The committee also discussed the 2010 guideline recommendations that provide a different treatment pathway for patients with any previous MI (these patients were referred directly for echocardiography and specialist assessment, without prior natriuretic peptide testing). The committee noted that this was based on the MICE clinical decision rule developed by the Mant 2009 IPD, which included evidence that was outside the scope of this review (for example, it included studies in acute populations, and studies using a wider range of reference standards and target conditions than specified in this protocol). The committee agreed that this distinction between patients who had and had not had any previous MI was not supported by the latest clinical evidence in the population of interest to this review. The committee also noted that the definition of MI had changed over time. The committee agreed that the distinction between patients with and without previous MI should be removed from the diagnostic pathway. NT-proBNP testing should be done in all patients with suspected heart failure regardless of whether or not they have had a previous MI. The committee agreed to remove a recommendation from the 2010 guideline suggesting that a serum natriuretic peptide test should be considered when heart failure is still suspected after transthoracic Doppler 2D echocardiography has shown a preserved left ventricular ejection fraction. The committee recalled that this recommendation was made to inform an individual s prognosis from the NT-proBNP level. However, the Chronic Heart Failure Diagnosing heart failure NICE 2018. All rights reserved. Subject to Notice of rights. ISBN: 978-1-4731-3093-7 committee noted that according to these recommendations, and the removal of the different diagnostic pathway for those with previous MI, all patients should receive an NT-proBNP level and therefore this recommendation was no longer necessary. 