What happens to pressure with atherosclerosis?

Two answers: Generally speaking, atherosclerosis hardens the arteries, increasing both the systolic and diastolic number. However, it is an interesting paradox that when these arteries become hard, the usual blood pressure technique (with a cuff) becomes much less reliable and can frequently register abnormally high systolic (top number) pressures.

Wider Pulse Pressure: In very advanced disease, the pulse pressure, the difference between the systolic (top, heart contracting) and diastolic (bottom, heart relaxed, in between beats) pressure increases. However, widened pulse pressure is a very late sign, after atherosclerosis is extensive, body-wide and advanced. This also occurs due to aortic valve leaks (not so common) and/or aortic-venous malformations (rare).