Effect of the 5HT_2A Receptor Antagonist, Sarpogrelate Hydrochloride, on the Rate of Restenosis After Percutaneous Old Balloon Angioplasty

〔背景〕セロトニン受容体,特に5HT_2受容体は血管収縮および血小板凝集に大いに関与し,また,経皮的冠動脈形成術(PTCA)後の血管内皮機能障害の進行にも影響を及ぼしている. 〔目的〕5HT_2A受容体拮抗薬(塩酸サルポグレラート)が経皮的旧バルーン動脈形成術(POBA)後の再狭窄率の減少に有用であるか否かアスピリンと対比し検討する.〔方法〕1996年3月より1997年6月までに急性冠症候群の診断で入院となりPOBAを施行した56例(男性45例,女性11例;平均年齢63歳)について検討した. 56例中無作為に抽出した26例に対し5HT_2A受容体拮抗薬150mg(分3)を投与し,残りの30例に対してはアスピリン81mg(分1)を投与した.また,QCA法により計測し6ヵ月後(follow up時)の冠動脈造影上で標的血管に50%以上の狭窄を認めた場合を再狭窄と定義した.〔結果〕56例すべてにおいてfollow upを行った. POBA前後での両群間における対照血管最小血管経(MLD)に有意差は認めなかった(5HT_2A群vsアスピリン群:2.67±0.53mm vs 2.79±0.56mm; p=0.42). POBA後6ヵ月後(follow up時)のMLDは5HT_2A群の方がアスピリン群より有意に大きい結果であった(5HT_2A群vsアスピリン群: 1.64±0.69mm vs 1.06±0.91mm; p=0.03).再狭窄率は5HT_2A群7/26(27%),アスピリン群13/30(43%)であった.また, 5HT_2A群において,診断造影上右冠動脈に有意狭窄を認めた症例でPOBA後の再狭窄が少ない傾向を認めた.全経過中に明らかな合併症は認めなかった.〔結語〕5HT_2A受容体拮抗薬(塩酸サルポグレラート)はPOBA後の再狭窄率の減少に有用かつ明らかな合併症を認めない安全な薬剤であり,診断造影上右冠動脈に有意狭窄を認めた症例においては特に有用な薬剤であると思われる.

Background: Serotonin receptors, especially 5HT_2 receptors, are important in vasoconstriction and platelet aggregation and are involved in the chronic progression of endothelial dysfunction after percutaneous transluminal coronary angioplasty (PTCA). Objective: To determine whether the 5HT_2A receptor antagonist, sarpogrelate hydrochloride, was more effective than aspirin in reducing the rate of restenosis after percutaneous old balloon angioplasty (POBA). Methods: Between March 1996 and June 1997, 45 men and 11 women (average age of 63 years) underwent POBA for acute coronary syndromes. Of these, 26 received the 5HT_2A receptor antagonist 50 mg three times a day and 30 received aspirin 81 mg daily in a randomized, open trial. Restenosis was defined as a narrowing of the target vessel of at least 50% at follow-up, as measured by quantitative coronary angiography (QCA). Results: The angiographic follow-up rate was 100%. The reference minimal lumen diameter (MLD) before and after POBA did not differ significantly between the two groups (post MLD: 2.67 (0.53) in the 5HT_2A group and 2.79 (0.56) in the aspirin group; p=0.42). The mean (SD) MLD at 6 months was significantly larger in the 5HT_2A group than in the aspirin group (1.64 (0.69) mm vs 1.06 (0.91) mm; p =0.03). Angiographically identified restenosis occurred in 7/26 (27%) of the patients in the 5HT_2A group and in 13/30 (43%) of those in the aspirin group. In the 5HT_2A group, restenosis rate was likely to be less frequent in patients with right coronary artery (RCA) stenosis on the initial diagnostic angiogram (p=0.040). No complications were observed during the follow-up period. Conclusions: The 5HT_2A receptor antagonist, sarpogrelate hydrochloride, reduced the rate of restenosis after POBA, especially in patients with RCA stenosis on the initial diagnostic angiogram. No adverse events were reported in this series.