Effects

Hypertension is one of the chief causes of a disease of the arteries called atherosclerosis, where a build-up of fatty deposits called plaques occurs in the lining of the artery walls which can thicken, calcify and narrow the arteries to the point where they restrict the flow of blood. This can result in a blood clot, called a thrombus; forming at the site of the plaque, which may block the artery altogether and cause the tissues normally supplied by the artery to die from lack of oxygen.

This can happen in other organs in the body, but most commonly occurs in the heart, brain, the arteries of the limbs, the kidneys and the retina.

Renal Disease

The renal vasculature shows changes with hypertension.

• "Benign" nephrosclerosis:
  Modest elevations in blood pressure over the years result in thickening of small renal arteries and   arterioles, known as hyaline arteriolosclerosis. This vascular disease leads to formation of small cortical scars, with reduction in renal size.
• "Malignant" nephrosclerosis:
  In a small number of persons with previously mild hypertension or as the initial event, there is a marked rise in blood pressure. Diastolic pressure may exceed 120 to 150 mmHg. The changes seen in arterioles may include:
• Fibrinoid necrosis
• Necrotizing arteriolitis
• Hyperplastic arteriolosclerosis

Heart Disease

The pressure load placed on the left ventricle results in left ventricular hypertrophy. The heart enlarges and dilates, with hypertrophy more marked than dilation, until the left heart begins to fail, particularly when the heart reaches 500 gm in size. Congestive heart failure and cardiac arrhythmias may result from the failing heart.

CNS Disease

The effect of hypertension on small arteries and arterioles in the brain is to cause thickening and loss of resilience. This hypertensive hyalinization may produce occlusion with resultant small lacunar infarcts, or "lacunes" that appear most commonly in the region of the basal ganglia, internal capsule, thalamus, basis pontis, and hemispheric white matter. This arteriolar sclerosis also results in in vessels that are more prone to rupture. The most common site for rupture is the region of the basal ganglia. The hypertensive hemorrhage that results from rupture is one of the causes for a "stroke".