Selection of anesthesia methods in endovascular treatment of acute anterior circulation ischemic stroke

Abstract

Objective

To compare the prognostic effects of two different anesthesia methods on endovascular treatment (EVT) of acute anterior circulation ischemic stroke.

Methods

We collected 90 cases of patients with acute anterior circulation ischemic stroke who received endovascular treatment, and these patients were randomly divided into general anesthesia (GA) group and conscious sedation (CS) group before operation. We recorded the related parameters of EVT under the two anesthesia methods for comparative study. The main outcome index of this study was a good neurological prognosis after 90 days of EVT.

Results

In this study, a total of 174 patients with acute ischemic stroke were screened, 90 cases met the inclusion criteria. The 90 cases were randomly divided into GA group and CS group before receiving EVT. Of the 90 cases, 88 cases achieved different degrees of vascular recanalization, and all cases were followed up. There was no significant difference in baseline data, mortality, vascular recanalization, incidence of pneumonia, hospitalization time in ICU, postoperative intracranial hemorrhage, improvement of MRS and NIHSS scores between patients in the two groups. Arterial dissection occurred in 6 cases in CS group and 1 case in GA group, with significant difference. The mean arterial pressure at 10, 20, 30, 60min after anesthesia were different. The time of arterial puncture was different in the two groups, but there was no difference in the time of vascular recanalization. There was no significant difference in neurological function prognosis between patients in the two groups at 90 days. However, there are differences in terms of lung infection, mortality and ICU hospitalization time of elderly patients between the two groups.

Conclusion

There was no significant difference in neurological prognosis between the two anesthesia methods for 90 days after endovascular treatment of acute anterior circulation ischemic stroke. Conscious sedation was superior to general anesthesia for elderly patients.

Introduction

Acute ischemic stroke is a common clinical disease with high mortality and disability rate. EVT is the most effective method for large intracranial vascular occlusion[1, 2]. The understanding of neurointerventional doctors for endovascular therapy technology, clinical prognosis and influencing factors is constantly improving. However, there are still controversies about the choice of anesthesia methods and anesthesia management during the operation.

As for the anesthesia method used in EVT, the results of current related studies are inconsistent. Bekelis et al. published a research report in 2017, including 1176 patients with ischemic stroke, and compared the clinical neurological prognosis of EVT with GA and CS. The results showed that the clinical prognosis of GA was worse than that of CS group[3, 4]. However, some studies showed that the GA group was superior to CS, and some studies showed that there was no significant difference in clinical prognosis between the two anesthesia methods[5, 6]. However, almost all the above studies are retrospective studies, because there is no uniform standard for intraoperative anesthesia management which may affect the research results. Therefore, a randomized controlled study is needed to further confirm the relationship between anesthesia methods and clinical prognosis of EVT in AIS. In this study, a prospective randomized controlled method was used to analyze and compare the prognosis and related influencing factors of EVT in AIS under two anesthesia types. The report was as follows:

Information And Methods

1.2 Criteria For Diagnosis, Inclusion And Exclusion:

The admission and exclusion criteria of this study were based on Chinese Guidelines for Early Intravascular Interventional Diagnosis and Treatment of Acute Ischemic Stroke 2018 and Chinese Guidelines for Diagnosis and Treatment of Acute Ischemic Stroke 2018[7, 8]. Inclusion criteria: (1) Age ≥ 18 years old; (2) Patients with AIS were randomized and received emergency EVT before operation; Diagnostic criteria: Ischemic stroke: cerebral ischemia caused by local blood supply disorder, necrosis and softening of brain tissue caused by hypoxia, resulting in corresponding clinical symptoms of brain functional defect. Infarct volume ≤ 1/3 MCA or ASPECTS score ≥ 6 points; The patient's medical history and signs, head CT, CTA, TCD or multimodal perfusion CT supported macroangiopathy, and the NIHSS score was ≥ 6; (3) mRS ≤ 2 before stroke; (4) The onset time is less than 6 hours; (5) Sign the informed consent form; Exclusion criteria: (1) Those who do not meet the above inclusion criteria; (2) Posterior circulation infarction; (3) Coma on admission (Glasgow coma scale less than 8); (4) Restlessness or epilepsy at admission, which is not suitable for grouping; (5) Known allergy to anesthetics or analgesics; (6) Missing clinical data or dropping out of the researcher.

