DIABETES AND CIRCULATORY PROBLEMS
People with diabetes,
especially those with type 2 diabetes, are two to fi ve times more likely to have problems with circulation to
the heart, the legs, and the head when compared to individuals without diabetes. This is because diabetes
predisposes a person to a condition called atherosclerosis. If you imagine a blood vessel as a water or
drainage pipe, then atherosclerosis is buildup in the pipe narrowing the channel and impairing the flow. In the
case of the blood vessel the buildup, called plaque, consists of a core of inflammatory cells, cholesterol, and
lipids with a fibrous cap of smooth muscle cells. The plaque can narrow the blood vessel, impairing blood flow.
Occasionally the fibrous cap can rupture, and when this happens a blood clot forms, causing an acute blockage of
the blood vessel. If the acute blockage happens in one of the blood vessels to the heart, it results in a heart
attack. If it occurs in one of the blood vessels supplying brain tissue, it results in a stroke.
What is it about diabetes that
predisposes a person to atherosclerosis? First, having high glucose levels for long periods can injure the cells
lining the blood vessels, initiating the plaque buildup. Second, the high blood pressure and the elevated lipids
frequently present in people with diabetes are known risk factors for plaque buildup. There are also other less
well understood factors such as blood clotting factors and platelet function that are also altered in people
with diabetes.
Even though people with type 1
diabetes generally do not have high blood pressure and high cholesterol problems, they can develop heart
disease after many years. This is especially likely to occur if they have diabetic kidney
disease.
Diabetes and the
Heart
Diabetes affects the heart in a number of different ways. Atherosclerosis of the coronary
arteries (coronary artery disease) can limit the delivery of nutrients to the heart muscle. When this occurs you
can develop chest pain with exercise (angina). If there is acute blockage then this is referred to as a heart
attack or myocardial infarction.
Heart
failure is more common in
people with diabetes. Many times it occurs because of heart muscle damage following a heart attack.
Long-standing high blood pressure associated with diabetes is also an important cause. It is now also
recognized that high glucose levels themselves damage the heart muscles. People with heart failure feel tired,
short of breath at rest and/ or on exertion, and have leg swelling.
It is therefore important to have a physical checkup to rule out heart disease before you
begin an exercise program.
Diabetes and
Brain Circulation
Interruptions of blood supply to the brain due to atherosclerosis can lead to transient or
permanent neurological abnormalities—referred to as a transient ischemic attack (TIA) or stroke. Older people
with diabetes have an increased risk of memory problems, and it is thought that in at least some of them, this
is a result of small strokes.
Diabetes and
Circulation to the Legs
When there is atherosclerosis in the blood vessels supplying the leg, the decrease in the
blood flow can lead to cramps and pain (typically in the calves) when exercising. This is called intermittent
claudication, and the pain is relieved by rest. If the blood supply is severely impaired, there is pain even at
rest. Eventually, the lack of blood flow can cause tissue death, especially of the toes (gangrene). Cigarette
smokers are particularly at risk.
Prevention of Circulatory
Problems
Circulatory problems, especially heart disease, are the major cause of premature death in
people with diabetes, and prevention of these problems is a central goal in the treatment of diabetes. You can
take a number of steps to reduce your risk of heart disease and circulatory
problems:
-
Improve glucose control.
-
Lower blood pressure.
-
Take aspirin. Clinical studies show that aspirin reduces the risk of heart attacks
and stroke. Aspirin works by making platelets (the cells in the blood that are responsible for blood
clotting) less sticky. Recent studies indicate that lower doses are just as effective as higher doses,
so low-dose aspirin therapy (a 75–81 mg dose once a day) is recommended if you already have heart
disease or circulatory problems. If you cannot tolerate aspirin because of allergic reaction or
another reason, your doctor may prescribe a medicine called clopidogrel (Plavix), which also makes the
platelets less sticky. Individuals with type 1 and 2 diabetes without heart disease or circulatory
problems should also take low-dose aspirin therapy if they have a strong family history of heart
disease; if they have kidney damage, high blood pressure, or lipid problems; if they are smokers; or if
they are older than forty years.
-
Stop smoking. Smoking increases the risk of both macrovascular and microvascular
damage in people with diabetes.
-
Improve your lipid profi le. People with type 2 diabetes frequently have abnormalities
of their lipid profile—a collective term for cholesterol, triglycerides, HDL cholesterol, and LDL
cholesterol levels. Almost all people with type 2 diabetes and many with type 1 diabetes need to take
medicines for the lipid abnormalities.
In people with diabetes, the levels of triglycerides are frequently too high and the levels of
HDL are too low. In addition, people with diabetes tend to have a form of LDL particles called small, dense LDL,
which can abnormally collect in the blood vessel walls and cause atherosclerosis. Research has shown that
correcting these lipid abnormalities in people with diabetes reduces the development of atherosclerosis. The
goals of treatment are to
-
Lower the LDL cholesterol to at least below 100 mg/dl but ideally to 60 to 70
mg/dl
-
Lower the triglyceride level to below 150 mg/dl
-
Raise the HDL cholesterol to more than 40 mg/dl in men, and to more than 50 mg/dl in
women
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