Adenosine-Induced Flow Arrest to Facilitate Intracranial Aneurysm Clip Ligation

2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage: A Guideline From the American Heart Association/American Stroke Association

AIM

The "2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage" replaces the 2012 "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage." The 2023 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with aneurysmal subarachnoid hemorrhage.

METHODS

A comprehensive search for literature published since the 2012 guideline, derived from research principally involving human subjects, published in English, and indexed in MEDLINE, PubMed, Cochrane Library, and other selected databases relevant to this guideline, was conducted between March 2022 and June 2022. In addition, the guideline writing group reviewed documents on related subject matter previously published by the American Heart Association. Newer studies published between July 2022 and November 2022 that affected recommendation content, Class of Recommendation, or Level of Evidence were included if appropriate. Structure: Aneurysmal subarachnoid hemorrhage is a significant global public health threat and a severely morbid and often deadly condition. The 2023 aneurysmal subarachnoid hemorrhage guideline provides recommendations based on current evidence for the treatment of these patients. The recommendations present an evidence-based approach to preventing, diagnosing, and managing patients with aneurysmal subarachnoid hemorrhage, with the intent to improve quality of care and align with patients' and their families' and caregivers' interests. Many recommendations from the previous aneurysmal subarachnoid hemorrhage guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

Inadequate Adenosine-Induced Flow Arrest During Intraoperative Basilar Aneurysm Surgery

Aneurysmal subarachnoid hemorrhage (SAH) is an acute neurologic emergency. We report the case of a 48-year-old male with a massive SAH caused by a ruptured aneurysm of the vertebrobasilar transition. During an urgent craniotomy, due to an aneurysm re-rupture, adenosine was given for flow arrest but no sinus pause was observed. Esmolol was administered and strategies for cerebral protection were implemented. The surgeon was able to clip the aneurysm and the patient was discharged after 78 days without sequelae. The highest adenosine dose given did not result in an efficient cardiac pause. Atropine given one hour before could have contributed to this. This case highlights a successfully managed case of ruptured aneurysm with refractory adenosine-induced flow arrest.

Optic Foraminotomy versus Anterior Clinoidectomy for Small Superior-Projecting Paraclinoid Aneurysms: Visual and Angiographic Outcome Evaluation

INTRODUCTION

Optic foraminotomy (OF) has been recently proposed as an alternative to anterior clinoidectomy (AC) for selected types of paraclinoid aneurysms. In this study, OF and AC were compared for small superior-projecting paraclinoid aneurysms assuming visual and angiographic results as outcome measures. Indications for OF are also discussed.

METHODS

Data of patients who underwent surgery for a paraclinoid aneurysm in the last 10 years were collected across 3 tertiary hospitals. Small to regular-size and superior projecting aneurysms were sorted. Multiple and complex aneurysms were excluded. Records of patients who went through OF were compared with those of patients who underwent AC. Neurologic outcome was reported as a modified Rankin Scale. Aneurysm complete occlusion rate and rate of approach-related worsened vision were selected as outcome measures of efficacy and safety, respectively, of the OF versus AC. Unpaired t test and χ2 test were used for numerical and categorical variables, respectively. A P value less than 0.05 was considered statistically significant.

RESULTS

OF and AC groups involved 18 and 25 patients, respectively. Complication rate, overall neurologic outcome, rate of approach-related worsened vision, and complete occlusion rate did not differ between the groups. The average follow-up was 51 ± 34 and 60 ± 41 months in the OF and AC groups, respectively.

CONCLUSIONS

Compared to AC, OF did not show either a higher rate of approach-related worsened vision or a lower aneurysm complete occlusion rate. OF can be considered a valid alternative to the AC for small superior-projecting dorsal ICA wall paraclinoid aneurysms.

Enhance Safety in Aneurysm Surgery: Strategies for Prevention of Intraoperative Vascular Complications

Complications during surgery for intracranial aneurysms can be devastating. Notorious pitfalls include premature rupture, parent vessel occlusion, local cerebral injury and brain contusion, and incomplete neck obliteration. These unfavorable intraoperative events can result in major neurological deficits with permanent morbidity and even mortality. Herein, the author highlights the relevant surgical strategies used in his daily practice of aneurysm surgery (e.g., aneurysm clipping with adenosine-induced temporary cardiac arrest), application of which may help prevent vascular complications and enhance surgical safety through reduction of the associated risks, thus allowing improvement of postoperative outcomes. Overall, all described methods and techniques should be considered as small pieces in the complex puzzle of prevention of vascular complications during aneurysm surgery.

Penetrating cardiac injury repaired under "intentional cardiac arrest" with adenosine triphosphate

Background

Repairing a cardiac injury with beating heart is sometimes difficult and is associated with increased risks of complications. Here we report a case of cardiac injury repaired with administration of adenosine triphosphate (ATP).

Case Presentation

A 46‐year‐old man was stabbed in his chest with a knife and transferred to our hospital. He was hemodynamically unstable, and echocardiography showed pericardial effusion. Emergency thoracotomy revealed a full‐thickness injury in the right ventricle next to the coronary artery. He went into cardiac arrest and was resuscitated with adrenaline administration. We tried to suture immediately, but it was difficult because of tachycardia. After administering 20 mg of ATP (80 mg in total over 15 min), bradycardia was induced that led to “intentional cardiac arrest” after which suturing was performed. He was discharged on the 13th day without complications.

Conclusion

Cases of penetrating cardiac injury repaired using ATP are rare. Administration of ATP may be a useful option while repairing cardiac injuries.

