Until very recently, blood pressure and cholesterol levels were the only measurements taken to help determine someone's risk of heart disease. While these are still considered standard tests to predict a patient's heart attack or stroke risk, physicians have learned that many people with heart disease have normal cholesterol and blood pressure. Realizing this, other indicators of heart disease have been studied and new tests are being developed to better predict who may suffer from heart disease.

One of the newer tests measures levels of high-sensitivity C-reactive protein (hs-CRP). Studies have shown that hs-CRP is associated with inflammation in the bloodstream and high levels may indicate higher risk of heart disease. Statins may lower hs-CRP, but currently there are no studies to indicate that lowering hs-CRP changes the risk of developing heart disease. University of Maryland is participating in a large trial to help answer that question. hs-CRP is elevated by obesity, metabolic syndrome (a cluster of risk factors including low HDL cholesterol, high triglycerides, high blood pressure, central obesity [waist > 40 inches in men or > 35 inches in women], impaired glucose [> 100], or the presence of small, dense LDL).

Having any 3 of these factors indicates metabolic syndrome, also known as Syndrome X or pre-diabetes. Other factors that increase hs-CRP are inflammatory conditions such as arthritis, asthma or illnesses. A hs-CRP less than 1 is considered low risk. A hs-CRP > 3 and < 10 is considered high risk of developing heart disease. A hs-CRP > 10 is likely due to another inflammatory condition.

Another new blood test is the PLAC blood test. This test measures an enzyme in the blood called lipoprotein-associated phospholipase A2 (Lp-PLA2). The enzyme measured in the PLAC test is thought to be related to plaque in the arteries that can build up and cause heart problems. Like the test for CRP, the PLAC test can help determine who is at greater risk for heart disease. Someone with high levels of CRP or PLA2 may be at higher risk for heart disease, even if cholesterol levels are normal. As with hs-CRP, there are no randomized clinical trials to suggest that lowering PLAC will decrease the risk of heart disease.

There are several other tests that help determine risk of developing heart disease. These include measurements of lipoprotein particles. There are ample clinical trials with statistically significant evidence that changing LDL particle size from small, dense to large "fluffy" does reduce the risk of heart disease. The size of the LDL can be measured directly with one of three commercially available tests (VAP, NMR, or Berkeley HeartLabs) or indirectly through laboratory tests called Apo-B. Similarly, the size of the HDL cholesterol can be measured. Small HDL are not beneficial. One can have an adequate "total" HDL (> 40) but still not have the protection unless the HDL is large, called HDL2.

Lipoprotein (a) is another cholesterol abnormality that may suggest higher risk of heart and vascular disease. This is a chromosomal abnormality that is inherited by 50 percent of the offspring of a parent with the disorder. Generally, this is tested once to determine its presence. If one does not have it upon testing, they will never develop the disorder. If one does have elevations in lipoprotein (a), it can be treated with prescription medications. Lipoprotein (a) is more likely to cause plaquing in arteries than large LDL. This disorder can easily be determined through blood testing.

One more test that can be measured is homocysteine. This is a byproduct of protein metabolism. When elevated, homocysteine is very inflammatory to the artery lining. Elevations are associated with increased blood clotting and heart attacks. It is treated with vitamins and prescription strength folic acid. Talk with a physician to find out more about these tests and to learn more about your risk for heart disease.