Chemical Biomarkers: Identifying the Heart of the Matter

Cardiovascular disease, including stroke, is the number one killer in the United States today. February is American Heart Month, during which time awareness of heart disease is heightened. The intention of this is to raise funds for research and education and share current information about heart disease and stroke.

In honoring this trend, RN.com brings you a Clinical Flash on Chemical biomarkers for cardiovascular disease.
Chemical biomarkers are abnormal chemicals found in the blood that are useful in flagging a condition or indicating how a disease is progressing. With cardiac disease, physicians generally look at several biomarkers to identify the disease and its progression. Patients with higher than normal levels of one or more key biomarkers have been shown to have a far higher risk of developing congestive heart failure or of dying from heart disease than do individuals whose levels are normal.

An important biomarker for cardiac disease today is BNP (B-type natriuretic peptide). When heart failure occurs or worsens, the ventricles produce a substance that breaks down to form two proteins: B-type natriuretic peptide (BNP) and N-terminal-pro-BNP (NT-pro-BNP). Both BNP and NT-pro-BNP are secreted into the bloodstream, and their levels rise when heart failure symptoms worsen and fall when symptoms improve.

In recent tests, patients who had an elevated level of either protein had a higher risk of death and illness from heart failure. BNP and NT-pro-BNP help determine if the patient has heart failure rather than another condition that may cause similar symptoms. These proteins can also help determine if the cardiac disease has worsened, and more aggressive treatments are needed. Which test is ordered (BNP or NT-pro-BNP) depends on what is available at the particular laboratory. Both tests have been shown to be beneficial.

Another important biomarker of interest in cardiovascular disease is the Lipoprotein Profile. The American Heart Association recommends that everyone age 20 and older have a fasting "lipoprotein profile" every five years. This test identifies total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides levels.

A total cholesterol level of less than 200 mg/Dl is desirable to maintain a lower risk for cardiovascular disease. A HDL (good cholesterol) level of more than 40 mg/dL for men and more than 50 mg/dL for women is desirable. A LDL (bad cholesterol) level of more than 100 mg/dL would be a biomarker for heart disease. Triglyceride levels should be less than less than 150 mg/dL A high triglyceride level combined with low HDL cholesterol or high LDL cholesterol seems to speed up atherosclerosis which increases the risk for heart attack and stroke.

Elevated cardiac enzymes and the presence of C-reactive protein (CRP) are additional important biomarkers for cardiac disease. Cardiac enzymes include: creatine kinase (CK), creatine phosphokinase (CPK), lactic dehydrogenase (LD or LDH), troponin, and myoglobin. The presence of C-reactive protein indicates the presence of inflammation problems.

For additional resources for healthcare professionals, visit the American Heart Association at: http://www.americanheart.org/