Page 77 - Biomarkers for risk stratification and guidance in heart failure

Chapter 3
REPLY
We would like to thank Dr. Madias for his valuable comments on our study1 assessing the effect of N-terminal pro–B-type natriuretic peptide (NT-proBNP)- guided therapy in the management of chronic heart failure (HF). As rightfully indicated, quantification of fluid retention by physical examination is troublesome, and the correlation between symptoms and severity of cardiac dysfunction is poor. Trials such as the PRIMA (Can PRo-brain-natriuretic peptide-guided therapy of chronic heart failure IMprove heart fAilure morbidity and mortality?) study1 have been performed in order to assess the additive value of serial BNP or NT- proBNP measurements at the outpatient management of HF patients.
Dr. Madias asks for data on body weight (BW). This was not initially reported as we felt that with outpatient visits occurring at an interval of up to 3 months, the value of reporting outpatient BWs with such wide intervals would be quite limited.
However, we did collect data on BW at index admission, at discharge, and at every outpatient visit during the follow-up period of our study. During the index hospitalization because of acute HF, BW decreased with a median value of 4.48 kg (interquartile range: 1.8 to 6.2 kg). The change in BW during index admission correlated weakly, yet significantly, with changes in NT-proBNP levels (r = 0.144, p = 0.016). At the outpatient clinic, there was no statistically significant correlation between changes in BW and NT-proBNP levels.
In addition, Dr. Madias expresses an interest in possible correlations between the proportional pulse pressure (PPP) and NT-proBNP. We failed to find any correlation between PPP and NT-proBNP (correlation between PPP and NT- proBNP at admission: r = 0.019, p = 0.723; at discharge: r = 0.035, p = 0.532; and at 2-week follow-up: r = 0.023, p = 0.689).
We also did not find a correlation in the subgroups of patients with left ventricular systolic dysfunction HF or those with preserved left ventricular systolic function HF. In conclusion, Dr. Madias rightfully points out the value of physical examination in the management of outpatient HF with special emphasis on BW. In the PRIMA study, changes in BW during the index admission correlated weakly, yet statistically significantly, with NT-proBNP.1 No correlation was found between outpatient NT- proBNP values and either BW or PPP, which for the latter may be explained by the fact
that PPP seems to reflect cardiac output, a parameter correlating poorly with BNP.2
Luc W. M. Eurlings, MD Yigal M. Pinto, MD, PhD
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