How useful is the BNP level in predicting morbidity and mortality in asymptomatic left ventricular dysfunction?

The myocardium synthesizes and secretes a family of peptides with natriuretic, vasodilator, and antimitogenic properties in response to atrial and ventricular wall stretch and tension. Increased ventricular wall stress augments expression of the atrial natriuretic peptide (ANP) gene and its predominantly atrial-derived product, ANP, and N-terminal prohormone fragment (N-terminal proANP). The predominantly ventricular-derived brain-type natriuretic peptide (BNP) is increased in left ventricular hypertrophy and dysfunction, even if asymptomatic or minimally symptomatic. In advanced congestive heart failure, it is a more important predictor of morbidity and mortality than ANP or other neurohumoral markers of prognosis such as norepinephrine, angiotensin II, or endothelin-1.

Natriuretic peptide levels should be used to select individual patients for echocardiography, but they are not synonymous with a specific myocardial disease. Screening markedly reduces the number of echocardiograms performed, particularly as it correctly predicts absence of left ventricular dysfunction in 97% to 99% of cases. In practice, this means that a normal natriuretic peptide level excludes systolic dysfunction.

Tsutamoto et al showed that the predictive mortality and morbidity information provided by plasma BNP is independent of left ventricular hemodynamic parameters such as ejection fraction, end-diastolic pressure, and end-diastolic volume index. Measurement of this important biochemical marker is simple and cost-effective, and is readily incorporated into the standard monitoring and investigative battery of asymptomatic or minimally symptomatic left ventricular dysfunction.

Further reading

Schirmer H, Omland T. Circulating N-terminal pro-atrial natriuretic peptide is an independent predictor of left ventricular hypertrophy in the general population. The Tromso Study. Eur Heart J. 1999;20:755-763.

Strothers AD. Further defining the role for natriuretic peptide levels in clinical practice. Eur Heart J. 1999;20:712-714.

Tatwar S, Squire IB, Davies JE, Barnett DB, Ng LL Plasma N-terminal pro-brain natriuretic peptide and the ECG in the assessment of left ventricular dysfunction in a high risk population. Eur Heart J. 1999;20:1736-1744.

Tsutamoto T, Wada A, Maeda K, et al. Plasma brain natriuretic peptide level as a biochemical marker of morbidity and mortality in patients with asymptomatic or minimally symptomatic left ventricular dysfunction. Comparison with plasma angiotensin II and endothelin-1. Eur Heart J. 1999;20:1799-1807.

Keywords

biochemistry; BNP; natriuretic peptide; prognosis; mortality; morbidity; left ventricular dysfunction

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