High blood glucose due to diabetes can cause damage to many parts of the body, including the heart. Chronically high blood glucose can cause damage to the tiny blood vessels and nerves of the heart, just as it does in other organs of the body. People with diabetes also tend to develop other conditions that are risk factors for cardiovascular issues including high cholesterol and triglycerides, high blood pressure and being overweight or obese. Lifestyle factors can also contribute to these issues including smoking, not getting regular physical activity, drinking excessive amounts of alcohol and not eating a healthy diet.
The heart is a key part of the cardiovascular system (which also includes all of the blood vessels).
- The heart is a muscle that pumps blood with oxygen and nutrients through the body.
- The blood vessels carry blood from the heart throughout the body and then back to the heart.
- The atria receive blood back into the heart and pump it into the ventricles; the ventricles pump the blood out into the aorta, which feeds all the blood vessels to the body.
- A heart beat is a series of two contractions—one in the upper chambers and one in the lower chambers.
- The beating of the heart is controlled by electrical impulses.
- About 60 percent of people with diabetes have high blood pressure.1
- Atherosclerotic cardiovascular disease (ASCVD), including coronary heart disease (CHD), cerebrovascular disease, or peripheral arterial disease, is the leading cause of morbidity and mortality for people with diabetes.2
- An estimated $37.3 billion is spent per year on cardiovascular-related cost associated with diabetes.2
- People with diabetes are twice as likely to be hospitalized for heart failure compared to those without diabetes.3,4
- Heart disease is the leading cause of death among both men and women and nearly all race/ethnicities.8
- About 68 percent of people age 65 or older with diabetes die from some form of heart disease.13
- Adults with diabetes are two to four times more likely to die from heart disease than those without diabetes.13
High Blood Pressure
High blood pressure, known as hypertension, is blood pressure that is consistently higher than the healthy (“normal”) range. Blood pressure is the pressure of the blood pushing again the walls of the arteries, which can fluctuate throughout the day. The American Diabetes Association defines hypertension in people with type 1 and 2 diabetes as greater than 140/90 mmHg.5
There are several risk factors that put people at greater risk for developing high blood pressure including:
- Age (the risk goes up with age)
- Sex (females are more likely to develop high blood pressure)
- Race/ethnicity (African Americans develop high blood pressure more often than other races/ethnicities).5
Blood pressure is measured with a blood pressure cuff. The top number is called the systolic blood pressure and measures the pressure in the vessels when the heart beats. The bottom number, known as the diastolic blood pressure, measures the pressure in the vessels when the heart rests between beats. People don’t usually experience any symptoms of high blood pressure until other issues arise from it including heart attack, angina (chest pain) and heart failure.
High blood pressure develops over time and can be due to genetics, other health conditions such as diabetes, as well as lifestyle factors (inactivity, diet, etc.). It is important to treat high blood pressure (although there are usually no symptoms until more serious issues occur like a heart attack) because it is a major risk factor for ASCVD (e.g., coronary artery disease) and microvascular complications (retinopathy, neuropathy, nephropathy, etc.). It is also associated with cognitive issues (dementia) in later life.5
Management of blood pressure includes losing weight if the person is overweight or obese, increasing regular physical activity, drinking alcohol in moderation, stopping smoking, eating a healthy diet including increasing intake of fruits, vegetables and low-fat dairy products as well as reducing sodium and increasing potassium intake.6
Medication(s), called antihypertensives, are prescribed and adjusted until the blood pressure is well managed. It is recommended that all people with diabetes who have elevated blood pressure monitor at home. To monitor blood pressure at home, the person should be in a seated position with feet on the floor. This provides a more comprehensive picture of a person’s blood pressure and how treatment is working than just a single measurement at the doctor’s office. It is important to note that getting treatment for high blood pressure is important because antihypertensive therapy reduces ASCVD (e.g., coronary heart disease), heart failure and microvascular complications.5
Cholesterol is made by the body and found in some food. Our bodies need cholesterol—it is important to our overall health. There are two kinds of cholesterol—HDL (high-density lipoprotein or “good” cholesterol) and LDL (low-density lipoprotein or “bad” cholesterol). Cholesterol is used to build cells and produce certain hormones. Triglycerides store unused calories and provide the body with energy.
When cholesterol levels are going in the wrong direction (LDL or triglycerides high or HDL low) it is called dyslipidemia. When cholesterol levels are high (high LDL) it is known as hyperlipidemia. High triglyceride levels are known as hypertriglyceridemia. Having high LDL and triglycerides and low HDL cholesterol contributes to atherosclerosis.
There are no symptoms when a person’s cholesterol is high until it has progressed to more serious conditions such as ASCVD (e.g., coronary artery disease), heart attack, or stroke. Doctors regularly monitor a person with diabetes’ cholesterol via blood test called a lipid panel.
Treatment includes keeping blood glucose as close to the target range as possible. This may help to lower triglyceride levels. In addition, weight loss is recommended if the person is overweight or obese, increasing regular physical activity, drinking alcohol in moderation (or actually not drinking any alcohol if the triglycerides are high), eating a healthy diet including increasing fruits, vegetables and omega -3 fatty acids, and reducing intake of saturated fat and trans fats (unhealthy fats from food). Medications are also prescribed to help lower cholesterol levels. Additional medications may be prescribed by the doctor (such as aspirin) to prevent heart disease.
