Anesthesia for endovascular neurosurgery and interventional neuroradiology

Therapies for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is one of the most important complications of subarachnoid hemorrhage. Despite lack of prospective evidence, medical rescue interventions for DCI include hemodynamic augmentation using vasopressors or inotropes, with limited guidance on specific blood pressure and hemodynamic parameters. For DCI refractory to medical interventions, endovascular rescue therapies (ERTs), including intraarterial (IA) vasodilators and percutaneous transluminal balloon angioplasty, are the cornerstone of management. Although there are no randomized controlled trials assessing the efficacy of ERTs for DCI and their impact on subarachnoid hemorrhage outcomes, survey studies suggest that they are widely used in clinical practice with significant variability worldwide. IA vasodilators are first line ERTs, with better safety profiles and access to distal vasculature. The most commonly used IA vasodilators include calcium channel blockers, with milrinone gaining popularity in more recent publications. Balloon angioplasty achieves better vasodilation compared with IA vasodilators but is associated with higher risk of life-threatening vascular complications and is reserved for proximal severe refractory vasospasm. The existing literature on DCI rescue therapies is limited by small sample sizes, significant variability in patient populations, lack of standardized methodology, variable definitions of DCI, poorly reported outcomes, lack of long-term functional, cognitive, and patient-centered outcomes, and lack of control groups. Therefore, our current ability to interpret clinical results and make reliable recommendations regarding the use of rescue therapies is limited. This review summarizes existing literature on rescue therapies for DCI, provides practical guidance, and identifies future research needs.

Laryngeal mask airway for general anesthesia in interventional neuroradiology procedures

Objectives:

To evaluate whether using laryngeal mask airway (LMA) made a difference in terms of airway security, hemodynamic changes, complications, and recovery times compared to tracheal intubation during the procedure in patients undergoing general anesthesia for endovascular treatments of unruptured cerebrovascular aneurysms.

Methods:

The electronic medical records database, patient files, and anesthesia charts were examined between May 2008 and September 2016 to identify patients with the following inclusion criteria: 1) aged 18-70 years; 2) American Society of Anesthesiologists (ASA) classification I-III; 3) diagnosis of unruptured CVA; 4) Glasgow coma scale of 15 without neurological deficit; and 5) underwent elective EVT under general anesthesia.

Results:

Tracheal tube (TT) was used in 46 patients (group TT, n=46) and LMA in 42 patients (group LMA, n=42). Mean arterial pressure (MAP) levels were increased to >20% of baseline in 14 patients (30.4%) after intubation and in 6 (13%) after extubation in group TT. All LMA patients remained within normal MAP limits (p<0.05). Six patients (13%) displayed coughing or straining at extubation in group TT whereas none in group LMA (p<0.05). Recovery and discharge times were similar (p>0.05).

Conclusion:

Laryngeal mask airway and TT provided comparable airway security during procedure. Laryngeal mask airway attenuated stress response in hemodynamic parameters at intubation and extubation and smoother emergence compared to TT without delay in recovery.

The optimal anesthetic depth for interventional neuroradiology: comparisons between light anesthesia and deep anesthesia

Background

This study was designed to determine the optimal anesthetic depth for the maintenance and recovery in interventional neuroradiology.

Methods

Eighty-eight patients undergoing interventional neuroradiology were randomly allocated to light anesthesia (n = 44) or deep anesthesia (n = 44) groups based on the value of the bispectral index (BIS). Anesthesia was induced with propofol, alfentanil, and rocuronium and maintained with 1-3% sevoflurane. The concentration of sevoflurane was titrated to maintain BIS at 40-49 (deep anesthesia group) or 50-59 (light anesthesia group). Phenylephrine was used to maintain the mean arterial pressure within 20% of preinduction values. Recovery times were recorded.

Results

The light anesthesia group had a more rapid recovery to spontaneous ventilation, eye opening, extubation, and orientation (4.1 ± 2.3 vs. 5.3 ± 1.8 min, 6.9 ± 3.2 min vs. 9.1 ± 3.2 min, 8.2 ± 3.1 min vs. 10.7 ± 3.3 min, 10.0 ± 3.9 min vs. 12.9 ± 5.5 min, all P < 0.01) compared to the deep anesthesia group. The use of phenylephrine was significantly increased in the deep anesthesia group (768 ± 184 vs. 320 ± 82 µg, P < 0.01). More patients moved during the procedure in the light anesthesia group (6/44 [14%] vs. 0/44 [0%], P = 0.026).

