Association between high loop gain sleep apnea detected by respiratory self-similarity and left ventricular remodeling

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.