Michel J B, Bardou A, Tedgui A, Levy B
J Surg Res. 1984 Jan;36(1):17-24. doi: 10.1016/0022-4804(84)90063-5.
Myocardial infarctions during aortic surgery often occur after aortic clamping and unclamping. In order to investigate the aortic blood pressure (AoBP)-coronary blood flow (CBF) relationship, hemodynamic parameters and phasic circumflex CBF in 15 anesthetized and open-chest dogs during clamping and unclamping of the thoracic descending aorta have been recorded. During clamping, mean aortic blood pressure (MAoBP) rose from 97 + 17 to 150 + 42 mm Hg (P less than 0.001), and total combined left-ventricular power (Wtc) from 692 + 232 to 923 + 402 mW (P less than 0.001) while the ascending aortic blood flow (AoBF) and heart rate did not change significantly. The mean circumflex blood flow (MCBF) increased from 67 + 30 to 88 + 30 ml/min. The increase in systolic coronary blood flow (+73%) was larger than that in diastolic coronary blood flow (DCBF) (19%). The late coronary resistances were increased 39%. Conversely, after unclamping, MAoBP decreased while AoBF and Wtc increased. During the first cardiac cycles after aortic unclamping DCBF decreased 50% with a decrease in the diastolic blood pressure (DBP). Four cycles later, DCBF reincreased while DBP kept on decreasing. This may be related to an active coronary vasodilatation. A linear relationship between DCBF and DBP has been obtained during acute change in DBP due to clamping or unclamping. From these linear relationships, the change in diastolic zero flow pressure (PfO) has been found to be about + 40 mm Hg during clamping. This change in PfO may be responsible for the observed large fall in DCBF during unclamping. The decrease in DCBF associated with the increase in Wtc accounts for the delayed active vasodilatation.
主动脉手术期间的心肌梗死常发生在主动脉钳夹和松开之后。为了研究主动脉血压（AoBP）与冠状动脉血流（CBF）的关系，记录了15只麻醉开胸犬在胸降主动脉钳夹和松开过程中的血流动力学参数及相位性冠状动脉回旋支血流。钳夹期间，平均主动脉血压（MAoBP）从97±17mmHg升至150±42mmHg（P＜0.001），左心室总功率（Wtc）从692±232mW增至923±402mW（P＜0.001），而升主动脉血流（AoBF）和心率无显著变化。平均冠状动脉回旋支血流（MCBF）从67±30ml/min增至88±30ml/min。收缩期冠状动脉血流增加（+73%）大于舒张期冠状动脉血流（DCBF）增加（19%）。冠状动脉晚期阻力增加39%。相反，松开后，MAoBP下降，而AoBF和Wtc增加。主动脉松开后的第一个心动周期，DCBF随舒张压（DBP）下降而降低50%。四个周期后，DCBF再次增加，而DBP持续下降。这可能与冠状动脉主动扩张有关。在因钳夹或松开导致DBP急性变化期间，已得出DCBF与DBP之间的线性关系。从这些线性关系中发现，钳夹期间舒张期零流量压力（PfO）变化约为+40mmHg。PfO的这种变化可能是松开期间观察到的DCBF大幅下降的原因。与Wtc增加相关的DCBF降低解释了延迟的主动血管扩张。
