Introduction:
It is well known that obstructive sleep apnea (OSA) prevalence increases as body mass index (BMI) increases. Lesser known is patent foramen ovale (PFO) is found in 12 to 35 percent of adults. Patients with OSA experience nocturnal apnea which result in hypoxemia, elevation of right atrial pressure, and an increase in right to left shunting and a theoretical increased risk of stroke. A few studies have suggested an association between the severity of OSA and a PFO. As such, OSA diagnosis and therapy may be tailored to address right-to-left shunting in these patients. If the prevalence of PFO in OSA patients is increased, it may be appropriate to include transthoracic echocardiography (TTE) testing as a component of routine evaluation of patients with OSA.
Hypothesis:
We hypothesize that patients with hypoxemia related to OSA are more likely to have a PFO with right-to-left shunting than those with less dramatic hypoxemia. We hope to determine the prevalence and clinical relevance of intra-cardiac shunting in patients with OSA by prospectively analyzing and correlating polysomnography and TTE findings.
Methods:
80 patients with OSA were referred for TTE by the UNM Sleep Center. All patients underwent saline contrast TTE in the UNM echo lab. The prevalence of PFO in the general UNM echo population was calculated over the last year for comparison.
Results:
Of 80 patients with varying degrees of OSA, 12.5% had right to left shunting. PFO was not statistically associated with DI (Desaturation Index), nor any AHI (Apnea Hypopnea Index). The only statistically significant association was between OSA and BMI (p=0.013). BMI associated with DI and AHI was statistically significant (p=0.003 and p=0.005, respectively). Over the last year, 216 PFO’s were found from 1858 echo studies with contrast injection performed at UNM with a prevalence rate of 11.6%.
Conclusions:
In contrast to previous studies, there was no association between OSA of any severity and PFO in our study population. There was a statistically significant association between BMI and OSA, which is well established. Our study prevalence was found to be similar to the UNM general echo population as well, indicating that OSA patients within our study group were not as likely to have an associated PFO.
Prevalence and Impact of Patent Foramen Ovale in Patients with Obstructive Sleep Apnea
