無症候性心筋虚血に対するCa拮抗薬（ニソルジピン）の心筋灌流に及ぼす影響

The Efficacv of Nisoldipine on Myocardiai Perfusion in patients with Silent Myocardial Ischemia

　心筋viabilityならびに虚血性病変を有する陳旧性心筋梗塞を無痛群9例と有痛群9例に分類し，nisoldipineによる心筋灌流の改善様式を連動負荷²⁰¹T1心筋SPECT（心筋SPECT）を用いて両群で比較した．運動耐容時間はnisoldipine投与前後で有痛群では505秒から607秒と有意な（p＜0.05）延長が示されたが，無痛群では不変であった．負荷像において左室全周のextent score, severity scoreならび梗塞領域の％T1 uptakeはnisoldipine投与前後で両群とも有意な改善が示された．心筋灌流改善の機序として，有痛群では後負荷の低下に伴う心筋酸素需要の減少ならびに冠動脈拡張作用が，無痛群では主に冠動脈拡張作用の関与が示唆された．無痛群においてもnisoldipine投与前後で心筋灌流の改善が認められたことから，Ca拮抗薬が無症候性心筋虚血に対しても有効な内科的治療となり得る可能性が示唆された．

Patients who had old myocardial infarction associat-ed with myocardial viability and ischemia were divided into a pain-free group and a pain positive group of nine patients each. The improvement of myocardial per-fusion with nisoldipine therapy was compared between the two groups using exercise load Tl 201 myocardial SPECT (myocardial SPECT). The exercise time was significantly prolonged from 505 seconds to 607 seconds after administration of nisoldipine in the pain-positive group (p＜0.05). but there was no change in the pain free group. The extent score of the full circumference of the left ventricle, the severity score. and the %Tl uptake of the infarcted region were significantly improved in both groups by administration of nisoldipine. These findings suggested that nisoldipine caused a decrease in the myocardial oxygen requirements associated with reduction of the afterload and coronary artery dilata-tion in the pain- positive group, but mainly caused coro-nary dilatation in the pain-free group. Since myocardial perfusion also improved after nisoldipine administration in the pain-free group, the possibility that calcium antagonists can be used for prophylactic treatment of asymptomatic myocardial ischemia was suggested.