1.3 Treatment And Anesthesia Requirements

All patients were divided into preoperative groups, and complete 4-vessel cerebral angiography was performed by trained neurointerventional radiologists under two anesthesia methods. When anterior circulation artery occlusion is diagnosed, stent embolectomy, catheter aspiration and arterial thrombolysis are used for intravascular recanalization.

BIS, end-expiratory carbon dioxide (ETCO2), arterial oxygen saturation (SpO2), blood pressure (BP), heart rate (HR) and electrocardiogram (ECG) were routinely monitored in both groups. During the operation, the guidelines for EVT treatment of AIS patients formulated by Neurosurgical Anesthesia and Intensive Care Association were taken as the basic basis, and the monitoring objectives of various indicators were defined. Spontaneous breathing or mechanical ventilation should maintain normal PaO2 > 60 mmHg, SpO2 > 92%, PaCO2 35–45 mmHg; Maintain body temperature at 35 C-37 C; Diastolic blood pressure < 105 mmHg; Maintain systolic blood pressure between 140 mmHg and 180 mmHg; Maintain blood glucose level at 70–140 mg/dl. For patients with blood glucose concentration < 50 mg/dl, blood glucose should be supplemented in time to prevent complications.

Anesthesia methods: (1) Conscious sedation group: Propofol was used to maintain mild sedation (TCI target plasma concentration was 0.5-1.0µg/ml) and sufentanil (5–10µg) or remifentanil (0.03–0.05µg/kg/min) was used as auxiliary analgesia during intravascular operation, and BIS was maintained above 70. (2) In general anesthesia group, remifentanil (0.5-1µg/kg), propofol (TCI infusion, the initial target is plasma concentration 2µg/ml) and cis-atracurium (0.1-0.2mg/kg) were used for anesthesia induction. After the laryngeal mask was placed, mechanical ventilation was given with the following parameters: fresh gas flow rate was 1–2 L/min, inhaled oxygen concentration was 60%, PEEP was 5 cm H₂O, respiratory ratio was 1: 2, respiratory rate was 10–20/min, tidal volume was 6–8 mL/kg, and normal carbon dioxide concentration was maintained. At the same time, remifentanil (0.05–0.1µg/kg/min) + propofol (TCI plasma target concentration was 2–3µg/ml) were used to maintain anesthesia. If necessary, cis-atracurium was used to maintain muscle relaxation and BIS was maintained at 40–60. (3) Indications for local anesthesia to general anesthesia: In order to ensure the clinical safety of patients, patients in local anesthesia group will be converted to general anesthesia intubation once the following conditions occur; ① Intracranial hemorrhage or subarachnoid hemorrhage caused by vascular rupture; ② Vomiting, restlessness or epilepsy; ③ Respiratory failure with ETCO2 exceeding 60 mmHg or SpO2 < 90%; ④ Deep coma, disappearance of airway protective reflex;

1.4 Observation Indicators:

(1) Main Outcome Index: The main outcome index of this study was neurological function evaluated by modified Rankin score after 90 days of endovascular treatment, and the evaluation limit of good clinical prognosis was mRS ≤ 2. (2) Secondary Outcome Index: ① NIHSS score before and after operation (30 days and 90 days): The National Institute of Health stroke scale (NIHSS) was used to evaluate the prognosis of neurological function of patients. The score was inversely proportional to the neurological function, that is, the higher the score, the more serious the neurological deficit. ② Vascular recanalization: Modified Thrombolysis in cerebral infarct (mTICI) classification was used to evaluate vascular recanalization. At present, it was considered that mTICI grade 2b or 3 was the sign of successful vascular recanalization after thrombolysis, and the recanalization time and mTICI grade were recorded. 3. Complications and mortality: During the treatment, the complications of patients in the two groups were observed, including postoperative cerebral hemorrhage, carotid artery dissection and pneumonia, and the ICU hospitalization time and mortality of patients in the two groups were counted. ④ Time and hemodynamics: the time from entering the operating room to the successful puncture of femoral artery (puncture time), the time from entering the operating room to the recanalization of blood vessels (recanalization time), and the monitoring of mean arterial pressure (MAP) during operation. During the treatment, the above three indexes were recorded. (3) The basic data of patients (gender, age, BMI, smoking, drinking, etc.) was recorded, the baseline data of high-risk factors affecting the prognosis of endovascular treatment of ischemic stroke (hypertension, hyperlipidemia, diabetes, atrial fibrillation, etc.) were recorded, whether intravenous thrombolysis, NIHSS score and mRS score before operation, vascular occlusion site, endovascular treatment mode, etc. were recorded.

