BNP, CRP, NT-proB-NP Blood tests as markers for Cardiovascular Risks Compared to EKG, Echocardiogram

BNP, CRP, NT-proB-NP Blood tests as markers for Cardiovascular Risks

New innovations in blood markers are making the prediction of future cardiac damage or heart attacks easier. 

Some studies have shown that plasma NT-proBNP determination can improve the diagnostic capability of EKG (or ECG) for identifying Left Ventricular Hyperplasia (LVH) in hypertensive (patients with high blood pressure) patients without associated heart failure or atrial fibrillation. Furthermore, very low NT-proBNP values can be useful for planning imaging studies because they tell us that Left Ventricular Hyperplasia (LVH) is likely not present or an issue based on the chosen cut-off value. 

Still however EKG and Echocardiograms are the best initial tests to assess cardiovascular risks in healthy patients. If there is a strong family history of heart disease, a patient could conceivably ask his PCP to check these blood markers. 

References:

1. 

http://www.revespcardiol.org/en/diagnostic-accuracy-of-nt-probnp-compared/articulo/90027158/

2. 

Curr Vasc Pharmacol. 2007 Jan;5(1):15-25.

Use of BNP and CRP as biomarkers in assessing cardiovascular disease: diagnosis versus risk.

Miller VM1, Redfield MM, McConnell JP.

Author information

Abstract

Biomarkers are used in medicine to facilitate diagnosis, assess risk, direct therapy and determine efficacy of treatment. Sensitivity and specificity are essential in order for a biomarker to be useful. Brain natriuretic peptide (BNP) and C-reactive protein (CRP) are considered biomarkers of cardiovascular disease. However, they differ in function, sensitivity and specificity. BNP is released from the myocardium in response to myocardial stretch, a clear cause and effect relationship; therefore, it is useful in the diagnosis of heart failure when patients present with dyspnea of unknown origin and to assess treatment in high risk patients with diagnosed heart failure. Sex and age based reference ranges and partition values are established from clinical trials and from populations screened for the absence of cardiovascular disease. Highly sensitive and reproducible methods are also available to measure CRP. However, although CRP is associated with adverse cardiovascular events, unlike BNP, multiple stimuli increase production of CRP. Therefore, elevation in CRP is not specific to cardiovascular disease. Partition values for CRP and cardiovascular risk based on epidemiological studies predict risk for populations but may not always be useful when used alone to predict individual risk or to direct therapy. Given the non-specific stimuli which affect circulating concentrations of CRP, using CRP to monitor treatment to reduce cardiovascular risk may provide little benefit without understanding or targeting the underlying causes for its elevation.


3.

Simple blood test for the protein NT-proBNP predicts cardiac events

Published on January 9, 2007 at 4:36 PM · No Comments

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A simple blood test for the protein NT-proBNP accurately predicts the risk of heart attack, heart failure, stroke, and death in patients with known cardiovascular disease, according to a study led by a researcher at the San Francisco VA Medical Center.

The study of 987 men and women with stable coronary heart disease revealed that the higher a patient's level of NT-proBNP, the greater the chance the patient would die or have a cardiovascular event ? heart attack, heart failure, or stroke.
"After adjusting for all other risk factors, it's clear that this marker is picking up something that we are otherwise unable to detect with standard tests such as echocardiography," says principal investigator Mary Whooley, MD, a staff physician at SFVAMC and an associate professor of medicine at the University of California, San Francisco.
The study appears in the January 10, 2007 issue of Journal of the American Medical Association.
NT-proBNP is a marker in the blood for BNP, a hormone that "goes up during times of cardiac stretch or stress," explains Whooley. "When the heart wall is over-expanded by too much blood volume, or damaged by lack of blood flow to the heart itself, BNP goes up, and NT-proBNP along with it."
Patients in the study were divided into four quartiles depending on their NT-proBNP blood levels, and followed for an average of 3.7 years each. Twenty-six percent died or had a cardiovascular event during the course of the study. The study reports that "each increasing quartile ? was associated with a greater risk of cardiovascular events or death." Patients in the quartile with the highest levels of the biomarker were 3.4 times more likely to die or have a cardiovascular event than patients in the group with the lowest levels.

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Whooley cautions that the NT-proBNP test is "not something that we should order on every patient who comes in for a routine checkup," but would be most useful for patients with known coronary heart disease. "In the general population, the incidence of heart disease is so low relative to the incidence in heart disease patients that you get many more false positive results than true positives, which really lowers the value of the test," she says. "It's much better at predicting risk in a population with a high incidence of heart disease."
Whooley also notes that, even among heart patients, the value of the test is limited "because all of the therapies available to prevent cardiovascular events should already be used among these patients. The best it can do is help identify candidates for more aggressive therapy."
She says that one additional step for researchers is to see "whether there are therapeutic interventions that still remain to be developed that might prevent heart patients with elevated BNP from doing worse."
Patients in the current study were all enrolled in the Heart and Soul Study, a multi-year prospective study of one thousand heart patients directed by Whooley that is designed to investigate whether depression predicts heart disease. "Because the Heart and Soul Study measures heart disease so carefully, our data set has become extremely valuable for a wide range of cardiovascular studies, many of which have nothing to do with our original hypothesis," Whooley says. "This study is just one example."