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Basic Res Cardiol. 1989 Jan-Feb;84(1):42-54. doi: 10.1007/BF01907002.

Coronary collateral reserve during exercise induced ischemia in swine.

Basic research in cardiology

F C White, D M Roth, C M Bloor

Affiliations

  1. UCSD School of Medicine, La Jolla, California.

PMID: 2923605 DOI: 10.1007/BF01907002

Abstract

We determined coronary collateral vasodilator reserve during exercise-induced ischemia in 17 mini-swine. We induced coronary collateral development in the left circumflex bed by placing an ameroid occluder on that artery. Four weeks later we studied the animals at rest and during exercise (EX) eliciting heart rates (HR) of 240 and 265 beats/min. We measured myocardial blood flow with microspheres and myocardial function by wall thickness sonomicrometry gauges. At matched exercise HRs we treated the animals with nifedipine (10 micrograms/kg IV) (EXN 10), nifedipine (100 micrograms/kg IV), (EXN 100), and adenosine infusion (1.2 mg/min/kg) EXAD. EXN 10 did not significantly alter hemodynamics compared to EX but EXN 100 and EXAD both decreased blood pressure significantly (p less than 0.05). Ischemic endocardial/nonischemic endocardial flow ratios and collateral resistance served as indices of vasodilator reserve. In the ischemic zone exercise reduced vasodilator reserve to 24 +/- 3% in the endocardium and 64 +/- 7% in the epicardium. Neither EXN 10 nor EXAD improved exercise-induced ischemia measured either as flow or function. However EXN 100 improved function during exercise-induced ischemia without improving coronary collateral flow. We conclude there is no additional coronary flow reserve during exercise-induced ischemia in the collateral dependent bed of the pig a few days after occlusion that can be recruited. Large doses of nifedipine improve function by direct action on the myocardium or by reducing afterload. The lack of development and deep myocardial distribution of the coronary collateral vessels in the pig may be an important factor of why these nifedipine responses differ from those reported in species which have primarily large epicardial coronary collaterals.

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References

  1. J Cardiovasc Pharmacol. 1984 May-Jun;6(3):378-83 - PubMed
  2. J Pharmacol Exp Ther. 1982 Aug;222(2):494-500 - PubMed
  3. Circ Res. 1978 Sep;43(3):372-80 - PubMed
  4. Circ Res. 1981 Jun;48(6 Pt 1):937-42 - PubMed
  5. Am J Physiol. 1987 Nov;253(5 Pt 2):H1279-88 - PubMed
  6. Circulation. 1987 Feb;75(2):482-90 - PubMed
  7. Am J Physiol. 1985 Mar;248(3 Pt 2):H403-11 - PubMed
  8. Am J Physiol. 1985 Sep;249(3 Pt 2):H638-47 - PubMed
  9. Cardiovasc Res. 1984 Apr;18(4):249-56 - PubMed
  10. Circulation. 1985 Feb;71(2):370-7 - PubMed
  11. Circulation. 1980 Dec;62(6):1266-74 - PubMed
  12. Circulation. 1982 Jan;65(1):49-53 - PubMed
  13. Circulation. 1981 Apr;63(4):849-55 - PubMed
  14. Am J Cardiol. 1982 Oct;50(4):689-95 - PubMed
  15. Circulation. 1983 Nov;68(5):1035-43 - PubMed
  16. Basic Res Cardiol. 1975 Mar-Apr;70(2):159-73 - PubMed
  17. Chest. 1980 Jul;78(1 Suppl):193-9 - PubMed
  18. Circulation. 1984 Apr;69(4):801-14 - PubMed
  19. Prog Cardiovasc Dis. 1977 Jul-Aug;20(1):55-79 - PubMed
  20. J Am Coll Cardiol. 1986 May;7(5):1036-46 - PubMed
  21. Am J Physiol. 1981 May;240(5):H767-74 - PubMed
  22. Am J Physiol. 1987 Dec;253(6 Pt 2):H1425-34 - PubMed
  23. Circulation. 1982 Sep;66(3):579-88 - PubMed
  24. J Cardiovasc Pharmacol. 1985 Jul-Aug;7(4):630-6 - PubMed
  25. Am J Cardiol. 1985 Jan 1;55(1):26-32 - PubMed
  26. Basic Res Cardiol. 1981 Mar-Apr;76(2):189-96 - PubMed
  27. Am J Cardiovasc Pathol. 1987 Jan;1(1):69-77 - PubMed

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