Atherosclerotic cardiovascular disease (ASCVD)
Atherosclerotic cardiovascular disease (ASCVD), which is defined as coronary heart disease (also known as CAD which affects the heart), cerebrovascular disease (also known as CVD which affects the brain), or peripheral arterial disease (also known as PAD which affects the legs and feet), are thought to be due to the build-up of plaque in the blood vessels, narrowing the arteries. Coronary artery disease and peripheral artery disease will be discussed in this section. Cerebrovascular disease will be discussed on the section about diabetes complications affecting the brain.
Coronary artery disease
Coronary artery disease (CAD), also known as coronary heart disease or atherosclerosis, affects the blood flow to the heart. The coronary arteries are the blood vessels that supply oxygen and blood to the heart. Plaque (e.g., a waxy substance called cholesterol) builds upon the walls of the blood vessels around the heart. This makes the inside of the blood vessels narrower and decreases blood flow to the heart. There aren’t many symptoms until this decrease in blood flow causes a heart attack, heart failure, or a heart arrhythmia. Angina, which is chest pain and discomfort, is the most common symptom of CAD.
Risk factors for coronary artery disease include genetics (especially if there is a family history of heart disease before the age of 50), being overweight or obese, lack of physical activity, unhealthy eating, smoking and stress. In addition, high blood pressure, high cholesterol and diabetes also increase a persons’ risk.5,11
Doctors that treat people with diabetes regularly monitor them for risk factors for heart disease. This includes checking blood pressure, weight and ordering blood tests—checking HbA1c, kidney function, cholesterol and triglycerides levels.
There are different tests a doctor can order including:
- Chest X-ray
- Electrocardiogram (ECG or EKG) that measures the heart’s electrical activity
- Echocardiogram (Echo) uses ultrasound to measure how thick the heart muscle is and how well the heart pumps
- Cardiac catheterization which checks the inside of the arteries for a blockage
- Coronary angiogram which monitors the flow of blood through the coronary arteries
- Coronary artery calcium scan which monitors the arteries for calcium and plaque build-up
- Stress test during which a person walks on the treadmill to see how well the heart functions when it is working hard
Depending on the extent of blockage, treatment may include medications as well as procedures. Lifestyle changes are a major part of treatment for coronary artery disease. This includes closely managing blood glucose levels, eating a healthy diet (lower sodium and fat) as recommended by a dietician, increasing physical activity, stopping smoking, managing stress, managing blood pressure, cholesterol and taking medications as prescribed.
There are programs that include supervision and education regarding these lifestyle changes, called cardiac rehabilitation programs. People are enrolled in these programs when they are treating or recovering from any heart problems (e.g., heart attack or surgery). The team of health care providers includes doctors, nurses, exercise physiologists, dieticians, physical therapists and mental health professionals for comprehensive treatment.
Peripheral artery disease
Peripheral artery disease (PAD) is plaque (cholesterol) build-up in the arteries resulting in a decrease in blood flow to the legs and feet. Risk factors for PAD include diabetes, high cholesterol, high blood pressure, smoking, age (especially older than 60 years) and atherosclerosis.
Symptoms include pain or cramping due to lack of blood flow while being physically active (e.g., walking) in the calf, thigh, buttock, or hip, which often resolves when the movement is stopped.9 Other signs can include hair loss on the legs and feet; decreased pulse in the feet (or sometimes the pulse cannot be felt); cold legs and feet; or sores on the legs or feet that don’t heal.9,10
There are several different tests the doctor orders to help diagnose peripheral artery disease including an ankle-brachial index (ABI) that measures the blood pressure in the ankles and compares it with the blood pressure in the arms at rest and then after exercise. There are also imaging tests such as ultrasound, magnetic resonance angiography (MRA) and computed tomographic (CT) angiography may be ordered.2,3
Modifiable lifestyle factors are important including keeping blood glucose as close to the target range as possible, stopping smoking, losing weight if overweight or obese, managing blood pressure and cholesterol and taking medications (such as daily aspirin) that are prescribed. Depending on how blocked the artery is, surgery may be needed to bypass the blocked artery and return blood flow. Physical activity programs to improve the ability to walk further may also be helpful.
A heart attack or myocardial infarction occurs when there is a blockage in one of the arteries. The heart muscle begins to die without enough oxygen. The longer the blood flow is blocked, the greater the damage to the heart.
Coronary artery disease is the main cause of a heart attack, so treating CAD early is critical. Other major risk factors include genetics, diabetes, high blood pressure and high cholesterol, age (the older the more risk) and lifestyle factors such as physical activity, smoking and diet.12
Symptoms include chest pain or discomfort usually on the left side or center of the chest. There also may be pain or discomfort in the arms or shoulders (often the left) as well as in the jaw, neck, or back. The person may feel weak, light-headed, or short of breath. The person (more often females) feel very tired, nauseous, or vomit. The person needs immediate medical care.
