Changes of cerebrovascular reserve of obstructive sleep apnea hypopnea syndrome patients evaluated by transcranial cerebral Doppler and its relationship with stroke

Objective To evaluate the changes of cerebrovascular reserve (CVR) of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) by transcranial cerebral doppler (TCD) and to study its relation with stroke. Methods One hundred and twenty- six patients with OSAHS, admitted to our hospitals from July 2012 to January 2013 and diagnosed as having OSAHS, were chosen in our study; they were divided into mild OSAHS group (n=49), moderate OSAHS group (n=44) and severe OSAHS group (n=33) according to test results of polysomnography (PSG). Another 40 healthy controls were collected. The CVR of all subjects were evaluated by TCD merging with CO2 experiment and compared among different groups. All the subjects were accepted continued two-year follow-up and recorded the accidents of stroke. The morbidities of stroke were compared between different groups. Results As compared with those in the control group and mild OSAHS group, all of the contractile reserve, dilatation reserve and overall reserve descended in moderate OSAHS group and severe OSAHS group with statistically significant differences (P<0.05). As compared with those in the moderate OSAHS group, all of the contractile reserve, dilatation reserve and overall reserve descended in severe OSAHS group, and the differences were statistically significant (P<0.05). In the two years of follow-up, the incidence of stroke in the severe OSAHS group (12.12%) was significantly higher than that in the control group (0% ), mild OSAHS group (0% ) and moderate OSAHS group (4.55% ,P<0.05). Conclusion The heavier the condition of OSAHS, the more obviously descended the CVR; the stroke morbidity of severe OSAHS patients is increased significantly. Key words: Transcranial Doppler; Cerebrovascular reserve; Obstructive sleep apnea hypopnea syndrome; Stroke