Abstract
PURPOSE: Both obstructive sleep apnea (OSA)and patent foramen ovale (PFO) can lead to changes in blood oxygen. However, it is unclear whether PFO exacerbates the blood oxygen indicators of OSA. METHODS: This case series study included patients who underwent contrast-enhanced transcranial Doppler (c-TCD) and polysomnography (PSG examination) between January 2017 to December 2023 at the Third Affiliated Hospital of Yan'an University. Based on c-TCD and PSG results, patients were categorized into two groups: OSA and PFO double-positive group (OSA + PFO), OSA single-positive group (OSA). Furthermore, both the OSA + PFO and OSA groups were further subdivided into mild (5 times/hour ≤ AHI < 15 times/hour), moderate (15 times/hour ≤ AHI < 30 times/hour) and severe (AHI ≥ 30 times/hour) groups according to their apnea-hypopnea index (AHI). This study compared the minimum oxygen saturation, oxygen desaturation index (ODI), the percentage of cumulative time with oxygen saturation < 90% in total sleep time (T90) among all groups. RESULTS: A total of 509 patients were included (386 males,75.83%; 123females,24.17%), with an average age of 56.76 ± 10.23 years. The study cohort included 97 OSA + PFO cases (55.67% moderate to severe) and 412 OSA cases (63.35% moderate to severe). No significant differences were observed in minimum oxygen saturation (75.97 ± 12.70% vs. 76.34 ± 12.67%, respectively, P =0.607) and ODI (32.99 ± 24.16% vs. 34.31 ± 23.59%, respectively, P =0.173) between the OSA group and the OSA + PFO group. Similarly, no significant differences were found in T90 (14.20 ± 20.50% vs. 16.69 ± 21.62%, respectively, P =0.075) between the OSA group and the OSA + PFO group. However, the T90 values were significantly higher in the moderate-severe OSA + PFO group compared to the moderate-severe OSA group (26.21 ± 22.97% vs.18.68 ± 22.02%, respectively, P < 0.05). CONCLUSIONS: Although PFO has no significant effect on minimum oxygen saturation and ODI, PFO further aggravates intermittent hypoxia in patients with moderate to severe OSA.