The Prevalence of Iron Deficiency and the Effectiveness of Ferinject® in Patients With HFpEF (ID-HFpEF)

Inclusion Criteria: * Signed informed consent to participate in the study; * In New York Heart Association (NYHA) II-III functional class due to stable symptomatic chronic heart failure (CHF); * Left ventricular ejection fraction (LVEF) ≥50%; objective signs of structural and/or functional disorders of the heart consistent with the presence of LV diastolic dysfunction/increased LV filling pressure, including elevated levels of natriuretic peptide; * Screening ferritin below 100 µg/L, or below 300 µg/L when transferrin saturation (TSAT) is below 20%; * Screening haemoglobin (Hb) at the time of switching on ( 90-150 g/l). Exclusion Criteria: * Uncontrolled arterial hypertension; * Аnemia not related to iron deficiency; * Аnemia with a hemoglobin level of less than 90 g/l; * Less than 1 year after acute myocardial infarction; * Less than 1 year after acute cerebral circulation disorder; * Less than 1 year after surgical interventions, including non-cardiac operations and myocardial revascularization (coronary bypass surgery, coronary artery stenting), operations for valvular pathology; * Chronic alcoholism (including alcoholic heart disease), mental disorders; * Severe hepatic (increased transaminase levels above the upper three limits of normal) and renal insufficiency (glomerular filtration rate less than 15 ml/min/1.73 m2); * Known active infection, clinically significant bleeding, active malignancy; * Severe autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, etc.); * Severe bronchial asthma, COPD in the acute stage; * Allergic reactions to medications in the anamnesis, eczema, atopic allergic reaction; * Blood transfusions and taking erythropoiesis-stimulating drugs during the previous three months.