Conclusions

BIS values between 50 and 59 for interventional neuroradiology were associated with a more rapid recovery and favorable hemodynamic response, but also with more patient movement. We suggest that maintaining BIS values between 40 and 49 is preferable for the prevention of patient movement during anesthesia for interventional neuroradiology.

To Tube or Not to Tube? The Role of Intubation during Stroke Thrombectomy

In the 10 years since the FDA first cleared the use of endovascular devices for the treatment of acute stroke, definitive evidence that such therapy improves outcomes remains lacking. The decision to intubate patients undergoing stroke thrombectomy impacts multiple variables that may influence outcomes after stroke. Three main areas where intubation may deleteriously affect acute stroke management include the introduction of delays in revascularization, fluctuations in peri-procedural blood pressure, and hypocapnia, resulting in cerebral vasoconstriction. In this mini-review, we discuss the evidence supporting these limitations of intubation during stroke thrombectomy and encourage neurohospitalists, neurocritical care specialists, and neurointerventionalists to carefully consider the decision to intubate during thrombectomy and provide strategies to avoid potential complications associated with its use in acute stroke.

Is general anaesthesia preferable to conscious sedation in the treatment of acute ischaemic stroke with intra-arterial mechanical thrombectomy? A review of the literature

INTRODUCTION

Intra-arterial mechanical thrombectomy (IAMT) is an endovascular technique that allows for the acute retrieval of intravascular thrombi and is increasingly being used for the treatment of acute ischaemic stroke (AIS). There are currently two anaesthetic options during IAMT: general anaesthesia (GA) and conscious sedation (CS). The decision to use GA versus CS is the source of controversy, as it requires careful balance between patient pain, movement and airway protection whilst minimising time delay and haemodynamic fluctuations. This review examines and summarises the evidence for the use of GA versus CS in the treatment of AIS by IAMT.

METHODS

Studies were identified using systematic bibliographic searches. The five applicable studies were analysed with reference to overall outcomes and the key parameters that govern the decision to use GA or CS. The key parameters included the impact of GA and CS on pain, complication rates, time delays, airway protection and haemodynamic stability.

RESULTS

Several retrospective analyses have shown that the use of GA is associated with adverse outcomes.

CONCLUSION

Intra-arterial mechanical thrombectomy under general anaesthesia is associated with poor outcomes in observational studies. It is reasonable to offer conscious sedation as the preferred option where adverse patient factors such as agitation are lacking.

Elective stenting for intracranial stenosis under conscious sedation

BACKGROUND

Elective stenting for intracranial stenosis is under study as an effective means of reducing stroke risk. At most institutions, these procedures are performed and monitored after the induction of general anesthesia.

OBJECTIVE

To report our success with elective intracranial stenting and angioplasty performed in conscious patients after the administration of mild sedatives and local anesthetic agents.

METHODS

We retrospectively evaluated data from 66 patients who underwent elective intracranial stenting for atherosclerosis. Sixty-one procedures were performed under local anesthesia with mild sedation; 3 were performed under general anesthesia, and 2 were converted from local to general anesthesia during the procedure. Intraprocedural neurological changes were monitored and led to reevaluation of technique, immediate reimaging, modifying the endovascular procedure itself, or possibly mandating conversion to general anesthesia.

RESULTS

Thirty-nine anterior and 27 posterior circulation stenotic segments were treated. Angiographic success was achieved in 95.5% of patients with an overall reduction in stenosis of 75.5 to 22.3%. Percutaneous angioplasty and stenting were used in 58 cases; 8 patients were treated with stenting alone. Three patients (4.9%) developed neurological deficits mandating alteration or adjustment of endovascular technique or immediate postoperative management to avoid permanent sequelae. A total of 8 periprocedural complications occurred, 2 of which resulted in permanent neurological deficit. The overall mortality rate was 3.2%.

