Patent Foramen Ovale in Obstructive Sleep Apnoea and Chronic Obstructive Pulmonary Disease
Author(s)
Shaikh, Zarrin F
Type
Thesis
Abstract
The objective of this thesis was to determine the impact of right to left
shunting (RLS) through patent foramen ovale (PFO) on oxygen saturation in
obstructive sleep apnoea (OSA) and chronic obstructive pulmonary disease
(COPD).
The first aim was to determine the prevalence of PFO in severe OSA and
whether PFO closure improves nocturnal oxygen saturation. The data showed
that PFO with large shunts were more prevalent, however overall prevalence
was not statistically different when compared to healthy controls. PFO closure
did not reduce nocturnal desaturation.
The second aim was to determine whether severe COPD patients with PaO2
≤ 7.3kPa had a higher prevalence of PFO compared to patients with PaO2 >
8kPa, additionally to compare the prevalence of PFO in COPD with healthy
controls. The data showed no difference in PFO prevalence in patients
with PaO2 ≤ 7.3kPa compared to patients with PaO2 > 8kPa, however,
intrapulmonary shunts were more prevalent in hypoxaemic patients. Similar
to OSA, PFO with large shunts were more prevalent in severe COPD, however
overall prevalence was not statistically different to healthy controls.
The final aim was to determine whether patients with COPD and PFO
developed RLS during exercise and whether this was associated with reduced
oxygen saturation, reduced exercise endurance and increased intrathoracic
pressure swings. The data showed that RLS through PFO increased from
baseline during exercise and this was associated with increased swings in
intrathoracic pressure. There was no difference in desaturation or exercise
endurance when compared to patients with no PFO.
In summary, this thesis shows that PFO with large shunts are more prevalent
in both OSA and COPD. PFO closure in OSA did not reduce nocturnal
desaturation. Furthermore, the presence of a PFO in COPD did not influence
resting or exercise oxygen saturation despite the observed increase in RLS
with exercise.
shunting (RLS) through patent foramen ovale (PFO) on oxygen saturation in
obstructive sleep apnoea (OSA) and chronic obstructive pulmonary disease
(COPD).
The first aim was to determine the prevalence of PFO in severe OSA and
whether PFO closure improves nocturnal oxygen saturation. The data showed
that PFO with large shunts were more prevalent, however overall prevalence
was not statistically different when compared to healthy controls. PFO closure
did not reduce nocturnal desaturation.
The second aim was to determine whether severe COPD patients with PaO2
≤ 7.3kPa had a higher prevalence of PFO compared to patients with PaO2 >
8kPa, additionally to compare the prevalence of PFO in COPD with healthy
controls. The data showed no difference in PFO prevalence in patients
with PaO2 ≤ 7.3kPa compared to patients with PaO2 > 8kPa, however,
intrapulmonary shunts were more prevalent in hypoxaemic patients. Similar
to OSA, PFO with large shunts were more prevalent in severe COPD, however
overall prevalence was not statistically different to healthy controls.
The final aim was to determine whether patients with COPD and PFO
developed RLS during exercise and whether this was associated with reduced
oxygen saturation, reduced exercise endurance and increased intrathoracic
pressure swings. The data showed that RLS through PFO increased from
baseline during exercise and this was associated with increased swings in
intrathoracic pressure. There was no difference in desaturation or exercise
endurance when compared to patients with no PFO.
In summary, this thesis shows that PFO with large shunts are more prevalent
in both OSA and COPD. PFO closure in OSA did not reduce nocturnal
desaturation. Furthermore, the presence of a PFO in COPD did not influence
resting or exercise oxygen saturation despite the observed increase in RLS
with exercise.
Date Issued
2011-06
Date Awarded
2012-03
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Mullen, Michael
Morrell, Mary
Polkey, Michael
Creator
Shaikh, Zarrin F
Publisher Department
National Heart and Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)