Review ArticleTreatment of obstructive sleep apnea syndrome associated with stroke
Introduction
Cerebrovascular disease is one of the most important causes of morbity and increased mortality [1]. It has been demonstrated that stroke patients present a high prevalence of sleep-disordered breathing (SDB) and other sleep disturbances [2]. Obstructive sleep apnea (OSA) increases the risk of stroke by twofold even after controlling for potential confounding factors [3].
Marin et al. [4] concluded in an observational study that in men, OSA may increase the risk of fatal and non-fatal cardiovascular events. Considering the high prevalence of SDB in the stroke population, it seems reasonable that OSA diagnosis and treatment may be crucial for primary and secondary stroke prevention [5]. Some possible mechanisms have been suggested. Dysphagia and paralysis of the accessory respiratory muscles may contribute to the pathophysiological mechanism of OSA after stroke [6], [7]. The eventual central respiratory depression observed during the acute phase of stroke can also be linked to SDB prevalence in this period; however, there is a low prevalence of central sleep apnea post stroke [6].
Positive airway pressure (PAP) is the treatment of choice for OSA depending on its severity and patient's comorbidities [8]. When OSA is associated with cardiovascular complications, PAP is also the preferred treatment [9]. Excessive daytime sleepiness is an important indicator for OSA [10], [11], [12]. However, patients who suffer from stroke can have a weak perception of their daytime sleepiness or social isolation, and consequently, their Epworth scores are usually low [13]. The different clinical presentation of OSA in this patient group may lead to under-recognition and lack of treatment of SDB in these patients. Thus, considering the high prevalence of OSA, SDB must be investigated when there is a clinical history of obesity, snoring, systemic arterial hypertension, diabetes or stroke, particularly in male patients [14].
The standard method to diagnose SDB is full, attended polysomnography (PSG) or portable monitoring [15]. However, the higher complexity of cognitive and motor impairments in stroke patients and higher costs limit the use of PSG on a routine basis. A good alternative may be to conduct portable PSG studies on stroke patients admitted to hospital facilities. Currently, the ideal moment to perform a sleep study in these patients is not well established. In the present review, we discuss the association between stroke and SDB treatment with nocturnal non-invasive ventilation. We focused on the types and general indications of OSA treatment, PAP ventilation onset, choice of suitable equipment, PAP adherence, and the clinical outcomes after treatment.
Section snippets
Continuous positive airway pressure
Continuous positive airway pressure (CPAP) is considered the gold standard treatment for OSA [8], and it normalizes sleep architecture, increases productivity, improves mood, and reduces excessive daytime sleepiness, traffic accidents and the risk of cardiovascular events [16]. Adherence to CPAP by the patient is also a crucial factor for treatment success. Some important and prevalent aspects should be considered during the ventilatory support of OSA after stroke [17], [18]. Changes in the
CPAP adherence
For OSA treatment, CPAP must be used for at least 4 h per night for more than 70% of the time. There is a dose–response relationship between the amount of CPAP use and reduction of daytime sleepiness as well as improvement in the quality of life [26]. However, 39–83% of all OSA patients fail to adhere to the PAP treatment [27]. The main causes of non-adherence to PAP are claustrophobia, facial or thoracic discomfort, mask leakage or irritation, upper-airway obstruction, or other sleep disorders
PAP in stroke patients
It has been suggested that early treatment of SDB after stroke can be more cost-effective [39], [40]. Long-term studies evaluating the effectiveness will be necessary to establish these benefits. CPAP is the main treatment for OSA and has been proposed as the treatment for patients with concomitant stroke and SDB [18]. Despite the increasing body of evidence, the implementation of CPAP treatment is still a challenge. In different studies CPAP treatment has a limited adherence, ranging from a
Clinical effects after CPAP treatment
There are currently few studies demonstrating significant clinical benefits of SDB treatment with CPAP in stroke patients (Table 3). In a prospective observational study with 105 stroke patients with SDB, CPAP treatment improved subjective well-being of participants and decreased mean arterial blood pressure after 10 days of regular use [45]. In this study, intolerance to CPAP was higher in patients with aphasia and limitations evaluated by the ADL scale. Sixty-three of 105 stroke patients with
Other treatment options for OSA in stroke patients
Positional therapy has a significant influence on AHI. Approximately 56% of patients with OSA have position-dependent events. A few studies with small numbers of patients show that encouraging lateral sleep with pillows, inflatable backpacks, electronic position sensor bands or “tennis-ball t-shirt” are promising as additional measures to improve the success rate of other established treatments in stroke patients [52], [53]. In a sample of 55 acute stroke patients (ranging from 72 h to six
Conclusions
Stroke patients have a high incidence of SDB. CPAP is the gold standard treatment for OSA, and its effectiveness depends on patient adherence. SDB treatment in stroke patients with CPAP may lead to improvements in different clinical aspects, such as depression, well-being and arterial blood pressure. It has been also demonstrated that CPAP treatment for stroke may be associated with decreased mortality. Functional and motor aspects in rehabilitation may also improve with SDB treatment.
Conflicts of interest
There are no financial or other relationships that might lead to conflicts of interest for any of the authors.
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2014.12.017.
Acknowledgements
We appreciate the financial support of the Associação Fundo de Incentivo a Pesquisa (AFIP) [CEPID 98/14303-3]; and São Paulo Research Foundation (FAPESP) [grant #2013/14420-1 to L.J.K.]. S.T. and M.L.A. received CNPq fellowships.
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