Role of Bnp (Blood Test) In Cardiovascular Diseases

What Is BNP?

Brain natriuretic peptide (BNP) is a type of protein that is produced in the heart muscles, initially as pro-BNP. It belongs to a class of hormones known as natriuretic peptides.

These hormone groups are divided into atrial natriuretic peptide, brain natriuretic peptide, C-type natriuretic peptide, and dendroaspis natriuretic peptide. Each of them is produced in different areas of the circulatory system.

• Atrial Natriuretic Peptide (ANP): It is produced by the cardiac muscle cells in the heart's upper chambers (atria).

• Brain Natriuretic Peptide (BNP): These are made by the cardiac muscle cells in the heart's lower chambers (ventricles).

• C-Type Natriuretic Peptide (CNP): The endothelium of the blood vessels produces this protein.

• Dendroaspis natriuretic peptide (DNP): It is found in the blood plasma but is thought to originate in the heart itself.

What Is a BNP Test?

In instances of heart failure, two types of proteins are made by the heart. These include B-type natriuretic peptide (BNP) and N-terminal-pro BNP. Levels of both these proteins are measured in the BNP test. It holds the significance of determining the occurrence of heart failure in most cases. The levels of these proteins are increased during the event of heart failure and decrease with recovery.

When Is the BNP Test Indicated?

1. When there is a suspicion of heart failure due to symptoms such as difficulty breathing and swelling or fluid build-up in the extremities, the doctor might advise the patient to check their BNP levels.

2. To know the severity of heart failure in patients diagnosed with congestive heart failure.

3. To check for kidney (renal) failure.

4. To check the effectiveness of treatment in a patient treated for heart failure.

The following symptoms indicate the need for a BNP test:

• Irregular heart rate.

• Difficulty in breathing.

• Nausea.

• Appetite loss.

• Fatigue.

• Unexplainable weight gain.

• Persistent cough with phlegm production.

How Is BNP Checked?

BNP and NT-proBNP are measured using a simple blood test to help diagnose and monitor heart failure. BNP and NT-pro-BNP test results have different values.

• Abstain from eating food for seven to 12 hours before having a BNP test. However, drinking water is not a concern.

• Inform the doctor about the medications the patient is taking as it is recommended to stop taking some medications before the test. This is because there may be interference with the results.

• The test usually takes about 15 to 20 minutes.

• Blood is drawn from the veins in the arms by a process called venipuncture. A hypodermic needle helps in this process.

• A machine is then employed, over which the drawn blood is placed, to measure the BNP and NT-pro-BNP levels.

How to Prepare for the BNP Test?

Since it involves drawing blood, for patients in whom the sight of blood can bring about fainting, or those who are weak, it is always advisable to have someone accompany the patient to the test as they find driving by themselves or traveling difficult.

It is rather a simple test and does not need much preparation. The stress level has a transient impact on the BNP values. Therefore it is recommended not to stress oneself about the test.

What Takes Place During the BNP Test?

To prepare for a BNP test, there is nothing particular one needs to do. Using a tiny needle, a tiny amount of blood will be extracted. The area around the needle's entry and exit points may sting or pain a little. A finger stick test may be used in place of a blood sample drawn into a vial on occasion. They will bandage the arm after taking a blood sample. Later on, individuals can have some pain or perhaps bruising. However, there are no significant risks associated with a BNP blood test.

What Does an Abnormal BNP Level Mean?

BNP levels that are normal in healthy individuals are fewer than 100 picograms per milliliter (pg/mL). A BNP reading of more than 100 pg/mL might indicate heart failure. Greater than 400pg/mL indicates heart failure.

Below 125 pg/mL for those below 75 and less than 450 pg/mL for those over 75 are considered normal levels for NT-proBNP. Over 900 pg/mL of NT-proBNP may indicate cardiac failure. Each person's BNP or NT-proBNP level range is unique. Inquire with a doctor about the precise measurements of the NT-proBNP or BNP test.