Symptoms of a heart attack need treatment immediately. The doctor will check blood pressure and order an electrocardiogram (ECG), which will show if a heart attack occurred. Blood tests will also be ordered (if there is damage to the heart from a heart attack certain proteins and enzymes will be leaked into the blood).
If a heart attack occurred, the medical team will take immediate steps to treat the condition which may include medications and/or surgery. In addition, they may order additional tests including chest X-ray, echocardiogram, coronary catheterization, or cardiac CT or MRI (all described in the section above).
Depending on the extent of damage to the heart, medications and/or more invasive surgical procedures may be needed (e.g., coronary angioplasty and stenting or coronary artery bypass surgery). In addition, keeping blood glucose closely monitored and managed is critical during this time of recovery. Taking medication to manage blood pressure and cholesterol as well as additional medication to help blood flow needs to be taken as prescribed.
Cardiac rehabilitation programs described in the CAD section above are key. They include medication, lifestyle changes (i.e., physical activity, healthy diet, stopping smoking, etc.), managing stress and emotional issues and gradual returning to normal activities. It is very important to participate in these programs as it can help to prevent complications from a heart attack as well as reducing the risks of another heart attack.
Heart failure is a progressive condition that occurs when the heart can’t pump blood well. This means the body may not get the oxygen it needs. The body tries to compensate by stretching to contract more strongly, which over time causes the heart to enlarge. The heart also pumps faster to increase the heart’s output. The body also tries to compensate by narrowing vessels to keep blood pressure up and diverting blood from less important organs and tissue. Symptoms include shortness of breath, coughing, fatigue, tiredness, feeling weak, weight gain and swelling of the feet, ankles, or legs.
Heart failure tends to be progressive; however, early treatment can help relieve symptoms and/or delay its progression. Several factors increase the risk of developing heart failure including diabetes, coronary artery disease, previous heart attack, high blood pressure, obesity, smoking, unhealthy diet (high in fats and sodium), excessive alcohol intake and not getting regular physical activity.
Doctors treating people with diabetes regularly monitor for risk factors for heart disease. This includes checking blood pressure, weight, as well as ordering blood tests—checking HbA1c, kidney function, cholesterol and triglycerides levels. Attending recommended doctor visits is important for early detection and treatment.
If a doctor suspects heart failure, additional tests will be ordered including an electrocardiogram (ECG or EKG), an echocardiogram (echo), chest x-ray and stress test may be ordered (these diagnostic tests are described above in the CAD section).
Early diagnosis and treatment are key to improve a person’s health outcomes. Intensively managing diabetes and keeping blood glucose as close to the target range as possible is also very important. Modifying lifestyles such as getting daily physical activity, limiting fluid intake as directed by the health care team, reducing sodium in the diet, as well as stopping smoking. Taking medicines regularly and monitoring symptoms every day is crucial. In addition, depending on the severity of the disease, a person may need a heart transplant or other surgeries. Devices that remove excess salt and water from the blood may be also utilized.
Prevention of Cardiovascular Complications
Although, like many things, genetics may be involved in heart complications in people with diabetes. There are many things that we can do to help prevent heart disease and/or delay its progression including:
- Keeping blood glucose as close to the target range as possible
- Getting regular physical activity
- Eating a healthy diet
- Keeping a healthy weight
- Managing blood pressure
- Managing cholesterol levels
- Managing stress levels
- Stopping to smoke
- Getting enough sleep
- Keeping up with oral hygiene (brushing and flossing every day)
- Talking to a doctor about diabetes medication(s). The newer (non-insulin) glucose-lowering medications may also help to protect the heart
Psychosocial Aspects of Cardiovascular Complications
Several psychosocial factors have been associated with the development of coronary artery disease including lack of social support, lower household income, depression and anxiety and stress at work and at home.14 These same risk factors are associated with the progression of the disease as well as health outcomes for people with CAD. Risk factors such as depression and anxiety as well as lack of social support can decrease treatment adherence including lifestyle modifications recommended (e.g., eating healthier, stopping smoking, increasing physical activity, etc.). The National Institutes of Mental Health (NIMH) reports that up to 65 percent of people with coronary artery disease have some form of depression. People with heart disease tend to have more psychological and physical issues that can impact their quality of life (QoL) than those without.15,16
Having diabetes is overwhelming enough but adding another serious health condition like coronary artery disease, heart attack, or heart failure makes daily life and coping more difficult. Diabetes complications make it even more important to address all aspects of a person’s life—including their emotional, social and resource needs. Most people have difficulty with the news of a cardiovascular condition or that the disease has gotten worse.
Treatment for cardiovascular conditions include medication(s) and/or surgical treatment as well as lifestyle modifications. Making one lifestyle change can be difficult; but making many changes such as stopping smoking, eating differently, and/or getting physical activity daily, requires some outside support and encouragement as these tasks seem daunting.
Talking to your health care team about the difficulties you are having with treatment and about how you are feeling is important so you can get the care you need. Seeing a mental health provider that has experience in treating patients dealing with diabetes complications can be helpful. Taking care of your mental health can also improve your physical health, so addressing both the medical and psychological aspects can help to improve your overall quality of life.
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