Ultrasound indices of congestion in patients with acute heart failure according to body mass index

Background: The inverse relationship between body mass index (BMI) and natriuretic peptide levels complicates the diagnosis of heart failure (HF) in obese patients. Assessment of congestion with ultrasound could facilitate HF diagnosis but it is unclear if any relationship exists amongst BMI, inferior vena cava (IVC) diameter and the number of B-lines. Methods: We performed a comprehensive echocardiographic evaluation within 24 h from hospital admission in patients with HF, including lung B-lines and IVC diameter, and studied their relationship with BMI and outcome. Results: 216 patients (median age 81 (77–86) years) were enrolled. Median number of B-lines was 31 (IQR 26–38), median IVC diameter was 23 (22–25) mm and median BNP 991 (727–1601) pg/mL. BMI was inversely correlated with B-lines (r = − 0.50, p < 0.001), but not with IVC diameter (r = − 0.04, p = 0.58). Compared to overweight patients (BMI 25–29.9 kg/m2; n = 100) or with a normal BMI (BMI < 25 kg/m2; n = 59), obese patients (BMI ≥ 30 kg/m2; n = 57) had lower B-lines [28 (24–33) vs 30 (26–35), and vs 38 (32–42), respectively; p < 0.001] but similar IVC diameter. During the first 60 days of follow-up, there were 53 primary events: 29 patients died and 24 had a HF-related hospitalisation. B-lines and IVC diameter were independently associated with an increased risk. However, B-lines were less likely to predict outcome in the subgroup of patients with a BMI ≥ 30 kg/m2. Conclusions: Assessment of IVC diameter or B-lines in patients admitted with AHF identifies those at greater risk of death or HF readmission. However, assessment of B-lines might be influenced by BMI