目的探讨重度主动脉瓣狭窄（AS）瓣膜置换术肥厚心肌的保护方法。方法14例重度AS患者行主动脉瓣置换术，采用经左、右冠状动脉开口直接持续灌注，首次灌温4∶1氧合血高钾停搏液，待心脏停跳充分后使用冷4∶1氧合血低钾停搏液持续灌注。开放升主动脉前主动脉根部灌温血3～5min。应用碳酸氢钠及利尿剂，采用常规超滤滤出多余液体及钾。结果自动复跳9例，20Ws除颤1次后复跳2例，除颤3次后复跳3例。停机时血钾（5.20±0.39）mmol/L。无严重心律失常发生，术后22d院内死亡1例，为严重心功能不全。其余痊愈出院，随访1～31个月，效果良好。结论温血高钾诱导－冷血低钾持续灌注－温血灌注为AS患者进行了良好的心肌保护，联合应用利尿剂、碳酸氢钠及常规超滤，可避免高血钾及水肿的发生。

    Myocardial Protection  for Patients  with

    Severe Aortic Stenosis in Aortic Valve Replacement

    ZHAO Feng-hua, QI Hong-wei，WU Ming-ying, WANG Li-fang,

    MENG Ge, ZHAO Jian-gang, CUI Hua-nan, ZHOU Zi-qiang

    (The Cardiovascular Center，The Affiliated Tongren Hospital  of

    The Capital Medical University，Beijing 100730，China)

    Abstract: OBJECTIVE   The protective methods of hypertrophic myocardium in the severe aortic valve stenosis (AS) patients were studied to improve the effects of aortic valve replacement (AVR) in these patients. METHODS  The methods of myocardium protection in 14 AS patients undergoing AVR were analyzed. Blood cardioplegic solution (4 parts blood to 1 part St. Thomass) or warm blood was administered directly into the coronary ostia. First, warm-blood cardioplegia ( potassium 20 mmol/L) was perfused. Then, cold-blood cardioplegia (potassium 8 mmol/L) was perfused continuously. Warm blood was administered for 3 to 5 minutes to the ascending aorta before unclamping the aorta. The excrescent water and potassium was treated with sodium bicarbonate, diuretic and conventional ultrafiltration. RESULTS  The heart re-beat automatically at the end of  cardiopulmonary bypass （CPB） in 9 cases, 5 cases were defibrillated at 20 W/S. Blood potassium was （5.20±0.39） mmol/L when CPB was terminated. There was no serious arythmia after the operation. One patient died in hospital because of severe heart failure. All of the other patients discharged hospital and were followed 1 to 31 months with good results. CONCLUSION  Warm-blood with high potassium induction, cold-blood with low potassium continuous perfusion  and terminal warm-blood perfusion provide good myocardial protection to AS patients. The high level of potassium and edema could be avoided by combined using of diuretic, sodium bicarbonate and conventional ultrafiltration.

    Key words：  Aortic stenosis; Valve replacement; Myocardial protection; Blood cardioplegia; Ultrafiltration

　　主动脉瓣狭窄（AS）时左心室向主动脉排血阻力增加，引起左心室压力增加并出现向心性肥厚，而主动脉压力降低，可发生呼吸困难、心绞痛、晕厥等典型临床表现，若不进行治疗，患者病情进行性加重，可危及生命。目前，人工瓣膜置换术是治疗成人AS的主要方法。肥厚心肌代谢状态为无氧代谢，心肌更易于发生缺血－再灌注损伤［1］。因此术中良好的心肌保护极为重要。

　　1资料与方法

　　1.1临床资料2006年1月至2008年7月在体外循环（cardiopulmonarybypass,CPB）下行人工主动脉瓣置换术的AS患者14例，其中男性7例，女性7例，年龄 19～63（46.54±12.56）岁。均有心悸、心绞痛、晕厥等典型临床症状。NYHA心功能分级：Ⅱ级3例，Ⅲ级8例，Ⅳ级3例。心电图：左室高电压7例；超声心动图：左室舒张末直径（55.94±12.11）mm,左室收缩末直径（38.92±12.22）mm，室间隔厚度（13.05±2.35）mm，左室射血分数（EF）（58.54±13.67）%，术前跨瓣压差（94.73±28.95）mmHg，术后跨瓣压差（26.67±13.32）mmHg。二叶化畸形2例，主动脉瓣及瓣上狭窄1例，瓣膜钙化性心脏病2例，7例合并二尖瓣病变，2例合并冠心病。

　　1.2方法手术采用气管插管静脉复合麻醉，中度低温（29℃～30℃）、中度血液稀释（Hct0.20～0.24）、CPB下进行。氧合器为Medos7000，心肌保护装置为Vision型血液停搏液灌注装置。全身肝素化 ACT＞400s，常规建立CPB，主动脉、右房插腔房管或上、下腔静脉插管，经右上肺静脉建立左心引流，转机起动尽量做到平稳，升主动脉阻断前，避免血压、温度骤降，防止左室胀，避免室颤；升主动脉阻断后，于主动脉瓣环上1.5cm横行切开主动脉经左、右冠状动脉开口直接持续灌注4∶1氧合血停搏液，首次灌温（33℃～34℃）4∶1氧合血高钾停搏液（20mmol/L），流量70～80ml/min，灌注压＜80mmHg，待心脏停跳充分后使用冷 4∶1氧合血低钾停搏液（K＋8mmol/L），流量30～40ml/min持续灌注，同时心包腔置冰泥降温保护心肌。均采用进口双叶机械瓣。开放升主动脉前主动脉根部灌温血（34℃～35℃）3～5min，监测血清钾（维持在4.8～5.6mmol/L）、血气等满意后，开放升主动脉恢复心脏灌注，辅助停机。CPB中常规应用碳酸氢钠及利尿剂，采用常规超滤滤出多余液体及K＋。

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