Patent foramen ovale is not associated with hypoxemia in severe chronic obstructive pulmonary disease and does not impair exercise performance.

RATIONALE: Patent foramen ovale (PFO) may be disadvantageous in chronic obstructive pulmonary disease (COPD). It is unknown whether right-to-left shunting through PFO increases during exercise impairing exercise performance. OBJECTIVES: To determine whether (1) PFO prevalence is greater in hypoxemic versus less hypoxemic patients with COPD, (2) PFO is associated with clinically relevant impairment, and (3) right-to-left shunting increases during exercise and impairs exercise performance. METHODS: Patients with COPD and age-matched control subjects underwent contrast transthoracic echocardiography and transcranial Doppler to identify PFO. Patients with COPD with no shunt and patients with large PFO underwent cardiopulmonary exercise tests with contrast transcranial Doppler, esophageal, and gastric balloon catheters. MEASUREMENTS AND MAIN RESULTS: PFO prevalence was similar in 50 patients with COPD and 50 healthy control subjects (46% vs. 30%; P = 0.15). Large shunts were more common in patients with COPD (26% vs. 6%; P = 0.01). In an expanded COPD cohort, PFO prevalence was similar in 31 hypoxemic (Pao2 ≤ 7.3 kPa) and 63 less hypoxemic (Pao2 > 8.0 kPa) patients with COPD (39% vs. 52%; P = 0.27). Patients with intrapulmonary shunting had lower Pao2 than both patients with PFO and those with no right-to-left shunt (7.7 vs. 8.6 vs. 9.3 kPa, respectively; P = 0.002). Shunting significantly increased during exercise in patients with COPD with PFO. Endurance time at 60% Vo2max was 574 (178) seconds for patients with PFO and 534 (279) seconds for those without (P = ns). CONCLUSIONS: Hypoxemic patients with COPD do not have a higher prevalence of PFO. Patients with COPD with PFO do not perform less well either on a 6-minute walk or submaximal exercise testing despite increased right-to-left shunting during exercise.

Patent foramen ovale in severe obstructive sleep apnea: clinical features and effects of closure.

BACKGROUND: Patent foramen ovale (PFO) may contribute to nocturnal desaturation in patients with obstructive sleep apnea (OSA), and the effect of PFO closure in OSA is unknown. Our study tested the hypotheses that: (1) patients with severe OSA have a higher prevalence of PFO compared with healthy control subjects, (2) patients with severe OSA with clinically significant PFO experience more nocturnal desaturation than those without, and (3) PFO closure reduces nocturnal desaturation. METHODS: Patients with severe OSA and healthy control subjects underwent contrast transthoracic echocardiography and transcranial Doppler to detect PFO and determine shunt size. A subgroup of patients with OSA with large shunts underwent percutaneous PFO closure. Polysomnography was performed at baseline and 1, 6, and 12 months postclosure. RESULTS: One hundred patients with OSA (mean [SD] age, 52 [10] years; apnea-hypopnea index [AHI], 54 [18] events/h) and 50 control subjects (age, 52 [11] years; AHI, 2 [2] events/h) were studied. PFO prevalence was 43% in patients with OSA and 30% in control subjects ( P = .16). Large shunts were detected in 18% of patients with OSA and 6% of control subjects ( P = .049). Patients with OSA with clinically significant shunts had higher oxygen-desaturation index (ODI)/AHI ratios than patients without (ratio, 1.05 [0.27] vs 0.86 [0.26], P = .004). Six patients with OSA underwent PFO closure, which was not associated with a reduction in ODI (baseline, 48 [18]; 12 months, 51 [19] events/h; P = .92) or percentage of the night with arterial oxygen saturation , 90% (baseline, 23% [16%]; 12 months, 20% [22%]; P = .35). CONCLUSIONS: Patients with severe OSA have a higher prevalence of PFO with large shunts compared with control subjects. The ODI/AHI ratio is increased in patients with OSA with clinically significant shunts. PFO closure does not reduce nocturnal desaturation.

Obstructive sleep apnea syndrome is associated with deficits in verbal but not visual memory.

RATIONALE: Although cognitive deficits are well documented in patients with sleep apnea, the impact on memory remains unclear. OBJECTIVES: To test the hypotheses that (1) patients with obstructive sleep apnea have memory impairment and (2) memory impairment is commensurate with disease severity. METHODS: Patients with obstructive sleep apnea and healthy volunteers (apnea-hypopnea index <5 events/h) completed a test battery specially designed to differentiate between aspects of memory (semantic, episodic, and working) versus attention. Sleepiness was measured on the basis of the Epworth Sleepiness Scale and Oxford Sleep Resistance test. Memory performance in patients versus control subjects was compared (Mann-Whitney U test; P < 0.01, Bonferroni corrected for multiple comparisons) and relationships between performance and disease severity were analyzed by linear regression. MEASUREMENTS AND MAIN RESULTS: Sixty patients and healthy control subjects matched for age (mean +/- SD: patients, 51 +/- 9 yr; control subjects, 50 +/- 9 yr) and education (patients, 14 +/- 3 yr; control subjects, 15 +/- 3 yr) participated. Patients demonstrated impaired Logical Memory Test results (immediate recall: patients, median [range], 36 [9-69]; control subjects, 43 [19-64], P = 0.0004; and delayed recall: patients, 22 [6-42]; control subjects, 27 [10-46]; P = 0.0001). There were minimal differences in attention, visual episodic, semantic, or working memory; patients performed better than control subjects on Spatial Span forward and backward. Regression analysis revealed that Logical Memory Test performance was not significantly related to disease severity after controlling for age, education, and sleepiness. CONCLUSIONS: Obstructive sleep apnea is associated with impairment in verbal, but not visual, memory. The impairment was present across a range of disease severity and was not explained by reduced attention. Such verbal memory impairment may affect daytime functioning and performance.