Plaques are dynamic often driven by the processes of inflammatory cells. The more potential for movement, the more likely they are to rupture. Rupture will (usually) result in downstream embolization and/or thrombosis.
Calcification, adventitial fibrosis, and circumferentail plaque distribution are all factors that harden the plaque, stabilize it, or are more protective of the plaque. Calcification, when it occurs in atherosclerotic plaques, tends to create a more stable plaque. Adventitial fibrosis would also stabilize the plaque as well by reinforcing the arterial wall. Interestingly, a circumferential distribution of atherosclerotic disease will also stabilize the lesion when compared to an eccentric location within the arterial intima.
Inflammation will destabilize a plaque. Similarly, the other factors listed in the attached image (eccentric distribution, necrotic core, thin fibrous cap, angiogenesis) contribute to the instability of a plaque.
- Melanie Bois