CONCLUSIONS

Stenting of intracranial atherosclerosis performed under conscious sedation is associated with complication rates and effectiveness similar to historical rates for general anesthesia. Conscious sedation confers the additional benefit of continuous neurological assessment during the procedure.

Anesthesia and Sedation Practices Among Neurointerventionalists during Acute Ischemic Stroke Endovascular Therapy

BACKGROUND AND PURPOSE

Intra-arterial reperfusion therapies are expanding frontiers in acute ischemic stroke (AIS) management but there is considerable variability in clinical practice. The use of general anesthesia (GA) is one example. We aimed to better understand sedation practices in AIS.

METHODS

An online survey was distributed to the 68 active members of the Society of Vascular and Interventional Neurology (SVIN). Survey development was based on discussions at the SVIN Endovascular Stroke Round Table Meeting (Chicago, IL, 2008). The final survey contained 12 questions. Questions were developed as single and multiple-item responses; with an option for a free-text response.

RESULTS

There was a 72% survey response rate (N = 49/68). Respondents were interventional neurologists in practice 1-5 years (71.4%, N = 35). The mean (±SD) AIS interventions performed per year at the respondents' institutions was 42.5 ± 25, median 35.0 (IQR 20, 60). The most frequent anesthesia type used was GA (anesthesia team), then conscious sedation (nurse administered), monitored anesthesia care (anesthesia team), and finally local analgesia alone. There was a preference for GA because of eliminating movement (65.3% of respondents; N = 32/49), perceived procedural safety (59.2%, N = 29/49), and improved procedural efficacy (42.9%, N = 21/49). However, cited limitations to GA included risk of time delay (69.4%, N = 34), of propagating cerebral ischemia due to hypoperfusion or other complications (28.6%, N = 14), and lack of adequate anesthesia workforce (20.4%, N = 7).

CONCLUSIONS

The most frequent type of anesthesia used by Neurointerventionalists for AIS interventions is GA. Prior to making GA standard of care during AIS intervention, more data are needed about effects on clinical outcomes.

Preoperative assessment of adult patients for intracranial surgery

The preoperative assessment of the patient for neurosurgical and endovascular procedures involves the understanding of the neurological disease and its systemic presentation, and the requirements of the procedure. There is a wide spectrum of different neurosurgical disorders and procedures. This article provides an overview of the preoperative evaluation of these patients with respect to general principles of neuroanesthesia, and considerations for specific intracranial and vascular neurosurgical and interventional neuroradiological procedures.

Anesthetic concerns in patients with known cerebrovascular insufficiency

This review outlines the perioperative anesthesia considerations of patients with vascular diseases of the central nervous system, including occlusive cerebrovascular diseases with ischemic risks and various cerebrovascular malformations with hemorrhagic potential. The discussion emphasizes perioperative management strategies to prevent complications and minimize their effects if they occur. Planning the anesthetic and perioperative management is predicated on understanding the goals of the therapeutic intervention and anticipating potential problems.

[Anesthesia in interventional neuroradiology]

Interventional neuroradiology procedures have become increasingly complex, requiring planning and coordination. Key roles are played by the anesthesiologist and the radiologist, as well as by technicians and nurses. This review aims to analyze the anesthesiologist's part in managing these procedures, from the start of the intervention through the immediate postoperative period. First concerns are to assure patient safety during transfer, maintain the airway, keep the patient immobile and hemodynamically stable, and manage anticoagulant and antiplatelet treatments. Rapid awakening must also be assured so that the patient's neurologic status can be assessed in situ. The anesthesiologist should treat any neurologic complications that develop and that might lead to emergency situations during the procedures.

[Survey of anesthesiologists' practice in treating spontaneous aneurysmal subarachnoid hemorrhage]

OBJECTIVES

To evaluate the participation of Spanish anesthesiology departments in the management of patients hospitalized for spontaneous aneurysmal subarachnoid hemorrhage.

