肺動脈弁閉鎖不全症を伴った特発性肺動脈拡張症の1例

A Case of Idiopathic Dilatation of the Pulmonary Artery with Pulmonic Insufficiency

　先天性肺動脈弁閉鎖不全症は，Abbott^1）によると，先天性心疾患1,000例中8例に認められ，そのうちの6例が特発性肺動脈拡張症と共存するまれな疾患である。本疾患の診断には，同じくErb領域に聴取される大動脈弁閉鎖不全症の高調な拡張期逆流性雑音と鑑別する必要があり，その方法としてAmyl Nitrite,Methoxamine負荷心音図法の他，Aminophylline負荷心音図法の有用性が報告されている^2）。今回われわれは，特発性肺動脈拡張症に伴う先天性肺動脈弁閉鎖不全症の1例を経験したので，若干の文献的考察とともに，Aminophylline負荷心音図法およびAminophylline負荷超音波Pulsed　Doppler法の有用性について報告する。

A rare case of idiopathic pulmonary artery dilatation with congenital pulmonic insufficiency is presented. The patient is a 38-year-old man. The chest roentgenogram revealed a prominent main pulmonary artery segment without evidence of enlargement of the cardiac chambers. The electrocardiogram was within normal limits. Cardiac catheterization revealed no evidence of a left-to-rightshunt or abnormal transvalvular pressure gradient. Pulmonary angiogram showed a dilated main pulmonary artery and a moderate degree of pulmonic insufficiency. The phonocardiogram showed the diastolic murmur of high frequency and short duration at the pulmonic area. Amyl nitrite and methoxamine did not modify the intensity of the murmur, however, aminophylline marke-dly decreased the murmur in this case. Pulsed Doppler echocardiogram showed a wide diastolic Doppler shift scatter in the right ventricular outflow tract, which was indicative of diastolic turbulence due to pulmonic regurgitation. This Doppler shift did not change after the administration of amyl nitrite and methoxamine. However, it decreased after the administration of aminophylline. It is concluded in this paper that the administration of aminophylline is useful for the non-invasive diagnosis of pulmonic insufficiency.