Microsurgical Clipping of Carotid-Ophthalmic Tandem Aneurysms: Case Report and Surgical Nuances

Tandem intracranial aneurysms (TandIAs) are rare but inherently complex, and special technical considerations are required for their surgical management. The present case highlights the key surgical aspects of two carotid-ophthalmic TandIAs incidentally found in a 60-year-old female. Both the aneurysms were superiorly projecting, regular in size, and involved the left ophthalmic segment of the internal carotid artery (ICA). The minimum distance between the necks was 3 mm. The patient underwent microsurgery because of the reported major complications rate of the endovascular treatment in the case of a very short minimum distance between the TandIAs. After cervical ICA exposure, both the aneurysms were excluded through a pterional approach. Intradural anterior clinoidectomy and unroofing of the optic canal allowed the mobilization of the left optic nerve. The more distal aneurysm was clipped before the opening of the distal dural ring of the ICA. The proximal aneurysm was clipped with two straight clips stacked perpendicular to the ICA. A small remnant was intentionally left to avoid the stenosis of the ophthalmic artery. Postoperative angiography showed the exclusion of both the aneurysms with a small dog-ear of the more proximal one. The patient was discharged neurologically intact and, after one year, the remnant remained stable. Microsurgical clipping is a definitive and durable treatment for carotid-ophthalmic TandIAs. In the case of a very short minimum distance between the aneurysms, the distal one should be clipped first to make the anterior clinoidectomy, opening of the distal dural ring of the ICA, and clipping of the more proximal aneurysm easier.

Temporary Clipping of the Intracavernous Internal Carotid Artery: A Novel Technique for Proximal Control

BACKGROUND

Securing proximal control in complex paraclinoid aneurysm surgery through traditional techniques may be challenging and risky in certain situations. Advancements of anatomical knowledge of the cavernous sinus (CS) and hemostasis have made it more accessible as a surgical option.

OBJECTIVE

To describe the technique of temporary clipping of the horizontal segment of the intracavernous internal carotid artery (IC-ICA) in preparation for permanent clipping of complex paraclinoid aneurysms.

METHODS

Through an extradural pretemporal approach, the lateral wall of the CS is exposed. The dura between the trochlear nerve and V1 is opened, and access is made to the horizontal segment of the IC-ICA. After circumferential dissection, the temporary clip can be introduced to the artery, and the extradural clinoidectomy can be continued under secured proximal control.

RESULTS

Seven patients with complex paraclinoid aneurysms were treated between May 2013 and May 2016 by the senior author. Temporary clipping of the IC-ICA was performed in all cases. Average time to achieve proximal control was 22.6 min (22.6 ± 13.8). One patient developed transient oculomotor palsy postoperatively. There were no other complications.

CONCLUSION

When the exposed clinoidal segment of the internal carotid artery does not offer sufficient proximal space for temporary clipping, the extradural approach can be extended to the horizontal portion of the IC-ICA. In our experience, this technique is a quick, reliable, and safe alternative to the classical modalities of temporary occlusion.

Adenosine-induced Asystole during AVM Embolization : A Case Series

Background

Adenosine induced cardiac standstill has been used intraoperatively for both aneurysm and arteriovenous malformation (AVM) surgery and embolization. We sought to report the results of adenosine induced cardiac standstill as an adjunct to endovascular embolization of brain AVMs.

Material and Methods

We retrospectively identified patients in our prospectively maintained database to identify all patients since January 2007 in whom adenosine was used to induce cardiac standstill during the embolization of a brain AVM. We recorded demographic data, clinical presentation, Spetzler Martin grade, rupture status, therapeutic intervention and number of embolization sessions, angiographic and clinical results, clinical and radiological outcomes and follow-up information.

Results

We identified 47 patients (22 female, 47%) with average age 42 ± 17 years (range 6–77 years) who had undergone AVM embolization procedures using adjunctive circulatory standstill with adenosine. In total there were 4 Spetzler Martin grade 1 (9%), 9 grade 2 (18%), 15 grade 3 (32%), 8 grade 4 (18%), and 11 grade 5 (23%) lesions. Of the AVMs six were ruptured or had previously ruptured. The average number of embolization procedures per patient was 5.7 ± 7.6 (range 1–37) with an average of 2.6 ± 2.2 (range 1–14) embolization procedures using adenosine. Overall morbidity was 17% (n = 8/47) and mortality 2.1% (n = 1/47), with permanent morbidity seen in 10.6% (n = 5/47) postembolization. Angiographic follow-up was available for 32 patients with no residual shunt seen in 26 (81%) and residual shunts seen in 6 patients (19%). The angiographic follow-up is still pending in 14 patients. At last follow-up 93.5% of patients were mRS ≤2 (n = 43/46).

Conclusion

Adenosine induced cardiac standstill represents a viable treatment strategy in high flow AVMs or AV shunts that carries a low risk of mortality and permanent neurological deficits.

An Evaluation of the Safety and Feasibility of Adenosine-assisted Clipping Surgery for Unruptured Cerebral Aneurysms: Study Protocol

The effectiveness of adenosine-induced flow arrest in surgical clipping for the cerebral aneurysms with difficulties in temporary clip placement to the proximal main trunk has been reported. This is the first clinical trial to evaluate the safety and feasibility of adenosine-assisted clipping surgery for unruptured cerebral aneurysms (UCAs) in Japan. The inclusion criteria are as follows: patients over 20 years old, patients who agree to be enrolled in this study after providing informed consent, patients who undergo clipping surgery for UCA in our institute, and patients in whom the surgeons (T.H. or I.D.) judge that decompression of the aneurysm is effective. The primary endpoint is a modified Rankin Scale (mRS) score 30 days after surgery. We plan to enroll 10 patients in this study. The original protocol of adenosine administration was established in this trial. Herein, we present the study protocol.

