Heart failure (HF) with preserved (HFpEF) or reduced (HFrEF) ejection fraction is associated with poor prognosis and quality of life. While the incidence of HFrEF is declining and HF treatment is effective, HFpEF is increasing, with no established therapy. PREFERS Stockholm is an epidemiological study with the aim of improving clinical care and research in HF and to find new targets for drug treatment in HFpEF starting with a cardiac biopsy study in elective CABG patiens.

Patients with new-onset HF (n = 2000) will be characterized at baseline and after 1-year follow-up by standardized protocols for clinical evaluation, echocardiography, and ECG. In one subset undergoing elective coronary bypass surgery (n = 100) and classified according to LV function, myocardial biopsies will be collected during surgery, and cardiac magnetic resonance (CMR) imaging will be performed at baseline and after 1 year. Blood and tissue samples will be stored in a biobank.We will characterize and compare new-onset HFpEF and HFrEF patients regarding clinical findings and cardiac imaging, genomics, proteomics, and transcriptomics from blood and cardiac biopsies, and by established biomarkers of fibrosis, inflammation, haemodynamics, haemostasis, and thrombosis. The data will be explored by state-of-the-art bioinformatics methods to investigate gene expression patterns, sequence variation, DNA methylation, and post-translational modifications, and using systems biology approaches including pathway and network analysis.In this epidemiological HF study with biopsy studies in a subset of patients, we aim to identify new biomarkers of disease progression and to find pathophysiological mechanisms to support explorations of new treatment regimens for HFpEF.

Inclusion Criteria:CABG PREFERS

Inclusion criteria:

1. Patients undergoing elective coronary bypass surgery
2. History of heart failure not required
3. Age >18 years
4. Willingness to participate (written informed consent)
5. Possibility to obtain technically satisfactory echocardiography

Inclusion criteria PREFERS:

1. New-onset heart failure according to ESC guidelines including NT-proBNP >125 ng/L at heart failure clinic or >300 ng/L at emergency department visit or hospital admission
2. Age >18 years
3. Willingness to participate (written informed consent)
4. Possibility to obtain technically satisfactory echocardiography

Exclusion Criteria CABG PREFERS and PREFERS:

1. Cognitive impairment
2. Inability to understand Swedish language
3. Anaemia (haemoglobin level <90 g/L)
4. Heart failure primarily due to valvular disease, primary right ventricular failure, pulmonary artery hypertension, hypertrophic obstructive cardiomyopathy Infiltrative cardiomyopathy (e.g. amyloidosis, sarcoidosis, or haemochromatosis)
5. Severe co-morbidity, severe COPD, severe renal dysfunction (eGFR <30 mL/min/1.73m2). Any other co-morbid disease that will disable the ability to assess or treat heart failure.

CABG PREFERS: Patients undergoing elective coronary artery by pass surgery at the karolinska University hospital PREFERS: New onset heart failure patients at 5 hospitals in Stockholm ; Danderyds Hospital, Capio St Görans Hospital , Karolinska Solna Karolinska Huddinge, South Hospital

none described