OME Cardiac Modules Practice Test

Rupture of a vulnerable plaque with subsequent thrombosis is the event that directly leads to artery occlusion at this stage. When an atherosclerotic plaque becomes unstable, its fibrous cap thins and the underlying lipid-rich core is exposed to flowing blood. Inflammatory processes and enzymes weaken the cap, and a rupture allows platelets to adhere and the coagulation cascade to activate, forming a thrombus. This clot can rapidly grow and block the vessel, cutting off blood flow and causing acute ischemia or infarction. Calcification, while a marker of advanced disease, tends to stiffen plaques and is not the immediate cause of occlusion. Endothelial dilation is not the characteristic event driving occlusion at this stage, and systemic hypertension is a risk factor that accelerates atherosclerosis but does not itself cause the acute occlusive event.