Test may be better gauge of heart attack risk

A growing number of patients should consider blood tests that go beyond the standard cholesterol numbers to gauge their risk for heart disease, an expert panel says.

Patients considered at intermediate risk for heart disease, perhaps the majority of the population, should be tested for C-reactive protein, a panel of specialists concluded in the current Journal of Clinical Lipidology.

Total cholesterol, LDL and HDL do not do as well predicting heart attack and stroke risk in patients with diabetes or metabolic syndrome, especially if those patients are already taking a cholesterol-lowering statin medication, said Dr. Michael H. Davidson, who headed the 17-member panel.

“We wanted to give guidance. This is a common problem,” added Davidson, director of Preventive Cardiology at the University of Chicago Pritzker School of Medicine.

The problem is becoming more common as the prevalence of obesity, diabetes and metabolic syndrome increases. Metabolic syndrome is a combination of symptoms that can include abdominal obesity, low HDL (good cholesterol), high blood pressure, insulin resistance and inflammation.

“When a person walks into the office stomach first, that’s intermediate risk,” Davidson said. “Intermediate risk is the bulk of the population and we’re not sure what to do in many of those patients.”

Family history, lifestyle choices such as diet and exercise and whether a patient smokes also may be factors whether someone is considered intermediate risk.

Standard measures miss about 30% of patients who will develop cardiovascular disease, Davidson added.

The C-reactive protein (CRP) level is considered a marker for inflammation. CRP is associated with plaques in the blood vessels.  Plaque can narrow the blood vessels in coronary arteries and cause chest pain. They can also rupture and cause heart attacks and strokes.

The Women’s Health Study found C-reactive protein was better at predicting coronary events like heart attack than LDL, the bad cholesterol; HDL, the good cholesterol; total cholesterol; or a ratio between total and good cholesterol.

Another large-scale trial showed high C-reactive protein levels were able to identify risk of future heart disease in patients who had low LDL.

“Because traditional risk scoring and routine cholesterol screenings miss a significant percentage of patients at risk for events, consideration might be given to routine inclusion of CRP,” the task force wrote in the article.

In additional to coming out in favor of CRP, the expert panel said it would be “reasonable for many [intermediate risk] patients” to have a blood test measuring the number of LDL particles - in addition to the standard LDL cholesterol level.

LDL particles carry cholesterol to the blood vessels, but the amount of cholesterol each particle carries varies. A higher LDL particle number is associated with more plaque buildup.

Patients with a high LDL particle number are candidates for cholesterol-lowering statin drugs even if their standard LDL number is normal, the panel concluded.

The advice of the panel of lipidologists goes beyond what the American Heart Association recommends.

An American College of Cardiology Foundation/American Heart Association task force did not recommend any tests other than the traditional cholesterol in patients under 50 who did not have symptoms.

But this task force said CRP tests were “reasonable” in men over 50 and women over 60 and “may be considered” in younger men and women who were at intermediate risk.

Davidson said the panel’s opinions on assessing the risk of heart disease were the result of six months of work, but they do not constitute official guidelines. He added that the panel’s conclusions were based on the best evidence available, and he hopes they will prompt more research looking at how well these tests predict outcomes.