Modeling the effects of muscle contraction on the mechanical response and circumferential stability of coronary arteries.

Smooth muscle contraction regulates the size of the blood vessel lumen which directly affects the mechanical response of the vessel. Folding in arteries has been observed in arteries during excessive contraction, known as a coronary artery spasm. The interplay of muscle contraction, geometry, and material responses and their effects on stability can be understood through mathematical models. Here, we consider a three-layer cross-sectional model of a coronary artery with anisotropic properties and intimal thickening, and perform a linear stability analysis to investigate the circumferential folding patterns that emerge due to muscle contraction. Our model shows that a critical level of contractile activity yields a uniform strain distribution across the arterial wall. When the muscle is contracted above this critical level, the tissue behaves isotropically and it is more prone to circumferential instability. This theoretical framework could serve as a valuable tool to understand the relationship between arterial lumen morphology and wall contraction in health and disease.