Wong C K, Lau C P, Leung W H, Cheng C H
Department of Medicine, University of Hong Kong, Queen Mary Hospital.
Int J Cardiol. 1989 Nov;25(2):173-8. doi: 10.1016/0167-5273(89)90104-6.
Nifedipine has a vasodilatory effect on both the systemic and the pulmonary circulation. Its preferential effect on reducing the pulmonary vascular resistance has been studied in patients with primary pulmonary hypertension. In 4 patients with the Eisenmenger's syndrome complicating patency of the arterial duct (ductus arteriosus), we have studied the possibility of this selective pulmonary vasodilatory effect of nifedipine in reducing the right-to-left shunting. The degree of differential cyanosis was taken to reflect the right-to-left shunting. This was assessed continuously by 2 pulse oximeters applied to the right arm and leg. After sublingual nifedipine, the oxygen saturation of the right leg increased from pretreatment value of 79 +/- 5% (mean +/- SEM) to a maximum of 84 +/- 3% (P less than 0.01). Such a beneficial effect was maximal in the first 2 hours. On maintenance therapy, symptom-limited cycle ergometry showed increased exercise duration with comparable degrees of arterial desaturation and there was symptomatic improvement. This improvement disappeared on changing to placebo. It was concluded that nifedipine reduced right-to-left shunting and improved symptomatology.
硝苯地平对体循环和肺循环均有血管舒张作用。其对降低肺血管阻力的优先作用已在原发性肺动脉高压患者中进行了研究。在4例动脉导管（动脉导管未闭）通畅并发艾森曼格综合征的患者中，我们研究了硝苯地平这种选择性肺血管舒张作用降低右向左分流的可能性。差异性发绀的程度被用来反映右向左分流。通过将2个脉搏血氧仪分别应用于右臂和腿部来持续评估。舌下含服硝苯地平后，右腿的血氧饱和度从治疗前的79±5%（平均值±标准误）增加到最高84±3%（P<0.01）。这种有益效果在最初2小时内最大。在维持治疗时，症状限制的踏车运动试验显示运动持续时间增加，动脉去饱和程度相当，且症状有改善。改用安慰剂后这种改善消失。得出的结论是，硝苯地平减少了右向左分流并改善了症状。
