Arteriosclerosis

ARTERIOSCLEROSIS

Mönckeberg medial calcific sclerosis is a medial calcification of medium-sized(muscular) arteries, such as femoral, tibial, radial, and ulnar arteries. It is asymp-tomatic, but may be detected by x-ray.

Arteriolosclerosis refers to sclerosis of arterioles; it affects small arteries and arte-rioles. Microscopically, either hyaline arteriolosclerosis (pink, glassy arterial wall thickening with luminal narrowing seen in benign hypertension, diabetes, and aging) or hyperplastic arteriolosclerosis (smooth-muscle proliferation resulting in concentric [“onion skin”] wall thickening and luminal narrowing seen in malignant hypertension) may occur.

Atherosclerosis is a common vascular disorder characterized by lipid depositionand intimal thickening of large and medium-sized (elastic and muscular) arteries,resulting in fatty streaks and atheromatous plaques over a period of decades (a type of chronic inflammatory condition). Particularly likely to be affected are the aorta and a number of important muscular arteries (coronary, carotid, cerebral, renal, iliac, and popliteal arteries).

Risk factors for atherosclerosis are as follows:

·            The earliest (clinically reversible) stage in atherosclerosis is the fatty streak, which is seen grossly as a flat, yellow intimal streak and is characterized microscopically by lipid-laden macrophages (foam cells).

·            Stable atheromatous plaques have a dense fibrous cap, a small lipid core andless inflammation than their vulnerable counterparts. They cause chronic ischemia.

Vulnerable atheromatous plaques are at risk for rupture, thrombosis or embolizationdue to their composition (thin fibrous cap, large lipid core, dense inflammation).

Clinical complications of atherosclerosis are protean; these complications include ischemic heart disease (myocardial infarctions); cerebrovascular accidents (CVA); atheroemboli (transient ischemic attacks [TIAs] and renal infarcts); aneurysm for-mation; peripheral vascular disease; and mesenteric artery occlusion.