Abstract
INTRODUCTION: This study investigated if high loop gain (HLG), a specific sleep apnea endotype characterized by unstable respiratory control, is independently associated with adverse cardiac remodeling.
METHODS: Using the Multi-Ethnic Study of Atherosclerosis (MESA) data, a HLG surrogate was quantified using a polysomnographic algorithm measuring respiratory self-similarity (Central Respiratory Event Index [CREI] and respiratory Self-Similarity [SS%]). Cardiac structure was assessed via MRI. Multivariable linear regression analyzed probable HLG associations with the left ventricular mass-to-volume ratio (LVMVR). Propensity score matching compared SS and CREI between participants with and without reduced left ventricular ejection fraction (LVEF).
RESULTS: Severe expressed HLG was defined as the top 2.5 % of CREI values, a criterion that categorized 35 of the 1440 participants, and showed higher LVMVR (1.23 ± 0.31 vs 1.03 ± 0.22, p < 0.001). After central sleep apnea (CSA) adjustment, severe expressed HLG remained an independent predictor for LVMVR (β = 0.110 ± 0.068, p = 0.002) with a significant sex interaction (p for interaction = 0.041), observed in males (β = 0.15 ± 0.09, p < 0.001) but not females. Reduced LVEF participants exhibited elevated SS% (11.41 ± 8.07 vs 8.13 ± 6.26, p = 0.037) and CREI (29.25 ± 19.50 vs 21.49 ± 19.86, p = 0.032). Post-PSM, differences persisted (SS%: 11.53 ± 8.26 vs 7.26 ± 7.07, p = 0 0.032; CREI: 28.96 ± 19.60 vs 18.15 ± 18.46, p = 0.041).
CONCLUSION: Expressed HLG may be an important biomarker for left ventricular modeling/HF progression and allow risk stratification for targeted management.