Heart disease: an introduction
Heart disease and related disease of the blood vessels that feed the heart are common complications associated with type 2 diabetes. These refer to several different diseases that affect the heart muscle and the cardiovascular system. One of the most common forms of heart disease associated with diabetes is coronary heart disease (CHD) (also called coronary artery disease [CAD]), in which the arteries that provide oxygen to the heart (the coronary arteries) become blocked. Other types of heart disease include conditions involving the valves of the heart, the electrical system that keeps the heart beating steadily, and the weakening of the heart muscle.
People with diabetes face a significantly increased risk for heart disease, particularly CHD in which the coronary arteries become blocked, interfering with the ability of heart to do its job. CHD can begin in anyone early in life as low-density lipoprotein (LDL) cholesterol is deposited on the inner surface of the artery wall. These fatty deposits are called plaques. Gradually, the inner walls of the arteries thicken and narrow, reducing the blood flow to the heart muscle.1
Diabetes is equivalent to CHD in terms of increased heart risk
The US National Cholesterol Education Program has concluded that type 2 diabetes significantly increases your risk for death from heart attack, as much as if you had heart disease. That is, even if you don’t have heart disease, if you have type 2 diabetes and you are in your late 50s, you stand the same chance of having a heart attack (myocardial infarction [MI]) as someone in the same age range with heart disease who has already had an MI.2,3
These statistics are scary. But if you have type 2 diabetes you can use these scary numbers as a motivation to make heart-healthy choices in your life, and decrease your risk for developing heart problems.2
What are the risk factors for heart disease?
If you have type 2 diabetes, you are at increased risk for heart disease. This is due, in part, to the disease process that goes on with type 2 diabetes when it is uncontrolled. If your diabetes is uncontrolled, changes occur in your body make it more likely that you will have both hypertension and a lipid disorder (such as elevated LDL cholesterol, elevated triglycerides, or decreased high-density lipoprotein [HDL] cholesterol).
Additionally, high blood sugar (also called hyperglycemia), which is the hallmark diabetes when it is not controlled, has been shown to increase risk for cardiovascular events, such as MI or stroke. In fact, one study found that for every percentage point increase in hemoglobin A1C, one of the most accurate tests for measuring blood sugar control over the previous 2 to 3 months, the risk for experiencing any cardiovascular event (such as an MI or stroke) went up by 18%. This underscores the importance of controlling your blood sugar if you have diabetes.2
The good news about risk factors for heart disease is that for most of them, you can take powerful steps to reduce your risk, either by making healthy lifestyle changes or taking medications (such as a statin to lower LDL cholesterol or an antihypertensive agent to lower blood pressure).
If you have diabetes, the heart disease risk factors that you need to be concerned about include2:
- Your specific lipid profile (levels of LDL and HDL cholesterol and triglycerides)
- High blood sugar
- Lack of regular exercise
- Consumption of too much alcohol (for men, more than 2 drinks per day (2 12 oz beers, 10 oz wine, or 3 oz 80-proof whiskey), and for women and lighter-weight men, more than 1 drink per day)
In addition to these factors, others that increase risk for heart disease include our gender (women have higher risk than men, which decreases somewhat after age 60), family history, high homocysteine levels (a chemical found in our blood), and abnormal kidney function.2
What are the symptoms of heart disease?
A common form of heart disease results when the arteries that provide blood to the heart muscle (these are called the coronary arteries) get blocked. When blockage becomes severe, this results in a feeling of pressure or pain in the chest that can extend down the left arm and even up to the neck, shoulder, and jaw. This condition is known as angina. If you have a significant blockage in your coronary arteries, you may also experience other symptoms, including a clammy or sweaty feeling, shortness of breath (called dyspnea), and nausea. Angina may also involve back pain, upper abdominal pain (like the pain we get when we have indigestion), fatigue, a tingling sensation in either arm or shoulder, an irregular or rapid heart beat, fainting (called syncope), dizziness. These symptoms may come and go and may be triggered by exercise (when we put stress on the heart muscle). Because diabetes can affect the way our nervous system normally works, people with diabetes can sometimes have heart disease, with angina, but may not experience typical symptoms.4
A heart attack occurs when a coronary artery becomes completely blocked and the heart is deprived of the oxygen it needs to function. Typically what causes a heart attack is that a plaque in a coronary artery breaks open and ruptures and a blood clot forms on the ruptured plaque. When this blood clot becomes dislodged and is large enough, it can travel down the artery to the area of the heart fed by that artery. The clot blocks blood and oxygen from reaching that area. If the blockage continues more than 15 minutes, the muscle can become damaged (the technical term for this is infarcted, which means that the muscle dies from lack of oxygen). The symptoms of a heart attack are similar to those experienced with angina, but perhaps more extreme. A person having a heart attack may experience some or all of the following symptoms5:
- Pain, pressure, or discomfort in the chest
- Nausea, vomiting, burping, or heartburn
- A fast or uneven heartbeat
- Pain, tingling, or discomfort in parts of the upper body (arms, shoulders, jaw, or stomach)
- Sweating or cold, clammy skin
- Sensation of being out of breath
If you or someone you are with experiences the symptoms of a heart attack, it is important to call for help (911 for an ambulance) immediately.
