Assessing cardiac function in obstructive sleep apnea using a novel metric: integrating the respiratory event frequency and desaturation duration
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Objectives
Obstructive sleep apnea (OSA) is associated with impaired cardiac function, evidenced by a decreased left ventricular ejection fraction (LVEF). Traditional measures, including the apnea-hypopnea index (AHI) and lung-to-finger circulation time (LFCT), do not simultaneously consider the hypoxemic duration, frequency, and severity. This study introduces the respiratory event response time area (RERTA), integrating duration- and frequency-based OSA indices, and examined its associations with the LVEF.
Methods
We retrospectively analyzed data from individuals who underwent polysomnography (PSG) and echocardiography within the previous 6 months. LFCT was calculated as the mean time from desaturation onset after a respiratory event to the lowest recorded oxygen saturation (SpO2). The RERTA, a joint metric that reflects the event frequency and desaturation duration, was determined as the square root of the product of the AHI and mean LFCT. PSG parameters and related metrics were then examined for associations with echocardiographic measures.
Results
Among 34 participants (10 with mild-to-moderate and 24 with severe OSA), the severe group exhibited a lower median LVEF than the mild-to-moderate group (64.00% [61.00%–68.50%] vs. 70.00% [66.50%–72.75%], p < 0.05). After adjusting for age, gender, and the body-mass index (BMI), each 1-event/h increase in the AHI was linked to a borderline reduction in the LVEF (-0.71%, 95% CI: -1.42 to 0.00; p = 0.05). A 1-unit increase in the RERTA corresponded to a 0.33% decrease in the LVEF (95% CI: -0.62% to -0.04%, p < 0.05).
Conclusions
The RERTA combines the AHI and mean LFCT, providing a joint assessment of circulatory stress in patients with OSA. This study highlights its potential utility in evaluating cardiac function associated with OSA, which can serve as a basis for future prospective research.
Obstructive sleep apnea (OSA) is associated with impaired cardiac function, evidenced by a decreased left ventricular ejection fraction (LVEF). Traditional measures, including the apnea-hypopnea index (AHI) and lung-to-finger circulation time (LFCT), do not simultaneously consider the hypoxemic duration, frequency, and severity. This study introduces the respiratory event response time area (RERTA), integrating duration- and frequency-based OSA indices, and examined its associations with the LVEF.
Methods
We retrospectively analyzed data from individuals who underwent polysomnography (PSG) and echocardiography within the previous 6 months. LFCT was calculated as the mean time from desaturation onset after a respiratory event to the lowest recorded oxygen saturation (SpO2). The RERTA, a joint metric that reflects the event frequency and desaturation duration, was determined as the square root of the product of the AHI and mean LFCT. PSG parameters and related metrics were then examined for associations with echocardiographic measures.
Results
Among 34 participants (10 with mild-to-moderate and 24 with severe OSA), the severe group exhibited a lower median LVEF than the mild-to-moderate group (64.00% [61.00%–68.50%] vs. 70.00% [66.50%–72.75%], p < 0.05). After adjusting for age, gender, and the body-mass index (BMI), each 1-event/h increase in the AHI was linked to a borderline reduction in the LVEF (-0.71%, 95% CI: -1.42 to 0.00; p = 0.05). A 1-unit increase in the RERTA corresponded to a 0.33% decrease in the LVEF (95% CI: -0.62% to -0.04%, p < 0.05).
Conclusions
The RERTA combines the AHI and mean LFCT, providing a joint assessment of circulatory stress in patients with OSA. This study highlights its potential utility in evaluating cardiac function associated with OSA, which can serve as a basis for future prospective research.
Date Issued
2025-11-12
Date Acceptance
2025-10-08
Citation
BMC Pulmonary Medicine, 2025, 25
ISSN
1471-2466
Publisher
BMC
Journal / Book Title
BMC Pulmonary Medicine
Volume
25
Copyright Statement
© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/41225481
PII: 10.1186/s12890-025-03974-6
Subjects
Cardiac function
Left ventricular ejection fraction
Lung-to-finger circulation time
Obstructive sleep apnea
Respiratory event response time area
Humans
Sleep Apnea, Obstructive
Male
Female
Middle Aged
Retrospective Studies
Polysomnography
Echocardiography
Stroke Volume
Aged
Oxygen Saturation
Ventricular Function, Left
Adult
Severity of Illness Index
Publication Status
Published
Coverage Spatial
England
Article Number
520
Date Publish Online
2025-11-12