Primary Hypertension

Hypertension is sustained elevation of arterial pressure. It develops when systemic vascular resistance, cardiac output, or both remain too high. Renin–angiotensin–aldosterone system activation, sympathetic overactivity, sodium and water retention, arterial stiffening, and impaired vascular relaxation can all maintain the elevation. The pressure load is initially tolerated, so a patient may feel entirely well while vascular injury accumulates. Over time, persistently high pressure promotes atherosclerosis and damages small vessels. The left ventricle thickens against increased afterload; the kidneys develop nephrosclerosis and lose filtration capacity; the retina may show vascular injury; and cerebral small-vessel disease increases the risk of stroke and cognitive decline. The clinical task is therefore not simply to lower a number. It is to confirm sustained hypertension, estimate the patient’s cardiovascular risk, identify existing organ injury, and choose a reduction that protects tissue without causing hypoperfusion.