The Heart and Kidney Connection

Healthy kidneys remove wastes and extra fluid from your body. They balance salts and minerals in your blood. They also help control blood pressure, make red blood cells, and keep bones strong.

The heart pumps blood filled with oxygen and nutrients to all parts of your body to work properly and stay alive. Blood pumped by the heart also picks up carbon dioxide and waste products so that your body can get rid of them. To move blood to each part of your body, your heart relies on your blood vessels. Together, the heart, blood and blood vessels make up a system called “the cardiovascular system.”

The kidneys clean the blood, removing waste products and extra water. Without the kidneys, your blood would have too much waste and water. The heart would be working too hard or would not function at all without the help of your kidneys.

The heart pumps blood filled with oxygen through all parts of your body, including the kidneys. Without the heart, your kidneys would not have the oxygen-filled blood needed to do its many important jobs.

Researchers have been working to understand the clear relationship between kidney disease and heart disease. It is important to know that having kidney disease can directly affect your chances of developing heart disease. Having heart disease can directly affect your chances of developing kidney disease. In fact, kidney disease and heart disease share many of the same risk factors, such as diabetes and high blood pressure.

The links between kidney disease and heart disease have led to the creation of the term cardiovascular-kidney-metabolic (CKM) syndrome, which is a group of health conditions including heart disease, kidney disease, diabetes, and obesity.

There are multiple types of kidney diseases:

• Chronic kidney disease (CKD): When the kidneys have become damaged over time (for at least 3 months) and have a hard time doing all their important jobs.
• Kidney failure: When your kidneys are no longer able to work well enough to keep you alive. People with kidney failure will need dialysis or a kidney transplant to survive. CKD can lead to kidney failure.
• Glomerular diseases: A condition where glomeruli (tiny filtering units in the kidney) become damaged. Glomerular diseases include many conditions with many different causes.
• Acute kidney injury (AKI): A sudden temporary drop in kidney function that happens within a few hours or a few days.

CKD is the most common type of kidney disease.

There are also different types of heart diseases. Some types include:

• Heart failure: When the heart has trouble pumping blood throughout your body.
• Heart attack: Happens when blood flow bringing oxygen to the heart is blocked. As a result, the heart can’t get enough oxygen and heart muscle starts to die.
• Angina: Chest pain caused by reduced blood flow to the heart. Not all chest pain is angina. A heart attack is a medical condition and angina is a symptom.
• Stroke: Happens when the blood supply to the brain is blocked (“ischemic stroke”), or when there is sudden bleeding in the brain from a broken blood vessel (“hemorrhagic stroke”).
• Arrythmia: Also known as an irregular heartbeat. It is a problem with the heart’s rate or rhythm, or the way the heart is beating. The most common type is atrial fibrillation (also known as a-fib).

The most common CKD risk factors are:

• Diabetes
• High blood pressure (hypertension)
• Heart disease and/or heart failure
• Obesity
• Over the age of 60
• Family history of CKD or kidney failure
• Personal history of acute kidney injury (AKI)

These CKD risk factors can also raise the risk of heart disease, in addition to:

• Smoking and/or use of tobacco products
• High blood cholesterol
• Unhealthy diet
• Physical inactivity
• Excessive alcohol use
• Family history of heart disease (especially heart attack or stroke before the age of 50)

Many people living with CKD do not have any symptoms until the more advanced stages and/or complications develop.

Many people with heart disease also may not have symptoms until it advances, or if they suffer a heart attack or stroke. Symptoms for certain types of heart disease can include:

• Heart failure: Exercise intolerance (having a very hard time doing physical exercise), trouble breathing, fatigue, swelling (ankles, feet, legs, abdomen, neck), cough, loss of appetite, weight gain, irregular pulse, and/or palpitations (sensation of feeling the heartbeat).
• Heart attack: Chest pain or discomfort, extreme fatigue, dizziness, shortness of breath, nausea or vomiting.
• Angina: Chest pain or discomfort.
• Stroke: Numbness or weakness, especially on one side of the body, severe headache, dizziness, loss of balance or coordination, sudden confusion, or trouble speaking
• Arrhythmia: fatigue, chest pain, a rapid or fluttering heartbeat (palpitations), dizziness, and shortness of breath.

Kidney disease can raise the risk of heart disease. As kidney disease worsens, the risk of getting complications goes up. Many complications of kidney disease can also raise the risk of heart disease or lead to serious heart problems, including:

• High blood pressure: Strains the heart and blood vessels.
• Anemia (low levels of red blood cells): Reduces oxygen to the to the body’s organs.
• Mineral and bone disorder (when blood levels of calcium and phosphorus are out of balance leading to bone and/or heart disease): Raises the risk of calcium build-up in your blood vessels making them harder (less flexible).
• Hyperkalemia (high levels of potassium in the blood): Affects the heart’s ability to keep a regular rhythm.

