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Myogenic reactivity and resistance distribution in the coronary arterial tree: a model study
A J Cornelissen1, J Dankelman, E VanBavel
1Faculty of Design, Engineering and Production, Mechanical Engineering and Marine Technology, Man Machine Systems and Control Group, Delft University of Technology, 2628 CD Delft, The Netherlands.
Insights
This study modeled coronary arterial blood vessels to understand how their myogenic response aids autoregulation. Findings show larger vessels dampen smaller ones, and myogenic responsiveness is key for blood flow control.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
Background:
- The coronary arterial tree exhibits complex interactions influencing blood flow regulation.
- Understanding the myogenic response is crucial for comprehending vascular autoregulation.
Purpose of the Study:
- To evaluate the myogenic behavior of blood vessels within the coronary arterial tree.
- To assess the role of the myogenic response in achieving vascular autoregulation.
Main Methods:
- A computational model with 10 serial compartments representing different vessel sizes.
- Analysis of vessel diameter and resistance based on full dilation values and myogenic response.
- Evaluation of nine cases with varying distributions of resistance and myogenic strength (M(i)).
Main Results:
- Larger vessels were found to attenuate the myogenic activity of smaller vessels.
- Myogenic responsiveness was demonstrated to be sufficient for effective autoregulation.
- The maximal effect of perfusion pressure on active diameter occurred in specific vessel size ranges (123-181 microm), dependent on resistance distribution.
Conclusions:
- The distribution of resistance and control mechanisms within the coronary arterial tree significantly impacts vascular function.
- Myogenic responsiveness plays a vital role in the autoregulation of coronary blood flow.
- Interpreting in vivo individual vessel responses requires considering the integrated behavior of the arterial tree.
Abstract:
The objectives of this study were to evaluate the myogenic behavior of blood vessels and their interaction within the coronary arterial tree and to evaluate the possible role of the myogenic response in autoregulation. The model consists of 10 compartments in series, each representing a class of vessel sizes. Diameter and resistance in each class are determined by their value at full dilation (d(p,) R(p)) and by the myogenic response. Three distributions of R(p) and three distributions of myogenic strength, M(i) (slope of pressure-diameter curve, range -0.05 to -0.4%/mmHg) were evaluated (9 cases). It was found that larger vessels attenuate the myogenic activity of smaller vessels and that myogenic responsiveness is sufficient to achieve autoregulation. When M(i) has a maximum in vessels of 84 microm, the maximum effect of perfusion pressure on active diameter occurs in vessels between 123 and 181 microm, depending on the distribution of R(p). Distribution of resistance and control mechanisms in the coronary arterial tree are important for interpretation of individual vessel responses as observed in vivo.