1.5 Statistical Analysis:

The data was analyzed by SPSS 25.0 software, in which the counting data was expressed by percentage (%), the comparison between patients in the two groups was performed by X2 test, the measurement data was expressed by mean ± standard deviation (x ± s), and the difference between patients in the two groups was statistically significant by P < 0.05. All analyses are based on the principle of intentional treatment. Therefore, patients with CS to GA were still analyzed in the CS group (ITT analysis), but at the same time, the actual anesthesia method group analysis (PP analysis) will also be presented.

Results

2.2 Comparison of baseline data

There was no significant difference between patients in the two groups in baseline data such as sex, age, BMI, body weight, smoking, drinking, blood pressure and blood glucose at admission, NIHSS score and mRS score before operation, onset time, number of intravenous thrombolysis cases, intravascular occlusion site and intravascular treatment mode (P > 0.05) (Table 1).

2.3 Comparison of clinical data

After intravascular therapy, 13 cases achieved mTICI (0-2a) recanalization, 77 cases achieved mTICI (2b-3) recanalization, including 39 cases in GAgroup and 38 cases in CS group. 48 cases (50.3%) had a good prognosis (mRS ≤ 2) at 90 days, and 22 cases (24.4%) died, including 14 cases in GA group and 8 cases in CS group. There was no statistical difference in the recanalization rate (mTICI 2b-3), 90-day good prognosis (mRS ≤ 2), mortality and recanalization time between patients in the two groups (all p > 0.05). The hospitalization time in ICU was (5.80 ± 3.35) days in CS group and (7.22 ± 5.42) days in GA group, with no statistical difference (p > 0.05). There was no difference in the incidence of intracranial hemorrhage and pneumonia after operation. Arterial dissection occurred in 6 cases (13.6%) in CS group and 1 case (2.1%) in GA group, with significant difference. Comparison of puncture time: CS group (14.93 ± 4.34) min, GA group (26.74 ± 6.84) min, the difference between patients in the two groups (P < 0.05), vascular recanalization time: CS group (103.64 ± 40.23) min, GA group (100.40 ± 29.01) min, no significant difference (P > 0.05) (Table 2).

2.4 NIHSS score and mRS score after operation (30 days and 90 days)

The neurological function of patients in the two groups was improved at 30 days and 90 days after operation. There was no difference in NIHSS score and mRS score at 30 days and 90 days, and there was no difference in improvement rate between NIHSS score and mRS score at 30 days and 90 days (P > 0.05) (Table 3).

2.5 Intraoperative Mean Arterial Pressure Monitoring (MAP)

The MAP decreased in different degrees in patients in the two groups. There was no significant difference in the MAP at the beginning of anesthesia and 2 hours after anesthesia (all P > 0.05), but there were differences in the MAP at 10 min, 20 min, 30 min and 1 h after anesthesia (all P < 0.05). Moreover, the mean arterial pressure in general anesthesia group decreased more within 1 h after anesthesia(Table 4, Fig. 3).

2-6 Statistics of patients of different ages

Statistical analysis of the two groups showed that there were differences in pneumonia incidence, mortality and ICU hospitalization time among the elderly patients (≥ 80 years old) in the two groups (all P < 0.05), but there was no difference in clinical index statistics between 60–79 years old and less than 60 years old (all P > 0.05) (Table 5).

Discussion

Acute ischemic stroke is a common disease, which has the characteristics of high disability rate, high mortality rate and high recurrence rate. With the development of nerve interventional technology and interventional materials, the recanalization rate of endovascular treatment has been continuously improved. Of the 90 cases in this study, 88 cases achieved different degrees of vascular recanalization, and the recanalization rate reached 97.7%, among which the good recanalization rate (mTICI 2b-3 grade) reached 85.5%.

