Effect of Patent Foramen Ovale Closure on Obstructive Sleep Apnea

Prognostic significance of patent foramen ovale in anticoagulated patients with atrial fibrillation

Objective

Previous studies have postulated a causal role of patent foramen ovale (PFO) in the aetiology of embolic stroke in the general population. We hypothesised that the presence of concomitant PFO and atrial fibrillation (AF) will add incremental risk of ischaemic stroke to that linked to AF alone.

Methods

We analysed data on 3069 consecutive patients (mean age 69.4±12.2 years; 67.1% men) undergoing transoesophageal echocardiography-guided electrical cardioversion (ECV) for AF between May 2000 and March 2012. PFO was identified by colour Doppler and agitated saline contrast study. All patients were followed up after ECV for first documentation of ischaemic stroke. Outcomes were compared using Cox regression models.

Results

The prevalence of PFO was 20.0% and the shunt direction was left-to-right in the majority of patients (71.4%). Patients with PFO had a higher frequency of obstructive sleep apnoea (21.7% vs 17.1%, p=0.01) and higher mean peak left atrial appendage emptying velocity (38.3±21.8 vs 36.1±20.4 cm/s; p=0.04) compared with those without PFO. Otherwise, baseline characteristics were similar between groups. During a mean follow-up period of 7.3±4.6 years, 214 patients (7.0%) had ischaemic stroke. Multivariable analysis showed no significant association between PFO and ischaemic stroke (HR, 0.82 (95% CI 0.57 to 1.18)). PFO shunt direction was strongly associated with stroke: HR, 1.91 (95% CI 1.16 to 3.16) for right-to-left shunt and HR, 0.58 (95% CI 0.36 to 0.93) for left-to-right shunt.

Conclusions

The presence of concurrent PFO in this largely anticoagulated group of patients with AF was not associated with increased risk of ischaemic stroke.

Effects of Patent Foramen Ovale Closure on Obstructive Sleep Apnea Syndrome: PCOSA Study

BACKGROUND

Previous studies have shown a higher prevalence of patent foramen ovale (PFO) in patients with obstructive sleep apnea syndrome (OSAS). Right to left shunting through a PFO may be encouraged by the respiratory physiology of OSAS, contributing to the disease pathophysiology. We assessed whether PFO closure would improve respiratory polygraphy parameters compared with baseline measurements in patients with OSAS.

METHODS

Twenty-six patients with newly diagnosed OSAS and a moderate-large PFO (prevalence, 18% of 143 patients screened) were referred for PFO closure. The oxygen desaturation index (ODI), apnea-hypopnea index (AHI), Epworth Sleepiness Scale (ESS), 6-minute walk test (6MWT), and Sleep Apnea Quality of Life Index (SAQLI) results were compared in these patients at baseline (before continuous positive pressure ventilation [CPAP]) and at 6-month follow-up (after interrupting CPAP for 1 week).

RESULTS

All PFOs were safely sealed at 6 months, as confirmed by repeated transthoracic echocardiography. The ODI (44.8 [interquartile range (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]; P = 0.99) did not change after PFO closure nor did the 6MWT, although the ESS (13.0 [IQR, 12.0-16.8] vs 6.0 [IQR, 4.0-8.8]; P < 0.001) and the SAQLI (3.4 [IQR, 2.8-4.3] vs 4.4 [IQR, 3.9-5.3]; P < 0.001) did improve.

CONCLUSIONS

The prevalence of PFO in OSAS appears to be no higher than that in the general population. Although PFO closure is safe and effective, it did not improve respiratory polygraphy measures of OSAS severity. The improvement in the ESS and SAQLI likely reflect residual benefits from CPAP.

Patient Management of Hypertensive Subjects without and with Diabetes Mellitus Type II

The description of blood pressure (BP) curve has evolved to include several noninvasively determined parameters, such as aortic stiffness, BP variability, wave reflections, and pulse pressure amplification. These techniques are likely to improve the efficacy of assessing pulsatile arterial hemodynamics and changes in arterial stiffness. The goal for future antihypertensive treatments should not only reduce steady BP, but also control pulsatile pressure and modify the stiffness gradient between central and peripheral arteries, which is frequently elevated. These changes have the potential to reduce residual cardiovascular risk but also to define drug strategies adapted to the needs of individual hypertensive subjects.

Sleep-Disordered Breathing and Vascular Function in Patients With Chronic Mountain Sickness and Healthy High-Altitude Dwellers

BACKGROUND

Chronic mountain sickness (CMS) is often associated with vascular dysfunction, but the underlying mechanism is unknown. Sleep-disordered breathing (SDB) frequently occurs at high altitude. At low altitude, SDB causes vascular dysfunction. Moreover, in SDB, transient elevations of right-sided cardiac pressure may cause right-to-left shunting in the presence of a patent foramen ovale (PFO) and, in turn, further aggravate hypoxemia and pulmonary hypertension. We speculated that SDB and nocturnal hypoxemia are more pronounced in patients with CMS compared with healthy high-altitude dwellers, and are related to vascular dysfunction.

METHODS

We performed overnight sleep recordings, and measured systemic and pulmonary artery pressure in 23 patients with CMS (mean ± SD age, 52.8 ± 9.8 y) and 12 healthy control subjects (47.8 ± 7.8 y) at 3,600 m. In a subgroup of 15 subjects with SDB, we assessed the presence of a PFO with transesophageal echocardiography.

