Direct observation of epicardial coronary capillary hemodynamics during reactive hyperemia and during adenosine administration by intravital video microscopy
Direct observation of epicardial coronary capillary hemodynamics during reactive hyperemia and during adenosine administration by intravital video microscopy
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DOI：
10.1152/ajpheart.00088.2004
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发表时间：
2005-03-01
影响因子：
4.8
通讯作者：
Kajiya, F
中科院分区：
文献类型：
--
作者：
Kiyooka, T;Hiramatsu, O;Kajiya, F
使用高分辨率活体电荷耦合装置视频显微镜，我们在活体内可视化了犬心脏不停跳的心外膜毛细血管网络，以阐明其在控制条件下、反应性充血(RH)期间和冠脉内给药期间的功能作用。将铅笔镜视频显微镜探头置于左前降支供血的毛细血管上方，以60~90次/min的频率起搏麻醉开胸犬心脏。在对照条件下的单个毛细血管中，红细胞血流在收缩或舒张期占主导地位，表明舒张期动脉和收缩期静脉血流之间的分水岭位于毛细血管内。RH过程中毛细血管流量增加，峰值流速(2.1+/-0.6 mm/S)是对照组(1.2+/-0.5 mm/S)的两倍，毛细血管间交叉连接流量增强，管径增大(17%)。加入腺苷后，毛细血管血流速度显著增加(1.80±0.7 mm/S)。然而，根据红细胞速度和直径估计的腺苷增加的毛细血管流量小于动脉流量的增加，而RH期间的增加几乎等于动脉流量的增加。在RH过程中，毛细血管的充盈有与1.5 S相似的时间滞后，表明它们具有电容血管的功能。综上所述，冠状毛细血管网络在RH期间起主要作用：1)舒张期为主的动脉血流和收缩期为主的静脉血流的主要分水岭；2)电容；3)RH期间显著的局部血流放大和血供均衡器，但腺苷使毛细血管血流速度的增加小于动脉血流的增加。
Using high-resolution intravital charge-coupled device video microscopy, we visualized the epicardial capillary network of the beating canine heart in vivo to elucidate its functional role under control conditions, during reactive hyperemia (RH), and during intracoronary adenosine administration. The pencil-lens video-microscope probe was placed over capillaries fed by the left anterior descending artery in atrioventricular-blocked hearts of open-chest, anesthetized dogs paced at 60-90 beats/min (n = 17). In individual capillaries under control conditions, red blood cell flow was predominant during systole or diastole, indicating that the watershed between diastolic arterial and systolic venous flows is located within the capillaries. Capillary flow increased during RH and reached a peak flow velocity (2.1 +/- 0.6 mm/s), twice as high as control (1.2 +/- 0.5 mm/s), with enhancement of intercapillary cross-connection flow and enlargement of diameter (by 17%). With adenosine, capillary flow velocity significantly increased (1.8 +/- 0.7 mm/s). However, the increase in volumetric capillary flow with adenosine estimated from red blood cell velocity and diameter was less than the increase in arterial flow, whereas that during RH was nearly equivalent to the increase in arterial flow. There was a time lag of similar to1.5 s for refilling of capillaries during RH, indicating their function as capacitance vessels. In conclusion, the coronary capillary network functions as 1) the major watershed between diastolic-dominant arterial and systolic-dominant venous flows, 2) a capacitor, and 3) a significant local flow amplifier and homogenizer of blood supply during RH, but with adenosine the increase in capillary flow velocity was less than the increase in arterial flow.