There are many factors affecting the clinical prognosis of endovascular therapy for acute ischemic stroke. For example, age, time factors, collateral compensatory ability, baseline NIHSS score, blood pressure, blood sugar, thrombus load, anesthesia methods, etc.[9]. According to Table 1, there was no statistical difference in baseline data such as age, onset time and baseline NIHSS score between the two groups (all P > 0.05). In addition, there are clear and unified requirements for blood pressure, blood sugar and other indicators in the research and implementation process. The elimination of these common influencing factors makes the comparative study of the two anesthesia methods true and reliable.

The influence of anesthesia methods on EVT in AIS has been debated endlessly. Due to the need of preoperative preparation, the puncture time in GA group was delayed, and the prolongation of puncture time could lead to the decrease of good vascular recanalization rate (mTICI 2b-3 grade) and the prolongation of recanalization time, resulting in poor clinical neurological prognosis. Therefore, some doctors prefer local anesthesia or conscious sedation when performing EVT in AIS[10–12]. Retrospective analysis showed that the neurological function improvement effect of intravascular treatment under GA for 90 days was worse than that of CS group[13]. In a Mate analysis published by Adeel Ilyas et al. in 2018, 9 studies were included, and 1379 cases were collected, including 761 cases in GA group and 618 cases in CS group. The good prognosis of all patients at 90 days was evaluated (mRS ≤ 2 points). The final results showed that there was no significant difference in clinical prognosis between patients in the two groups[14]. Another meta analysis showed that the clinical prognosis of patients in GA group was better than that of CS group[15]. The above research results are all retrospective research results. Because there are some defects in retrospective study, retrospective analysis will lead to patient selection bias: age, ischemia severity, etc. There is no clear and unified standard to define general anesthesia and anesthesia depth, and the information provided for intraoperative anesthesia management, including blood pressure management, respiratory management and blood sugar control, is even more limited. The results showed that there was no significant difference in 90-day good prognosis (mRS ≤ 2) between patients in the two groups (P > 0.05). NIHSS scores and MRS scores were improved in different degrees at 30 and 90 days after operation, but there was no significant difference in average improvement rate between the two groups (P > 0.05). This study showed that the puncture time in patients in the CS group was faster than that in GA group. The results showed that the operation in in patients in the CS group started faster than that in GA group, the puncture time was shortened, and the corresponding vascular recanalization time, vascular recanalization rate and clinical prognosis should be better than that in GA group. However, the results showed that there was no difference in clinical neurological prognosis, mTICI grade of vascular recanalization and vascular recanalization time between patients in the two groups. The reason is that although CS shortens the puncture time of femoral artery, it may prolong the operation time when intravascular operation is performed under CS. There will be irritability symptoms caused by catheter and guide wire stimulating intracranial blood vessels, and it will increase respiratory frequency and make the head shake obviously, which will have a significant impact on DSA acquisition and fluoroscopy, which will not only prolong the operation time of patients, increase the fluoroscopy radiation dose of patients, but also prolong the opening time of blood vessels, and fail to obtain satisfactory results. Although there was no difference in prognosis between patients in the two groups, there were advantages and disadvantages between the two anesthesia methods. The advantages of CS were as follows: (1) The neurological function of patients can be evaluated at any stage of intravascular treatment; (2) It can shorten the puncture time of femoral artery and shorten the start-up time of operation; (3) Reduce iatrogenic hemodynamic fluctuations; (4) It can prevent some patients from entering ICU because of postoperative anesthesia recovery difficulties, and reduce related complications, such as lung infection[16, 17]. Advantages of GA: (1) Using anesthesia can avoid artifacts caused by exercise, and the doctor's operation process becomes smooth; (2) It can improve the patient's tolerance and ensure the smooth operation; (3) It can reduce the risk of respiratory obstruction, respiratory depression, carbon dioxide accumulation and reflux aspiration in the absence of airway protection, and keep the respiratory tract unobstructed; (4) It can keep patients quiet and reduce vascular injury induced by guide wire[18–19].

