del Nido P J, Mickle D A, Wilson G J, Benson L N, Coles J G, Trusler G A, Williams W G
Division of Cardiovascular Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.
Circulation. 1987 Nov;76(5 Pt 2):V174-9.
Evidence of human myocardial oxygen-mediated free radical injury (OFRI) during cardiovascular repair is lacking. We studied six cyanotic children (ages 3.5 to 5.5 years) during elective repair of tetralogy of Fallot. Right ventricular biopsy specimens, obtained on bypass just before aortic cross-clamping, at the end of 40 +/- 8 min (mean +/- SD) cold arrest with blood cardioplegia, and during reperfusion, were analyzed for hydroxy conjugated dienes, a chemical signature of free radical injury. Structural confirmation of the dienes was done by mass spectroscopy. Conjugated dienes were detected before ischemia on bypass, at end-ischemia, and during reperfusion. The products identified are 9 and 13 OH isomers of linoleic acid and 5, 8, 9, 11, and 15 OH isomers of arachidonic acid. Microscopic examination of right ventricular biopsy specimens obtained on bypass just after cross-clamping showed focal myocyte necrosis. The hydroxy conjugated diene levels in control canine hearts subjected to 105 min of cardiopulmonary bypass without aortic cross-clamping were not detectable. Our results support the occurrence of oxygen-mediated free radical injury during elective repair of tetralogy of Fallot. The presence of conjugated dienes before aortic cross-clamping suggests oxygen toxicity with reoxygenation from cardiopulmonary bypass.
目前缺乏关于心血管修复过程中人类心肌氧介导的自由基损伤（OFRI）的证据。我们对6名法洛四联症择期修复手术期间的紫绀型儿童（年龄3.5至5.5岁）进行了研究。在体外循环期间，于主动脉阻断前、40±8分钟（平均±标准差）冷血心脏停搏加血液心肌保护结束时以及再灌注期间获取右心室活检标本，分析其中羟基共轭二烯（自由基损伤的化学标记物）。通过质谱对二烯进行结构确认。在体外循环缺血前、缺血末期以及再灌注期间均检测到了共轭二烯。鉴定出的产物为亚油酸的9和13羟基异构体以及花生四烯酸的5、8、9、11和15羟基异构体。在主动脉阻断后立即于体外循环期间获取的右心室活检标本的显微镜检查显示有局灶性心肌细胞坏死。在未进行主动脉阻断的情况下接受105分钟体外循环的对照犬心脏中未检测到羟基共轭二烯水平。我们的结果支持在法洛四联症择期修复过程中存在氧介导的自由基损伤。主动脉阻断前共轭二烯的存在提示体外循环再氧合导致的氧中毒。
