Hemodynamic and Humoral factors in Coronary Collateral Development

在犬模型中研究了预先存在的侧支循环和灌注大小对缺血诱导的侧支循环发育的影响。在无菌手术下，用成对的超声晶体对犬进行器械化，以测量左回旋支（LCX）和左前降支冠状动脉区域中的局部室壁运动。使用植入式微型微压计测量左心室（LV）压力。术后2 ~ 3周，采用AM/AM遥测指令系统，每隔32 min自动重复LCX冠状动脉闭塞（CO）2 min。通过FM/FM遥测系统昼夜连续监测局部室壁运动和LV压力。预先存在的侧支循环的功能状态，通过在第一个2 min CO结束时局部室壁运动减少的%水平来估计，范围为-11%至-141%。LCX的灌注量范围为35%至54%。侧支循环形成所需的冠状动脉阻断次数与侧支循环功能状态呈指数相关（r=0.77，P<0.01），但与灌注量无关，当侧支循环功能成熟时，停止阻断2 min。阻断刺激24 h后，侧支循环功能状态仍继续恶化。为了阐明高脂血症（WHHL兔）等疾病状态如何调节侧支循环的发育速度，我们采用兔作为实验模型，成功地设计了微型化的传感器，用于评估瞬时冠状动脉血流量或心室泵功能。因此，我们不仅能够研究局部室壁运动，而且还可以在纯种动物模型中研究与侧支功能相关的体液因素。

The effects of pre-existing collateral and the perfusion size on the ischemia-induced collateral development were studied in a canine model. The dogs were instrumented under sterile surgery with pairs of ultrasonic crystals to measure regional wall motion in the territory of the left circumflex(LCX) and left anterior descending coronary arteries. An implantable miniature micromanometer was used to measure left ventricular (LV) pressure. Two to 3weeks after surgery, 2min coronary occlusion (CO) of the LCX was repeated every 32 min automatically using an AM/AM telemetry command system. Regional wall motion and LV pressure were monitored via a FM/FM telemetry system consecutively day and night. The functional state of pre-existing collaterals which estimated by the level of % reduction of regional wall motion at the end of the first 2min CO, ranged from-11 to -141%. The perfusion size of the LCX ranged from 35 to 54%. Number of coronary occlusion needed for collateral development was exponentially related to the functional state of pre-existing collaterals(r=0.77, P<0.01), but not to the perfusion size.When the collateral function was functionally matured in the same model as above, an episode of 2 min coronary occlusion was stopped. After 24 hours'interruption of occlusion stimuli, the functional state of collaterals remained deteriorated. Thus, the presence of ischemic stimuli is important to maintein the developed state of collateral function.To elucidate how the diseased state such as hyperlipidemia(WHHL rabbits) modulates the speed of collateral development, we adopted rabbit for an experimental model.We successfully devised miniaturized sensors for assessing instantaneous coronary bood flow or ventricular pump function. Thus, we are able to study not only regional wall motion, but also humoral factors related to collateral function in purely-bred animal models.