Cardiac Risk Factor Laboratory Assessment Client information:
Southwest Preventive Health knows that risk factor modification can save lives. We have put together some information for you to understand and interpret your labs.
Understanding Cholesterol
Cholesterol is not as bad as it is made out to be and actually serves many important functions in the human body. Cholesterol makes up our cell membranes, the lining around our nerves and is the building block for many of our hormones like testosterone and estrogen.
If you have high cholesterol, this does put you into a certain risk category but it does not specify who in this specific group will develop atherosclerosis or have a heart attack. At Southwest Heart and Southwest Preventive Health we feel we can individualize your care by utilizing the only electron beam CT in Tucson. This technology is the only FDA approved device to track calcified cholesterol deposits in the heart arteries and can determine if you are the type that lays down plaque or not.
Cholesterol cannot dissolve in the blood and it is transported to and from the liver by carrier proteins called lipoproteins. There are good carriers (HDL: high density lipoprotein) and bad ones (LDL: low density lipoprotein). High serum cholesterol is a risk factor for heart disease (although not the most important). Cholesterol is what forms the plaque that causes atherosclerosis
Elevated cholesterol can be lowered by adhering to a diet low in refined carbohydrates as well as minimizing the intake of the bad fats like saturated fats (whole dairy products or fatty red meat and deep fried foods and the trans-fats (all the hydrogenated and partially hydrogenated oils found in so many of our foods). In addition, we must eat the healthy fats (Omega 3 fatty acids) found in olive oil, flax seed oil, nuts and seeds, avocado, or cold water fish (like Salmon or sardines) as some examples. This should also be combined with a regular exercise program. However, many people have elevated cholesterol despite a healthy diet and regular exercise, in this case it can be difficult to discern if you need aggressive treatment. Again, this is one of the strengths of utilizing the electron beam CT scanner. Many people with high cholesterol do not lay down plaque and can work through diet and exercise and avoid medication, whereas others with low cholesterol may have aggressive atherosclerotic disease and need medication. If you have known heart disease, or evidence that you are laying down atherosclerotic plaque more aggressively by the electron beam CT scan, the research has convincingly shown that medication (specifically statins like lipitor or zocor to name a few) can actually slow or even sometimes reverse atherosclerotic heart disease and the risk of heart attack.
Total Cholesterol:
National guidelines say total cholesterol should not be above 200. However, the data shows that total cholesterol does not predict heart attack risk. In fact, 80% of people who had heart attacks in the landmark Framingham heart study had identical total cholesterol levels to those who did not. Again, we feel we can prognosticate and individualize your risk for heart disease utilizing our electron beam CT as well as exploring the subclass patterns of your “healthy” (HDL) and “lousy” (LDL) cholesterol.
National guidelines (NCEP III) currently define:
- Desirable total cholesterol: Below 200 mg/dl
- Borderline high risk total cholesterol 200-239 mg/dl
- High risk total cholesterol: greater than 240 mg/dl
HDL (high density lipoprotein) cholesterol or “healthy cholesterol” should be above 40 for men and above 50 for women. HDL carries cholesterol from the arteries back to the liver. The average for a man is roughly 45 and for a woman, 55. Smoking, a sedentary lifestyle, and being overweight can all contribute to a low HDL. Ways to raise your healthy cholesterol include nutritional intervention by limiting refined carbohydrate and unhealthy fats (saturated and trans fats), eating the healthy fats, whole grains, fruits and vegetables combined with a sound exercise program. In addition, there are some medications that will raise your HDL. A low HDL cholesterol may also be a signal of insulin resistance (pre-diabetes) especially if your triglycerides are elevated. It is also important to know the subclasses of HDL like if you have the more protective HDL2 or less protective HDL3 pattern. We can determine this with the Vertical Automated Profile (VAP) lab work.
LDL cholesterol: “Lousy cholesterol” should not be above 130 according to national guidelines. However, if you have heart disease or diabetes national guidelines suggest LDL should be 100. The LDL is what deposits in arteries that are inflamed or damaged forming the plaque. LDL cholesterol can be attacked by free radical oxygen species and can be oxidized which can damage the artery further and set up many other reactions that lead to further damage. Again, there are people who have high LDL cholesterol but have no evidence of calcified cholesterol deposits on the electron beam CT (link to heart scan). Therefore, more conservative measures can be used to improve it and medication may be able to be avoided. At Southwest Heart and Southwest Preventive Health we can check the subclass patterns of LDL. In this way we know if you have the smaller more atherogenic LDL particles (type B) or the larger, more buoyant, more protective LDL (type A).
