Knothe C, Boldt J, Dehne M, Zickmann B, Porsch S, Dapper F, Hempelmann G
Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University Giessen, Germany.
J Cardiovasc Surg (Torino). 1996 Aug;37(4):367-75.
Different prophylactic myocardium saving strategies are often routine in open heart surgery. Even if theoretically well established, they must be critically reviewed in times of limited financial resources.
Troponin-T (TnT) is a valuable tool to detect even minor myocardial damages independently from concomitant muscle injuries. We measured intra- and postoperative TnT-values and ST-wave deviations on the ECG in a control group and in patients receiving one of the following prophylactic
hypothermia during cardiopulmonary bypass (CPB), nitroglycerine ([0.5 microgram/kg/min]) or nifedipine [0.1 microgram/kg/min] after aortic cross-clamping until end of operation, or perioperative Mg2+ per os.
The study included 65 patients of a university hospital with preoperative good heart function scheduled for elective aorto-coronary bypass operation.
TnT values increased in all groups after CPB and peaked between end of operation and first post-operative day. TnT values above the critical border of 1.0 microgram/l in the early period after CPB were less often seen in the nitroglycerine and nifedipine group. No pronounced differences could be observed after the first postoperative day. Patients of the hypothermia group had most often TnT values above 1.0 microgram/l. Maximum TnT values of the control, the hypothermia and the Mg(2+)-group correlated with the duration of aortic-crossclamping. No correlation existed between ST-deviations and TnT-values.
The prophylactic measures failed to reduce myocardial damage as evidenced by the course of TnT values. They can therefore not be recommended as routine strategies in patients with good left heart function. Especially hypothermia should be considered carefully.
在心脏直视手术中，不同的心肌保护预防策略常常是常规操作。即便在理论上已确立，但在资金资源有限的情况下，仍必须对其进行严格审视。
肌钙蛋白T（TnT）是一种有价值的工具，可独立于伴随的肌肉损伤检测出即使是轻微的心肌损伤。我们在对照组以及接受以下预防措施之一的患者中测量了术中和术后的TnT值以及心电图上的ST段偏差：体外循环（CPB）期间低温、主动脉阻断后至手术结束时使用硝酸甘油（[0.5微克/千克/分钟]）或硝苯地平[0.1微克/千克/分钟]，或围手术期口服镁离子。
该研究纳入了一家大学医院的65例术前心功能良好、计划进行择期主动脉冠状动脉搭桥手术的患者。
CPB后所有组的TnT值均升高，并在手术结束至术后第一天达到峰值。CPB后早期TnT值高于1.0微克/升临界值的情况在硝酸甘油和硝苯地平组中较少见。术后第一天后未观察到明显差异。低温组患者的TnT值最常高于1.0微克/升。对照组、低温组和镁离子组的最大TnT值与主动脉阻断时间相关。ST段偏差与TnT值之间无相关性。
如TnT值的变化所示，这些预防措施未能减少心肌损伤。因此，对于左心功能良好的患者，不建议将其作为常规策略。尤其应谨慎考虑低温措施。
