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Utility of B-natriuretic peptide levels in identifying patients with left ventricular systolic or diastolic
P Krishnaswamy1, E Lubien, P Clopton
1Division of Cardiology, Department of Medicine, Veteran's Affairs Medical Center, 3350 La Jolla Village Drive, San Diego, CA 92161, USA.
Insights
A rapid B-natriuretic peptide test accurately identifies left ventricular dysfunction, correlating with echocardiography results. This can help determine if echocardiography is necessary for diagnosing heart conditions.
Area of Science:
- Cardiology
- Biomarkers
- Diagnostic Imaging
Background:
- Echocardiography is crucial for diagnosing left ventricular dysfunction but is limited by cost and availability.
- B-Natriuretic peptide (BNP) levels reflect ventricular pressure and show promise in diagnosing heart failure.
- Rapid BNP assays may offer a sensitive and specific alternative for screening.
Purpose of the Study:
- To investigate the correlation between B-natriuretic peptide levels measured by a rapid assay and echocardiographic findings of ventricular dysfunction.
- To determine if BNP levels can reliably predict the presence or absence of left ventricular abnormalities.
Main Methods:
- 400 patients referred for echocardiography were studied.
- B-natriuretic peptide levels were measured using a point-of-care immunoassay.
- Patients were categorized based on echocardiographic findings: normal function, systolic dysfunction, diastolic dysfunction, or both.
Main Results:
- Mean BNP levels were significantly higher in patients with abnormal left ventricular function (416 pg/mL) compared to those with normal function (30 pg/mL).
- BNP levels showed a high accuracy (ROC curve area 0.95) in detecting any abnormal echocardiographic finding.
- BNP levels could not differentiate between systolic and diastolic dysfunction but were highly predictive of diastolic abnormalities in symptomatic patients with normal systolic function.
Conclusions:
- A rapid B-natriuretic peptide test reliably predicts left ventricular dysfunction identified by echocardiography.
- Normal BNP levels may obviate the need for echocardiography in certain patient populations.
- This rapid assay offers a valuable tool for assessing ventricular function and guiding diagnostic pathways.
Purpose:
Although echocardiography is important for making the diagnosis of left ventricular dysfunction, its cost and lack of availability limit its use as a routine screening test. B-Natriuretic peptide levels accurately reflect ventricular pressure, and preliminary studies with a rapid assay have found that levels are sensitive and specific for diagnosing heart failure in patients with dyspnea. We hypothesized that B-natriuretic peptide levels obtained through the use of a rapid assay should correlate with echocardiographic abnormalities of ventricular function.
Subjects And Methods:
We studied 400 patients who were referred for echocardiography at the San Diego Veteran's Healthcare System between June and August 2000 to evaluate ventricular function. B-natriuretic peptide levels were measured by a point-of-care immunoassay; cardiologists assessing left ventricular function were blinded to the assay results. Patients were grouped into those with normal ventricular function, systolic dysfunction only, diastolic dysfunction only, and both systolic and diastolic dysfunction.
Results:
Mean (+/- SD) B-natriuretic peptide concentration was 416 +/- 413 pg/mL in the 253 patients diagnosed with abnormal left ventricular function, compared with 30 +/- 36 pg/mL in the 147 patients with normal left ventricular function. Patients with both systolic and diastolic dysfunction had the highest levels (675 +/- 423 pg/mL). The area under the receiver operating characteristic (ROC) curve for B-natriuretic peptide levels to detect any abnormal echocardiographic finding was 0.95 (91% confidence interval: 0.93 to 0.97). B-Natriuretic peptide levels were unable to differentiate systolic vs. diastolic dysfunction. In patients with symptoms of heart failure and normal systolic function, B-natriuretic peptide levels >57 pg/mL had a positive predictive value of 100% for diastolic abnormalities.
Conclusions:
A simple, rapid test for B-natriuretic peptide levels can reliably predict the presence or absence of left ventricular dysfunction on echocardiogram. For some patients, a normal level may preclude the need for echocardiography.