The Effect of Nebivolol on Endothelial Dysfunction in African Americans With Hypertension
Status:
Completed
Trial end date:
2012-06-01
Target enrollment:
Participant gender:
Summary
High blood pressure (hypertension) is called the "silent killer" because many people do not
know they have it, and do not know when it is well controlled. Unfortunately, over time
uncontrolled hypertension can cause irreversible organ damage that can lead to heart attack,
stroke, heart failure, and kidney failure. If a person cannot control their blood pressure
with diet and exercise, doctors often prescribe medications to help control the blood
pressure. Nebivolol is a medication that has been recently approved by the FDA for the
treatment of hypertension. Our study will investigate whether treatment with nebivolol, as
compared to another medication called metoprolol, in African Americans with hypertension will
be more effective in protecting blood vessels against the harmful effects of high blood
pressure.
Over time high blood pressure causes hardening of the arteries (atherosclerosis) which leads
to narrowing of the blood vessels and reduces blood flow to our organs. Arteries also relax
and contract naturally, which further changes the blood supply. When arteries are narrowed,
exercise can bring on a condition in which the blood supply is inadequate, and this might
result in the sensation of pain.
Cells lining our blood vessels produce a variety of substances that normally cause arteries
to relax. Two of these substances are called nitric oxide (NO) and endothelium-derived
hyperpolarizing factor (EDHF). We are trying to determine the nature of these substances in
African Americans with high blood pressure and how it is affected by nebivolol and
metoprolol. One way to determine this is to inject drugs such as L-NMMA
(N(G)-monomethyl-L-arginine) or TEA (tetraethylammonium chloride), which block the production
of NO and EDHF respectively, and then study what happens to the blood flow at rest and during
exercise. It is our thought that nebivolol, in comparison to metoprolol, will increase the
substances that naturally cause arteries to relax and improve blood supply.