By George R. Aronoff, MD, FACP Heart disease is a frequent problem for people with kidney disease. Although heart disease has decreased in the United States over the past 30 years, patients with chronic kidney disease have not enjoyed the same reduction in the chances of having a heart attack or developing heart failure. People who have diabetes, high blood pressure, high cholesterol, are overweight, smoke, have had a previous heart attack or who have close family members with heart trouble are at the greatest risk of developing heart disease. Hardening of the arteries is the most frequent cause of heart disease. This process starts with fat deposits in the arteries and may begin at a young age, even in people without kidney disease. Over time, the fat deposits contain calcium and form plaques that can block small arteries, like those in the heart, the brain and the kidneys. Many factors contribute to hardening of the arteries. This article will consider some of the risk factors for the development of hardening of the arteries and heart disease in people with chronic kidney disease and present specific strategies for prevention. High blood pressure is a well-known risk factor for heart disease and strokes. Blood pressure is usually reported as two numbers, the top number is the systolic blood pressure and the bottom number is the diastolic blood pressure. Both systolic and diastolic blood pressures increase the risk when they are too high, particularly in people who smoke, have diabetes or abnormal cholesterol. A blood pressure of 130/85 is normal and it is recommended for patients younger than 65. Achieving a normal blood pressure should be the goal of therapy. For people over the age of 65, the risk of strokes is even higher than the risk of a heart attack and a blood pressure of 140/90 is suggested. Patients, who have protein in their urine or decreased kidney function, may benefit from an even lower blood pressure of 125/75, which is thought to slow down kidney damage in people who already have kidney disease. There are several ways to lower blood pressure without taking medications. A low salt diet, quitting smoking, losing weight, exercising and decreasing the amount of alcohol you drink to no more than one glass of beer, wine, or mixed drink each day. However, most people have to take medicines to get their blood pressure low enough to decrease the risk of heart disease and protect their kidneys. On average, many people with high blood pressure will have to take three or four medications to get their blood pressure under control. Fat in the blood stream, called lipids, contributes to hardening of the arteries. Cholesterol and triglycerides are fats in the blood stream. Both of these fats are necessary and help the body’s cells to work normally and they provide fuel for the body. Only if the levels get too high, can they contribute to hardening of the arteries. Doctors frequently measure the total cholesterol as an indication of a patient’s risk of developing heart disease. The total cholesterol consists of LDL cholesterol, the so-called bad cholesterol, and HDL, the good cholesterol. Depending on how many other risk factors for heart disease a person has, the target for total cholesterol may be as low as 200 mg/dl. The same level is desirable for triglycerides in people with several risk factors for heart disease. Lowering the total cholesterol and particularly, the bad cholesterol decreases the risk of heart disease. People with high cholesterol levels should consider changing their diet to avoid fatty foods and other foods high in cholesterol, like red meat. However, diet alone can only lower the cholesterol by a relatively small amount and many people with high cholesterol will need to be on specific medications to lower their cholesterol levels. Medications that lower cholesterol decrease the risk of heart disease and heart attacks. Although these medications are very effective, they may have side effects that doctors need to monitor. They can also interact with other medications that people with kidney disease may be taking. Consequently, doctors follow blood tests closely in patients taking cholesterol-lowering drugs. Triglycerides are also a kind of fat normally found in the blood stream. When triglyceride levels are abnormally increased, they may be a risk factor for hardening of the arteries. Decreasing the amount of sugar in the diet may lower triglyceride levels and there are medications, which are also effective for that purpose. Smoking is a very dangerous risk factor for hardening of the arteries. Smoking decreases the good cholesterol, increases blood pressure, decreases the oxygen in the blood stream and makes it easier for blood to clot in the tiny blood vessels in the heart and brain. Smoking can cause heart attacks and sudden death, particularly in patients who already have heart disease. Smoking may also worsen kidney disease. Quitting smoking is an important way to decrease the risk of strokes and heart attacks. Even among persons who have smoked heavily in the past, the risk of a heart attack can be cut in half regardless of how long or how much they have previously smoked. Diabetes mellitus or sugar diabetes is an important cause of hardening of the arteries. Diabetes is a leading cause of blockage of the tiny blood vessels in the kidneys, heart, brain and eyes. Diabetes is also the most common cause of kidney failure. Consequently, high blood sugar levels are associated with worsening kidney function, heart attacks, strokes and blindness. Diabetes in adults is often associated with being overweight. Weight loss through sensible diet and exercise decreases the risk of heart disease and may improve diabetes control. In order to achieve the best control of blood sugar, diabetics may take medications by mouth or insulin injections. Some diabetic medicines are not good for patients with kidney disease, because they can cause acid to accumulate in the blood stream. Doctors familiar with kidney patients will avoid using these medicines. Homocysteine is a chemical normally found in the blood that is important in making proteins. Levels sometime increase in people with chronic kidney disease and may cause hardening of the arteries. Homocysteine blood levels decrease when patients take large doses of folic acid and other B-vitamins. Doctors do not know for sure whether lowering homocysteine levels in this way decreases the risks of heart attacks and strokes. Individuals with kidney disease are at a high risk of developing hardening of the arteries resulting in heart attacks, heart failure and strokes. Multiple factors are involved. The table below shows multiple strategies to prevent hardening of the arteries. Much of what we believe to be true about prevention is known from patients with normal kidney function. We think these strategies will work in patients with kidney disease. However, much more research is needed to learn which factors are most important and which preventive measures are most effective. Strategies to Lower the Risk of Heart Disease Dr. Aronoff is Professor of Medicine and Pharmacology and Chief, Division of Nephrology at the University of Louisville School of Medicine. Dr. Aronoff is a member of the AAKP Medical Advisory Board. This article originally appeared in the December 2002 issue of Kidney Beginnings: The Magazine, Vol. 1, No. 2.
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