(精选)Vascular Diseases教学课件.pptVIP

Hypertension Hypertension affects 20% of the population. It is seen in more that half of cases of myocardial infarction, stroke and chronic renal failure. Hypertension is more severe in blacks and results in complications. Hypertension is seen in more than ? of cases of dissecting aortic aneurysm, intracerebral hemorrhage, and rupture of myocardial wall. 95% of hypertension is due to unknown cause, “essential” or primary hypertension. Definition: WHO: systolic pressure 160 mmHg, and/or diastolic 90 In 20 year-old men the normal blood pressure range is 105-150 (mean 130) In 80 year-old men the normal blood pressure range is 125-220 (mean 170) Pathogenesis Blood pressure is the product of cardiac output and the systemic peripheral resistance. Hypertension results from imbalance between factors controlling cardiac output and systemic peripheral resistance. Renin-Angiotensin system In experiment: renal artery occlusion - production of renin - converts Angiotensinogen to AngiotensinI - AngiotensinII which result in: Increase sympathetic activity leading to vasoconstriction Increase aldosterone production leading to Na and water retention Direct vasoconstriction action The end result is increase in cardiac output and increase in the systemic peripheral resistance. Atrial Natriuretic Factor (ANF) With atrial distention, there is release of ANF by specialized cells in the atrium. ANF acts on specific receptors in the kidney and results in Na excretion. This leads to decrease in blood volume and in cardiac output. In Hypertension there is disturbance of the balance and the control of these systems. The end result is high blood pressure, mainly due to increase in systemic peripheral resistance. Therapy Sympathetic antagonists (beta-adrenergic blockers) Diuretics ACE inhibitors Secondary Hypertension Renal artery stenosis Chronic renal diseases Conn syndrome Cushing syndrome Pheochromocytoma Hyperthyroidism Coarctation of aorta Renin-secreting tumors Atheroscleros