Rao V, Cohen G, Weisel R D, Shiono N, Nonami Y, Carson S M, Ivanov J, Borger M A, Cusimano R J, Mickle D A
Division of Cardiovascular Surgery, Toronto Hospital, Ontario, Canada.
J Thorac Cardiovasc Surg. 1998 Jan;115(1):226-35. doi: 10.1016/s0022-5223(98)70461-1.
Antegrade cardioplegic delivery may be impaired by coronary occlusions, whereas retrograde delivery of cardioplegic solution may be inhomogeneous, leading to an accumulation of lactate and hydrogen ions, the products of anaerobic metabolism. Integrated cardioplegia using continuous retrograde cardioplegia and antegrade infusions into completed vein grafts washes out metabolites accumulated in regions inadequately perfused by retrograde cardioplegia alone. To determine the flow rates required to achieve the greatest washout, we compared a high flow rate (200 ml/min) to a low flow rate (100 ml/min).
Twenty patients scheduled for isolated coronary bypass surgery were prospectively randomized to compare two flow rates for integrated cardioplegic protection using tepid (29 degrees C) blood cardioplegia. Arterial and coronary sinus blood samples were collected to evaluate myocardial metabolism. After antegrade arrest, cardioplegic solution was delivered by coronary sinus perfusion and simultaneous infusions into each completed vein graft at either high or low flow.
Increasing from low to high flow increased the washout of lactate and hydrogen ions during the aortic crossclamp period. Two hours after crossclamp removal, ventricular function was better in the high flow groups.
Tepid retrograde cardioplegia resulted in an accumulation of toxic metabolites. The addition of antegrade vein graft infusions at a flow rate of 100 ml/min resulted in a washout of these metabolites. A flow rate of 200 ml/min further improved this washout and resulted in improved ventricular function. An integrated approach to myocardial protection using a flow rate of 200 ml/min may improve the results of coronary bypass surgery.
顺行性心脏停搏液灌注可能会因冠状动脉阻塞而受到影响，而逆行性心脏停搏液灌注可能不均匀，导致乳酸和氢离子（无氧代谢产物）积聚。采用持续逆行性心脏停搏并向已完成的静脉移植物中顺行灌注的综合心脏停搏法可清除仅通过逆行性心脏停搏灌注不足区域积聚的代谢产物。为了确定实现最大清除所需的流速，我们将高流速（200毫升/分钟）与低流速（100毫升/分钟）进行了比较。
将20例计划进行单纯冠状动脉搭桥手术的患者前瞻性随机分组，比较使用温血（29摄氏度）心脏停搏液进行综合心脏停搏保护的两种流速。采集动脉和冠状窦血样以评估心肌代谢。在顺行性心脏停搏后，通过冠状窦灌注并同时以高或低流速向每个已完成的静脉移植物中输注心脏停搏液。
在主动脉阻断期间，从低流速增加到高流速可增加乳酸和氢离子的清除。松开主动脉阻断钳2小时后，高流速组的心室功能更好。
温血逆行性心脏停搏导致有毒代谢产物积聚。以100毫升/分钟的流速在顺行性静脉移植物中输注可清除这些代谢产物。200毫升/分钟的流速进一步改善了这种清除效果，并改善了心室功能。采用200毫升/分钟的流速进行心肌保护的综合方法可能会改善冠状动脉搭桥手术的效果。
