Effects of hypertension on the kidney. Hypertension (high blood pressure) has caused atrophy and scarring. The normal smooth appearance has been replaced by noduled surface and necrosing areas at the pelvis of the kidney. The kidneys are especially vulnerable to the changes to blood vessels that occur in hypertension. In chronic hypertension the arteriole walls are thickened. The resulting reduced renal blood flow causes chronic ischaemia and gradual atrophy of the tubules. Slow progressive loss of functioning nephrons may eventually lead to chronic renal failure and the kind of shrunken 'end-stage' kidney seen here.