The evolution of intracranial aneurysm treatment techniques and future directions

Treatment techniques and management guidelines for intracranial aneurysms (IAs) have been continually developing and this rapid development has altered treatment decision-making for clinicians. IAs are treated in one of two ways: surgical treatments such as microsurgical clipping with or without bypass techniques, and endovascular methods such as coiling, balloon- or stent-assisted coiling, or intravascular flow diversion and intrasaccular flow disruption. In certain cases, a single approach may be inadequate in completely resolving the IA and successful treatment requires a combination of microsurgical and endovascular techniques, such as in complex aneurysms. The treatment option should be considered based on factors such as age; past medical history; comorbidities; patient preference; aneurysm characteristics such as location, morphology, and size; and finally the operator’s experience. The purpose of this review is to provide practicing neurosurgeons with a summary of the techniques available, and to aid decision-making by highlighting ideal or less ideal cases for a given technique. Next, we illustrate the evolution of techniques to overcome the shortfalls of preceding techniques. At the outset, we emphasize that this decision-making process is dynamic and will be directed by current best scientific evidence, and future technological advances.

Intracranial Vascular Procedures

Anesthesia for intracranial vascular procedures is complex because it requires a balance of several competing interests and potentially can result in significant morbidity and mortality. Frequently, periods of ischemia, where perfusion must be maintained, are combined with situations that are high risk for hemorrhage. This review discusses the basic surgical approach to several common pathologies (intracranial aneurysms, arteriovenous malformations, and moyamoya disease) along with the goals for anesthetic management and specific high-yield recommendations.

Use of Adenosine to Facilitate Localization and Repair of Internal Carotid Artery Injury during Skull Base Surgery: A Case Report and Literature Review

BACKGROUND

Internal carotid artery (ICA) injuries represent a rare, potentially fatal complication of endoscopic endonasal skull base surgery (EESBS). The use of adenosine to induce transient hypotension and facilitate management of high-flow, high-pressure arterial lesions has been well-documented in neuro-endovascular literature. A similar setting in which adenosine-induced hypotension may prove beneficial is during the management of major vascular injury encountered during EESBS.

METHODS

A case of ICA injury and subsequent repair during EESBS is presented.

RESULTS

A 74-year-old female underwent endoscopic transsphenoidal resection for a recurrent pituitary adenoma. During suprasellar resection, the right cavernous ICA was inadvertently injured resulting in brisk bleeding. Immediate vascular tamponade was applied, and a crushed muscle graft was obtained. Two intravenous doses of adenosine were administered in quick succession to produce transient hypotension and facilitate repair of the injury with the graft. Neurovascular imaging revealed a small pseudoaneurysm which remained stable throughout the postoperative course. The patient underwent definitive stent embolization of the pseudoaneurysm 1 month following discharge.

CONCLUSION

Prompt repair of ICA injury during EESBS is crucial, but often limited by poor visualization. Adenosine-induced hypotension has demonstrated great efficacy as an adjuvant in neurovascular clipping of intracranial aneurysms and remains a valuable tool for the endoscopic skull-base surgeon as well. In cases with high risk for ICA injury, adenosine should be readily available.

Perioperative Management of Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage is an acute neurologic emergency. Prompt definitive treatment of the aneurysm by craniotomy and clipping or endovascular intervention with coils and/or stents is needed to prevent rebleeding. Extracranial manifestations of aneurysmal subarachnoid hemorrhage include cardiac dysfunction, neurogenic pulmonary edema, fluid and electrolyte imbalances, and hyperglycemia. Data on the impact of anesthesia on long-term neurologic outcomes of aneurysmal subarachnoid hemorrhage do not exist. Perioperative management should therefore focus on optimizing systemic physiology, facilitating timely definitive treatment, and selecting an anesthetic technique based on patient characteristics, severity of aneurysmal subarachnoid hemorrhage, and the planned intervention and monitoring. Anesthesiologists should be familiar with evoked potential monitoring, electroencephalographic burst suppression, temporary clipping, management of external ventricular drains, adenosine-induced cardiac standstill, and rapid ventricular pacing to effectively care for these patients.

Low-dose adenosine-induced transient asystole during intracranial aneurysm surgery

Background

Few studies have evaluated the adenosine dose that induces cardiac arrest during intracranial aneurysm surgery. We present our experiences with adenosine-induced transient asystole (AiTA) during intracranial aneurysm surgery and dosage recommendations.

Methods

We retrospectively reviewed the medical records of all patients who underwent intracranial aneurysm surgery between July 2016 and December 2018. Patients who experienced AiTA during intracranial aneurysm surgery were included in the study.

Results

Our study included nine intracranial aneurysm surgeries performed in eight patients. Thirteen episodes of AiTA were reported. Five of these were performed to facilitate bleeding control due to intraoperative aneurysm rupture (IAR), and adenosine doses were 9 mg (0.20 mg/kg), 12 mg (0.25 mg/kg), 12 mg (0.26 mg/kg), 18 mg (0.34 mg/kg), and 18 mg (0.39 mg/kg), resulted in transient asystole for 12, 14, 9, 44, and 18 s, respectively. For episodes without IAR, adenosine doses ranging from 6 to 18 mg (0.11-0.39 mg/kg) caused asystole for 8-33 s. In five episodes without IAR, low-dose adenosine (lower than 0.2 mg/kg) was used and caused asystole ranging from 8 to 12 s. Postoperatively, two patients had elevated cardiac troponin T levels but normal electrocardiograms.

Conclusion

AiTA can facilitate the clipping of intracranial aneurysms at low-risk of serious cardiac complications. An adenosine dose of 0.2-0.4 mg/kg is safe and effective in both IAR and non IAR situations. In non IAR cases, we propose that low-dose AiTA is an option to facilitate aneurysm clipping. A starting dose of 6 mg or 0.1-0.2 mg/kg can adequately induce brief asystole by softening the aneurysmal sac during clip application.

The effect of adenosine in inducing cardiac arrest for endovascular treatment of paediatric high-flow brain and spinal vascular malformation

INTRODUCTION

Endovascular treatment of high-flow vascular lesions with onyx may be very dangerous due to premature occlusion of the vein resulting from high flow-induced migration of this embolic substance without occlusion of the feeding vessels and the nidus. It is also dangerous because of the risk of occlusion of the normal vessels around the lesion. Inducing temporary cardiac arrest using adenosine may be helpful in limiting and minimizing these risks. However anaesthetic management of this procedure in children suffering from high-flow vascular lesions is difficult and challenging.

