Pleural Effussion caused by Pulmonary Hypertension

Have had Pleural Effussion since major Cardiac Surgery (Dual bypass) in July 2008. Never had an indication of a pulmonary problem before the surgery. The PE is concentrated on the right side. Have had four Thoracentesis with volumes of 700 to 1500 Milli liters of  fluid extracted.Tests have shown the substance to be transudative rather then exudate. Echo and stress tests continue to show valve conditions moderate for my age.No indications of heart failure! Pulmonary Artery Pressure from Echo test is high at 44 mmHg. The only medication prescribed for treatment are Diuretics.

If Pulmonary Hypertension is confirmed with a Right Heart Catherization, is the PH the likely cause of of the Pleural  Effusion?