Key Points
- To examine the distribution of coronary blood flow in the left ventricular wall under different hemodilution conditions.
- Performed progressive hemodilution in anesthetized dogs until diastolic reactive hyperemia disappeared.
- Measured tissue activity concentrations of Xe-133 and radioactive microspheres after injection into the aortic root.
- Evaluated effects of coronary artery occlusion on blood flow distributions.
- At 'optimum' hemodilution, systolic coronary flow increased sixfold and diastolic flow tripled.
- Endocardial blood flow reserve was lower than epicardial blood flow.
- Epi- and endocardial distribution of blood flow was uniform during maximum coronary vasodilatation.
Structured PICO
PPopulationAnesthetized dogs
IInterventionProgressive hemodilution to 'optimum' level or maximum coronary vasodilatation via 10 s occlusion of the left coronary artery
OOutcomeDistribution of blood flow in the left ventricular free wall (measured by tissue activity concentrations of Xe-133 and radioactive microspheres)surrogate
In a canine model, endocardial blood flow reserve is lower than epicardial reserve during optimum hemodilution.