Koning M M, Gho B C, van Klaarwater E, Duncker D J, Verdouw P D
Laboratory for Experimental Cardiology, Erasmus University Rotterdam, Netherlands.
Cardiovasc Res. 1995 Dec;30(6):1017-27.
Recently, we reported that a partial coronary artery occlusion immediately preceding a sustained coronary artery occlusion limited infarct size. We now investigated whether the protection by partial coronary artery occlusions (i) depends on the severity and(or) duration of the flow reduction and (ii) varies in the different myocardial layers.
In 71 open-chest pigs (eight groups) left ventricular area at risk (AR) and infarct area (IA) were determined for the endocardial (IAendo and ARendo) and epicardial halves (IAepi and ARepi).
In control animals (60 min total coronary artery occlusion (TCO) followed by 120 min reperfusion (Rep)) there were highly linear relations between IA and AR in the endocardium (r = 0.98, P < 0.01) and epicardium (r = 0.97, P < 0.01), which could be described by IAendo = 1.01 ARendo - 4.5 and by IAepi = 0.88ARepi - 3.6, respectively. In animals that underwent a 10 min TCO + 15 min Rep prior to the 60 min TCO + 120 min Rep, IA in both myocardial layers were again highly linearly related with AR, with less steep slopes for both the endocardium (0.63) and epicardium (0.57) (both P < 0.01). Two groups of pigs were subjected to either a 30 or 90 min 70% reduction in coronary blood flow (FR) immediately preceding the 60 min TCO + 120 min Rep, without intervening reperfusion. A 30 min 70% FR decreased IA to the same degree in the endo- and epicardial half. A 90 min 70% FR resulted in protection in the epicardium (P < 0.01) but not in the endocardium, most likely because 90 min 70% FR without 60 min TCO already caused infarction which was more severe in the endo- than in the epicardium (P < 0.01). Endocardial and epicardial IA after either a 30 or 90 min 30% FR prior to the 60 min TCO was not different from that in the control group, indicating that this mild flow reduction failed to limit irreversible damage.
Thirty or ninety min of severe (70%) but not mild (30%) coronary flow reductions protected against myocardial infarction. The protection by a 70% FR was influenced by the duration of FR as a 30 min 70% FR similarly decreased IA in the endocardial and epicardial halves, while 90 min 70% FR preferentially limited IA in the epicardial half. These findings suggest that perfusion abnormalities immediately preceding an infarction could be an important source of infarct size variability in patients.
最近，我们报道了在持续性冠状动脉闭塞之前立即进行的部分冠状动脉闭塞可限制梗死面积。我们现在研究部分冠状动脉闭塞的保护作用是否（i）取决于血流减少的严重程度和（或）持续时间，以及（ii）在不同心肌层中是否有所不同。
在71只开胸猪（八组）中，测定心内膜（IAendo和ARendo）和心外膜半层（IAepi和ARepi）的左心室危险面积（AR）和梗死面积（IA）。
在对照动物（60分钟完全冠状动脉闭塞（TCO）后再灌注120分钟（Rep））中，心内膜（r = 0.98，P < 0.01）和心外膜（r = 0.97，P < 0.01）的IA与AR之间存在高度线性关系，分别可用IAendo = 1.01ARendo - 4.5和IAepi = 0.88ARepi - 3.6来描述。在60分钟TCO + 120分钟Rep之前先进行10分钟TCO + 15分钟Rep的动物中，两层心肌的IA与AR再次高度线性相关，心内膜（0.63）和心外膜（0.57）的斜率均较平缓（均P < 0.01）。两组猪在60分钟TCO + 120分钟Rep之前立即进行30或90分钟70%的冠状动脉血流减少（FR），且无中间再灌注。30分钟70%的FR使心内膜和心外膜半层的IA降低程度相同。90分钟70%的FR导致心外膜受到保护（P < 0.01），而心内膜未受保护，很可能是因为90分钟70%的FR在没有60分钟TCO的情况下已经导致梗死，心内膜的梗死比心外膜更严重（P < 0.01）。在60分钟TCO之前进行30或90分钟30%的FR后，心内膜和心外膜的IA与对照组无差异，表明这种轻度血流减少未能限制不可逆损伤。
30或90分钟的严重（70%）而非轻度（30%）冠状动脉血流减少可预防心肌梗死。70%的FR所提供的保护受FR持续时间的影响，因为30分钟70%的FR同样降低了心内膜和心外膜半层的IA，而90分钟70%的FR优先限制了心外膜半层的IA。这些发现表明，梗死前立即出现的灌注异常可能是患者梗死面积变异性的重要来源。
