心筋梗塞症急性期における肺うっ血の成因に関する検討

Clinical investigation into the mechanisms of pulmonary congestion in acute myocardial infarction

　急性心筋梗塞症に伴う肺うっ血は，重篤な合併症の一つであり，その成因を知ることは治療上極めて重要と考えられる^1）。

　一般に，急性心筋梗塞症による肺うっ血は広範な心筋虚血の結果としての左室のglobalな収縮，ならびに拡張機能低下に基づく左室充満圧，ひいては肺毛細管圧の上昇に起因するとされている。しかるに，臨床上，理学的ならびに胸部レ線より診断される肺うっ血所見と肺毛細管圧との間に解離を示す症例は，時に経験されるところである^2〜5）。この様な解離の原因としては，血漿ならびに組織の膠質浸透圧，リンパ管機能あるいは血管透過性などの関与が推察されるが，その詳細は不明である。

We investigated the mechanisms of pulmonary congestion (PC) other than an elevation of pulmo-nary capillary pressure in patients (pts) with acute myocardial infarction (AMI). 102 pts with AMI were classified into 4 groups according to pulmo-nary arterial end-diastolic pressure (PAEDP) and PC which was detected radiologically: Group I (58 pts) PAEDP<18mmHg and PC (-); Group II (11 pts) PAEDP<18mmHg and PC (+) ; Group III (9 pts) PAEDP≧18mmHg and PC (-) ; Group IV (24 pts) PAEDP≧18mmHg and PC (+). The results were as follows; (1) Group II was more older than Group I (69 years vs 61 years) and Group III was younger than Group IV (58 years vs 63 years). (2) Infarct sites were not significantly different in four groups. (3) Serum albumin and PaO₂ were significantly decreased in Group II and IV. Plasma norepinephrine were tended to be higher in Group II and IV compared with Group I and III. (4) Although PAEDP in Group II was higher than that in Group I, cardiac index and left ventricular stroke work index in Group II were significantly lower than those in Group I. (5) In spite of the same levels of right atrial pressure, right ventricular stroke work index in Group III was lower than that in Group IV. Based on these findings, we concluded that an increased capillary permeability by aging, low col-loid osmotic pressure and left heart-right heart interaction other than an elevated pulmonary cap-illary pressure might be related to development of PC in patients with AMI.