Based on the BNP test results, the doctor can prescribe additional testing, including an electrocardiogram (ECG or EKG). With the use of skin-attached sensors, this test tracks the heart rate. It supports the doctor in diagnosing heart failure and other cardiac issues.

In general, the normal BNP values of women are a bit higher than those of men. BNP values usually increase with age, but they may stay within the normal range unless heart failure is present. The normal range varies from one laboratory to another, and one laboratory may have a different range for what is normal. The patient's laboratory report should contain the range the laboratory uses. The doctor will evaluate the results based on the patient's age and gender.

What Interpretations Are Obtained From the BNP Test?

From the reports, the doctor can tell if:

• There is an increased amount of fluid or high pressure inside the heart.

• There is severe heart failure.

• There is a higher chance of sudden cardiac death in patients diagnosed with heart failure.

• There are early signs of heart failure in people with kidney failure or insufficiency.

Overall, the result will be determined to be positive or negative by the doctor based on the reason the test was ordered.

What Factors Affect the Level of BNP?

BNP level is decreased in:

• People who are obese.

• Patients undergoing treatments with medications such as ACE inhibitors, diuretics such as Spironolactone, and beta-blockers.

It is increased in:

• Females, more commonly.

• Lung diseases like emphysema.

• High blood pressure patients.

• An overactive thyroid, like in a case of hyperthyroidism.

• Very high cortisol levels.

• Patients with kidney failure.

• Advanced liver disease or end-stage liver disease.

• Certain rare tumors.

• Brain hemorrhages.

• Older adults

How Accurate Is the BNP Test in Indicating Heart Failure?

The BNP test is very accurate in detecting heart failure. Accuracy is around 98 %. However, factors like stress and exercise may cause a temporary rise in BNP values.

What Risks Are Associated With BNP Tests?

As it is not a complex procedure, it does not bring about serious complications. However, since drawing blood is involved, there may be associated symptoms of venipuncture like:

• Bleeding from the venipuncture site.

• Soreness and formation of bruises at the site of puncture.

• Lightheadedness.

Since this might bring about lightheadedness, the patient is not advised to drive by themselves. Other than this, all the above symptoms are transient and do not bring about serious health concerns.

What Are Additional Tests Performed for Diagnosing Heart Failure?

In addition to the BNP test, the below tests help diagnose heart failure:

• Complete blood count.

• Electrocardiogram.

• Echocardiogram

• X-ray of the chest.

• MRI (magnetic resonance imaging) of the chest.

• Cardiac catheterization.

What Advantages Might a BNP or NT-proBNP Test Offer?

This test provides vital information about the heart's health to the doctor using a tiny amount of blood. A doctor can identify heart failure and other medical illnesses that might be causing comparable symptoms by doing a BNP or NT-proBNP test. A BNP or NT-proBNP test's results also help the doctor plan therapies and track their efficiencies.

How to Naturally Reduce BNP Levels?

In addition to therapy, one can manage heart failure and lower BNP levels by following the doctor's instructions and doing some at-home activities. For example:

• According to one study, those who reduced their intake of salt also had lower BNP levels.

• Another study discovered that omega-3 fatty acids had some modest anti-BNP effects.

• Consuming a balanced diet rich in fruits and vegetables could be beneficial.

• Steer clear of alcohol as it can weaken the cardiac muscle.

• Steer clear of processed meats and highly processed cereals like white bread and spaghetti.

• Additionally, exercise therapy considerably lowers BNP levels.

Conclusion:

BNP test is a blood test that is a useful means of diagnosing heart failure. Incidences of heart attacks can also be detected in this test. Being a relatively simple blood test, not much preparation is required. If a person has been proposed to have a BNP test, it is always advisable to bring an attendee with him. The values differ for different laboratories; therefore, to get it interpreted correctly, seeking the help of a physician is a must.