Abstract

Background: The interaction between the heart and spleen plays a crucial role in the cardio-splenic axis in patients with heart failure (HF). Several studies reported that spleen stiffness (SS) measured by magnetic resonance elastography (MRE) (SS-MRE) was a useful determinant of hepatic fibrosis and portal / venous pressure in patients with chronic liver disease. However, it is unclear whether higher SS-MRE is associated with elevated central venous pressure and worse clinical outcomes in patients with HF. Methods: We prospectively examined 216 consecutive chronic HF patients (120 male, mean age 66 ± 14 years, left ventricular ejection fraction 47 ± 17%) between April 2018 and February 2023 after excluding those with organic liver and spleen diseases. All patients underwent 3.0 Tesla MRE within 4 days of right heart catheterization. Representative images of MRE are shown in Figure 1A . We also assessed liver stiffness (LS) measured by MRE (LS-MRE). The primary outcome was a composite of all-cause death and hospitalization for HF. Results: Median SS-MRE and LS-MRE were 6.50 (interquartile range [IQR] 5.65-7.27) kPa, and 2.55 (IQR 2.33-2.83) kPa, respectively, with moderate correlation between the two parameters (r = 0.25, P <0.001). There was a significant correlation between SS-MRE and right atrial pressure (r = 0.15, P = 0.032). During a median follow-up period of 2.86 (IQR 1.30-4.12) years, the primary outcome occurred in 50 patients (18 all-cause deaths and 32 hospitalizations for HF). Cox regressions showed that SS-MRE was independently associated with the risk of the primary outcome (HR 1.18, 95% CI 1.03-1.37) after adjustments for age, sex, and other significant prognostic covariates. When divided the patients into two groups according to a median LS-MRE value, SS-MRE was associated with the risk of adverse events in patients with lower LS-MRE but not in those with higher LS-MRE ( P for interaction = 0.014) ( Figure 1B and C ). Conclusion: Elevated SS-MRE was independently associated with worse clinical outcomes, especially in patients with lower LS-MRE. These findings suggest that elevated SS-MRE would reflect central venous congestion even in low LS, and is useful for risk stratification in patients with HF.