RESULTS

The major new findings were that in patients with CMS, (1) SDB and nocturnal hypoxemia was more severe (P < .01) than in control subjects (apnea-hypopnea index [AHI], 38.9 ± 25.5 vs 14.3 ± 7.8 number of events per hour [nb/h]; arterial oxygen saturation, 80.2% ± 3.6% vs 86.8% ± 1.7%, CMS vs control group), and (2) AHI was directly correlated with systemic blood pressure (r = 0.5216; P = .001) and pulmonary artery pressure (r = 0.4497; P = .024). PFO was associated with more severe SDB (AHI, 48.8 ± 24.7 vs 14.8 ± 7.3 nb/h; P = .013, PFO vs no PFO) and hypoxemia.

CONCLUSIONS

SDB and nocturnal hypoxemia are more severe in patients with CMS than in control subjects and are associated with systemic and pulmonary vascular dysfunction. The presence of a PFO appeared to further aggravate SDB. Closure of the PFO may improve SDB, hypoxemia, and vascular dysfunction in patients with CMS.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01182792; URL: www.clinicaltrials.gov.

Sleep Apnea in Patients with and without a Right-to-Left Shunt

OBJECTIVES

To assess the presence of right-to-left shunting (RLS) in patients with obstructive sleep apnea (OSA), and compare clinical characteristics and parameters of the sleep studies of patients with and without RLS.

BACKGROUND

The most common cause of RLS is due to intermittent flow through a patent foramen ovale (PFO). PFO occurs more frequently in patients with OSA and may be involved in the exacerbation of OSA.

METHODS

Patients with an abnormal polysomnogram seen at UCLA-Santa Monica Sleep Medicine Clinic were enrolled. A diagnosis of RLS was made using a transcranial Doppler (TCD) bubble study. Gender and age-matched controls were drawn from patients referred for cardiac catheterization who underwent a TCD. The frequency of RLS in OSA patients and the controls was evaluated. Clinical characteristics and polysomnogram parameters were compared between OSA patients with and without a RLS.

RESULTS

A total of 100 OSA patients and 200 controls participated in the study. The prevalence of RLS was higher in patients with OSA compared to the control group (42% versus 19%; p < 0.0001). Patients with OSA and a RLS had a lower apnea-hypopnea index (AHI), less obstructive apnea, and fewer hypopnea episodes than patients with OSA without a RLS. The baseline and nadir SpO2 were similar in both groups and did not correlate with the level of RLS assessed by TCD. The degree of desaturation for a given respiratory disturbance, as measured by oxygen desaturation index (ODI)/AHI ratio, was higher in OSA patients with RLS versus OSA patients without RLS (0.85 ± 0.07 versus 0.68 ± 0.04; p < 0.0001).

CONCLUSION

RLS, most commonly due to a PFO, occurs 2.2 times more frequently in OSA patients compared to a control population that was matched for age and gender. The severity of sleep apnea is not greater in OSA patients who have a PFO. However, patients with OSA and a PFO are more likely to become symptomatic at a younger age with an equivalent decrease in nocturnal SpO2, and have greater arterial desaturation in proportion to the frequency of respiratory disturbances.

Patent Foramen Ovale Closure in Obstructive Sleep Apnea Improves Blood Pressure and Cardiovascular Function

Obstructive sleep apnea (OSA) is a frequent syndrome characterized by intermittent hypoxemia and increased prevalence of arterial hypertension and cardiovascular morbidity. In OSA, the presence of patent foramen ovale (PFO) is associated with increased number of apneas and more severe oxygen desaturation. We hypothesized that PFO closure improves sleep-disordered breathing and, in turn, has favorable effects on vascular function and arterial blood pressure. In 40 consecutive patients with newly diagnosed OSA, we searched for PFO. After initial cardiovascular assessment, the 14 patients with PFO underwent initial device closure and the 26 without PFO served as control group. Conventional treatment for OSA was postponed for 3 months in both groups, and polysomnographic and cardiovascular examinations were repeated at the end of the follow-up period. PFO closure significantly improved the apnea-hypopnea index (ΔAHI -7.9±10.4 versus +4.7±13.1 events/h, P=0.0009, PFO closure versus control), the oxygen desaturation index (ΔODI -7.6±16.6 versus +7.6±17.0 events/h, P=0.01), and the number of patients with severe OSA decreased significantly after PFO closure (79% versus 21%, P=0.007). The following cardiovascular parameters improved significantly in the PFO closure group, although remained unchanged in controls: brachial artery flow-mediated vasodilation, carotid artery stiffness, nocturnal systolic and diastolic blood pressure (-7 mm Hg, P=0.009 and -3 mm Hg, P=0.04, respectively), blood pressure dipping, and left ventricular diastolic function. In conclusion, PFO closure in OSA patients improves sleep-disordered breathing and nocturnal oxygenation. This translates into an improvement of endothelial function and vascular stiffening, a decrease of nighttime blood pressure, restoration of the dipping pattern, and improvement of left ventricular diastolic function.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01780207.

Patent foramen ovale (PFO): is there life before death in the presence of PFO?

Patent foramen ovale (PFO) is an embryologic remnant with incomplete postnatal adhesion of the cardiac atrial septum primum and secundum. After birth, the prevalence of PFO decreases from about 35% at young to approximately 20% at old age. PFO has been associated with numerous conditions such as decompression illness in divers, migraine, high-altitude pulmonary oedema, cerebrovascular and coronary ischaemia, and obstructive sleep apnoea syndrome. PFO is the cause of intermittent atrial right-to-left shunt, and it can be the source of cardiac paradoxical embolism. So far, randomized controlled trials have not documented a reduced rate of cerebrovascular recurrent events in patients receiving PFO device closure as compared to those on medical treatment. The purpose of this article was to critically evaluate evidence on the pathophysiologic, clinical as well as prognostic relevance of PFO.