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Results from the BACH (Biomarkers in Acute Heart Failure) Trial

Clinical Trial Update II

Presenter : Maisel Alan (United States of America)


Discussant report:

McDonagh, Theresa


BACH is a large, prospective trial involving 1600 patients in 15 centres and 3 continents. It is the biggest natriuretic peptide diagnostic study in acute heart failure, to date. It is also the only large study to examine the diagnostic potential of a form of atrial Natriuretic peptide-mid regional ANP (MR-ANP).

Although ANP was discovered prior to BNP, its diagnostic potential in chronic heart failure (for both its C-terminal and N-terminal fragment) was inferior to BNP and assays were not developed further. However, recent evidence suggests that an assay targeting the more stable region of MR-ANP is just as accurate as BNP in diagnosing heart failure (in a retrospective sample) and that the concentrations of MR-ANP predict a poor prognosis. So BACH is a timely study.

The BACH results confirm in their primary endpoint that MR-ANP is not inferior to BNP/NT-BNP in the diagnosis of acute heart failure on the ROC characteristics. Their secondary endpoint was also reached in that MR-ANP added diagnostic power to that of B type peptides in the logistic regression analysis particularly in the grey zone where B type peptides can have some problems, namely in those with renal dysfunction, obesity, the elderly and those with oedema. There was a third end point which I will not address here, namely that of procalcitonin in the diagnosis of pneumonia.

The findings of the BACH Trial are important and they continue the theme of a multi marker approach to the diagnosis of heart failure being superior to just using one. However, some questions remain to be answered as a result of this study. The presenters state that MR-ANP reduced clinical indecision by 29%, what did BNP and NT-pro-BNP do to this outcome variable?  Of more clinical relevance, what would be the additional cost of adding MR-ANP to BNP/NT-proBNP evaluation in the emergency room? Would the cost justify these modest gains in diagnostic accuracy? This will be challenging to prove in a study conducted in many different health care settings.
We have convincing evidence from 3 randomised studies of BNP/NT-proBNP in the diagnosis of heart failure in the emergency room showing that such an approach reduces costs, improves length of stay and may lower readmission rates. The challenge is now to show this for MR-ANP. Will using MR-ANP as a single marker predict outcomes as well as the B-type peptide markers, and will using MR-ANP and B-type peptides add value and be cost effective.

This study is a landmark one on the way to achieving these goals and shows for the first time is a large prospective trial that MR-ANP is equivalent to BNP diagnostically in acute heart failure and can add value to the information the B-type peptides produce.



This congress report accompanies a presentation given at the ESC Congress 2008. Written by the author himself/herself, this report does not necessarily reflect the opinion of the European Society of Cardiology.




Clinical Trial Update II

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.