NITRIC-OXIDE AND PROSTACYCLIN LOWER SUPRASYSTEMIC PULMONARY-HYPERTENSION AFTER CARDIOPULMONARY BYPASS

In a 3-week-old male newborn persistent suprasystemic pulmonary hypert ension developed after surgical valvulotomy for a critical aortic valv e stenosis. Because of a residual transvalvular pressure gradient of 3 5 mm Hg and postoperative left as well as right ventricular dysfunctio n, treatment with inhaled nitric oxide (NO) and intravenously infused prostacyclin (PGI2) was attempted. Low-dose inhaled NO and low dose PG I2 corrected severe pulmonary hypertension and led to an increase in c ardiac output. Treatment with NO but not PGI2 was accompanied by a ris e in PaO2 and systemic blood pressure. Interruption of NO administrati on led to a rapid increase in pulmonary arterial pressure to suprasyst emic levels. With continued i.v. PGI2 and decreasing concentrations of NO, severe pulmonary hypertension resolved after a few days suggestin g that a transient endothelial dysfunction was partially responsible f or pulmonary vasoconstriction. NO inhalation appears to be an effectiv e new tool in the treatment of severe pulmonary hypertension following cardiac surgery.