This enzyme causes the formation of a protein called Angiotensin I. Angiotensin I directly stimulates the kidneys to retain sodium and fluid. As BP elevates, the whole system begins again with pressure diuresis. In healthy individuals, this feedback loop maintains a constant blood pressure with only minor fluctuations. In patients with essential hypertension, this feedback loop fails for undiscovered reasons. The result is a higher than normal level of pressure within the renal artery necessary for pressure diuresis to occur.
Hypertension plays a significant role in the development of arteriosclerosis and atherosclerosis.
Hypertension reduces the elasticity of vessels allowing lipids to deposit in the form of atheromas, which in turn leads to thrombus formation and possible emboli formation. This impedes blood flow and leads to ischemic disease. Coronary heart disease is the leading cause of death in hypertensive patients. Ventricular hypertrophy occurs as a result of increased cardiac output in the face of systemic vascular resistance. Eventually, the heart is unable to maintain this constant output and the hypertrophied muscle outstrips its oxygen supply.