NPs and guidelines for specialist referral
The diagnosis of heart failure can only be fully established by specialist assessment coupled with appropriate imaging, most commonly echocardiography.
Measurement of blood concentrations of NPs is recommended by the National Institute for Health and Care Excellence (NICE) in all patients with suspected heart failure. It can be used to guide appropriateness of referral, and to increase the speed with which referrals are seen by specialists.
NICE guidance for chronic heart failure gives detailed guidance on thresholds of NP concentration to guide referral.6
- Patients in whom heart failure is suspected and who have a history of prior myocardial infarction (MI) do not require NP testing, but rather should be referred for specialist assessment and should be seen within two weeks of referral as the likelihood of significant myocardial dysfunction is high.
- Patients without prior history of MI should be referred according to the guidance (table 3).
The European Society of Cardiology Heart Failure Guidelines 2016 have lower serum NP thresholds for referral for echocardiography: BNP >35 pg/mL and NTproBNP >125 pg/mL.5
A normal NT-proBNP excludes the diagnosis of heart failure without the need for an echocardiogram. Essential initial investigations include a 12-lead electrocardiogram (ECG) and laboratory tests (see below).5 Other diagnostic tests are generally only required if the diagnosis remains unclear.
HeFNEF versus HeFREF
Heart failure is a clinical diagnosis based on symptoms and signs combined with echocardiographic evidence of impaired systolic or diastolic function and raised NPs (figure 2).
The distinction between heart failure with a normal ejection fraction (HeFNEF) and heart failure with a reduced ejection fraction (HeFREF) at diagnosis changes management. While there are several evidence-based drug and device treatments for HeFREF, no treatment for patients with HeFNEF has shown convincing outcome benefit in randomised controlled trials. Symptomatic relief with diuretics and treatment of co-morbidities are the best treatment strategies for these patients.