Atherosclerosis I: Introduction

Atherosclerosis is a progressive disorder characterized by the accumulation of atheromas or plaques comprising lipids, calcium, and fibrous tissue within the intima of large and medium-sized arteries, causing them to harden and narrow.

The etiological factors include hypertension, elevated levels of low-density lipoprotein or LDL, smoking, and inflammatory conditions like arthritis, which contribute to endothelial damage.

Damaged endothelium allows LDL infiltration, which oxidizes and triggers inflammation.

Monocytes migrate into the arterial wall and transform into macrophages that ingest oxidized LDL, forming foam cells. These foam cells cluster into fatty streaks, marking the early stage of atherosclerosis.

As foam cells accumulate and inflammation persists, atherosclerotic plaque develops. It comprises cholesterol, foam cells, cellular waste, calcium, and a fibrous cap.

Over time, these plaques can enlarge and harden, causing arterial narrowing, a condition known as stenosis.

Plaques vary in stability; unstable plaques have a thin fibrous cap that may rupture, attract platelets, and cause thrombus formation.