LDL cholesterol guidelines according to the current National guidelines (NCEP III)
- Desirable: Below 130 mg/dl
- Borderline high risk: 130-159 mg/dl
- High Risk: Above 160 mg/dl
Triglycerides are the fats in the bloodstream and come mostly from the simple carbohydrates you eat. The level should be below 150 and optimal is below 100. A level above 200 mg/dl for triglycerides associated with a low HDL cholesterol (below 35 mg/dl) can mean insulin resistance which is a precursor to adult onset diabetes. There are roughly 90 million Americans with insulin resistance, and increases your risk of obesity and coronary disease four-fold. This is why sticking to a good diet outlined in the book Eat, Drink and Be Healthy by Dr. Willett can improve your numbers. There are some people that need medication for high triglycerides.
Additional important laboratory tests for heart disease
Homocysteine:
Kilmer McCully discovered that people with high homocysteine had an elevated risk for having a heart attack. In fact, in the physicians’ health study, high homocysteine tripled the chances of having a heart attack. Homocysteine can cause damage to the arterial wall lining. Homocysteine levels are high often because of a lack of B vitamins in the body, especially folate, B6, and B12. Treatment therefore includes at least 400mcg-800mcg of folate, 1.5-2 mg of B6, and 6-10 mcg of B12.
C Reactive Protein: CRP- highly sensitive type.
HS-CRP is a marker of inflammation. It is a very sensitive, but not specific marker. Therefore, inflammation can be located in other areas of the body and not be a reflection of inflammation in the heart. For instance, arthritis may give you an elevated CRP as well. A high HS-CRP creates
inflammation facilitating plaque formation and rupture, especially if combined with high cholesterol or if you have a advanced percentile of calcified cholesterol deposits on the electron beam heart scan. Treatment includes medication that lowers your cholesterol and dietary changes to decrease the overall inflammatory response of the immune system.
Lp(a): Lipoprotein “little a”:
This tends to run high in families. Lp(a) directs cholesterol to an inflamed artery. It also prevents clots from dissolving thus promoting blood clot formation leading to heart attacks. Again, if you have evidence of plaque on the electron beam heart scan, treatment of a high LP(a) includes the use of niacin usually about 1 to 2 grams (1000 to 2000 mg) a day. Also, an elevated LP(a) would lead a doctor to treat your LDL “lousy” cholesterol more aggressively. The most common side effects of niacin are flushing in the face and liver function tests have to be checked regularly.
Fibrinogen:
Fibrinogen causes clots to form and is also a marker for inflammation. Fibrinogen tends to run high in those people who develop early atherosclerosis. It can be lowered with the omega 3 fatty acids supplements like fish oil or flax seed oil usually 4-6 grams per day.
Hemoglobin A1C:
This is a marker of glucose sticking to your red blood cells if your serum sugar level has been elevated over the last 60-90 days. It is thus a marker of insulin resistance and or adult onset diabetes. It appears, the higher your HgA1c the higher your risk of cardiovascular disease, ischemic heart disease and even non-cardiovascular death. Diabetics usually have an HgA1c above 6.5, however a recent study in the British Medical Journal suggests a HgA1c above 5 increases risk heart disease and death.
| HgA1Cc | HgA1c | HgA1c | HgA1c | |
| Cause of Death | <5 (n=1204) | <5-5.4 (n=1506) | 5.5-6.9(n=1611) | >7 (n=81) |
|---|---|---|---|---|
| All Cases (n=135) Age-adjusted rate/100 (No. of events) | 1.65 (18) | 2.33 (35) | 3.43 (61) | 4.34 (5) |
| Relative Risk | 1.00 | 1.41 | 2.07 | 2.64 |
| Cardiovascular disease (n=60) | .50 (5) | 1.27 (19) | 1.24 (22) | 2.54 (3) |
| Relative Risk | 1.00 | 2.53 | 2.45 | 5.04 |
This data is from the British Medical Journal 2001; 322 15-18.