Myocardial oxygenation in dogs during partial and complete coronary artery occlusion.

Published

Journal Article

Regional myocardial oxygenation was assessed during partial and complete coronary artery occlusion using near infrared spectroscopy. In eight open-chest dogs, partial occlusions resulting in an approximately 42% decrease in left anterior descending coronary artery (LAD) blood flow produced an approximately 21% decrease in tissue O2 stores (tissue oxyhemoglobin plus oxymyoglobin) and no change in the oxidation level of mitochondrial cytochrome aa3. An approximately 81% reduction in LAD blood flow produced nadir levels of tissue oxyhemoglobin plus oxymyoglobin, maximal levels of deoxyhemoglobin plus deoxymyoglobin, a decline in tissue blood volume, and an approximately 39% decrease in cytochrome aa3 oxidation level. These changes were associated with an approximately 52% decrease from the preischemic baseline in mean transmural myocardial blood flow, measured by radiolabeled microspheres, and an approximately 41% decrease in myocardial O2 consumption. Complete occlusion resulted in further decreases in myocardial blood flow, O2 consumption, tissue blood volume, and cytochrome aa3 oxidation state but also produced increases in tissue O2 stores to above the nadir levels noted during partial occlusion. These results indicate that decreases in O2 delivery during partial coronary occlusion increase O2 extraction to sustain mitochondrial O2 availability, but as little as a 52% reduction in myocardial blood flow produces maximal O2 extraction and depletion of tissue O2 stores. Mitochondrial O2 availability is restricted further during complete occlusion because of limited O2 delivery and, possibly, decreases in tissue blood volume and O2 extraction.

Full Text

Duke Authors

Cited Authors

  • Parsons, WJ; Rembert, JC; Bauman, RP; Duhaylongsod, FG; Greenfield, JC; Piantadosi, CA

Published Date

  • September 1, 1993

Published In

Volume / Issue

  • 73 / 3

Start / End Page

  • 458 - 464

PubMed ID

  • 8348690

Pubmed Central ID

  • 8348690

International Standard Serial Number (ISSN)

  • 0009-7330

Digital Object Identifier (DOI)

  • 10.1161/01.res.73.3.458

Language

  • eng

Conference Location

  • United States