Abstract 1890: Sleep-Disordered Breathing Related to Gray Matter Loss in Heart Failure
Gray matter/brain volume loss has been reported in heart failure (HF), yet the underlying etiology of these neural changes is unknown. Hypoxia or perfusion changes associated with sleep-disordered breathing (SDB), present in a majority of HF pts, may contribute. However, the association between HF gray matter loss and SDB is unclear.
Methods: To examine this relationship, nine HF pts (mean age 51 ± 10 yrs; LVEF 0.27 ± 0.06%; NYHA I-II; 6 males) previously undiagnosed for SDB, underwent overnight polysomnography and structural T1-weighted, brain magnetic resonance imaging (MRI). SDB was defined as an apnea-hypopnea index (AHI) >5. Regional gray matter volumes were compared in HF subjects with and without SDB to 28 healthy controls (mean age 46 ± 12 yrs; 23 males) using voxel-based morphometry, while controlling for age, gender, and handedness. Statistical analysis for MRI gray matter volumes included ANCOVA, with significance set at p < 0.01.
Results: SDB was found in six of the nine HF pts (sample AHI range 2–74). HF pts with higher levels of SDB (AHI > 10) showed more gray matter loss in comparison to HF pts without SDB (AHI < 5; p < 0.01; figure⇓). All HF pts had specific sites of decreased gray matter volumes (insula, cingulate cortex, deep cerebellar nuclei, hippocampal cortex) in comparison to controls.
Conclusion: While all HF pts had gray matter volume loss relative to controls, the extent of loss was associated with the level of SDB in this small sample of advanced HF pts. Longitudinal studies with larger sample sizes are needed to determine whether there are causative links between SDB and gray matter volume changes in this high-risk patient population.