We assessed the effect of oxygen, nitric oxide (NO) and prostanoids (prostacyclin and iloprost) on pulmonary hemodynamics and plasma levels of vasoactive mediators in children with pulmonary hypertension (PH). It is not known whether the hemodynamic response during acute vasodilator testing correlates with changes in plasma levels of endothelin-1 (ET-1), cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP). In this retrospective analysis 14 children at a median age of 4 years and 3 months [1.8 months-13 years] with a median pulmonary resistance to perfusion of 10.1 [2.1-37.7]. Wood-Units x m2 were studied. Diagnoses included PH due to congenital heart disease (AVSD n = 5; VSD n = 2; PDA n = 1) or unknown causes (n = 6). The ratios of pulmonary/systemic pressure (Pp/Ps) and of pulmonary/systemic resistance (Rp/Rs) were recorded a) at baseline, b) during oxygen (FiO2 = 1.0) and c) while on NO (80 ppm max., at FiO2 = 0.23). In 13 out of 14 children prostanoids were given additionally: 7 received prostacyclin (i.v.) and 6 were given iloprost which was nebulized. ET-1, cGMP and cAMP were measured in blood samples taken from the pulmonary vein or left ventricle at baseline, during increased FiO2, during NO inhalation and while on prostanoids. Pulmonary vasodilation in response to oxygen was found in 2/14 patients. 4/14 patients responded to NO and 2/7 to prostacyclin i.v. Increased FiO2 was not associated with changes in plasma concentrations of ET-1, cGMP or cAMP. NO inhalation was followed by an increase in cGMP levels from 10.9 [5.5-55.4] nM/L to 21.3 [6.4-76.3] nM/L independent from the individual hemodynamic response. Oxygen and NO identify most children with reactive pulmonary vasculature. cGMP plasma levels do not correlate with individual hemodynamic responses to NO.

This study was performed to evaluate the role of endogenous endothelin-1 (ET-1), atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (cGMP) in patients with left-to-right shunt and pulmonary hypertension. Further objectives were to study a possible feedback mechanism between ANP and ET-1 and to examine the influence of ANP on cGMP plasma levels. Finally, the role of these hormones in oxygen-mediated pulmonary vasodilation was examined. Plasma concentrations of ET-1, ANP and cGMP were studied in 39 patients with congenital heart disease and left-to-right shunt. Blood samples were taken from the pulmonary artery and pulmonary vein at cardiac catheterization at baseline and after breathing oxygen for 20 min. Patients were grouped according to the presence or absence of pulmonary hypertension (defined as mean Pp/Ps > or = 0.5). Patients with pulmonary hypertension (n = 18) were found to have significantly higher plasma ANP (665 [59-1358] versus 267 [47-832] pg/ml) and cGMP (21.5 [3.6-82.2] versus 7.8 [0-14.6] nM/L) levels than patients without pulmonary hypertension (n = 21). Pulmonary venous ET-1 plasma concentrations were above normal limits in one patient only. ANP plasma levels were not related to ET-1 and cGMP concentrations. There was no transpulmonary gradient for any of the factors. Pulmonary vasodilation in response to oxygen was found in 7 of 18 patients with PH, but was not associated with significant changes in ET-1, ANP or cGMP plasma concentrations. Patients with congenital heart disease and PH show an increase both in vasoconstrictive and vasodilating factors. The mechanism of oxygen-mediated vasodilation in these patients remains to be elucidated.

The IPVD is not helpful to predict surgical mortality during the first year of life. Patients with trisomy 21 and cAVSD may show advanced pulmonary vascular disease in infancy.

Our experience demonstrates that resection of tracheal stenosis and end-to-end anastomosis can be achieved successfully even in cases with stenosis of more than 30 % of the total tracheal length. The use of CBP allowed extensive mobilization of the tracheobronchial tree and resection with end-to-end tension-free anastomotic reconstruction.