What is the significance of a fibrous cap over the fatty lesion in atherosclerosis?

The fibrous cap over the fatty lesion in atherosclerosis plays a critical role in the stability of the plaque. A stable plaque is characterized by a thick fibrous cap that protects the underlying lipid core from rupture and exposure to the bloodstream. When the fibrous cap is intact, it serves to contain the atherosclerotic plaque and prevent thrombosis, which could lead to acute cardiovascular events such as heart attacks or strokes.

In contrast, a thin or ruptured fibrous cap can make the plaque unstable, increasing the risk of clot formation and potentially resulting in significant complications. Therefore, when a fibrous cap is present, it indicates that the plaque is stabilized, reducing the likelihood of rupture and subsequent acute cardiovascular issues.