冠攣縮性狭心症におけるマグネシウム欠乏

Magnesium Deficency in Patients with Vasospastic Angina

　本研究の目的は，冠攣縮性狭心症例におけるマグネシウム欠乏の有無を明らかにすることである．対象は1993年6月から1995年12月までに薬剤を用いた冠攣縮誘発負荷試験で冠攣縮が確認された冠攣縮性狭心症連続84例である．明らかなST上昇を認める異型狭心症が31例，残りの53例はST上昇を伴わない非異型狭心症であった．男性は72例，女性は12例，平均年齢は63.3±6.9歳，75％以上の器質的冠動脈狭窄を28例に認めた．コントロール群は，同時期に心臓カテーテル検査を施行し，薬剤誘発負荷試験で冠攣縮が認められなかった19例である．方法は，マグネシウム負荷試験施行当日と翌日の血清マグネシウム，カルシウム，燐濃度，一日尿量，尿中マグネシウム濃度を測定し，一日尿中マグネシウム排泄量を求めた．コントロール群と冠攣縮性狭心症群で血清電解質濃度に当日，翌日ともに差異はなかった．24時間マグネシウム停滞率は冠攣縮性狭心症群で58.7±26.8％とコントロール群の44.7±11.7％に比し有意に高値を示した．しかし異型狭心症と非異型狭心症，75％以上の器質的狭窄の有無では2群間にマグネシウム停滞率に差異は認められなかった．また異型狭心症例では有意差はなかったが，器質的狭窄を認めない群が器質的狭窄を認める群に比しマグネシウム停滞率が高値を示した．1ヵ月以上カルシウム拮抗薬を内服した7例では症状の増悪改善に関係なく全例でマグネシウム欠乏状態の改善を認めた．

　冠攣縮性狭心症は異型狭心症ばかりでなく非異型狭心症例にもマグネシウム欠乏状態を認めた．

　The purpose of this study is to determine whether magnesium deficiency was present or not in patients with vasospastic angina. From 1993 June to 1995 December, 84 consecutive angiographically confirmed patients with vasospastic angina, consisting of 72 men and of 12 women with a mean age of 63.3±6.9 years old were studied. These consisted of 31 patients with variant angina pectoris and 53 patients in whom there was no demonstration of ST segment elevation. 28 of these patients had fixed stenosis (≥75%). As a control 19 patients in whom no spasm had been provoked by pharmacologic agents were also studied. Serum concentration levels of magnesium, calcium and potassium and total amount of urinary excretion of magnesium for 24 hours were measured on both the first and second day of the magnesium retention test. There was no difference in serum electrolyte levels on either the just or second day between patients with vasospastic angina and controls. However, the 24-hour magnesium retention rate was significantly higher (p＜0.01) in patients with vasospastic angina (58.7±26.8%) than in the controls (44.7±11.7%). In patients with vasospastic angina, the value of the 24-hour magnesium retention rate didn't differ between patients with variant angina and nonvariant angina or between patients with fixed stenosis and non-fixed stenosis. However, in patients with variant angina, the value of the 24-hour magnesium retention rate was higher in patients without fixed stenosis than those with fixed stenosis but was not different between 2 groups. Seven patients who were treated with calcium-channel blockers and isosorbide dinitrates for at least 1 month showed a greater improvement of magnesium deficiency as chest symptoms worsened.

　In conclusion, magnesium deficiency was present in patients with not only variant angina but also nonvariant angina.