target organ damage

If hypertension is years of excessive pressure in the plumbing, target organ damage is the wear that pressure eventually leaves on the appliances downstream. It is the cumulative injury that sustained high blood pressure inflicts on the organs that depend most on healthy blood vessels: the heart, brain, kidneys, eyes, and large arteries.

In the heart it shows as thickening of the left ventricle and a rising risk of heart failure and heart attack; in the brain as stroke and small-vessel changes linked to cognitive decline; in the kidneys as protein leaking into the urine and falling filtration; in the eyes as retinal vessel damage seen on examination; and in the large arteries as accelerated stiffening and aneurysm risk. These are the very reasons hypertension is treated.

Detecting target organ damage matters because it sharpens the picture of risk and the urgency of treatment. Tests such as an ECG or echocardiogram for ventricular thickening, urine protein and blood creatinine for the kidneys, and an eye examination help reveal damage that the patient cannot feel, since much of it accumulates silently long before symptoms appear.