Related Experiment Videos
Extracardiac to coronary anastomoses support regional left ventricular function in dogs
E F Unger1, M Shou, C D Sheffield
1Laboratory of Experimental Physiology and Pharmacology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
The American Journal of Physiology
|May 1, 1993
Summary
Implanting the internal mammary artery (IMA) in dogs created new blood vessels, but acidic fibroblast growth factor (FGF) did not improve this process. IMA blood flow is important but only noticeable when other coronary arteries are blocked.
Area of Science:
- Cardiovascular Research
- Surgical Innovation
- Angiogenesis Studies
Background:
- Systemic artery implantation, specifically the internal mammary artery (IMA), can induce angiogenesis and form new connections to coronary arteries.
- The functional significance of IMA-derived collateral flow and the potential of angiogenic peptides like acidic fibroblast growth factor (FGF) to enhance myocardial neovascularization require further investigation.
Purpose of the Study:
- To assess the magnitude of IMA-derived nutritive flow in dogs.
- To determine the influence of IMA-derived flow on regional myocardial contraction.
- To evaluate if acidic fibroblast growth factor (FGF) can enhance myocardial neovascularization induced by IMA implantation.
Main Methods:
- 23 dogs underwent left anterior descending coronary artery (LAD) occlusion and IMA implantation into the LAD territory.
- Dogs received continuous infusions of acidic FGF with heparin, heparin alone, or placebo into the IMA for 8 weeks.
- Regional myocardial blood flow and left ventricular function were assessed at 3 days and 8 weeks post-operation.
Main Results:
- IMA implantation reduced LAD zone perfusion by 28% but did not affect regional contraction initially.
- Superimposed IMA occlusion on left circumflex coronary artery (LCX) occlusion significantly impaired regional contraction.
- Both acidic FGF plus heparin and heparin alone improved IMA-derived collateral flow, with no added benefit from FGF.
Conclusions:
- Acidic FGF did not enhance myocardial angiogenesis in this canine model.
- IMA-derived collateral flow is functionally important, particularly when other collateral sources are compromised.
- Heparin alone improved collateral flow, suggesting its potential in managing compromised myocardial perfusion.