TAKAYA Junji Kansai Medical University, Department of Pediatrics, Research Associate, 医学部, 助手 (80247923)
IKEMOTO Yumiko Kansai Medical University, Department of Pediatrics, Research Associate, 医学部, 助手 (50278610)
OGINO Hirotaro Kansai Medical University, Department of Pediatrics, Assistant Professor, 医学部, 講師 (40131429)
Pulmonary vascular tone is regulated by multiple mediators. Among these factors, endothelin (ET) is the most potent vasoconstrictor, and nitric oxide (NO) is a potent vasodilating factor. The purpose of this study is to evaluate the physiological significance of both NO and ET in pulmonary hypertension associated with congenital heart diseases.
A total of 50 patients (age, 7months to 13 years) with congenital heart diseases (VSD,ASD,PDA,valvular PS,and TOF) were studied during cardiac catheterization. Blood samples were obtained from the main pulmonary artery and left ventricle. We measured metabolites of NO (NO<@D2X@>D2) by using high power liquid chromatography and ET-1 by radioimmunoassay. Nineteen patients with pulmonary hypertension [PH group : mean pulmonary artery pressure (MPAP), 30(]SY+-[)10 mmHg] were compared with 31 patients without pulmonary hypertension (non-PH group : MPAP,15(]SY+-[)3 mmHg). Plasma ET levels were significantly higher in the PH group (3.4(]SY+-[)2.0pg/ml,
p<0.01) than in the non-PH group (1.6(]SY+-[)0.7 pg/ml). Plasma NO<@D2X@>D2 levels were also significantly higher in the PH group (2.4(]SY+-[)1.1 ppm, P<0.01) than in the non-PH group (1.6(]SY+-[)0.7 ppm). There was a significant correlation between plasma NO<@D2X@>D2 levels and MPAP (r=0.42, P<0.01). Plasma ET levels were also correlated with MPAP (r=0.4, P<0.01). In the PH group, plasma ET showed a positive correlation with the ratio of pulmonary to systemic blood flow (Qp/Qs) (r=0.68, P<0.01), although plasma NO<@D2X@>D2 levels showed no correlation with Qp/Qs. Moreover in this group, plasma NO<@D2X@>D2 showed a significant correlation with pulmonary vascular resistance (r=0.55, P<0.05). Among the 10 postoperative cases, plasma NO<@D2X@>D2 levels were siginificantly higher in the PH group (3.1(]SY+-[)1.3 ppm, p<0.05) than in the non-PH group (1.4(]SY+-[)0.6 ppm), although plasma ET-1 levels showed no significant difference between the both groups.
We concluded that plasma levels of ET-1 and NO were elevated in pulmonary hypertension. Elevated levels of ET-1 were related to increased pulmonary blood flow and the secretion of NO might be stimulated by the increase of pulmonary vascular resistance. Both of them a different role in the modulation of pulmonary hypertention. Less