or varices seen on computerized tomography scan or ultrasound, and/or splenomegaly with no other explanation, and/or ascites with no other explanation) 2. Intrapulmonary vascular dilatations (IPVDs) diagnosed on contrast echocardiogram (CE) 3. AaDO2 \> 15 mm Hg on standing room air arterial blood gas (ABG) 4. Ability and willingness to give informed consent Exclusion Criteria: * Age \< 18 or \> 64 * Intrinsic significant cardiopulmonary disease * Inability to perform pulmonary function tests * Moderate to severe Pulmonary hypertension * Advanced hepatic encephalopathy * Inadequate echocardiographic window to allow for accurate transthoracic contrast echocardiography * Antibiotic use within the last one month * Listed for liver transplant in next 4 weeks * Current use of exogenous nitrates * Active bacterial infections * Known malignancy * Known intolerance to Pentoxifylline or rifaximin