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Updated: Aug 8, 2026
12:03
Myocardial Infarction and Functional Outcome Assessment in Pigs
Published on: April 25, 2014
Repeated dipyridamole administration enhances collateral-dependent flow and regional function during exercise. A role
J D Symons1, E Firoozmand, J C Longhurst
1Department of Internal Medicine, University of California, Davis 95616.
Circulation Research
|September 1, 1993
Summary
Chronic vasodilation with dipyridamole enhanced coronary collateral function in pigs. This suggests mechanical factors, not just ischemia, drive collateral growth, improving blood flow during exercise.
Area of Science:
- Cardiovascular Science
- Physiology
- Pharmacology
Background:
- Coronary collateral growth mechanisms are debated, with chemical and mechanical factors proposed.
- Previous research indicated collateral development is not solely dependent on ischemia extent or duration.
Purpose of the Study:
- To investigate if chronic, repeated vasodilation with dipyridamole enhances coronary collateral development in a miniswine model.
- To determine if mechanical stimulation from vasodilation, independent of ischemia, promotes collateral growth.
Main Methods:
- Miniswine with an occluded left circumflex coronary artery (LCx) received daily dipyridamole, diltiazem, or vehicle for 8 weeks.
- Transmural blood flow and systolic wall thickening were measured at rest and during exercise.
- Coronary collateral capacity was assessed by comparing blood flow and function in the collateral-dependent region to non-occluded regions.
Main Results:
- Both dipyridamole and diltiazem increased blood flow without causing ischemia during infusion.
- During maximal exercise, dipyridamole treatment significantly increased collateral-dependent myocardial blood flow compared to diltiazem or vehicle.
- Myocardial function in the collateral-dependent region during exercise was significantly improved in the dipyridamole group.
Conclusions:
- Chronic, repeated vasodilation with dipyridamole effectively enhances coronary collateral function in a setting of chronic coronary occlusion.
- Mechanical forces generated by vasodilation appear to be a significant driver of coronary collateral development.
- These findings support the hypothesis that mechanical factors play a crucial role in promoting coronary collateral growth.
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