How can I decrease my risk for CHD?
You can take several very powerful steps to decrease your risk for heart disease and CHD, specifically. These include:6
Stop smoking (if you smoke)
Cigarette smoking promotes a number of health problems, including heart disease. If you have diabetes and smoke, you should consider stopping. Talk with your doctor about your options for quitting smoking. There are many smoking cessation programs and some medications that you can use to help you kick the habit.
Keep in mind that quitting smoking is hard to do and often takes several attempts. You may need some help, so talk to your doctor about what you can do to kick the habit and don’t give up until you’ve succeeded!
Get and keep your blood pressure under control
Control blood pressure at or below your target level, using lifestyle modifications and/or medication. The American Diabetes Association (ADA) recommends that you keep your blood pressure below 140/80 mmHg or perhaps lower (130/80 mmHg) if you are in a certain patient group.7)
Keep your low-density lipoprotein (LDL) cholesterol and triglyceride levels under control
Keep LDL cholesterol at or below target levels, using lifestyle modifications and/or medications (specifically statins). LDL cholesterol level should generally be below 100 mg/dL and in some cases below 70 to 80 mg/dL. Talk to your doctor about what your lipid targets should be as they can depend on underlying illnesses or health conditions.8
Consider taking aspirin
Daily low-dose aspirin (75-162 mg per day) is recommended for some people with type 2 diabetes who are at risk of cardiovascular disease. Daily low-dose aspirin is recommended by the ADA for people with type 2 diabetes who are at increased risk for cardiovascular disease, including most men over the age of 50 years and women over the age of 60 years who have at least one additional major risk factor for cardiovascular disease (family history of cardiovascular disease, high blood pressure, smoking, abnormal lipids, or albuminuira).
Get and keep your blood sugar under control
It is necessary to keep your blood sugar under control to prevent many of the complications of diabetes, heart disease included. For many people, this will involve monitoring your blood sugar and checking it with a blood glucose meter. For most people, the target before a meal is 70 to 130 mg/dL. Make sure you check with your doctor to determine your target blood sugar level, as it can vary from person to person depending on individual factors.7
Get regular moderate exercise
Regular exercise can help you lower your risk for heart disease and can benefit you in many other ways if you have diabetes. Talk to your doctor before you start an exercise program.
If you are overweight or obese, lose weight and keep it off
Try to lose 5% to 10% from your starting weight and keep as much of this weight off as possible.
Moderate your consumption of alcohol
If you have diabetes, you should limit your consumption of alcohol to no more than 2 drinks per day (2 12 oz beers, 10 oz wine, or 3 oz 80-proof whiskey) for men and no more than 1 drink per day for women and ligher-weight men.9
Are there tests for CHD?
Your doctor can usually determine whether you have CHD by finding out what symptoms you are experiencing, conducting a physical exam, and using a test that measures the function of your heart. These tests include an electrocardiogram (ECG), a stress test, an echocardiogram, and an invasive procedure called cardiac catheterization. An ECG involves putting electrical leads on your chest to check the electrical activity of your heart. An echocardiogram involves using sound waves to create an image of your heart as it beats. A stress test involves measuring heart function (using ultrasound or echocardiogram) while the physical demand on your heart is increased (making your heart pump faster) using exercise or medication. Cardiac catheterization involves placing a thin tube into a blood vessel (in a leg or arm), moving it to the heart, then injecting a dye through the tube that makes blockages in arteries visible on x-ray5
How is CHD treated?
CHD is typically treated with the lifestyle changes and medications listed above under preventing CHD. In addition, there are several medications that are effective at relieving the pain caused by angina, including nitrates and beta blockers. Some people with significant CHD may be candidates for invasive procedures including angioplasty (this involves placing a stent in a coronary artery to open a blockage and stabilize an area of plaque formation) or bypass surgery, where blood vessels from other places in the body are used to bypass blocked arteries in the heart.5
What is congestive heart failure?
Congestive heart failure (CHF) is a type of heart disease that is common in people with diabetes. It occurs when the heart muscle becomes weakened for a variety of reasons, including the effects of being overweight, consuming too much alcohol, or an infection, coronary artery blockage, damage to the heart from previous heart attacks, or leaks in heart valves. These factors can contribute to making the heart unable to pump efficiently. The symptoms of CHF include shortness of breath (both at rest and during exertion) and waking at night due to breathing difficulty, swelling or weight gain, particularly in the abdomen and/or ankles and feet, and heart palpitations. Similar to CHD, your doctor will use a physical exam and reported symptoms, as well as testing (ECG, chest x-ray, echocardiogram).10
How is CHF treated?
CHF is typically treated using the lifestyle modifications discussed above under CHD, including decreased consumption of sodium and fluids. In addition, there are a variety of medications that are often used to improve the symptoms of CHF, including diuretics, angiotensin-converting enzyme (ACE) inhibitors or angiotensin 2 receptor blockers (ARBs), beta blockers, and blood thinners (eg, warfarin [Coumadin]).10