MATERIAL AND METHODS

Chiefs of anesthesiology departments of hospitals listed in the Spanish National Catalog of Hospitals of the Ministry of Health and Consumer Affairs were sent a questionnaire with 30 items covering protocols for the management of patients with spontaneous aneurysmal subarachnoid hemorrhage. Items asked about the participation of anesthesiologists during both admission and the perioperative period.

RESULTS

The questionnaire was sent to 132 hospitals, of which 18 (13.6%) responded. Forty-six percent of anesthesiology departments do not participate in the initial resuscitation. Only 4 reported having a protocol for treating these patients. The initial diagnosis was reportedly made by cranial computed tomography in all cases. Endovascular treatment was the most common procedure reported (66%) and it was given within the first 48 hours (66%). Basic monitoring was used more than nervous system monitoring. Total intravenous anesthesia was used for craniotomy in 53% of the hospitals and for endovascular treatment in 64%. Complications reported most often were vasospasm (100%) and hydrocephalus (69%).

CONCLUSIONS

Even though few questionnaires were returned, the results reveal scarce use of protocols for the treatment of spontaneous aneurysmal subarachnoid hemorrhage by anesthesiologists. It was also evident that the participation of anesthesiology department staff in the treatment of this condition takes place almost exclusively in the intraoperative period and that the use of nervous system monitoring is scarce. Endovascular treatment is increasing in our practice settings.

Anesthetic management in an angiographic suite: a retrospective review of 88 cases

BACKGROUND

Advances in the field of interventional and diagnostic radiology have resulted in anesthesiologists becoming involved in angiographic suites. In the present study, we evaluated the characteristics of patients and the anesthetic management in an angiographic suite, to determine what factors influenced the patient outcome.

METHODS

Data pertaining to patients that were anesthetized at an angiographic suite in a university hospital between 1 January 2007 and 31 December 2007 were evaluated retrospectively. Specifically, we evaluated the patient characteristics and the types of anesthesia administered, to determine which factors were related to patient outcome.

RESULTS

Sixty-four percent of the patients enrolled in this study were women. Cases involving coiling for unruptured and ruptured aneurysm, embolization for intracranial arteriovenous malformation and fistula, pediatric diagnostic angiography, embolization for extracranial arteriovenous malformation, and implantable cardioverter-defibrillator (ICD) implantation all required the involvement of anesthesiologists. Major postoperatve complications included pneumonia, atelectasis, and hydrocephalus. In addition, GCS, net fluid balance, and anesthesia time had influence on patient outcome.

CONCLUSIONS

We evaluated the characteristics of patient groups, procedures, and postoperative complications in an angiographic suite. The results of our analysis revealed that a through understanding of nervous and vascular pathology, as well as knowledge of current interventional radiology, neuroanesthesia and vascular anesthesia techniques is essential for development of safe and effective care.

Revascularization for complex intracranial aneurysms

The modern management of intracranial aneurysms includes both constructive and deconstructive strategies to eliminate the aneurysm from the circulation. Both microsurgical and endovascular techniques are used to achieve this goal. Although most aneurysms can be eliminated from the circulation with simple clip reconstruction and/or coil insertion, some require revascularization techniques to enhance tolerance of temporary arterial occlusion during clipping of the aneurysm neck or to enable proximal occlusion or trapping. In fact, the importance of revascularization techniques has grown because of the need for complex reconstructions when endovascular therapies fail. Moreover, the safety and feasibility of bypass have progressed due to advances in neuroanesthesia, technological innovations, and ~ 5 decades of accumulating wisdom by bypass practitioners. Cerebral revascularization strategies become necessary in select patients who possess challenging vascular aneurysms due to size, shape, location, intramural thrombus, atherosclerotic plaques, aneurysm type (for example, dissecting aneurysms), vessels arising from the dome, or poor collateral vascularization when parent artery or branch occlusion is required. These techniques are used to prevent cerebral ischemia and subsequent clinical sequelae. Bypass techniques should be considered in cases in which balloon test occlusion demonstrates inadequate cerebral blood flow and in which there is a need for Hunterian ligation, trapping, or prolonged temporary occlusion. This review article will focus on decision making in bypass surgery for complex aneurysms. Specifically, the authors will review graft options, the utility of balloon test occlusion in decision making, and bypass strategies for various aneurysm types.