From this study, it can be seen that men, smoking and high blood pressure may be associated with internal carotid artery stenosis, and they are mostly not smoking cessation and have poor blood pressure control. This is consistent with the findings of several studies [7-9]. Limited data can not prove that obesity, coronary heart disease and diabetes are related to internal carotid artery stenosis, but because abdominal color ultrasound, coronary CTA and glucose tolerance test are not routine examinations, and coronary heart disease was found in 3 cases of coronary CTA, and blood glucose abnormalities were found in 5 cases after admission, their prevalence may be underestimated.
Obesity, hypertension, diabetes and dyslipidemia are the causes of a variety of chronic diseases in the whole body, and the four are combined to be MS. Because height and weight records sometimes rely on patients' own descriptions, not everyone has standardized blood pressure and blood sugar assessment, the number of MS patients may be more. In addition, high BMI can not distinguish between obesity and muscular development, nor can it reflect the distribution of fat in the internal organs, especially in the liver [10]. Blood pressure, blood sugar and blood lipids may also be elevated due to the stress response of the body when admitted to hospital, so there are many difficulties in the accurate diagnosis of MS. Among the few MS diagnostic criteria commonly used internationally are stricter criteria for blood pressure and blood sugar, and the use of waist circumference instead of BMI. The circulatory system of the whole body is a whole, and the damage to blood vessels caused by MS is widespread [11,12]. At present, there are no sufficient clinical trials to provide evidence for whether routine screening of intracranial blood vessels, neck blood vessels, coronary arteries and blood vessels of both lower limbs is necessary. Some studies agree that screening of high-risk groups should be conducted [13-16], and long-term follow-up of large sample groups is also needed in China to judge risk factors [17]. In order to develop a more suitable standard for Chinese people, and the hemodynamic characteristics of the initial and predilection sites of atherosclerosis are the focus of our future research.
In our study, carotid sinus reaction was indeed relatively common, but good results could be obtained after fluid rehydration or vasoactive drugs. No statistically significant differences were found in smoking, blood lipids, blood pressure, MS and stenosis among the three groups treated with normal blood pressure, fluid rehydration after hypotension and drug treatment after hypotension. Only a statistical difference in HDL was found among the three groups, but a number of indicators have shown a trend of differences, which may be found after increasing the sample size. Considering the absence of routine ambulatory blood pressure monitoring before surgery, the maintenance of blood pressure balance due to routine fluid rehydration after surgery, and the error of non-invasive blood pressure monitoring, the decrease in blood pressure after surgery may be underestimated. In the literature, HCY levels higher than 10.7umol/L were defined as hyperhomocysteinemia, and we did not find the difference among the three groups. Whether it is a cause or a result, or a concomitant phenomenon, there is no consensus in the academic community [18].
At present, there is no reliable way to predict the occurrence of postoperative hypotension, and it has been reported in the literature that it is feasible to build a risk score model [19]. A number of studies have shown that hypertension should be controlled before surgery to reduce the variation rate of systolic blood pressure, but it should not be lower than 140/90mmHg, especially in patients with moderate or above stenosis, to ensure adequate cerebral blood flow [20,21].
Despite the intraoperative use of cerebral umbrella, perioperative use of antiplatelet aggregation drugs, and no balloon dilation after stent implantation, there was still one patient with acute ischemic stroke aggravation after surgery, and no significant large vessel occlusion was found in reexamination of the angiography, which was considered as perforator artery occlusion. The use of cerebral umbrella can effectively reduce the occurrence of cerebral infarction after CAS surgery [22,23], but there is no consensus on whether tirofiban and other antiplatelet drugs should be routinely used [24]. Perhaps preoperative cervical vascular color ultrasound and magnetic resonance vascular plaque imaging should be used to determine whether it is vulnerable plaque, in order to conduct targeted preventive treatment [25]. Perioperative blood pressure control was relatively stable, but there was still one patient admitted with large-scale acute ischemic stroke who developed cerebral hemorrhage caused by hyperperfusion syndrome after surgery. After rehabilitation therapy, the symptoms of neurological impairment at discharge were improved compared with that at admission. Studies have shown that postoperative blood pressure should be controlled below 130mmHg to prevent cerebral hemorrhage caused by normal perfusion pressure breakthrough [26]. We need more rational blood pressure control to keep a balance between the prevention of cerebral hemorrhage and the occurrence of postoperative hypotension. Due to the small number of complications in this study, we could not explore the rule of surgical complications.
Currently, a few of guidelines continue to treat CEA as the preferred treatment for symptomatic internal carotid artery stenosis of moderate and severe stenosis [27,28], and CAS as an alternative, but based on earlier clinical evidence [29-34]. Stent technology has been gradually widely developed in recent years, and the upgrading of materials, technologies and concepts has reduced the complications to an acceptable range. New clinical trials have shown that CEA and CAS have no significant difference in the incidence of surgical complications and long-term prognosis of patients [35-39], and more clinical trials are needed in the later stage to support the more widespread application of stent technology, in order to further explore the surgical indications of these two [40].
This study is a single-center retrospective study with a small sample size, and the records of postoperative blood pressure changes of patients are not uniform, which is inferred based on the operation and course records, nursing records and doctor's orders. Not all patients undergo blood biochemical examination on an empty stomach, and the weight is sometimes described by the patients themselves, and other conditions are described by family members instead, which may be biased from the actual situation.
HDL levels do not predict whether blood pressure will decrease after surgery, but if carotid sinus response occurs, high HDL (≧1.0mmol/L) may be more likely to require vasopressor medication treatment while low HDL (< 1.0mmol/L) can be treated with fluid rehydration. The role of hypertension, MS and stenosis in post-CAS hypotension remains to be further studied.