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Studies have shown a higher prevalence of patent foramen ovale (PFO) in patients with obstructive sleep apnoea (OSA). Right to left shunting via a PFO may be encouraged by OSA respiratory physiology, contributing to OSA pathophysiology. We assessed whether PFO closure would improve respiratory polygraphy parameters compared to baseline in patients with OSA.
Twenty-six patients with newly diagnosed OSA and a moderate-large PFO (prevalence 18% of 143 patients screened) were referred for PFO closure. PFO closure was completed in 24 patients (1 withdrew and 1 technically not feasible). The oxygen desaturation index (ODI), apnoea-hypopnoea index (AHI), Epworth Sleepiness Score (ESS), 6-minute walk test (6MWT), Sleep Apnoea Quality of Life Index (SAQLI), Functional outcome of sleep questionnaire (FOSQ) and Short form 36 (SF36) were compared in these patients at baseline (before continuous positive pressure ventilation (CPAP) was initiated) and at 6-months follow-up (after interrupting CPAP for 1 week).
All PFO were safely sealed at 6-months as confirmed by repeat transthoracic echocardiography bubble study. The ODI (44.8 IQR 31.2-63.5 vs. 42.3 IQR 34.0-60.8, p=0.89) and AHI (47.9 IQR 31.5-65.2 vs. 42.3 IQR 32.1-63.7, p=0.99) did not change after PFO closure, and nor did the 6MWT although the ESS and quality of life indices did improve (Table: p-value by Wilcoxon’s rank sum test). CPAP adherence prior to discontinuation, did not completely explain the ESS findings (regression coefficient = -0.29 ESS decrease/ hour of CPAP use, se=0.34, p=0.40).
|Baseline pre closure||6 months post closure||p-value|
|AHI||47.9||31.5 - 65.2||42.3||32.1 – 63.7||0.99|
|ODI||44.8||31.2 – 63.5||42.3||34.0 – 60.8||0.89|
|6MWT (m)||505.5||478.8 – 526.8||489.5||443.8 – 523.8||0.73|
|ESS||13||12 – 16.8||6||4.0 – 8.8||<0.001|
|SF36||51.9||45.0 – 55.6||48.5||43.1 – 54.3||0.44|
|SAQLI||3.4||2.8 - 4.3||4.4||3.9 – 5.3||<0.001|
|FOSQ||2.9||2.7 – 3.2||3.6||3.4 – 3.7||<0.001|
The prevalence of moderate-large PFO in OSA appears to be no higher than in the general population. Although PFO closure is safe and effective it did not improve respiratory polygraphy measures of OSA severity and therefore should not be recommended. The improvement in ESS and SAQLI likely reflect residual benefits from CPAP.
STRUCTURAL: Congenital and Other Structural Heart Disease