Kazmaier S, Hanekop G-G, Grossmann M, Dörge H, Götze K, Schöndube F, Quintel M, Weyland A
Department of Anesthesiology, Emergency Medicine and Intensive Care, Georg-August-University, Germany.
Eur J Anaesthesiol. 2006 May;23(5):373-9. doi: 10.1017/S0265021505001985. Epub 2006 Jan 27.
The objective of this study was to describe the diastolic pressure-flow relationship and to assess critical occlusion pressure in arterial coronary bypass grafts in human beings.
Fifteen patients were studied following elective surgical coronary artery bypass grafting. Flow in the left internal mammary artery bypass to the left anterior descending artery was measured and simultaneously, aortic pressure, coronary sinus pressure and left ventricular end-diastolic pressure were recorded. The zero-flow pressure intercept as a measure of critical occlusion pressure was extrapolated from the linear regression analysis of the instantaneous diastolic pressure-flow relationship. Mean diastolic flow was 46 +/- 17 mL min(-1), mean diastolic aortic pressure was 60.5 +/- 10.0 mmHg. Diastolic blood flow was linearly related to the respective aortic pressure in all patients (R-values 0.7-0.99). The regression lines had a mean slope of 2.1 +/- 1.2 mL min(-1) mmHg(-1). Mean critical occlusion pressure was 32.3 +/- 9.9 mmHg and exceeded mean coronary sinus pressure and mean left ventricular end-diastolic pressure by factors of 3.1 and 2.6, respectively.
Our data demonstrate the presence of a vascular waterfall phenomenon in the coronary circulation after internal mammary artery bypass grafting. Critical occlusion pressure in arterial grafts considerably exceeds coronary sinus pressure as well as left ventricular end-diastolic pressure and should thus be used as the effective downstream pressure when calculating coronary perfusion pressure. Our data further suggest that the slope of diastolic pressure-flow relationships provides a more rational approach to assess regional coronary vascular resistance than conventional calculations of coronary vascular resistance.
本研究的目的是描述舒张压与血流的关系，并评估人体冠状动脉搭桥术中动脉搭桥血管的临界闭塞压。
对15例择期行冠状动脉搭桥术的患者进行了研究。测量了左乳内动脉至左前降支搭桥血管的血流，同时记录主动脉压、冠状窦压和左心室舒张末期压力。通过对瞬时舒张压-血流关系进行线性回归分析，外推得到零流量压力截距作为临界闭塞压的指标。平均舒张期血流为46±17 mL·min⁻¹，平均舒张期主动脉压为60.5±10.0 mmHg。所有患者的舒张期血流与各自的主动脉压呈线性相关（相关系数R值为0.7 - 0.99）。回归线的平均斜率为2.1±1.2 mL·min⁻¹·mmHg⁻¹。平均临界闭塞压为32.3±9.9 mmHg，分别比平均冠状窦压和平均左心室舒张末期压力高出3.1倍和2.6倍。
我们的数据表明，乳内动脉搭桥术后冠状动脉循环中存在血管瀑布现象。动脉搭桥血管的临界闭塞压大大超过冠状窦压以及左心室舒张末期压力，因此在计算冠状动脉灌注压时应将其用作有效的下游压力。我们的数据还表明，与传统的冠状动脉血管阻力计算方法相比，舒张压-血流关系的斜率为评估局部冠状动脉血管阻力提供了一种更合理的方法。
