Summary

Brain natriuretic peptide (BNP) has been found in increased levels in heart failure patients. It has therefore been proposed that therapy might be optimized if it was used to guide therapy, with the goal being to reduce levels. However, a trial comparing BNP-guided with symptom-guided therapy showed no overall advantage to the former, though younger patients did seem to gain a benefit.

Introduction

There is an increasing trend towards the use of biomarkers for diagnosis and therapy of disease. A biomarker is a substance, often a protein, which is secreted into the blood in a disease state. Increased levels denote disease, while decreased levels may indicate response to therapy. N-terminal brain natriuretic peptide (BNP), despite its name, is produced mainly by heart muscle cells and levels are increased in congestive heart failure. Therefore, using BNP as a biomarker in therapy - looking for reduced levels as a guide to response - has been proposed and, indeed, backed by promising results in small scale trials. What has been lacking is a larger trial to confirm these findings.

What was done

Researchers in Basel, Switzerland, compared BNP-guided versus symptom-guided therapy in a group of 499 patients with heart failure. They were aged 60 years or older and had all been hospitalized for heart failure in the previous year. Their BNP levels were two or more times the upper limit of normal. Their treatment was given either to reduce BNP levels to normal or to reduce symptoms to a clinically significant level. Then they were followed up for 18 months and hospitalizations for all causes and for heart failure recorded, along with mortality data.

What was found

There was no difference in the rate of 18-month survival free of hospitalization for any reason between the two groups, with the figures being 41 percent for the BNP group and 40 percent for the symptom-guided group. When it came to survival free of hospitalization for heart failure, then BNP therapy was beneficial, with figures being 72 percent and 62 percent respectively. Overall, the researchers found that it was those in the 60 to 75 years age group that had most to gain from BNP-guided therapies. Older patients did not benefit.

What this study means

Another finding was that quality of life improved significantly for both groups from the start of the trial to month 12 and through to the end. This shows that intensive therapy for heart failure is worthwhile, whether biomarker or symptom guided. Heart failure often leads to a very poor quality of life and it is a condition on the increase as the population ages. Also, more needs to be done to find approaches, other than BNP, which improve outcome in the older patient with heart failure.

Source

BNP-guided vs symptom-guided heart failure therapy
M. Pfisterer, P. Buser,  et al, Journal of the American Medical Association, January 28 2009, vol. 301, pp. 383--392