Relationship between spleen size and exercise tolerance in advanced heart failure patients with a left ventricular assist device

Objective Spleen volume increases in patients with advanced heart failure (HF) after left ventricular assist device (LVAD) implantation. However, the relationship between spleen volume and exercise tolerance (peak oxygen consumption [VO 2 ]) in these patients remains unknown. In this exploratory study, we enrolled 27 patients with HF using a LVAD (median age: 46 years). Patients underwent blood testing, echocardiography, right heart catheterization, computed tomography (CT), and cardiopulmonary exercise testing. Spleen size was measured using CT volumetry, and the correlations/causal relationships of factors affecting peak VO 2 were identified using structural equation modeling. Results The median spleen volume was 190.0 mL, and peak VO 2 was 13.2 mL/kg/min. The factors affecting peak VO 2 were peak heart rate (HR; β = 0.402, P = .015), pulmonary capillary wedge pressure (PCWP; β = − 0.698, P = .014), right ventricular stroke work index (β = 0.533, P = .001), blood hemoglobin concentration (β = 0.359, P = .007), and spleen volume (β = 0.215, P = .041). Spleen volume correlated with peak HR, PCWP, and hemoglobin concentration, reflecting sympathetic activity, cardiac preload, and oxygen-carrying capacity, respectively, and was thus related to peak VO 2 . These results suggest an association between spleen volume and exercise tolerance in advanced HF.