METHODS

We report three paediatric patients with high-flow cerebrospinal vascular lesions that underwent endovascular treatment under general anaesthesia and temporary cardiac arrest with adenosine. Adenosine was administered in escalating doses to induce a few seconds of cardiac standstill and the onyx injection was synchronized with the onset of adenosine-induced cardiac standstill, the fistula being occluded by onyx.

RESULTS

There were no complications in peri-procedural treatment in all three cases. Post-embolization angiography revealed complete obliteration of the lesion, and the patients' neurological status progressively improved at follow-up.

CONCLUSION

Adenosine-induced temporary cardiac standstill was successfully used to facilitate safe and controlled endovascular onyx embolization of high-flow central nervous system vascular lesions.

Adenosine-induced transient asystole to control intraoperative rupture of intracranial aneurysms: institutional experience and systematic review of the literature

BACKGROUND

Intraoperative rupture of an intracranial aneurysm is a life-threatening situation that carries a high risk of morbidity and mortality. Since 2000, adenosine has been used successfully to induce transient hypotension and/or asystole to control bleeding and facilitate surgical clipping of aneurysms that rupture intraoperatively. Given the paucity of reports describing this method in a limited number of patients, we performed a systematic review of the literature detailing the use and outcomes of this technique.

METHODS

The authors performed a systematic review and identified all studies in which adenosine was used in the setting of an intracranial aneurysm that ruptured intraoperatively. We then determined overall morbidity and mortality rates, adding an additional six of our own patients.

RESULTS

Data was analyzed for a total of 29 patients, including 23 previously reported patients from the literature and 6 additional cases from our own experience (mean age 54.8 years, 58.6% female). Most patients (82.8%, 24/29) presented with subarachnoid hemorrhage (SAH). Overall mean dose of adenosine was 51.8 mg. Successful clipping was achieved in 100% of patients. Transient or permanent morbidity was reported in 5/29 (17.2%) and the overall mortality rate was 31% (9/29), which occurred primarily due to an initial severe SAH and its resultant complications.

CONCLUSIONS

Adenosine-induced circulatory arrest appears to safely control intraoperative bleeding and facilitate the clipping of ruptured intracranial aneurysms based on the limited published literature available. Further studies comparing patient outcomes using this technique to traditional approaches are required to validate the safety and efficacy of adenosine in this high-risk setting.

Adenosine-Induced Cardiac Arrest for Transvenous Embolization of Midbrain Arteriovenous Malformation

BACKGROUND AND IMPORTANCE

Few studies describe the use of adenosine-induced cardiac systole for treatment of cerebrovascular pathologies. We describe a midbrain arteriovenous malformation (AVM) treated with transvenous embolization using adenosine-induced asystole to achieve transient systemic hypotension with the purpose of furthering discussion on the technique and operative considerations for adenosine use in endovascular AVM treatments.

CLINICAL PRESENTATION

A 29-yr-old man presented with sudden onset of severe bilateral headache, blurred vision, and numbness on the right side of his face and tongue. Noncontrast head computed tomography revealed fourth ventricle hemorrhage. Diagnostic cerebral angiography revealed a high-flow midbrain AVM with a posterior wall perforator from the basilar artery terminus and a draining vein into the straight sinus. Transarterial AVM embolization was successful. The patient was discharged with no residual neurological deficits but returned 1 wk later with slurred speech and left-sided dysmetria. Repeat angiography revealed partial AVM filling. Attempts at transarterial embolization were unsuccessful. Thus, transvenous AVM embolization with adenosine-induced cardiac asystole and systemic hypotension was performed. A total of 60 mg of adenosine was administered, followed by 2 additional doses of 60 and 40 mg; and complete cardiac asystole with a mean arterial pressure of 40 mmHg was maintained, resulting in successful embolization of the AVM. No residual filling was visualized on postembolization arterial angiography runs. The patient was neurologically stable and discharged on postoperative day 2.

CONCLUSION

With appropriate and safe dosing, adenosine-induced asystole and systemic hypotension may be a feasible, safe option to reduce flow and assist endovascular transvenous embolization of high-flow AVMs.

Adenosine-Induced transient asystole during surgical treatment of basilar artery aneurysms

Aim

To evaluate the safety and efficacy of adenosine-induced transient asystole (AITA) during surgery for basilar artery aneurysms.

Materials and Methods

All the patients with basilar artery aneurysms operated using AITA at our institute during two years period (August 2013-July 2015) were included in this study.

Results

Adenosine was used in 11 patients with 13 basilar artery aneurysms. Seven of these aneurysms were basilar bifurcation aneurysms, four were basilar-superior cerebellar artery junction aneurysms, and two were distal basilar trunk aneurysms. The indications for AITA were narrow corridor for placement of temporary clip in 11 aneurysms, intraop rupture in 1 aneurysm, and circumferential dissection of a large aneurysm in 1. The mean dose of adenosine used for inducing asystole was 19.4 mg (range: 15-30 mg) and the mean total dose of adenosine used was 40.6 mg (range: 18-90 mg). A mean of 2 (range: 1-5) AITAs were required during surgical treatment of these aneurysms. The mean duration of a systole was 27 s (range: 9-76 s). There were no complications related to AITA in these patients except for transient rebound hypertension in one patient. Check angiogram revealed complete obliteration of 11 aneurysms and small residual neck in 2 aneurysms. Modified Rankin Scale at three months of follow-up was 0 in seven patients, 1 in two patients, 4 in one patient, and 6 in one patient.

Conclusion

AITA during surgical management of basilar artery aneurysms is a safe and effective technique and has an important role during surgery for these aneurysms.

