Of 139 consecutive patients admitted to our center with a diagnosis of ischemic stroke or TIA, 110 patients survived for at least 2 months after the ischemic cerebrovascular episode. Of these patients, two who had received CPAP treatment previously were excluded. Twelve patients either failed to give consent or did not report to the sleep study, and 3 patients could not be contacted following the acute episode. The diagnostic polygraphic study was carried out after 64 ± 11 days in 95 patients, except in 3 patients who had a new VE (repeat ischemic stroke in all cases) during this period of time. In these patients, polygraphy was performed 2 months later, A total of 51 patients (53.7%) with an AHI > 20 were finally included. Mean age was 72.7 ± 9.4 years (range, 57 to 82 years; 63% men; BMI, 26.8 ± 4.4 kg/m2; neck circumference, 40.2 ± 6.3 cm). Of these, 39 patients (76.8%) had a chronic snoring disorder, and 10 patients (20%) presented with witnessed apneic episodes. The mean Epworth sleepiness scale score was 7.6 ± 4.2. The VRFs were distributed as follows: 68.6% AHT (43% with poor control); 39.2% diabetes mellitus; 19.6% internal carotid stenosis; 25.5% AF; 25.5% active smoking habit; 15.7% ischemic heart disease; 35.3% hypercholesterolemia; and mean fibrinogen concentration, 335 ± 78 mg/dL. Twelve of the neurologic events (23.5%) consisted of TIAs. The mean Barthel index was 76.9 ± 32.7, with a Canadian scale score of 8.17 ± 1.9. There were no significant differences in the baseline data between groups with respect to age, sex, VRF, or characteristics of stroke (Table 1). The mean duration of Autoset Portable Plus II registry was 6.3 ± 3.1 h (range, 3.5 to 9 h). The mean AHI was 37.4 ± 7.9, with an obstructive apnea index of 31.5 ± 10.8, a central apnea index of 2.1 ± 2.1, and a counting time with an oxygen saturation of < 90% of 10.2 ± 4.4%.
According to our results, CPAP treatment protected against the appearance of a new VE after ischemic stroke or TIA in patients with an AHI > 20 following stabilization of the neurologic process, without inducing changes in the neurologic recovery parameters, although tolerance of the treatment was low. Some studies have analyzed the course of patients with ischemic stroke in relation to the incidence of SAHS after stabilization of the ischemic event. Good et al reported poorer neurologic recovery and an increase in mortality after 1 year of follow-up in patients who presented with greater nocturnal oxygen desaturation, while Dyken et al found that 4 years after stroke, the patients who died (21%) presented with greater AHI.
Very few studies have evaluated the role of CPAP treatment after stabilization of the neurologic event in the recovery of patients with high AHI values. After patients had 4 weeks of CPAP treatment.
The present study selected all patients with ischemic stroke or TIA admitted to our center during the year 2002, and who had passed the acute phase of the neurologic event and were in a stable phase. Patients previously treated with CPAP were excluded. Patients with a new VE prior to conduction of the sleep diagnostic study were temporarily excluded until 2 months after the last cerebral vascular event. The study protocol was approved by the local ethics committee, and all patients gave informed consent to inclusion in the study.
Assessment of Stroke and VRFs
The diagnosis and location of ischemic stroke or TIA were determined by a neurologist, based on evaluation of the existing neurologic defects and of brain CT scans conducted in the first few hours after patient admission to the emergency department, and again several days later. Stroke subtypes were classified according to the Oxfordshire classification. Functional disability and neurologic impairment at hospital admission were evaluated using widely used neurologic scales: the Barthel index, which assesses daily activity on a scale of 0 to 100 (a score of 100 corresponding to full patient autonomy) and the Canadian scale, quantifying stroke-related symptoms severity from 0 to 10 (decreasing scores indicating greater severity).
The relation between sleep apnea-hypopnea syndrome (SAHS) and certain vascular disorders has gained consistency in recent years. The most widely accepted hypothesis is that SAHS could constitute an independent vascular risk factor (VRF) for the development of cardiac ischemia, cardiac arrhythmias, congestive heart failure, cerebrovascular diseases, and particularly systemic arterial hypertension (AHT). In this sense, some authors have reported a drop in BP, a decrease in fibrinogen concentration, or stabilization of sympathetic tone in patients with SAHS during treatment with continuous positive airway pressure (CPAP), although the studies conducted to date in this sense have been contradictory.
The relation between SAHS and ischemic stroke has been the subject of much debate in recent years, Different studies have shown an excessive presence of obstructive respiratory events weeks after ischemic stroke or transient ischemic attack (TIA) following stabilization of the neurologic process.