The effects of chronic kidney disease on the cardiovascular system
Heart disease is the most common cause of death in people with chronic kidney disease.
Chronic kidney disease is a disease where the function of the kidneys is poorer than normal. The functions of the kidneys are to remove waste products in urine, regulate the water and salt balance and blood pressure of the body, and make hormones that are important in producing red blood cells and making vitamin D.
Kidney function is measured by the glomerular filtration rate (GFR), which is calculated from the concentration of creatinine measured in blood. The lower your GFR, the worse the kidney disease. In end stage kidney disease, the GFR is close to zero and the kidneys are unable to make urine. People with end stage kidney disease need to undergo dialysis daily or at least a few times a week.
There is a clear association between chronic kidney disease and heart disease. The mechanisms by which chronic kidney disease cause heart disease are not so clear. One possible reason is that kidney disease increases the calcification of the blood vessels in the heart and this increases the risk of ischaemic heart disease or blockage of the blood vessels to the heart resulting in lack of oxygen to the heart.
Chronic kidney disease is commonly due to diabetes and hypertension. People with diabetes and hypertension tend also to have obesity and high cholesterol, leading to increased risk of heart disease. Kidney disease itself also causes hypertension by activating hormones that cause narrowing of the blood vessels. Narrow blood vessels caused by hypertension, cholesterol deposits on vessel walls and calcification within the vessel walls, all contribute to heart disease in kidney disease patients.
People with kidney disease should be screened for heart disease. They will need an electrocardiogram (ECG) and an exercise ECG to look for signs of blockage of heart vessels. An echocardiogram (ECHO) is also useful to look at the reserve of the heart. Recently, cardiac computed tomography (CT) scans have been used to look at blockage of the arteries of the heart. Warning symptoms include chest pain and shortness of breath.
To prevent heart disease in kidney disease, reduce the other risk factors of heart disease. Keep your blood pressure under control. People with end stage kidney disease should avoid consuming too much water and going into fluid overload as this puts a strain on the heart. Avoid high cholesterol foods, avoid smoking, get some exercise. If you are overweight, consider losing weight. If you have diabetes, keeping your blood sugar under control also helps. Aspirin could also be considered to reduce the risk of ischaemic heart disease.