| BackgroundPulmonary hypertension (PH) is a progressive disease that refractory to treatment and can ultimately lead to right ventricular failure or even death. PH may be associated with congenital heart disease with increased pulmonary blood flow. Early correction of congenital defect is the best treatment of this kind of PH. But increases in pulmonary vascular resistance may occur in the postoperative period after repair of these defects. It is very important to find an efficient treatment, which can decrease pulmonary hypertension and prevent or ameliorate pulmonary vascular remodeling.Up to now the treatment of PH after cardiac surgery include oxygen administration, hyperventilation induced by mechanical ventilation and pulmonary vasodilators. At present, pulmonary vasodilators are still the main treatment. Among them, inhaled nitric oxide (iNO) has proved to be the most effective and pure selective pulmonary dilator in the management of PH.However, there are inherent problems with nitric oxide which may limit its use. These include the potential toxicity, a sub-optimal or only partial response in some patients, the development of rebound PH upon its withdrawal after even relatively short periods of its use,the mode of delivery, which generally requires a special device, and the expensive cost. In order to overcome these limitations ,there has been recent interest in the development of other pulmonary vasodilators. One such agent, which increases the levels of the vasodilator cyclic-guanosine 5'-monophosphate (cGMP) within pulmonary vascular smooth muscle ,the same pathway of NO, is the phosphodiesterase inhibitor, the sildenafil. Sildenafil increases intracellular cGMP by inhibiting its breakdown by phosphodiesterase-5 isoenzyme, and its potent pulmonary vasodilative effects have been demonstrated in primary and secondary pulmonary hypertension. However, experience with sildenafil in PH after cardiac surgery in children is limited, and its interaction with intravenous prostaglandin El (Alprostadil) is unknown.Materials and MethodsSetting This was a prospective, randomized, controlled crossover trial, which performed at the pediatric cardiovascular surgical ICU, the Children's Hospital, Zhejiang University School of Medicine, China.Patients All children with severe PH due to ventricular septal defect or atrioventricular septal defects, diagnosed on pre-operative echocardiography, were eligible for entry to this study. Data were collected on 24 consecutive children (aged from 4 Months to 9 years) with postoperative mean pulmonary arterial pressure (mPAP) ≥35mmHg who underwent open-heart surgery in our hospital between August 2004 and March 2005. Children with post-operative hypotension, severe arrhythmia (not include sinus tachycardia )and residual intracardiac shunt or significant atrioventricular valve regurgitation by post-operative transthoracic echocardiography were excluded from the study.Studies were commenced within 12 h following cardiopulmonary bypass when all children were stable. The children were sedated and muscle-relaxed with fentanyl and vecuronium and mechanically ventilated during the study .All children received intravenousdopamine, dobutamine at a dose of 2-8μg/kg per min and 10% calcium gluconate (l-2ml/kg) during the study period .24 children were randomly assigned to one of three study groups. The total study duration was 60 min for all participants. 8 children (group A) initially received sildenafil citrate tablet (0.35mg/kg orally by nasal gastric tube, followed by the addition of intravenous Alprostadil (20ng/kg per min ,infused over 20 min)at 40 min. The second group of 8 children(group C) initially received intravenous Alprostadil (20ng/kg per min ,infuse over 60min), followed by the addition of sildenafil at 20 min (dose as above). And remains (group B) received only dopamine, dobutamine and 10% calcium gluconate .No patient received alpha-blocks, other phosphodiesterase inhibitors or nitrovasodilators during the study. A complete set of haemodynamics, an arterial blood gas and parame...
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