Introduction:
Diastolic heart failure, or heart failure with preserved ejection
fraction (HFpEF) accounts for approximately 50% of all heart failure
and it is associated with increased morbidity and mortality similar to
systolic heart failure (1). It has been suggested that DD is the result
of a response to systemic inflammation predisposed by multiple
comorbidities such as obesity, hypertension, and diabetes that may lead
to remodeling of the myocardium, signaling dysfunction and finally
cardiomyocyte hypertrophy, myocardial stiffness and progressive
interstitial fibrosis (2). Noteworthy, DD has been found to be an
independent predictor of mortality in patients with normal left
ventricular ejection fraction (1). Therefore, the early detection of
susceptible persons and the identification of new risk factors for DD
and HFpEF and attempting to control such conditions is crucial for the
management of these patients.
Although observational data suggest a bidirectional relationship between
obstructive sleep apnea (OSA) and HFpEF (3), it remains unknown whether
this association is due to OSA itself or is mediated by the higher
burden of co-existing cardio-metabolic disorders frequently seen in OSA
patients.
OSA is a chronic respiratory sleep disorder characterized by repetitive
apnea/hypopnea episodes induced by narrowing of the upper airway during
sleep. The intermittent episodes of hypoxemia and sympathetic overdrive
shown to be associated with these apneas and hypopneas lead to
endothelial dysfunction, systemic inflammation, oxidative stress,
arterial hypertension exerting deleterious effects in the cardiovascular
system. OSA has been associated with increased risk for coronary artery
disease, heart failure, arrhythmias, and pulmonary hypertension (4).
Although previous studies have suggested an association between OSA and
DD, the majority of them were limited by the retrospective nature, small
sample size, and the high prevalence of clinical confounders including
hypertension, obesity, and diabetes that these patients exhibit.
Therefore, in this meta-analysis we sought to investigate the
correlation between DD and OSA in patients free of conventional
cardiovascular risk factors.