Microsurgical Clipping of Distal Basilar Trunk Aneurysm during Adenosine-Induced Profound Hypotension

A 46-year-old male presented with a history of sudden severe headache 1 week back, altered sensorium and right hemiparesis for 2 days. On examination, Glasgow Coma Scale (GCS) was E4V4M6 and the patient had right hemiparesis (power – 4/5). Computed tomography (CT) revealed diffuse subarachnoid hemorrhage (Fisher's Grade III). CT angiogram revealed distal basilar trunk aneurysm arising between the origin of the left posterior cerebral artery and superior cerebellar artery, ectatic dilatation of distal basilar trunk, and a left middle cerebral artery (MCA) bifurcation aneurysm. Basilar trunk aneurysm was approached through subtemporal route and aneurysm was clipped during adenosine-induced profound hypotension (AIPH) without application of temporary clip. Single bolus 6 mg of adenosine was given, and aneurysm was successfully clipped during AIPH (systolic <60 mmHg). There were no complications related to adenosine. Ectatic part of distal basilar trunk was wrapped with Teflon. The left MCA bifurcation aneurysm was clipped in the same session. At 3-month follow-up, the patient's sensorium was normal (GCS-E4V5M6) and the right hemiparesis improved (4+/5). Adenosine enhances the safety of clipping these aneurysms by providing transient cardiac arrest or profound hypotension. In developing countries, microsurgical clipping is a cost-effective treatment option for basilar artery aneurysms.

Cognitive Aids for the Diagnosis and Treatment of Neuroanesthetic Emergencies: Consensus Guidelines on Behalf of the Society for Neuroscience in Anesthesiology and Critical Care (SNACC) Education Committee

Cognitive aids and evidence-based checklists are frequently utilized in complex situations across many disciplines and sectors. The purpose of such aids is not simply to provide instruction so as to fulfill a task, but rather to ensure that all contingencies related to the emergency are considered and accounted for and that the task at hand is completed fully, despite possible distractions. Furthermore, utilization of a checklist enhances communication to all team members by allowing all stakeholders to know and understand exactly what is occurring, what has been accomplished, and what remains to be done. Here we present a set of evidence-based critical event cognitive aids for neuroanesthesia emergencies developed by the Society for Neuroscience in Anesthesiology and Critical Care (SNACC) Education Committee.

A Retrospective Study in Microsurgical Procedures of Large and Giant Intracranial Aneurysms: An Outcome Analysis

OBJECTIVE

Intracranial aneurysms are considered large if >10 mm and giant if >25 mm. The risk of aneurysmal rupture compounds with increase in size of the aneurysm, thus, warranting appropriate intervention. In this study, we have analyzed the outcome and effectiveness of microsurgical procedures in large and giant aneurysms.

METHODS

A retrospective analysis of all the patients who underwent microsurgical procedures for large and giant cerebral aneurysms from 2014-2018 in our institute was conducted. There were a total of 52 patients, in which direct clipping was performed in 42 (80.7%) patients, proximal trapping in 3 (5.7%) patients, trapping with bypass in 3 (5.7%) patients, suction decompression in 3 (5.7%) patients, and 1 (1.9%) patient underwent surgical reconstruction.

RESULTS

Among the 52 patients, in the postoperative period, 1 (1.9%) patient became comatose, 1 (1.9%) patient developed hemiplegia, 1 (1.9%) patient had a transient hemiparesis, and 1 (1.9%) patient had transient lower cranial nerve palsy. Two (3.8%) patients had chronic subdural hematoma during the 3-month follow-up. There was no mortality in our series.

CONCLUSIONS

There are several treatment strategies available to manage large and giant cerebral aneurysms. In this study, we had minimal morbidity (3.8%), favorable outcome (96.1%), and no mortality. Therefore, we would like to conclude that appropriate microsurgical procedures, in experienced hands, can be considered as first line in the management for large and giant intracranial aneurysms, especially those with complex anatomy, wide neck, mass effect, partial thrombosis, and the presence of critical perforating vessels from the aneurysm wall.

Adenosine-induced Flow Arrest to Facilitate Intracranial Complex Aneurysm Clip Ligation: Review of the Literature

Complex intracranial aneurysms (CIAs) rank high among the most technically demanding neurosurgical pathologies. Microsurgery and clip ligation can be challenging in CIAs as circumferential visualization of the aneurysm, parent vessels, branches, perforators, and other neurovascular structures is important to prevent residual aneurysms or strokes from vessel or perforator occlusion. Decompression of the aneurysm sac is often required for CIAs. We reviewed the literature and PubMed advanced search showed 13 results of adenosine-induced flow arrest to facilitate intracranial complex aneurysm clip ligation which included three independent case reports and ten cases in a case series from 1999 to May 2016. Few case series have described the use of adenosine in intracranial aneurysm surgery. Satisfactory aneurysm decompression was achieved in all cases, and all aneurysms were clipped successfully. We recommend that adenosine cardiac arrest is a relatively novel method for decompression of intracranial aneurysms to facilitate clip application. With appropriate safety precautions, it is a reasonable alternative method when temporary clipping of proximal vessels is not desirable or not possible.

Adenosine-induced cardiac arrest as an alternative to temporary clipping during intracranial aneurysm surgery

OBJECTIVE

The purpose of this study was to analyze the impact of adenosine-induced cardiac arrest (AiCA) on temporary clipping (TC) and the postoperative cerebral infarction rate among patients undergoing intracranial aneurysm surgery.

METHODS

In this retrospective matched-cohort study, 65 patients who received adenosine for decompression of aneurysms during microsurgical clipping were identified (Group A) and randomly matched with 65 selected patients who underwent clipping but did not receive adenosine during surgery (Group B). The matching criteria included age, Fisher grade, aneurysm size, rupture status, and location of aneurysms. The primary outcomes were TC time and the postoperative infarction rate. The secondary outcome was the incidence of intraoperative aneurysm rupture (IAR).

