How do we assess one’s risk of having a “cardiac event?”Nearly half of all heart attack patients were considered by their doctors to have no prior elevated risk for heart disease. While we can never know what plans are in store for us, we can take steps to keep ourselves healthy and active as we age. A group of tests and health factors have been proven to help predict a person's chance of having a cardiovascular event such as a heart attack or stroke. Perhaps the most important indicators for cardiac risk are those of a person's personal health history. These include:
- Exercise, physical activity
- Family history
- Smoking status
- Blood pressure
- History of prior cardiovascular events
The lipid profile (i.e. “cholesterol test”) is an important screening test blood test for cardiac risk assessment.
The basic lipid profile has long been used to help determine an individual's risk of heart disease and to help make decisions about what treatment may be best if borderline or high risk is determined. The results of the lipid profile are considered along with other known risk factors for heart disease to develop a plan for treatment and follow-up.
Depending on the results and other risk factors, treatment options may involve lifestyle changes such as diet and exercise, appropriate directed nutritional interventions, herbal medicine, or various directed medications to lower cholesterol, blood pressure, inflammation, insulin levels, or risk of clotting.
The basic lipid profile measures cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-C, so called "good" cholesterol) as well as calculates low density lipoprotein cholesterol (LDL-C, so called "bad" cholesterol). Triglycerides are a form of fat and a major source of energy for the body. Below are the desirable ranges for the components of the lipid profile:
- Cholesterol <200 mg/dL (5.18 mmol/L)
- HDL-cholesterol > 40 mg/dL (1.04 mmol/L)
- LDL-cholesterol <100 mg/dL* (2.59 mmol/L)
- Triglycerides <150 mg/dL (1.70 mmol/L)
Some other information may be reported as part of the lipid profile. These parameters are calculated from the results of the tests identified above.
- Non-HDL-C — calculated by subtracting the HDL-C result from the total cholesterol result; this is considered to be the portion of cholesterol that is most likely to lead to hardening of the arteries (atherosclerosis).
- Very low-density lipoprotein cholesterol (VLDL-C) — calculated by dividing the triglyceride value by 5; there is growing evidence that VLDL-C plays an important role in the process that leads to the formation of plaques in arteries.
- Cholesterol/HDL ratio — calculated by dividing the HDL-C result into the total cholesterol result; a higher ratio indicates a higher risk of heart disease while a lower ratio indicates a lower risk.
Recent studies have suggested that the conventional lipid profile alone may not provide enough information to accurately assess ones risk of a cardiac event. As more research is coming out, we are beginning to understand the role several other testable factors play in cardiovascular disease risk. Some additional factors to consider include:
· Lipid particle size
· Elevated levels of homocysteine
· Fibrinogen level (involved in clotting)
· Insulin level (involved in sugar metabolism)
· The degree of inflammation present in the body
· Vitamin D level
· Omega -3 and -6 fatty acids status
· Genetic predisposition
Advanced Cardiovascular Testing
In our clinic, we have begun using a basic lipid profile as a screening tool along with family history and lifestyle factors to assess “risk” of a cardiac event. If there are abnormalities noted in the basic lipid profile, we strongly recommend follow-up evaluation utilizing more comprehensive testing to assess for some of the additional risk factors noted above.
Cardiac IQ from Berkeley Heart Lab
The Berkeley labs series of cardiovascular tests (Cardiac IQ) is a more advanced and comprehensive set of blood tests that evaluate multiple risk factors of cardiovascular disease. We recommend these tests particularly for those patients who have “borderline” or elevated cholesterol numbers on their basic lipid panel. Gathering more complete information helps us to more accurately and effectively target treatment toward the problem area(s), and hopefully reach a goal of lowering the risk of a cardiac event.
Our basic Cardio IQ panel includes:
· Conventional lipid measurements (mainly for comparison to prior lab results).
· Lipid subclasses (fractionation by particle size). Smaller particles tend to be more atherogenic, meaning they can cause plaque build-up faster than larger particles.
· ApoB –LDL particle number, which is a numerical assessment of how many “non-helpful” lipid particles are present. The ApoB is largely influenced by diet and exercise.
· Inflammatory markers Lp-PLA2 and high sensitivity C-reactive protein, which are both closely linked with vascular inflammation. It is thought that high levels of these markers indicate the lipid particles will become more “sticky” and likely to form into a plaque within vessel walls. When these markers are elevated and blood pressure is high, stroke risk significantly increases.
· Lp(a), a genetic marker which if elevated suggests diet and exercise will have a limited effect.
Our expanded Cardio IQ panel for those with elevated risk factors includes all of the above tests plus:
· Homocysteine. High levels result in injury to blood vessel walls and are associated with low folate or poor folate metabolism.
· Fibrinogen which is involved in clotting. When elevated there is a high risk of abnormal clot formation.
· Insulin involved in glucose (blood sugar) regulation
· Vitamin D level
Multiple genetic tests are becoming available, but the research is somewhat unclear regarding the clinical usefulness of many of these tests at this time. In some cases it can be very helpful to identify genetic metabolic errors, as when these errors are discovered we may be able to supplement specific nutrients the body is unable to manufacture on its own, or help the body eliminate “build-up” of undesirable substances that would normally be easily excreted because of a faulty biochemical pathway. The build-up of harmful homocysteine is an example of a faulty biochemical pathway.
There are many nutritional and lifestyle interventions we may employ once we fully understand individual cardiovascular risk and whether intervention is even warranted. Understanding a broader spectrum of risk helps specifically target treatment toward a particular risk factor, rather than suggesting nutrients, herbs, or other treatments because they are “known to be good for heart heath.” As a rule, we do not treat numbers found in labs, but the whole patient, taking into consideration as part of the picture what is revealed in laboratory studies along with understanding the environment in which each patient lives.