Cerebrovascular Reactivity In Patients With Obstructive Sleep Apnea Hypopnea Syndrome And Its Relationship With Acute Cerebral Infarction

Background and Objective:Obstructive sleep apnea hypopnea syndrome is caused by anatomic or physiological impairment of the upper airway which is narrowed or even completely blocked.Symptoms are apnea and hypopnea at night,causing hypoxemia and hypercapnia during sleep,leading to sleep structure disorder,daytime sleepiness and multiple system complications.Among them,hypertension,coronary heart disease and cerebrovascular disease are the most prominent.In 2014,OSAHS was officially listed as one of the secondary prevention risk factors for acute ischemic cerebrovascular disease in China.At present,the mechanism of OSAHS leading to acute ischemic cerebrovascular disease is still unclear,which may include endothelial dysfunction,neuromodulation abnormalities,metabolic abnormalities,changing in cerebral hemodynamics,hypercoagulability,and circadian rhythm abnormalities.Cerebrovascular reactivity is the ability of cerebral blood vessels to contract and expand when cerebral perfusion pressure and arterial blood partial pressure of carbon dioxide have changed,which reflects the reserving capacity of cerebral blood vessels.Multiple studies have shown that CVR impairment is an independent risk factor for acute ischemic stroke.At present,there is no consensus on the change of CVR in OSAHS patients.In this study,the cerebrovascular reactivity of OSAHS patients was measured,and several risk factors for the occurrence of acute cerebral infarction in OSAHS patients were analyzed.The study will provide a new idea for the prevention of the occurrence of acute cerebral infarction in OSAHS patients.Methods:A total of 176 patients with obstructive sleep apnea hypopnea syndrome who visited the department of neurology and otolaryngology of Weihai Central Hospital Affiliated to Qingdao University from September 2017 to October 2019 were collected.They were all completed polysomnography monitoring and transcranial doppler ultrasound examinations.According to the symptoms,signs and cranial magnetic resonance imagings,the patients were divided into OSAHS group(n=92)and OSAHS with acute cerebral infarction group(n=84).OSAHS group was divided into mild group(n=30),moderate group(n=33)and severe group(n=29)according to the index of apnea hypopnea.The OSAHS with ACI group was divided into NIHSS(1-5 points)group(n=24),NIHSS(6-10 points)group(n=32),and NIHSS(11-15 points)group(n=32)according to the national institute of research health stroke scale score of the patients.During the same period,25 patients with sleep snoring were selected as the control group(n=25).They have finished PSG and head MRI and confirmed that they were patients with simple snoring when did health examination in our hospital.The age,gender,body mass index,smoking,drinking,history of hypertension,history of diabetes,blood lipid level,blood uric acid,blood homocysteine,breath holding index,carotid artery color doppler ultrasound and other relevant test results were recorded.Two independent sample t test and one-way anova were used to analyze the changes of cerebrovascular reactivity in OSAHS patients,the impacting factors of cerebral infarction in OSAHS patients were analyzed by binary logistic regression,and the impacting factors of the severity of neurological impairment in OSAHS patients with cerebral infarction were analyzed by multiple ordered logistic regression.Results:BHI in OSAHS group was lower than that in the control group,and the difference was statistically significant[1.03(0.63,1.59)vs1.49(1.44±0.52),P<0.05].BHI in the mild OSAHS group was higher than that in the moderate and severe groups,and the moderate group was higher than that in the severe group,with a statistically significant difference[(1.58±0.57)vs(1.06±0.53)vs(0.74±0.33),P<0.05].There was a negative correlation between AHI and BHI[r_s=-0.770,P<0.01],and a positive correlation between AHI and BHI[rs=0.711,P<0.01].BHI in the OSAHS group with cerebral infarction was lower than that in the OSAHS group,and the difference was statistically significant[0.61(0.51,0.97)vs 1.03(0.63,1.59),P<0.05].Increased age,history of hypertension,elevated serum uric acid level and BHI impairment are risk factors for cerebral infarction in OSAHS patients(P<0.05).The sensitivity and specificity of BHI in predicting cerebral infarction in OSAHS patients were 82.1%and 47.8%,respectively,with a critical value of 1.025,and the area under the working characteristic curve of the subjects was 0.697.Decreased BHI and elevated blood homocysteine levels are risk factors for more severe neurological deficits in OSAHS patients with cerebral infarction(P<0.05).Conclusion:The cerebrovascular reactivity of OSAHS patients decreases,the more serious the OSAHS is,and the worse the cerebrovascular reactivity is.Risk factors for cerebral infarction in OSAHS patients include BHI impairment,increasing age,history of hypertension,and increasing blood uric acid level.BHI value is valuable for early prediction of cerebral infarction in OSAHS.Decreased BHI and elevated blood homocysteine levels are risk factors for more severe neurological damages in OSAHS patients with cerebral infarction.