原発性肺高血圧症の1例—血管拡張薬の急性ならびに慢性効果

A case of primary pulmonary hypertension:acute and chronic effect of vasodilators

　原発性肺高血圧症（primary pulmonary hypertension以下PPH）は原因不明の前毛細管圧の著しい肺高血圧症をきたす進行性の疾患である^1）。確定診断は"plexi—form lesion"などの病理組織学的所見にて得られるが^2,3），反復性肺血栓塞栓症（recurrent pulmonarythromboembolism）との鑑別は必ずしも容易ではない症例も存在する。治療法すなわち肺高血圧症に対して最近種々の血管拡張薬の有効性が報告されているが，それに対する異論もありさらに長期効果に関する報告は極めて少ない。今回我々は臨床的にPPHと診断した症例に対しprazosinとlong-acting isosorbide dinitrateの併用により臨床症状ならびに1，3，6カ月さらに1年後の時点で右心カテーテルにて得られた肺循環動態に改善を職たので報告する。

A forty three year old female was admitted for the complaint of exertional dyspnea and cough, which started 3 years before the admission. The patient had no past histories of thromboembolic disease. Electro-cardiogram showed right axis deviation and right ventricular hypertrophy. Chest rentogenogram showed a prominence of proximal pulmonary arteries and diminished vascularity of peripheral pulmonary arte-ries. Right heart catheterization revealed a markedly elevated pulmonary arterial pressure (PAP) in addition to increased total pulmonary resistence (TPR). Pul-monary capillary wedge pressure was within normal range and results of oximetry excluded the possibility of intracardiac shunt. No evidence of pulmonary scintigraphy and pulmonary arteriography was found.

From above findings primary pulmonary hyperten-sion (PPH) was finally diagnosed for the patient. Isosorbide dinitrate, Nifedipine, Prazosin and Captopril were independently administered to the patient in order to evaluate a short term-effect of the vasodilators. As a result, Isosorbide dinitrate and Prazosin were found to be effective of reduction in PAP and TPR, while the remaining drugs were not effective. The combined administration of long acting ISDN (10mg/day) and Prazosin (6mg,day) was, therefore, initiated in order to assess its long-term effect. A marked reduction in PAP from 114 10 (mean 66) mmHg to 70/30 (mean 431 mmHg and in TPR from 1.191 to 841 dyn･sec･ cm^-5 were found one month after the drug admini-stration. Moreover, we recognized persistent reduction in PAP and TPR one year after the administration. It was concluded that the combined administration of long acting ISDN and Prazosin could be fairly effec-tive as a long-term treatment of PPH.