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CAD.(coronary artery disease)


Ischemic heart disease( coronary artery disease)

Includes

Stable angina
Acute coronary syndromes
Sudden cardiac death due to arrythmia
Chronic IHD with CHF

Acute coronary syndromes include:

Unstable angina
New onset angina
Non ST elevation MI( NSTEMI)
Myocadial infarction

Risk factors
Non modifiable risk factors:

Age
Sex
Genetics and familial predisposition
Homocystinuria
Thrombophilic conditions

Modifiable risk factors:

Smoking
Heavy drinking
Diabetes mellitus
Hypercholesterolemia and hyperlipidemia
Hypertension
Obesity and sedentary lifestyle
Increased consumption of saturated fats and decreased intake of PUFA

Pathogenesis:

Coronary artery perfusion – pressure differential between the ostia (aortic diastolic) and coronary sinus (right atrial)
Critical stenosis of coronary arteries: >75% of lumen occlusion- cannot dilate during increased physiological need
Plaque rupture is the commonest initiating event in acute coronary syndrome- caused by the digestion of collagen cap of the atheroma by proteinases from macrophages. The exposed thrombogenic lipid and collagen initiate the coagulation cascade, causing thrombosis and embolism of the thrombus into end arteries.
Vasospasm is rarely implicated in IHD; esp in Prinzmetal’s angina; the vasospasm is in response to
1)Adrenergic stimulation
2)Decreased NO and prostacyclin( PG I2)
3)Increased endothelin and TX A2

Vasculitis like kawasaki disease
Myocardial hypertrophy increases oxygen demand and predisposes to IHD
Hypotension and shock also causes myocardial anoxia and precipitate acute events like MI.