As early as 2002, a major study appearing in the New England Journal of Medicine concluded that, at least in women, an elevated blood level of C-reactive protein (CRP) is strongly predictive of future cardiovascular events (such as heart attack and stroke.) These results came from an analysis of over 20,000 blood samples taken from women enrolled in the Women's Health Study, a long-term study which enrolled and followed apparently healthy women for a number of years.
This study gave evidence that elevated CRP may be just as important as elevated LDL cholesterol levels; and that furthermore, high CRP levels may identify high-risk patients who would be "missed" by just measuring cholesterol levels. In this study, women with low CRP and low cholesterol did well; while those with high CRP and high cholesterol had very high risk. Women with either high CRP or high cholesterol also had elevated risk - indeed, those with high CRP but normal cholesterol apparently had a higher risk than those with normal CRP and high LDL cholesterol.
In other words, CRP is an independent marker of cardiovascular risk, and may be a partial explanation for why some patients develop significant coronary artery disease despite normal cholesterol levels.
CRP is a protein released into the bloodstream any time there is active inflammation in the body. (Inflammation occurs in response to infection, injury, or various conditions such as arthritis.) Evidence is accumulating that atherosclerosis (coronary artery disease) is an inflammatory process. The fact that elevated CRP levels are associated with an increased risk of heart attack tends to support the proposed relationship between inflammation and atherosclerosis.
If you do have your CRP level measured, and it turns out to be high, you and your doctor will need to assess whether this elevated CRP level indicates an increased cardiac risk in your specific case, and if it does, what you should do about it.
Ridker, PM, Nader Rifai,N, Rose L, et al. Comparison of C-Reactive Protein and Low-Density Lipoprotein Cholesterol Levels in the Prediction of First Cardiovascular Events. N Engl J Med 2002; 347:1557-1565, DOI: 10.1056/NEJMoa021993