Weisel R D, Hoy F B, Baird R J, Ivanov J, Hilton J D, Burns R J, Mickle D A, Mickleborough L L, Scully H E, Goldman B S, McLaughlin P R
J Thorac Cardiovasc Surg. 1983 Jul;86(1):97-107.
Cold potassium cardioplegia provides adequate protection for coronary bypass operations, but severe coronary stenoses limit cardioplegic delivery to ischemic regions. The traditional technique delivers cardioplegic solution into the aortic root during the performance of distal anastomoses. The proposed alternative technique constructs proximal as well as distal anastomoses during a prolonged cross-clamp period, but permits more uniform cooling. The two techniques were compared in a prospective concurrent trial of 45 patients undergoing elective coronary bypass grafting. The traditional technique was employed in 26 patients (Group A) and the alternative technique in 19 patients (Group B). In both groups, 700 to 1,000 ml of a crystalloid cardioplegic solution was infused into the aortic root after application of the aortic cross-clamp. In Group A (traditional technique), 500 ml was infused into the aortic root after each distal anastomosis. In Group B (alternative technique), cardioplegic solution was administered through the vein graft after each distal anastomosis, and a proximal anastomosis was constructed after distal anastomoses to the most ischemic regions to permit continued cardioplegic delivery to these regions. The cross-clamp period was shorter in Group A than in Group B (44 +/- 15 versus 60 +/- 18 minutes, p less than 0.01), but the mean temperature in the most ischemic region was warmer (Group A, 19 degrees +/- 3 degrees C; Group B, 15 degrees +/- 3 degrees C, p less than 0.05). The postoperative CK-MB was higher in Group A (Group A, 47 +/- 36; Group B, 21 +/- 9 IU/L, p less than 0.01). Cardiac lactate production persisted longer in Group A (Group A, 4 +/- 1; Group B, 1 +/- 1 hours postoperatively, p less than 0.05). Volume loading 4 hours postoperatively produced a similar increase in left atrial pressure and cardiac index in both groups. In response to volume loading, Group A patients produced lactate, but Group B patients extracted lactate (change in cardiac lactate extraction: Group A, -1.7 +/- 2.3; Group B, +2.5 +/- 5.1 mg/dl, p less than 0.05). The construction of proximal as well as distal anastomoses during a prolonged cross-clamp period permits more uniform cooling and immediate reperfusion. This alternative technique resulted in less injury (CK-MB release) and more rapid recovery of myocardial metabolism.
冷钾停搏液可为冠状动脉搭桥手术提供充分的心肌保护，但严重的冠状动脉狭窄会限制停搏液输送至缺血区域。传统技术是在进行远端吻合术时将停搏液注入主动脉根部。所提出的替代技术是在延长的主动脉阻断期间构建近端和远端吻合口，但能实现更均匀的心肌降温。在一项对45例行择期冠状动脉搭桥术患者的前瞻性同期试验中对这两种技术进行了比较。26例患者采用传统技术（A组），19例患者采用替代技术（B组）。两组在应用主动脉阻断钳后均向主动脉根部注入700至1000毫升晶体停搏液。在A组（传统技术组），每完成一个远端吻合术后向主动脉根部注入500毫升。在B组（替代技术组），每完成一个远端吻合术后通过静脉移植物给予停搏液，在完成向最缺血区域的远端吻合术后构建近端吻合口，以允许继续向这些区域输送停搏液。A组的主动脉阻断时间比B组短（44±15分钟对60±18分钟，p<0.01），但最缺血区域的平均温度更高（A组，19℃±3℃；B组，15℃±3℃，p<0.05）。A组术后肌酸激酶同工酶（CK-MB）水平更高（A组，47±36；B组，21±9 IU/L，p<0.01）。A组心肌乳酸生成持续时间更长（A组，术后4±1小时；B组，术后1±1小时，p<0.05）。术后4小时容量负荷使两组的左心房压力和心脏指数有相似的升高。在容量负荷反应方面，A组患者生成乳酸，而B组患者摄取乳酸（心肌乳酸摄取变化：A组，-1.7±2.3；B组，+2.5±5.1毫克/分升，p<0.05）。在延长的主动脉阻断期间构建近端和远端吻合口可实现更均匀的心肌降温及即刻再灌注。这种替代技术导致的心肌损伤（CK-MB释放）更少，心肌代谢恢复更快。
