Schulz R, Guth B D, Heusch G
Department of Pathophysiology, University of Essen, FRG.
Circulation. 1991 Apr;83(4):1390-403. doi: 10.1161/01.cir.83.4.1390.
The hypothesis that increases in coronary perfusion increase ventricular performance independently from providing enhanced oxygen supply ("Gregg phenomenon") remains controversial.
To study the physiological significance of changes in coronary perfusion on global and regional myocardial function in situ, the left anterior descending coronary artery of isoflurane-anesthetized swine was cannulated, and perfusion was varied. In one group of swine (n = 5), coronary arterial pressure was increased in four steps from 88 +/- 11 to 186 +/- 11 mm Hg by increasing the speed of the pump circuit providing coronary blood flow. No changes in left ventricular end-diastolic pressure, peak pressure, or maximum left ventricular dP/dt were observed. Subendocardial blood flow (by radiolabeled microspheres) increased from 0.96 +/- 0.27 to 2.04 +/- 0.73 ml/min/g without any increase in systolic wall thickening (by sonomicrometry) or myocardial oxygen consumption of the anterior myocardium. In a second group of swine (n = 8), coronary arterial pressure was kept constant and coronary blood flow was increased stepwise by intracoronary adenosine infusion. End-diastolic pressure, peak pressure, and maximum left ventricular dP/dt remained unchanged when coronary blood flow increased from 21.7 +/- 9.8 to 93.8 +/- 34.1 ml/min. Subendocardial blood flow increased from 0.89 +/- 0.26 to 3.28 +/- 1.02 ml/min/g, again without any increase in systolic wall thickening (45.6 +/- 8.6 versus 42.6 +/- 9.8%) and myocardial oxygen consumption (5.75 +/- 1.18 versus 5.87 +/- 1.67 ml/min/100 g). In a third group of swine (n = 10), coronary arterial pressure was lowered by intracoronary adenosine infusion during constant coronary inflow. Left ventricular hemodynamics remained unchanged. With a decrease in coronary arterial pressure from 130 +/- 25 to 71 +/- 14 mm Hg, no decreases in subendocardial blood flow and systolic wall thickening were observed. Only when coronary arterial pressure was further reduced to 57 +/- 13 mm Hg did systolic wall thickening fall to 25.7 +/- 9.9% (control, 31.1 +/- 11.1%), associated with a decrease in subendocardial blood flow from 1.17 +/- 0.39 to 0.87 +/- 0.52 ml/min/g.
Thus, the Gregg phenomenon plays no significant role within or above the autoregulatory pressure-flow range normally seen in anesthetized swine in situ.
冠状动脉灌注增加可独立于提供增强的氧气供应而增加心室功能的假说（“格雷格现象”）仍存在争议。
为研究冠状动脉灌注变化对整体和局部心肌功能的生理意义，对异氟烷麻醉的猪的左前降支冠状动脉进行插管，并改变灌注。在一组猪（n = 5）中，通过增加提供冠状动脉血流的泵回路速度，将冠状动脉压力分四步从88±11毫米汞柱增加到186±11毫米汞柱。未观察到左心室舒张末期压力、峰值压力或左心室最大dP/dt的变化。心内膜下血流（通过放射性微球）从0.96±0.27增加到2.04±0.73毫升/分钟/克，而前壁心肌的收缩期壁增厚（通过超声心动图）或心肌耗氧量没有任何增加。在第二组猪（n = 8）中，冠状动脉压力保持恒定，通过冠状动脉内注入腺苷逐步增加冠状动脉血流。当冠状动脉血流从21.7±9.8增加到93.8±34.1毫升/分钟时，舒张末期压力、峰值压力和左心室最大dP/dt保持不变。心内膜下血流从0.89±0.26增加到3.28±1.02毫升/分钟/克，同样，收缩期壁增厚（45.6±8.6%对42.6±9.8%）和心肌耗氧量（5.75±1.18对5.87±1.67毫升/分钟/100克）没有任何增加。在第三组猪（n = 10）中，在冠状动脉流入量恒定的情况下，通过冠状动脉内注入腺苷降低冠状动脉压力。左心室血流动力学保持不变。随着冠状动脉压力从130±25毫米汞柱降至71±14毫米汞柱，未观察到心内膜下血流和收缩期壁增厚的降低。只有当冠状动脉压力进一步降至57±13毫米汞柱时，收缩期壁增厚才降至25.7±9.9%（对照组为31.1±11.1%），同时心内膜下血流从1.17±0.39降至0.87±0.52毫升/分钟/克。
因此，在麻醉猪原位正常的自动调节压力-血流范围内或之上，格雷格现象不起重要作用。
