Selective Impairment Of Attentional Networks In Elderly Hypertensive Patients During The Perioperative Period

Objective Hypertension(HTN) is the most common phenomenon seen in the elderly, the incidence increased year by year. HTN is an important risk factor for cognitive impairment. The impairment of attention network of aged hypertensive patients during the perioperative period and the mechanisms are still unclear. Attention network is viewed as an essential component of cognitive function. Cognitive dysfunction may often exist with attention network impairment. Attention network test is an appropriate method to study attention deficit because of its clear anatomical location and neurotransmitter. However, few studies focus on the mechanism of attention impairment in early mild cognitive impairment during the perioperative period in the aged hypertensive patients. We aim to use ANT to study the attention impairment of aged hypertensive patients during the perioperative period.Methods 1.Montreal Cognitive Assessment(Mo CA) scale is used to investigate the cognitive function of the patients. We evaluated 30 untreated hypertensive patients who had a recent history of stage 1 essential HTN for 3–5 years. We compared these patients to 30 healthy persons who were matched with the hypertensive patients by sex, age, educational level and MMSE scores and who served as the control group. Three attention networks(i.e., alerting, orienting, and executive control) were estimated using the ANT.2.We evaluated 25 elderly patients assigned to a planned hip or knee arthroplasty surgery and in age over 60 years without preoperative cognitive dysfunction as the operation group. Age–education-matched controls(n = 25) served as the control group to eliminate learning effects of the ANT. All the participants of the operation groupcompleted the Mini-Mental State Examination(MMSE) and the ANT before surgery. They were retested in ANT on the postoperative days 2 and 7. The participants of the control group completed the MMSE before and performed the ANT for three times at the same time intervals as the operation group.3.We evaluated 20 untreated hypertensive patients assigned to a planned hip or knee arthroplasty surgery and in age over 60 years, and 20 healthy persons matched with HTN patients by sex, age, and educational level as the control group. All the participants completed the Mini-Mental State Examination(MMSE) before the operation and they underwent the Attention Network Test(ANT) on the preoperative and the 7th postoperative day. Data analysis was performed using SPSS(Version 13.0). The threshold for significance was set at P < 0.05Results 1.Hypertension group compared with the normotensive group, the visuospatial and executive function, attention, delayed recall and total scores of Mo CA significantly lower, the difference was statistically significant(P<0.05). The normotensive group demonstrated greater attention efficiencies than the hypertensive participants in the alerting and executive control attention networks(P<0.05). There were no differences in the orienting attention network, mean reaction time, or accuracy.2.In the operation group, there were no differences in the overall mean reaction time or accuracy during the perioperative period. After surgery, the elderly patients demonstrated a significantly worse attention efficiency in the alerting(P=0.004) and executive control(P=0.035) attention networks on the second day after surgery, but recovered to the baseline level(P=0.349, P=0.342) on the seventh day after surgery. However, they performed significantly worse attention efficiency in the orienting(P<0.001) on the second day after surgery, only partially recovered(P<0.001) on the seventh day after surgery compared with the preoperative level. However, there was no difference of the attention network during the three different time periods in the control group.3. The hypertensive patients demonstrated a significantly worse attention efficiency in the alerting(P=0.007), orienting(P<0.001)and executive control(P=0.005)attention networks on the postoperative day 7 than the preoperative. There were no differences in the alerting(P=0.113) or executive control(P=0.404) between the preoperative and the 7th day postoperative of the control group and the efficiency of the orienting network was worse(P<0.001)on the seventh day postoperative than the preoperative. However, there was no difference in the accuracy between the preoperative and postoperative period in the two groups.Conclusion 1. Elderly patients of stage 1 essential hypertension without treatment are significantly lower on the visuospatial and executive function, attention, delayed recall and total scores of Mo CA, indicating that hypertensive patients were cognitive dysfunction. Elderly hypertensives have a significantly worse performance on the attention networks especially alerting and executive control.2. Elderly patients showed different efficiencies of the three attention networks during the perioperative period. The trial demonstrated that general anesthesia and surgery impaired the performance on an established spatial memory task in the elderly on the 2th day postoperative. However, it produced a sustained impairment in orienting effect in aged patients within 1week after surgery. The efficiencies of the alerting and executive control networks recovered in advance to the orienting network after surgery.3. Elderly hypertensive patients showed worsen efficiency of attention network especially in alerting and executive control network during the postoperative period.