RESULTS

In Group A, 40 patients underwent clipping with AiCA alone and 25 patients (38%) received AiCA combined with TC, and in Group B, 60 patients (92%) underwent aneurysm clipping under the protection of TC (OR 0.052; 95% CI 0.018–0.147; p < 0.001). Group A required less TC time (2.04 minutes vs 4.46 minutes; p < 0.001). The incidence of postoperative lacunar infarction was equal in both groups (6.2%). There was an insignificant between-group difference in the incidence of IAR (1.5% in Group A vs 6.1% in Group B; OR 0.238; 95% CI 0.026–2.192; p = 0.171).

CONCLUSIONS

AiCA is a useful technique for microneurosurgical treatment of cerebral aneurysms. AiCA can minimize the use of TC and does not increase the risk of IAR and postoperative infarction.

Rapid ventricular pacing for clip reconstruction of complex unruptured intracranial aneurysms: results of an interdisciplinary prospective trial

OBJECTIVE

To date, treatment of complex unruptured intracranial aneurysms (UIAs) remains challenging. Therefore, advanced techniques are required to achieve an optimal result in treating these patients safely. In this study, the safety and efficacy of rapid ventricular pacing (RVP) to facilitate microsurgical clip reconstruction was investigated prospectively in a joined neurosurgery, anesthesiology, and cardiology study.

METHODS

Patients with complex UIAs were prospectively enrolled. Both the safety and efficacy of RVP were evaluated by recording cardiovascular events and outcomes of patients as well as the amount of aneurysm occlusion after the surgical clip reconstruction procedure. A questionnaire was used to evaluate aneurysm preparation and clip application under RVP.

RESULTS

Twenty patients (mean age 51.6 years, range 28–66 years) were included in this study. Electrode positioning was easy in 19 (95%) of 20 patients, and removal of electrodes was easily accomplished in all patients (100%). No complications associated with the placement of the pacing electrodes occurred, such as cardiac perforation or cardiac tamponade. RVP was applied in 16 patients. The mean aneurysm size was 11.1 ± 5.5 mm (range 6–30 mm). RVP proved to be a very helpful tool in aneurysm preparation and clip application in 15 (94%) of 16 patients. RVP was used for a mean duration of 60 ± 25 seconds, a mean heart rate of 173 ± 23 bpm (range 150–210 bpm), and a reduction of mean arterial pressure to 35–55 mm Hg. RVP leads to softening of the aneurysm sac facilitating its mobilization, clip application, and closure of the clip blades. In 2 patients, cardiac events were documented that resolved without permanent sequelae in both. In every patient with successful RVP (n = 14) a total or near-total aneurysm occlusion was documented. In the 1 patient in whom the second RVP failed due to pacemaker electrode dislocation, additional temporary clipping was required to secure the aneurysm, but was not as sufficient as RVP. This led to an incomplete clipping of the aneurysm and finally a remnant on postoperative digital subtraction angiography. A pacemaker lead dislocation occurred in 3 (19%) of 16 patients, but intraoperative repositioning requires less than 20 seconds. Outcome was favorable in all patients according to the modified Rankin Scale.

CONCLUSIONS

To the best of the authors’ knowledge this is the first prospective interdisciplinary study of RVP use in patients with UIAs. RVP is an elegant technique that facilitates clip reconstruction in complex UIAs. The safety of the procedure is good. However, because this procedure requires extensive preoperative cardiological workup of the patient and an experienced neurosurgery and neuroanesthesiology team with much cerebrovascular expertise, actually it remains reserved for selected elective cases and highly specialized centers.

Clinical trial registration no.: NCT02766972 (clinicaltrials.gov)

Adenosine-Assisted Clipping of Intracranial Aneurysms

BACKGROUND

Temporary parent vessel clip occlusion in aneurysm surgery is not always practical or feasible. Adenosine-induced transient cardiac arrest may serve as an alternative.

METHODS

All patients who underwent microsurgical clipping of intracranial aneurysms under adenosine-induced asystole performed by the author between September 2011 and July 2014 were retrospectively reviewed.

RESULTS

A total of 16 craniotomies were performed and 16 aneurysms were clipped under adenosine-induced asystole (in 8 basilar arteries, 7 internal carotid arteries, and 1 middle cerebral artery) in 14 patients (8 females, 6 males). Seven cases were elective and 7 were performed after subarachnoid hemorrhage. The patients' mean age was 54 years (range, 39-70 years). The indications for adenosine use were proximal control in narrow surgical corridors in 11 cases, aneurysm softening in 4 cases, and aneurysm rupture in 1 case. A single dose was used in 12 patients; 2 patients had multiple boluses. The median (range) total dose was 30 (18-60) mg. Adenosine induced bradycardia with concomitant arterial hypotension in all patients and the majority also had asystole for 5-15 s. Transient cardiac arrhythmias were noted in 1 patient (atrial fibrillation in need of electroconversion after two boluses).

CONCLUSION

Nine clinical scenarios were identified in which adenosine-induced temporary cardiac arrest and deep hypotension was an effective adjunct to temporary clipping during the microsurgical clipping of intracranial aneurysms.

Adenosine to facilitate the clipping of cerebral aneurysms: literature review

Cerebral aneurysms have a high mortality rate when ruptured. Endovascular techniques have improved substantially in treating this pathology. However, surgical clip ligation remains the preferred option for some aneurysms. Various techniques are used intraoperatively to assist the surgeon in dissecting the aneurysmal dome free of surrounding tissue and placing a clip around the neck safely and effectively so that no nearby perforating vessels are affected and no residual remains. These techniques include temporary clip ligation, endovascular balloon occlusion and cardiac standstill. Adenosine use is one viable option for induced cardiac arrest leading to a short period of controlled hypotension. Its predictable course of action, rapid onset and offset and rare incidence of adverse side effects make it an attractive agent in this regard. Below, we provide an introduction to adenosine use, describing its pharmacokinetic properties, indications, contraindications, complications and future directions.

