论文部分内容阅读
目的评价多巴酚丁胺对正常和狭窄冠状动脉微循环的直接效应,并与腺苷对比。方法实验应用9条健康杂种犬,制备左前降支静息无血流限制性狭窄。在静息状态和左冠状动脉主干内连续输注多巴酚丁胺(2mg·kg~-1·min~-1)和腺苷(5mg·kg~-1·min~-1)时,进行间断谐波心肌对比成像评估心肌血流容积(A)和心肌血流速度(b),并同步应用放射性标记微球测定心肌血流量(MBF),计算心率血压乘积和心肌血管阻力(MVR)。结果两种药物引起正常和狭窄冠状动脉供血区MBF明显增加和MVR明显降低(P<0.05)。在正常冠状动脉供血区,腺苷对A无明显影响,MVR的降低完全是阻力血管的扩张所致(99%),MBF增加主要是由于b的加快(△β/△A=13.6);多巴酚丁胺可引起部分A增加(28%),使总MVR降低中的32%来自这种毛细血管征募,但MBF增加主要还是由于b的加快(△β/△A=5.9)。在狭窄冠状动脉供血区,两种药物引起MBF增加的程度相同,MBF增加均完全是由于b的加快;多巴酚丁胺和腺苷引起毛细血管的关闭分别导致14%和15%心肌毛细血管阻力的增加。结论经冠状动脉内直接给药物时,多巴酚丁胺对冠状动脉微循环的直接效应与腺苷对冠状动脉微循环的直接效应非常相近,MBF增加主要由于心肌血流速度的增快所致。
Objective To evaluate the direct effect of dobutamine on normal and narrow coronary microcirculation and to compare with adenosine. Methods Nine healthy mongrel dogs were used in the experiment to establish the left anterior descending coronary artery without restrictive flow restriction. At rest and continuous infusion of dobutamine (2 mg · kg -1 · min -1) and adenosine (5 mg · kg -1 -1 min -1) in the left main coronary artery Cardiac blood flow volume (A) and myocardial blood flow velocity (b) were assessed by discontinuous harmonic myocardial contrast imaging. Cardiac blood flow (MBF) was measured simultaneously with radiolabeled microspheres to calculate the product of heart rate and pressure and myocardial vascular resistance (MVR). Results Both drugs caused a significant increase of MBF and a significant decrease of MVR in normal and narrow coronary artery blood supply areas (P <0.05). In the normal coronary artery blood supply area, adenosine had no significant effect on A, and the decrease of MVR was completely caused by the expansion of resistance vessels (99%). The increase of MBF was mainly due to the acceleration of b (△ β / △ A = 13.6) Increased fraction A (28%) led to a partial increase in A (30%), resulting in 32% of the total decrease in MVR from this capillary recruitment, but the increase in MBF was mainly due to an acceleration of b (Δβ / ΔA = 5.9). In the narrow coronary artery blood supply area, both drugs induced the same increase in MBF, and the increase in MBF was all due to the acceleration of b; the closure of the capillaries by dobutamine and adenosine resulted in 14% and 15%, respectively, of myocardial capillaries Resistance increases. Conclusions The direct effect of dobutamine on coronary microcirculation is similar to the direct effect of adenosine on microcirculation of coronary arteries when injected directly into the coronary artery. The increase in MBF was mainly due to an increase in myocardial blood flow velocity .