原発性肺高血圧症におけるprostacyclin（epoprostenol）持続静注療法の短期効果

Short-term Effect of Continuous Intravenous Prostacyclin (Epoprostenol) in Patients with Primary Pulmonary Hypertension

　原発性肺高血圧症（PPH）は予後が極めて悪い原因不明の疾患であり，本邦で従来から行われている治療の有効性は低い．欧米では既に臨床的に確立されているprostacyclin静注製剤（epoprostenol）を5例の重症PPH症例に使用し，以下の知見を得た．①急性効果においては，心拍出量の増加が主体であり肺動脈圧の低下は少なく，体血圧の低下はやや高度であった．②慢性投与では，心拍出量の増加のみならず肺動脈圧の低下（平均13％）も得られ，その程度は体血圧と比較して大きく，肺血管選択性が存在した．血行動態のみならず全例で自覚症状も改善し生活能力が向上した．③5例中3例で，一旦投与を中止することができ，血行動態上の効果は中止後ほとんど消失したが，自覚症状の改善は持続した．以上より，epoprostenolは少なくとも短期的には重症PPH症例の血行動態と自覚症状を改善し，本邦においても今後有望な治療法であると考えられた．

Continuous intravenous infusion of prostacyclin (epo-prostenol) is clinically established and considered to be the most effective vasodilating therapy in patients with primary pulmonary hypertension (PPH) in European and American countries.

Recently we have encountered 5 patients (one male, 4 females, 32±9 years old) with severe (NYHA functional class III or IV) PPH successfully treated with epopros-tenol. Hemodynamic measurements by means of cardiac catheterization were performed before and immediately after acute administration, and restudied after 1 to 3 months of chronic treatment.

(1) In the acute phase, there was an increase in cardiac output (CO) (3.2±1.1 to 4.3±1.8 l/min, +36%) and a decrease in total pulmonary resistance (TPR) (23.7±9.9 to 18.0±7.8 units, -24%), although pulmonary arterial pressure (PAP) (mean ; 67± 12 to 67±10 mmHg) was not altered at the point of maximum effect. In addition, systemic arterial pressure (SAP) (mean; 81±13 to 66±19 mmHg, -19%) decreased in all patients and obvious-ly in 1 patient. (2) In the chronic phase, PAP (mean; 58±9 mmHg, -13%) and TPR (16.7±6.7 units, -29%) decreased, and CO (3.8±1.1 l/min, +20%) increased. TPR decreased more than 20% in 4 of 5 patients and SAP (mean; 84±11 mmHg) was not reduced in any patient compared with baseline values. (3) Subjective symptoms also improved in all patients. (4) Three of 5 patients are alive and still in better condition more than one year after quitting the regimen. One patient died at 10 days after tapering off and one is still on the regimen.

In conclusion, epoprostenol could be a promising vasodilating remedy in patients with PPH in Japan, also.