Clin Res Cardiol (2022).

Iron Deficiency in Heart Failure Patients with Implantable Cardioverter-Defibrillators (ICD) and Cardiac Resynchronization Therapy Devices (CRT): Prevalence and Association with Symptom Severity
L. K. Krieglstein1, S. Achenbach1, M. B. Arnold1, C. Merkel1, L. Anneken1
1Med. Klinik 2 - Kardiologie, Angiologie, Universitätsklinikum Erlangen, Erlangen;
Iron deficiency is a common comorbidity in heart failure. Iron substitution may improve symptoms and reduces the rate of heart failure-related hospitalizations, but heart failure patients who may benefit from such treatment are often unrecognized and therefore cannot be adequately treated. Heart Failure patients with implantable cardioverter-defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices undergo regular follow-up visits which may be an opportunity to identify iron deficiency. We therefore analysed the prevalence of iron deficiency in a cohort of patients with heart failure undergoing regular scheduled follow-up in an outpatient ICD/CRT clinic.

A cohort of 83 patients with Heart Failure with reduced Ejection Fraction (HFrEF, LV EF < 40%) and implanted ICD (n=46) or CRT devices (n=37) undergoing scheduled follow-up in a cardiac rhythm outpatient clinic were included. Blood samples were obtained and iron deficiency determined by definition as ferritin < 100 ng/ml or ferritin 100-300 ng/ml and transferrin saturation <20%. ICD evaluation (rhythm analysis, determination of heart rate and shock delivery within the last 3 months) and transthoracic echocardiography was performed. Symptoms and quality of life were assessed through NYHA class and the Minnesota Living with Heart Failure Questionnaire (MLHFQ). After an average follow-up of 13.5 months (9-27 months), the same parameters were collected again.

Out of 83 patients (67 male, 16 female, mean age 66 years, mean LVEF 35.5%), a total of 28 patients (34%) had iron deficiency at baseline and 33 patients (40%) at follow-up. At baseline the mean total MLHFQ score of patients with iron deficiency was 21.1 compared to 16.8 without iron deficiency (p=0.2). In the physical dimension score, the values were 9.4 vs. 7.7 (p=0.18) and in the emotional dimension score 4 vs. 2.5 (p=0.4). At follow-up, the total score in patients with iron deficiency was 30.2 compared to 13.2 points (p=0.00012), the physical dimension score was 13.2 vs. 6.3 (p=0.00018), the emotional dimension score 5.8 vs. 2.2 points (p=0.006). NYHA class III was reported at baseline in 3/28 (10.7%) with and 4/55 (7.3%) patients without iron deficiency (p=0.67). At follow-up 6/33 (18.2%) patients with and 0/50 (0%) patients without iron deficiency were classified as class III (p=0.003). Baseline LVEF was 33.2% in the iron deficient group and 36.6% in the non-iron deficient group (p=0.23). Hemoglobin level was 13.4 ± 1.5 g/dl vs. 14.1 ± 1.5 g/dl. Patients with or without iron deficiency had comparable age (65.7 ± 12.2 years vs. 66.6 ± 11.9 years) and there were no relevant differences in creatinine (1.23 ± 0.42 mg/dl vs. 1.26 ± 0.7 mg/dl), heart rate (69 ± 12 bpm vs. 67 ± 11 bpm) or cardiac medication. In the 3 months preceding baseline or follow-up visits, none of the patients had arrythmias that would have triggered appropriate therapy.

Iron deficiency is highly prevalent in ICD/CRT patients with HFrEF. This leads to a progressive reduction in quality of life. Regular assessment of iron deficiency in ICD patients during scheduled follow-up offers a window of opportunity to initiate appropriate treatment at an early stage.