重度主动脉瓣狭窄瓣膜置换术中的心肌保护

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

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. Thomas＇s） 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.