The Role of Permissive and Induced Hypotension in Current Neuroanesthesia Practice

Background

Induced hypotension (IH) had been used for decades in neurosurgery to reduce the risk for intraoperative blood loss and decrease blood replacement. More recently, this method fell out of favor because of concerns for cerebral and other end-organ ischemia and worse treatment outcomes. Other contributing factors to the decline in its popularity include improvements in microsurgical technique, widespread use of endovascular procedures, and advances in blood conservation and transfusion protocols. Permissive hypotension (PH) is still being used occasionally in neurosurgery; however, its role in current anesthesia practice remains unclear. Our objective was to describe contemporary utilization of IH and PH (collectively called PH) in clinical practice among members of the Society for Neuroscience in Anesthesiology and Critical Care (SNACC).

Methods

A questionnaire was developed and distributed among SNACC members that addressed practice patterns related to the use of PH. The responses were analyzed based on the number of individuals who responded to each specific question.

Results

Of 72 respondents, 67.6% reported over 10 years of clinical experience, while 15.5% reported 5–10 years of post-training experience. The respondents admitted to providing anesthesia for 300 (median) neurosurgical cases per year. PH was applied most commonly during open interventions on cerebral aneurysms (50.8%) and arteriovenous malformations (46%). Seventy-three percent of respondents were not aware of any complications in their practice attributable to PH.

Conclusion

PH is still being used in neuroanesthesia practice by some providers. Further research is justified to clarify the risks and benefits of PH in modern neuroanesthesia practice.

The 2016 AANS Presidential Address: Leading the way

This AANS presidential address focuses on enduring values of the neurosurgical profession that transcend the current political climate. The address was delivered by Dr. Batjer during a US presidential election year, but the authors have intentionally avoided discussing the current chaos of the American health care system in the knowledge that many pressing issues will change depending on the outcome of the 2016 elections. Instead, they have chosen to focus on clarifying what neurosurgeons, and the American Association of Neurological Surgeons, in particular, stand for; identifying important challenges to these fundamental principles and values; and proposing specific actions to address these challenges. The authors cite "de-professionalism" and commoditization of medicine as foremost among the threats that confront medicine and surgery today and suggest concrete action that can be taken to reverse these trends as well as steps that can be taken to address other significant challenges. They emphasize the importance of embracing exceptionalism and never compromising the standards that have characterized the profession of neurosurgery since its inception.

Adenosine-induced transient asystole during intracranial aneurysm surgery: indications, dosing, efficacy, and risks

BACKGROUND

Several flow-arrest techniques have been introduced for the treatment of complex aneurysms that cannot be treated with conventional clipping or endovascular coil embolization. Adenosine-induced transient asystole is an alternative method of flow arrest. However, given the limited number of studies that have reported on this topic, there is no consensus regarding the dose, regimen, efficacy, and potential risks of adenosine.

METHOD

A total of 22 aneurysms in 22 different patients that underwent adenosine-induced transient asystole during aneurismal neck clipping within the past 4 years were retrospectively reviewed. Adenosine was administrated intravenously in a test-incremental manner (starting with 6-12 mg and then giving additional doses as needed) in 11 patients and in an estimated manner (pre-calculated as 0.3-0.4 mg/kg) in 11 patients.

RESULTS

Overall, the study consisted of 18 unruptured saccular aneurysms, three ruptured saccular aneurysms, and a ruptured pseudoaneurysm. Adenosine-induced transient asystole was used in cases of temporary clipping inability, wide necked aneurysm, deep-seated aneurysm, or a thin aneurysm wall. The number of administrations, dose (mg/kg in ideal body weight) and duration of asystole were 1-4 (mean, 2.3) times, 0.08-1.27 (mean, 0.36) mg/kg and 0-30 (mean 13) seconds in the test-incremental manner and 1-2 (mean, 1.09) times, 0.24-0.42 (mean, 0.34) mg/kg and 13-41 (mean, 24) seconds in the estimated manner, respectively. There was a linear relationship between the dose and the duration of asystole. Twenty out of 22 aneurysms were clipped successfully with adenosine-induced transient asystole. However, in the other two cases, additional suction decompression was required for the final clipping. Adenosine-related cardiologic complications occurred in two cases of self-limited atrial fibrillation during restoration of the cardiac rhythm.

CONCLUSIONS

In our experience, adenosine-induced transient asystole was safe and helpful for satisfactory clipping of a complicated aneurysm. An estimated dose injection of adenosine was more convenient than the test-incremental method and did not result in serious cardiologic problems.

Adenosine-induced transient asystole

Cerebral aneurysms are an important health issue in the United States, and the mortality rate following aneurysm rupture, or SAH, remains high. The treatment of these aneurysms uses endovascular options which include coil placement, stent assistant coiling and, recently, flow diversion. However, microsurgical clipping remains an option in those aneurysms not suited for endovascular therapy. These are often the more complicated aneurysms such as in large, giant aneurysms or deep-seated aneurysms. Circumferential visualization of the aneurysm, parent vessels, branches, perforators, and other neurovascular structures is important to prevent residual aneurysms or strokes from vessel or perforator occlusion. Decompression of the aneurysm sac is often required and we believe that adenosine-induced transient asystole should be an important option for clipping of complex cerebral aneurysms.

Transient Cardiac Arrest Induced by Adenosine: A Tool for Contralateral Clipping of Internal Carotid Artery-Ophthalmic Segment Aneurysms

BACKGROUND

The disadvantages of a contralateral approach (CA) include deep and narrow surgical corridors and inconsistent ability to achieve proximal control of the supraclinoid internal carotid artery (ICA). However, a CA remains as a microsurgical option for selected ICA-ophthalmic (opht) segment aneurysms.

