Atherosclerosis - Pathology - BSc anesthesia, OT

Course: 2nd year ATOT

Faculty: Pathology

Kanachur Institute of Medical Sciences

1. ATHEROSCLEROSIS 17/01/23 Dr. Salman Ansari Dept. of Pathology Kanachur Institute of Medical Sciences

2. Atherosclerosis Definition Risk factors Pathogenesis Morphology Clinical Significance Prevention

3. Definition Athero sclerosis Fatty paste hardening Definition : “thickening and hardening of large and medium sized arteries due to fibrofatty plaques(atheromas)” Affects mainly the aorta, coronary arteries(heart) and cerebral arteries(brain) Can cause heart attacks, stroke and other conditions

4. Etiology Modifiable Non-modifiable(constitutional) Risk factors Additional risk factors

5. Modifiable risk factors Hyperlipidemia : increase in serum cholesterol High levels of Low density lipoprotein(LDL) - “bad cholesterol” High-density lipoprotein(HDL) - “good cholesterol” Hypertension : increase in systolic and diastolic blood pressure Cigarette smoking : most important avoidable cause of atherosclerosis Diabetes mellitus

6. Non-modifiable/constitutional risk factors Age : risk increases with older age Sex : Males are more at risk Family history Race : blacks are at higher risk

7. Pathogenesis - “Response to Injury” hypothesis Exposure to risk factors -> Formation of fatty streaks -> lipoprotein particles accumulate inside intima and macrophages enter into the lesion -> macrophages ingest the lipoprotein and transform into "foam cells" -> macrophages release cytokines and lead to smooth muscle proliferation

8. -> some foam cells die - formation of lipid-rich core -> fibrous tissue forms around lipid-laden macrophage - formation of fibrous cap -> this fully developed plaque/atheroma can undergo calcification -> plaque can bulge into lumen of coronary artery and narrow it -> thrombosis can occur, leading to complete block of blood vessel and causing acute coronary syndrome

9. Pathogenesis(short version) Exposure to risk factors formation of fatty streak -> lipoproteins accumulate, macrophage migration -> streak develops into a fully-developed atheroma -> Atheroma can undergo calcification or thrombosis(“complicated plaque”) -> Leading to clinical events(acute coronary syndrome, stroke, limb ischemia)

10. Morphological features Gross : Site : lower abdominal aorta, coronary arteries, popliteal arteries, internal carotid arteries and circle of Willis Appearance : yellow oval lesions

11. Microscopy : Plaque is made up of: Superficial fibrous cap Necrotic core : cholesterol cleft, foam cells Shoulder : peripheral area below and on the sides of the cap

12. Clinical effects Artery becomes narrow ischemia and atrophy Artery can get blocked suddenly infarction and necrosis Plaque can break thrombus and embolisation Artery wall can became weak and dilate aneurysm and rupture

13. Clinical significance Causes a number of diseases, such as: Heart -> ischemic heart disease, myocardial infarction Brain -> chronic ischemic brain damage, stroke Aorta -> aneurysm formation, thrombosis and embolisation to other organs Small intestine -> ischemic bowel disease, infarction Lower extremities -> intermittent claudication, gangrene

14. Prevention Primary prevention : Targeting modifiable risk factors to prevent occurrence of disease Secondary prevention : after the disease process has already started Stop smoking - most important avoidable cause Maintain serum cholesterol : reduce levels of LDL , increase levels of HDL Can be done via diet and drugs Low cholesterol diet, cholesterol-lowering medications(statins)

15. Control blood pressure - via lifestyle(diet and exercise) and antihypertensive medications(ACE inhibitors, beta blockers, calcium channel blockers) Diabetic control (through diet/exercise/medications) Regular exercise (brisk walking, cycling or swimming for 20 minutes two or three times a week) has a protective effect.

16. Summary Definition Risk factors Too much cholesterol, sugar, blood pressure, smoking Pathogenesis Fatty s treaks, foam cells, fully developed plaque, complicated plaque Morphology Clinical effects Prevention

17. References: Ramadas Nayak - Textbook of Pathology for Allied Health Sciences Questions: [email protected]