Optimal Coronary Perfusion Flow for the Distal Coronary Area During Off-Pump Coronary Artery

目的：非体外循环冠状动脉搭桥术吻合时冠脉远端灌注是避免心肌缺血的必要条件。然而，最佳冠状动脉血流（CF）尚未阐明。本研究的目的是在评估心肌局部功的基础上确定最佳的CF。方法：选用7头猪。我们用导管尖端压力计测量左心室压力，用放置在左心室前后和底尖的两对超声晶体计算左心室容积，得到左心室的压力-容积环路（P-V环路）。与另外两对超声晶体对角放置1 cm，得到区域张力区环路（T-A环路）。将连接伺服泵的CF管插入左前降支。左行程功（PVA）为P-V回路内的面积，区域功（TAA）为T-A回路内的面积。CF从100 ml/min开始降低，每次CF时PVA和TAA均升高。结果：CF 30 ml/min时PVA和TAA较对照组显著降低（p<0.05）。结论：CF 30ml /min是维持心肌整体和局部工作的必要条件，有避免心肌缺血的可能。

Objective : Distal coronary perfusion is necessary to avoid myocardial ischemia during coronary anastomosis in Off-pump Coronary Artery Bypass. However, optimal coronary flow (CF) is not elucidated. The purpose of this study was to determine the optimal CF based on the assessment of regional work of the myocardium.Methods : We used seven porcines. We obtained pressure-volume loop (P-V loop) of the left ventricle (LV) with the LV pressure measured by a catheter tip manometer and the LV volume calculated with two pairs of ultrasonic crystals placed anterior-posterior and base-apex of the LV. Regional tension-area loop (T-A loop) was obtained with other two pairs of ultrasonic crystals placed with 1 cm distance diagonally. The CF tube connected to servo-pump was inserted into the left anterior descending branch. LV stroke work (PVA) was the area within P-V loop and regional work (TAA) was the area within T-A loop. CF was decreased from 100 ml/min as a control and PVA and TAA were obtained at each CF.Results : PVA and TAA decreased significantly at CF 30 ml/min from the control value (p<0.05).Conclusion : CF 30 ml/min was necessary to maintain global and regional myocardial work and possibility to avoid myocardial ischemia.