Macrovascular complications are the complications involving the large blood vessels of the body, particularly the coronary arteries in the heart. In this section, I discuss how diabetes can lead to damage to the heart by causing blockage of these arteries.
Heart disease and heart attacks are the major macrovascular complications found in people with T1DM. How does heart disease lead to a heart attack? Coronary artery disease (CAD), which is also known as atherosclerotic heart disease, is the progressive closure of the arteries that supply blood to the heart muscle. (To understand how coronary artery disease develops, see the later sidebar "Picturing a plaque.") When one or more of your heart arteries close completely, the result is a heart attack (or myocardial infarction).
People with diabetes have more CAD than people without diabetes. When X-ray studies of the blood vessels of the heart are compared, people with diabetes have more arteries of the heart involved with CAD than non-diabetics. The incidence of CAD is increased even in young patients with T1DM. The duration of diabetes promotes CAD in type 1 patients, and CAD affects males and females with T1DM to the same extent.
People with diabetes often are unaware of heart pain because of cardiac neuropathy (I explain general neuropathy earlier in this chapter). Assuming that they don't have cardiac neuropathy, the symptoms are chest pain, pain down the left arm, and shortness of breath along with sweating. If a heart attack occurs, the risk of death is much greater for the person with diabetes. More than half of all people with diabetes die of heart attacks. Even if a person with T1DM survives a heart attack, he faces more complications, such as shock and heart failure, than the person without diabetes, and the outlook is much worse for him. A second heart attack occurs in 50 percent of diabetics compared with 25 percent of non-diabetics, and the death rate in five years is 80 percent compared with 25 percent for non-diabetics.
CAD is found in the arteries of people with T1DM who die of other causes as young as age 20 or even younger, and it's extensive in older people with T1DM who die of other causes. However, it's not found in everyone. Those folks with T1DM who don't have other risk factors, such as uncontrolled high blood pressure, cigarette smoking, a sedentary lifestyle, and high cholesterol levels, rarely have problems with coronary artery disease. A family history of coronary artery disease is another risk factor and one that you can do nothing about, but its effect is minimized when the other risk factors are avoided or controlled.
The picture is not a pretty one for the person with diabetes who has coronary artery disease. The treatment options are the same as for non-diabetics.
1 Therapy to dissolve the blood clot obstructing the coronary artery (called percutaneous transluminal coronary angioplasty, or PTCA) can be used, but people with diabetes don't do as well with this form of treatment as non-diabetics because they may have many separate lesions in the artery. PTCA also can't be performed when an artery is completely closed.
1 The other option is the use of a coronary artery bypass graft (CABG), in which a blood vessel is attached above and below the obstructed artery, thereby bypassing the obstruction. The long-term prognosis for keeping the graft open isn't as good in people with diabetes as in non-diabetics because the diabetes leads to increased promotion of atherosclerosis. The complications of CABG include an acute heart attack, stroke, infection in the area of the body that undergoes surgery, and even death on the operating table. The risk of complications is especially serious in older patients (more than 70 years old) and those patients with other diseases, such as kidney disease.
Although there's no data yet in T1DM, studies have shown that lowering the LDL cholesterol and raising the HDL cholesterol (see Chapter 7) will prevent first heart attacks and decrease the occurrence of second heart attacks in the general population. Hopefully, data will soon be available that will allow a recommendation for treatment of blood fats in T1DM.
For general information about heart health, check out Heart Disease For Dummies by James M. Rippe, MD (Wiley).
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All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.