The kidneys play an important role in regulating blood pressure by controlling the amount of fluid and sodium in the blood. When the kidneys work properly, they excrete excess fluid and retain fluid during periods of dehydration. Normal kidneys also maintain a very narrow normal range of sodium in the circulatory system. When end-stage renal disease, also known as kidney disease, causes kidney function to decline, the kidneys do not maintain these functions properly. As fluid builds up in the circulatory system, it increases the volume of the blood. Increased blood volume makes the heart work harder to pump blood to the organs. Kidney disease also damages the blood vessels that supply the kidneys, which makes it even more difficult for the heart to pump enough blood to the kidneys.
Before or after a kidney transplant, patients should aim for a blood pressure level of 130/80 or lower, according to the National Kidney Foundation. If a patient cannot maintain this blood pressure level via diet and exercise, several drugs control blood pressure so it does not cause further kidney damage or increase the risk of cardiovascular disease. Calcium channel blockers limit the amount of calcium that enters the muscle cells of the heart, which relaxes the blood vessels and reduces blood pressure. Diuretics increase the amount of fluid excreted by the kidney, which reduces blood volume and makes it easier for the heart to pump blood. Beta-blockers reduce the effects of adrenaline on the heart, which causes the heart to slow down. ACE inhibitors prevent the body from converting angiotensin I to angiotensin II. Since angiotensin II constricts the blood vessels, ACE inhibitors cause the blood vessels to relax, which reduces blood pressure.
Hypertension affects nearly 80 percent of those who have undergone a kidney transplant. The presence of high blood pressure increases the risk of graft rejection and may affect survival rates after kidney transplant. One research study showed that transplant recipients with controlled blood pressure levels had better outcomes and improved survival rates. As of July 2010, no clinical studies have proven a link between blood pressure levels and long-term quality of life for transplant patients.
Factors Affecting Blood Pressure
One of the factors that affect blood pressure levels in transplant recipients is the use of immune suppressants. These drugs prevent tissue rejection, but they also reduce immune system function and increase the risk for complications after a transplant. Immune suppressants reduce the kidneys’ ability to filter waste and fluids from the blood, which increases the risk of high blood pressure. Some of the drugs used to treat high blood pressure can improve the filtration rate of the kidneys and reduce the risk of serious complications. Transplant patients should comply with all post-transplant instructions to improve their outcomes.
National Kidney Foundation: Clinical Practice Guidelines on Hypertension and Antihypertensive Agents in Chronic Kidney Disease
National Kidney and Urologic Diseases Information Clearinghouse: Treatment Methods for Kidney Failure: Transplantation