Development of collateral function with repetitive coronary occlusion in a canine model reduces myocardial reactive hyperemia in the absence of significant coronary stenosis.
نویسندگان
چکیده
The present study was designed to elucidate the role of collateral development, per se, on reactive hyperemia without persistent coronary stenosis in instrumented conscious dogs. Functional states of coronary collaterals were augmented by repetitive 2 minutes of coronary occlusion every 30 minutes for 2-9 days. Regional shortening measured sonomicrometrically recovered from -1.2 +/- 6.5% of the preocclusive state at the end of the first coronary occlusion to 100.5 +/- 1.2% (n = 8, P less than 0.01) after repeated coronary occlusions. Before and after collateral development, transient coronary occlusions of 5, 10, 20, 30, 60, 90, and 120 seconds were randomly performed. The degree of regional dysfunction and the following reactive hyperemic response were measured. Up to 20 seconds of coronary occlusion, the flow ratio and duration of coronary reactive hyperemia increased similarly, both before and after collateral development. However, when the duration of coronary occlusion was over 30 seconds, flow ratio and debt repayment ratio were reduced progressively after the collateral development. Among the indices exhibiting reactive hyperemia, debt repayment ratio decreased initially and correlated well with the recovery of regional dysfunction during coronary occlusion. Thus, the augmentation of collateral function after repetitive coronary occlusion reduces reactive hyperemia even in the absence of significant coronary stenosis.
منابع مشابه
Functional significance of collaterals during ameroid-induced coronary stenosis in conscious dogs. Interrelationships among regional shortening, regional flow and grade of coronary stenosis.
We studied the relationships among collateral flow, regional myocardial shortening and the grade of coronary stenosis during ameroid-induced chronic coronary constriction in 22 conscious dogs. A radiolucent ameroid, a Doppler flow probe and a cuff occluder were placed on the left circumflex coronary artery (LCx). Regional myocardial shortening and regional myocardial blood flow were assessed si...
متن کاملReactive oxygen species are critical mediators of coronary collateral development in a canine model.
Recent evidence suggests that reactive oxygen species (ROS) promote proliferation and migration of vascular smooth muscle (VSMC) and endothelial cells (EC). We tested the hypothesis that ROS serve as crucial messengers during coronary collateral development. Dogs were subjected to brief (2 min), repetitive coronary artery occlusions (1/h, 8/day, 21 day duration) in the absence (occlusion, n = 8...
متن کاملIschemia-induced coronary collateral growth is dependent on vascular endothelial growth factor and nitric oxide.
BACKGROUND We hypothesized that ischemia-induced expression of vascular endothelial growth factor (VEGF) and the production of NO stimulate coronary collateral growth. METHODS AND RESULTS To test this hypothesis, we measured coronary collateral blood flow and VEGF expression in myocardial interstitial fluid in a canine model of repetitive myocardial ischemia under control conditions and durin...
متن کاملLABORATORY INVESTIGATION CORONARY BLOOD FLOW Collateral conductance changes during a brief coronary occlusion in awake dogs
Function of the coronary collateral circulation during the course of a single abrupt coronary occlusion was evaluated in awake dogs instrumented over the long term. Studies were performed approximately 2 weeks after collateral development had been stimulated in the dogs by partial stenosis of the proximal left circumflex coronary artery. The pressure drop from the central aorta to the distal ci...
متن کاملCORONARY BLOOD FLOW Collateral conductance changes during a brief coronary occlusion in awake dogs
Function of the coronary collateral circulation during the course of a single abrupt coronary occlusion was evaluated in awake dogs instrumented over the long term. Studies were performed approximately 2 weeks after collateral development had been stimulated in the dogs by partial stenosis of the proximal left circumflex coronary artery. The pressure drop from the central aorta to the distal ci...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Circulation research
دوره 55 5 شماره
صفحات -
تاریخ انتشار 1984