Author + information
- Received May 21, 1991
- Revision received August 28, 1991
- Accepted September 12, 1991
- Published online March 1, 1992.
- Laurel Wright, MD1,
- David C. Homans, MD, FACC1,
- David D. Laxson, MD1,
- Xue-Zheng Dai, MD1 and
- Robert J. Bache, MD, FACC*,1
- ↵*Address for reprints: Robert J. Bache, MD, University of Minnesota, Box 338 UMHC, 420 Delaware Street S.E., Minneapolis, Minnesota 55455.
This study was performed to determine whether thromboxane A2(as the analogue U46619) and serotonin can cause vasoconstriction of moderately well developed coronary collateral vessels. Studies were carried out in seven adult mongrel dogs 2 to 4 months after embolic occlusion of the left anterior descending coronary artery had been performed to stimulate collateral vessel growth. At the time of study this artery was cannulated to determine interarterial collateral flow from measurements of retrograde blood flow. Radioactive microspheres were administered during retrograde flow collection to determine continuing tissue flow for evaluation of microvascular collateral communications.
Serotonin (50 μg/min) resulted in a 48 ± 11% decrease in retrograde flow (p < 0.01), with a 36 ± 10% decrease in total collateral blood flow (p < 0.02). Infusion of U46619 (0.01 μg/kg per min) caused a 38 ± 13% decrease in retrograde blood flow (p < 0.01), with a 34 ± 13% decrease in total collateral flow (p < 0.05). Serotonin caused a significant increase in tissue flow to the subepicardium of the collateral-dependent region, whereas U46619 caused no change in tissue blood flow.
These data demonstrate that both serotonin and thromboxane A2can cause vasoconstriction of interarterial coronary collateral vessels. The findings suggest that platelet activation in coronary arteries from which collateral vessels originate has potential for causing collateral vasoconstriction, thereby compromising blood flow to the dependent myocardium.
- Received May 21, 1991.
- Revision received August 28, 1991.
- Accepted September 12, 1991.
- American College of Cardiology Foundation