Hoffenberg E F, Ye J, Sun J, Ghomeshi H R, Salerno T A, Deslauriers R
Institute for Biodiagnostics, National Research Council, Winnipeg, Manitoba, Canada.
Ann Thorac Surg. 1995 Nov;60(5):1203-9. doi: 10.1016/0003-4975(95)00547-X.
Retrograde normothermic blood cardioplegia has been shown to provide myocardial protection during certain bypass procedures. However, a number of animal studies have shown less than optimal myocardial protection with this technique.
Isolated, beating porcine hearts were perfused antegradely (aortic root pressure = 75 to 95 mm Hg) for 30 minutes. Arrest was induced and maintained for 60 minutes with high K+ blood cardioplegia delivered either antegradely (n = 8) or retrogradely (n = 8) (coronary sinus pressure = 35 to 55 mm Hg). Perfusate was switched to normokalemic blood for recovery of sinus rhythm (30 minutes). Intracellular pH, creatine phosphate, inorganic phosphate, and adenosine triphosphate were monitored continuously and noninvasively with phosphorus 31 magnetic resonance spectroscopy throughout the experiment, and functional variables (rate-pressure product and the positive and negative first derivatives of left ventricular pressure) were assessed concurrently.
Antegrade cardioplegia maintained high-energy metabolites, intracellular pH, and myocardial function. Retrograde normothermic blood cardioplegia resulted in an increase in inorganic phosphate (197% +/- 15% of control) and a decrease in creatine phosphate (51% +/- 6% of control). There was no significant difference in myocardial function between the two groups (p > 0.05). The magnetic resonance spectroscopy data indicate ischemia occurred within 2 minutes of the initiation of retrograde perfusion.
This study suggests that retrograde normothermic blood cardioplegia causes a transition of the myocardium to ischemic metabolism in the normal porcine heart.
逆行常温血液心脏停搏已被证明在某些搭桥手术中可提供心肌保护。然而，多项动物研究表明该技术的心肌保护效果并不理想。
将离体跳动的猪心脏进行顺行灌注（主动脉根部压力 = 75至95毫米汞柱）30分钟。使用高钾血液心脏停搏液顺行（n = 8）或逆行（n = 8）（冠状窦压力 = 35至55毫米汞柱）诱导并维持心脏停搏60分钟。灌注液切换为正常血钾血液以恢复窦性心律（30分钟）。在整个实验过程中，使用磷31磁共振波谱连续无创监测细胞内pH值、磷酸肌酸、无机磷酸盐和三磷酸腺苷，并同时评估功能变量（心率 - 压力乘积以及左心室压力的一阶正导数和负导数）。
顺行心脏停搏可维持高能代谢产物、细胞内pH值和心肌功能。逆行常温血液心脏停搏导致无机磷酸盐增加（为对照组的197%±15%）和磷酸肌酸减少（为对照组的51%±6%）。两组之间的心肌功能无显著差异（p > 0.05）。磁共振波谱数据表明逆行灌注开始后2分钟内即发生缺血。
本研究表明逆行常温血液心脏停搏可使正常猪心脏的心肌转变为缺血代谢。
