Abstract
OBJECTIVES: The neutrophil-to-lymphocyte ratio (NLR) is defined as the ratio of neutrophils to lymphocytes measured in the full blood count. It has been studied across a range of conditions including cancer, sepsis and stroke. It has been proven that in patients with heart failure (HF) with reduced ejection fraction (HF-rEF), an elevated NLR reflects a higher risk of adverse outcomes. The aim of this study is to identify which clinical or cardiovascular magnetic resonance (CMR) factors are associated with an elevated NLR in patients with HF-rEF. DESIGN: This study was an analysis of the MATCH registry (MyocArdial Tissue Characteristics in patients with heart failure according to glycaemic status), a prospectively recruited registry of patients presenting with a new diagnosis of HF and referred to our centre for a CMR. SETTING: Single-centre study performed in the Advanced Imaging Centre, Leeds General Infirmary, UK. Data collection took place between February 2018 and March 2023. PARTICIPANTS: Patients (N=605) with newly diagnosed HF-rEF referred for CMR. INTERVENTION: Participants underwent clinical assessment, medication review, full blood count and CMR on the same day. The CMR protocol included quantitative assessment of myocardial blood flow at stress and rest, late gadolinium enhancement imaging and parametric mapping. Association between NLR, clinical and CMR parameters was examined by linear regression. RESULTS: The factors which were found to be significantly associated with an elevated NLR were age, atrial fibrillation, N-terminal pro-B-type natriuretic peptide (NT-proBNP), presence of ischaemic fibrosis and myocardial perfusion reserve (MPR). There was no association between NLR and CMR markers of inflammation (native T1 and T2). On multiple regression after correction for age, atrial fibrillation, New York Heart Association classification and left ventricular ejection fraction, the association between NLR and presence of ischaemic fibrosis (coefficient 0.68, 95% CI 0.23 to 1.12, p=0.003) and NT-proBNP (coefficient 0.0002, 95% CI 0.00006 to 0.0003, p=0.002) remained significant. However, the association between MPR was no longer significant (coefficient -0.09, 95% CI -0.28 to 0.09, p=0.330). CONCLUSION: In patients with HF with elevated NLR, these findings show an association with worsening congestion (NT-proBNP) and occult coronary artery disease (ischaemic fibrosis). Further studies are required to demonstrate if this accounts for the adverse prognosis. Importantly, there was no association between myocardial inflammation or oedema and NLR.