Cohort study of plasma natriuretic peptides for identifying left ventricular systolic dysfunction in primary careBMJ 1998; 317 doi: https://doi.org/10.1136/bmj.317.7157.516 (Published 22 August 1998) Cite this as: BMJ 1998;317:516
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Editor: McMurray et al suggest plasma brain natriuretic peptide (BNP) is not a useful screening test for detecting left ventricular systolic dysfunction (LVD) in ordinary clinical practice . Although some of the confounding factors have been considered, they have failed to take into account renal function. This is surprising since 24% of the patients in their study had peripheral vascular disease and we know that ~50% of patients with peripheral vascular disease have renal artery stenosis . Furthermore 38% of the patients were hypertensive and 18% diabetic, both of which may also contribute towards renal impairment in this population. Due to the renal clearance of BNP, levels in renal failure can be even higher than those seen in cardiac failure . It would be interesting to see whether consideration of renal impairment, would alter the conclusions of their study.
It is not clear how long after the myocardial infarction the samples were taken in their study. Given that remodelling takes several months, their ‘control’normal echocardiographic population with mildly elevated BNP levels may well progress to overt LVD and dilatation if samples are taken early after infarction. This would clearly reduce the positive predictive value for BNP.
From their data whilst 49% had echocardiographic evidence of LVD, only 21% were on an ACE inhibitor and only 29% were symptomatic. A simple screening test to identify the population with LVD, who may be missed on clinical criteria alone, is still much needed. In our opinion BNP may still be a good candidate for population screening for LVD provided its limitations are understood. Other isoforms of BNP such as NT-BNP or Pro-BNP may be more discriminatory in patients with mild to moderate LVD.
Suneel Talwar Clinical research fellow
Khalid Khan Clinical research fellow
Department of Medicine & Therapeutics
Clinical Sciences Building
Leicester Royal Infirmary
Leicester LE2 7LX
1. SJ McClure, L Caruana, AP Davies, Steven Goldthorp, J McMurray. Cohort study of plasma brain natriuretic peptides for identifying left ventricular systolic dysfunction in primary care. BMJ 1998;317:516-519.
2..Swartbol P, Thorvinger BO, Parsson H, Norgren L. Renal artery stenosis in patients with peripheral vascular disease and its correlation to hypertension. A retrospective study. Int Angiol 1992 jul; 11(3): 195-199.
3. Jensen KT, Carstens J, Ivarsen P, Pederson EB. A new, fast and reliable radioimmunoassay of brain natriuretic peptide in human plasma. Reference values in healthy subjects and in patients with differant diseases. Scan J Clin Lab Invest 1997 oct;57(6): 529-540.
Competing interests: No competing interests