Chapter 2.2 Ηypertension (High Blood Pressure) (HTN)

How does high blood pressure damage the kidneys?

HTN is a condition that can damage your kidneys. Your kidneys act like a filtering system to get rid of excess water and wastes in the blood. Blood pressure is the force, or pressure, of the blood on the walls of your blood vessels. Over time, uncontrolled high blood pressure can damage the blood vessels and nephrons (filtering units) in the kidneys. The damaged nephrons can not do their job of filtering out all of the wastes , sodium and excess fluids from your blood. The excess fluid and sodium stays in your bloodstream putting extra pressure on the walls of your blood vessels- raising your blood pressure even more. This extra pressure leads to further kidney damage. High blood pressure also affects many other organs, slowly destroying them. This includes the heart, brain and eyes.

My doctor told me that controlling my kidney disease means controlling my blood pressure. What does this mean?

Blood pressure is considered high if the top number (systolic pressure) is equal to or greater than 130 mmHg or the bottom number (diastolic pressure), is more than or equal to 80 mmHg. HTN can be both a cause and result of kidney disease. Patients with protein in their urine should have blood pressure controlled to 130/85 mmHg or lowered to 125/75 mmHg. This can help preserve kidney function and protect the kidneys from further damage.

HTN aggravates atherosclerosis, increases the workload on the heart and may lead to heart failure. HTN increases the risk of coronary artery disease, aneurysms, stroke, kidney disease, and eye problems. Most patients with HTN eventually develop microalbuminaria.

Are there medicines to slow down kidney damage?

Yes. The strategy to control blood pressure is to use medicines that have additional benefits. Angiotensin is a hormone your body makes that constricts smooth muscles in the vessels of the kidney and in other vessels as well. There are two types of drugs that can block this hormone: angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). ACE inhibitors decrease your blood pressure by opening or dilating blood vessels. ARBs work by blocking the hormone that causes blood vessels to narrow. Both types of drugs have been shown to help reduce the progression of kidney disease, especially in diabetics.

Calcium channel blockers (dilates the blood vessels by relaxing the muscles in the vessel walls ) are also useful antihypertensive drugs, but are generally recommended for use once you are already on an ACE inhibitor or ARB. Other drugs such as b blockers are also used. Diuretics are also used to remove extra sodium and fluid from the body. Eliminating excess fluid may lower your blood pressure and assist the other drugs mentioned above.

Blood pressure can also be reduced with diet, especially one lower in salt, and exercise which is very important. But most people with hypertension will also need to take medication over the course of their lifetime in order to achieve optimal blood pressure and slow the progression of CKD.