This study also pay attention to the interaction among anesthesia methods, blood pressure and neurological function improvement. Previous studies have shown that blood pressure fluctuation caused by GA is greater. Among several variables of blood pressure, MAP is the strongest predictor. For every 10% decrease of mean arterial pressure, adverse prognosis will increase by about 1.6 times. Intraoperative MAP decrease of > 40% or lower than (78 ± 8mmHg) is an independent predictor of neurological dysfunction[20–22]. It may be that the decrease of cerebral blood flow caused by hypotension aggravates cerebral ischemia and hypoxic injury[23]. According to the data in Table 4 and Fig. 3, the mean arterial pressure of both groups decreased after anesthesia, and the mean arterial pressure of general anesthesia group decreased more within 1 hour after anesthesia, which was different from that of conscious sedation group. It may be that induced hypotension may occur when using anesthesia inducers such as propofol and fentanyl[24]. The difference of MAP between the two groups did not lead to the difference of neurological prognosis. It may be that the MAP in GA group quickly returned to the ideal level after short-term fluctuation under the action of vasoactive drugs, and the lowest MAP in GA group also reached (83.50 ± 11.64), and the MAP in both groups remained at a relatively higher level during operation, thus avoiding cerebral tissue perfusion deficiency caused by sharp and long-term decrease of blood pressure. Therefore, the sharp changes of blood pressure during anesthesia should be closely monitored.

Arterial dissection is a common complication after mechanical embolectomy for AIS. According to literature reports, the incidence of arterial dissection after EVT treatment in AIS is 0.9%-3.9%[25, 26]. During intravascular treatment, the injury of intima caused by guide wire and catheter is considered as the main cause of carotid dissection[27]. In this study, the incidence of carotid artery dissection was significantly different between patients in the two groups (Table 2). Because of the shallow anesthesia depth of conscious sedation group, the patient's tolerance to pain and vascular stimulation during operation was poor, which leads to irritability and easy movement during operation, which can cause intimal injury of blood vessels and lead to arterial dissection during operation.

At present, in China, people over 60 years old are called old people, and those over 80 years old are called the old man[28]. Elderly patients with many basic diseases, poor reserve function of the body have high surgical risks during surgery, and any stimulation during anesthesia can cause excessive stress response of the body, thus causing metabolic changes and organ failure[29]. The incidence of pulmonary infection in elderly patients after GA is high and severe. The main reasons are as follows: 1. The elderly patients have poor respiratory muscle function, slow cough and expectoration reflex, and poor respiratory self-protection ability. 2. Elderly patients have many basic diseases, and most of them suffer from chronic lung diseases. Poor compliance of the lungs leads to poor systolic and diastolic functions, which easily leads to the accumulation of sputum in the lungs[30]. 3. General anesthetics and muscle relaxants can inhibit cough reflex. Because of the slow metabolism of anesthetics in elderly patients, patients can't wake up in time after operation, which is one of the causes of lung infection[31]. 4. Patients under GA are easy to accumulate sputum in throat and lung infection during endotracheal intubation and ventilator-assisted breathing[32]. Consistent with the literature, after stratified statistics of patients of different ages, the pulmonary infection rate and mortality rate of elderly patients in GA group were significantly higher than those in CS group, and the hospitalization time in ICU in GA group was significantly longer than that in CS group. Therefore, for elderly patients, surgery should be performed under CS as much as possible.

Conclusion

There is no difference between GA and CS on neurological function prognosis of patients with AIS at 90 days after EVT, but GA has a greater impact on intraoperative blood pressure, so it is necessary to closely monitor the sharp changes of blood pressure during anesthesia. For elderly patients, surgery should be performed under CS as much as possible. There are some shortcomings in this study, our sample size is small, and we need a larger sample size to study and confirm it.

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tables

Tables 1. Comparison of baseline data between the two groups

Tables 2. Comparison of clinical data between the two groups

Tables 3. Comparison of neurological function recovery between the two groups（30、90 days）

Tables 4. Comparison of intraoperative mean arterial pressure between two groups

The time point of two groups of cases at the beginning of induction of anesthesia is marked as T0, the 10min, 20min, 30min, 60min and 120min during anesthesia were labeled as T1, T2, T3, T4 and T5 respectively. Record the MAP (mmHg) at the above time points.

Tables 5. Clinical data statistics of different age groups