Manciet L H, Fox K A, Copeland J G, Wilson D S, Reimer P R, McDonagh P F
University of Arizona Health Sciences Center, Department of Surgery, Tucson 85724, USA.
Circulation. 1995 Nov 1;92(9 Suppl):II372-80. doi: 10.1161/01.cir.92.9.372.
A growing body of knowledge has led to the hypothesis that injury to the microcirculation during hypothermic myocardial preservation may result in decreased contractility of hearts upon reperfusion.
To test this hypothesis, we examined the relationship between no-reflow and left ventricular function after hypothermic cardiac preservation after reperfusion with solutions containing dilute whole blood (DWB) or washed red blood cells (K2RBC). Rat hearts were arrested with high-potassium cardioplegia, then flushed and stored for 6 hours in low-potassium cardioplegia at 4 degrees C. Hearts were reperfused at a constant flow rate (4 mL/min) with K2RBC for 60 minutes (group 1, n = 5) or DWB for 7 minutes followed by 53 minutes of K2RBC (group 2, n = 5). Left ventricular developed pressure (LVDP) was measured with an intraventricular balloon. Immediately after functional assessment, hearts were perfused with an india ink solution to mark flow, then glutaraldehyde. Morphometric techniques were used to determine the degree of capillary compression [delta d(c)], perfused capillary number per fiber area [QA(0)P], and perfused capillary surface area per fiber volume [Sv(c,f)P]. Capillaries were moderately compressed in both groups after reperfusion (group 1, 19 +/- 1%; group 2, 20 +/- 1%). QA(0)P and Sv(c,f)P were highly correlated with delta d(c) in hearts reperfused with K2RBC (r = .92 and r = .92; P < .01). Although statistically significant, the correlation was not as strong in DWB-reperfused hearts (r = .66 and r = .67; P < .05). LVDP was correlated to QA(0)P and Sv(c,f)P (r = .86 and r = .87, respectively) for groups 1 and 2.
The weaker correlation between capillary perfusion and capillary compression in DWB-reperfused hearts suggests that factors other than compression contribute to no-reflow after hypothermic preservation. Regardless of the composition of the reperfusate, recovery of left ventricular function after hypothermic ischemia is directly related to coronary capillary perfusion upon reperfusion.
越来越多的知识促使人们提出这样的假设，即低温心肌保存期间微循环损伤可能导致再灌注时心脏收缩力下降。
为验证这一假设，我们研究了用含稀释全血（DWB）或洗涤红细胞（K2RBC）的溶液进行再灌注后，低温心脏保存后无复流与左心室功能之间的关系。用高钾停搏液使大鼠心脏停搏，然后冲洗并在4℃的低钾停搏液中保存6小时。心脏以恒定流速（4 mL/分钟）用K2RBC再灌注60分钟（第1组，n = 5）或用DWB再灌注7分钟，随后用K2RBC再灌注53分钟（第2组，n = 5）。用室内球囊测量左心室舒张末压（LVDP）。在功能评估后立即用印度墨水溶液灌注心脏以标记血流，然后用戊二醛固定。采用形态计量学技术确定毛细血管压缩程度[δd(c)]、每纤维面积的灌注毛细血管数[QA(0)P]和每纤维体积的灌注毛细血管表面积[Sv(c,f)P]。再灌注后两组的毛细血管均有中度压缩（第1组，19±1%；第2组，20±1%）。在用K2RBC再灌注的心脏中，QA(0)P和Sv(c,f)P与δd(c)高度相关（r = 0.92和r = 0.9）；P < 0.01）。虽然具有统计学意义，但在DWB再灌注的心脏中这种相关性不那么强（r = 0.66和r = 0.67；P < 0.05）。第1组和第2组的LVDP与QA(0)P和Sv(c,f)P相关（分别为r = 0.86和r = 0.87）。
DWB再灌注心脏中毛细血管灌注与毛细血管压缩之间较弱的相关性表明，除了压缩之外的其他因素导致低温保存后的无复流。无论再灌注液的成分如何，低温缺血后左心室功能的恢复与再灌注时冠状动脉毛细血管灌注直接相关。
