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Published on: April 13, 2015
Myocardial cell volume and coronary resistance during diminished coronary perfusion
Insights
Reduced coronary blood flow causes myocardial cell swelling and increased coronary vascular resistance. This study in dogs links decreased blood flow to increased tissue water during ischemia, worsened by lack of reperfusion.
Area of Science:
- Cardiovascular Physiology
- Ischemic Heart Disease Research
Background:
- Myocardial ischemia is a critical condition affecting heart function.
- Understanding the relationship between blood flow and tissue water is vital for treating heart attacks.
Purpose of the Study:
- To investigate if reduced coronary blood flow without reperfusion causes myocardial cell swelling.
- To determine if increased tissue water correlates with coronary vascular resistance.
Main Methods:
- Anesthetized open-chest dogs with controlled coronary perfusion.
- Induction of ischemia by partial occlusion of the circumflex coronary artery.
- Measurement of myocardial water content and regional blood flow using the microsphere technique.
Main Results:
- Decreased coronary flow led to increased intracellular water and coronary resistance.
- 180 minutes of ischemia significantly increased myocardial water content.
- A strong negative correlation (r = -0.82) was found between decreased myocardial flow and increased myocardial water.
- Hypertonic mannitol administration prevented water accumulation and blood flow reduction.
Conclusions:
- Myocardial ischemia from reduced coronary perfusion causes cell swelling.
- This swelling is associated with a progressive deficit in myocardial blood flow.
- Preventing water accumulation may mitigate ischemic damage.
Abstract:
The present study was undertaken to determine whether diminished coronary blood flow without abrupt reperfusion results in myocardial cell swelling and, if so, whether the increment in tissue water is related to an increase in coronary vascular resistance. In 19 anesthetized open-chest dogs on right heart bypass with controlled coronary perfusion a decrease in coronary flow resulted in an increase in intracellular water and a progressive increase in coronary resistance. In 15 additional dogs, 180 min of ischemia produced by partially occluding the circumflex coronary artery resulted in significant increases in myocardial water content and progressive decreases in regional myocardial blood flow (microsphere technique). A significant correlation was found between the progressive decreases in myocardial flow and the increases in myocardial water (r = -0.82, P less than 0.001). In five experiments, hypertonic mannitol prevented water accumulation and progressive decreases in blood flow in the ischemic tissue. Thus myocardial ischemia produced by a decrease in antegrade coronary perfusion results in myocardial cell swelling and an associated progressive perfusion deficit.
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