Heart disease can also raise the risk of kidney disease and kidney failure. Heart disease can also have many complications, depending on the type of heart disease. For example, arrhythmia raises the risk of blood clots that can lead to a stroke. Heart failure can cause arrhythmia and stroke. Heart attack and stroke are serious medical emergencies that can lead to hospitalization, physical impairment or death.

Different tests are used to check how the kidneys and heart are working.

Tests

Tests for CKD include estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (uACR). Other tests (such as a kidney biopsy, ultrasound, or CT scan) may be used if more information is needed for a diagnosis.

Different tests or measurements can check for signs of heart disease.

• Blood pressure test: Measures how hard your heart is working to pump blood through your body.
• Cholesterol test: Measures the amount of cholesterol and other fats in your blood. It is also called a lipid panel because it includes multiple tests for different fats.
• EKG or ECG (electrocardiogram): A test using sensors stuck to your skin to record the electrical signals that keep your heart beating.
• Echocardiogram (ECHO): An ultrasound of your heart that shows the pumping strength and function.
• Stress test: Measures how your heart works during physical activity, such as walking, running on a treadmill, or riding a bike.

Other blood tests, such as B-type natriuretic peptide (or BNP) or troponin, can also help check for active problems with the heart.

Overview

Treatment can include a combination of nutrition and lifestyle recommendations and medicines. Your healthcare team will work with you to create a treatment plan to help prevent kidney disease or heart disease or keep it from getting worse. Be sure to keep up with medical visits. Steps to manage or prevent kidney disease and/or heart disease can include:

• Regular physical activity
• Lose weight, if you need to
• Eat less fat
• Keep your blood pressure, blood sugar, and blood fats in their goal range
• Stop smoking
• Reduce stress

Medications

Your health care professional may prescribe medicines to keep your blood glucose (diabetes) and/or blood pressure in the goal ranges recommended for you. Medicines for managing blood glucose can include pills, insulin, and other medicines that are injected. Certain medicines for blood pressure may also help keep your kidney disease from getting worse.

Your healthcare professional may prescribe one or more medicines to help slow down your kidney disease or manage your heart disease. These medicines can include an ACE inhibitor/ARB, diuretic (water pill), an SGLT2 inhibitor, low-dose aspirin and/or an nsMRA.

Your healthcare professional may also prescribe a statin (cholesterol medicine).

Anticoagulants and antiplatelets are medicines that can be used to help prevent blood clots that can lead to a stroke or heart attack. However, they can also carry a risk of preventing helpful clots, such as clots that stop a cut from bleeding. The use of these medicines may be restricted in people with advanced kidney disease or living with dialysis, given their higher risk of bleeding due to their condition. Your healthcare professional will carefully weigh the benefit and risk of these and any other medicines or procedures.

You may also need to take additional medications or supplements to manage any CKD complications you might have (if applicable).

Nutrition

Nutrition and healthy eating are important parts of your health. Healthy eating generally includes having more fruits and vegetables, and eating foods that are less processed and as close to fresh as possible.

You may need to limit your sodium (salt) intake, especially if you have high blood pressure. This means a lot more than not using a saltshaker, but also limiting foods with high levels of sodium listed on their nutrition facts label. Some foods that don’t taste salty can have a surprising amount of sodium when you check their nutrition facts label.

You may also need to limit your carbohydrate intake if you have diabetes and/or limit saturated fat to help with heart health. Nutrition and healthy eating can be a challenge for anyone, especially if you have kidney disease or heart disease. A dietitian can help with a meal plan that’s right for you.

Exercise

Exercise and physical activity, along with nutrition, are important parts of your health. The Centers for Disease Control and Prevention (CDC) recommends 150 minutes of physical activity per week, which can be done in any interval – spread it out. Don't confuse physical activity with vigorous exercise. Any type of body movement helps including walking, gardening, dancing or doing chores. The key is to find something that you enjoy and works best for you. Check with your healthcare team before starting any exercise and ask which exercises are best for you.

• What is my risk of getting kidney disease?
• What is my risk of getting heart disease or a stroke?
• What can I do to lower my risk for heart disease?
• Are there any changes I should make to my diet?
• Should I take any medication(s) to help with kidney disease and heart disease?
• Are there any concerns with me starting a new exercise routine? If so, what should I be aware of?

• Kidney Disease and Heart Disease
• Are You at Increased Risk for CKD?

• Cholesterol, Fats, and Heart Disease: What You Need to Know
• What Is High Blood Pressure?
• Heart Failure and Kidney Disease
• Blood Clots and Kidney Disease