OBJECTIVE

To describe transient cardiac arrest induced by adenosine as an alternative tool to obtain proximal vascular control and soften the aneurysm sac in selected patients while performing a CA.

METHODS

From January 1998 to December 2013, we retrospectively identified 30 patients with ICA-opht segment aneurysms treated through a CA. Of those, 8 patients received an intravenous bolus of adenosine to induce transient cardiac arrest for softening of the aneurysm sac. We reviewed preoperative clinical status, characteristics of the contralateral aneurysm, adenosine doses, asystole time, recovery of normal circulation, outcome, and complications.

RESULTS

No preoperative cardiac or pulmonary pathologies were found in the study population. All contralateral ICA-opht segment aneurysms were unruptured, small, and saccular in shape. Transient cardiac arrest was induced because it was impossible to apply a temporary clip on the parent contralateral supraclinoid ICA. The median dose of adenosine was 22.5 mg (range, 5-50 mg) and the asystole time ranged from 20 to 40 seconds. All patients (n = 8) had good postoperative outcomes. No brain infarction or cardiac complications appeared postoperatively.

CONCLUSIONS

In selected patients, transient cardiac arrest induced by adenosine during a contralateral approach allows a brief flow arrest and softening of the aneurysm for safer exposure and clipping.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a worldwide health burden with high fatality and permanent disability rates. The overall prognosis depends on the volume of the initial bleed, rebleeding, and degree of delayed cerebral ischemia (DCI). Cardiac manifestations and neurogenic pulmonary edema indicate the severity of SAH. The International Subarachnoid Aneurysm Trial (ISAT) reported a favorable neurological outcome with the endovascular coiling procedure compared with surgical clipping at the end of 1 year. The ISAT trial recruits were primarily neurologically good grade patients with smaller anterior circulation aneurysms, and therefore the results cannot be reliably extrapolated to larger aneurysms, posterior circulation aneurysms, patients presenting with complex aneurysm morphology, and poor neurological grades. The role of hypothermia is not proven to be neuroprotective according to a large randomized controlled trial, Intraoperative Hypothermia for Aneurysms Surgery Trial (IHAST II), which recruited patients with good neurological grades. Patients in this trial were subjected to slow cooling and inadequate cooling time and were rewarmed rapidly. This methodology would have reduced the beneficial effects of hypothermia. Adenosine is found to be beneficial for transient induced hypotension in 2 retrospective analyses, without increasing the risk for cardiac and neurological morbidity. The neurological benefit of pharmacological neuroprotection and neuromonitoring is not proven in patients undergoing clipping of aneurysms. DCI is an important cause of morbidity and mortality following SAH, and the pathophysiology is likely multifactorial and not yet understood. At present, oral nimodipine has an established role in the management of DCI, along with maintenance of euvolemia and induced hypertension. Following SAH, hypernatremia, although less common than hyponatremia, is a predictor of poor neurological outcome.

Neuroanesthesiology update

We review topics pertinent to the perioperative care of patients with neurological disorders. Our review addresses topics not only in the anesthesiology literature, but also in basic neurosciences, critical care medicine, neurology, neurosurgery, radiology, and internal medicine literature. We include literature published or available online up through December 8, 2013. As our review is not able to include all manuscripts, we focus on recurring themes and unique and pivotal investigations. We address the broad topics of general neuroanesthesia, stroke, traumatic brain injury, anesthetic neurotoxicity, neuroprotection, pharmacology, physiology, and nervous system monitoring.

Rapid ventricular pacing assisted hypotension in the management of sudden intraoperative hemorrhage during cerebral aneurysm clipping

Sudden intraoperative hemorrhage during intracranial aneurysm surgery from vascular injury or aneurysmal rupture has been known to dramatically increase the associated morbidity and mortality. We describe the first reported use of rapid ventricular pacing (RVP) assisted hypotension to control sudden intraoperative hemorrhage during intracranial aneurysm surgery where temporary arterial occlusion was not achievable.

Cardiac standstill and circulatory flow arrest in surgical treatment of intracranial aneurysms: a historical review

Since the first surgery for an intracranial aneurysm in 1931, neurological surgeons have long strived to determine the optimal methods of surgical correction. Significant challenges of aneurysm clipping include intraoperative rupture and complex dome morphology. Hypothermia, cardiopulmonary bypass, pharmacologically induced hypotension, and cardiac standstill are a few of the methodologies historically and currently employed in the management of these issues. In the 1980s, significant advances in pharmacology and anesthesiology led to the use of agents such as adenosine for chemically induced hypotension and eventually complete circulatory arrest. Since the institution of the use of these agents, the traditional methods of circulatory arrest under conditions of hypothermia and cardiopulmonary bypass have fallen out of favor. However, there still exists a subset of technically difficult aneurysms for which cardiac standstill, both chemical and hypothermic, remains a viable therapeutic option. In this paper, the authors describe the history of cardiac standstill by both hypothermic and chemically induced means as well as provide examples in which these techniques are still necessary.

Perioperative Cardiac Complications and 30-Day Mortality in Patients Undergoing Intracranial Aneurysmal Surgery With Adenosine-Induced Flow Arrest

BACKGROUND:

Adenosine-induced flow arrest is a technique used to assist in the surgical clipping of complex aneurysms.

OBJECTIVE:

To assess the safety associated with adenosine-assisted intracranial aneurysm surgery.

METHODS:

Medical records of all patients presenting between January 1, 2009, and December 31, 2012, for intracranial aneurysm surgery were analyzed. Patients were divided into 2 groups based on the intraoperative administration of adenosine: the nonadenosine group (n = 262) and the adenosine group (n = 64). The primary outcome compared between groups included a composite of 30-day mortality and incidences of perioperative cardiac complications (perioperative myocardial infarction or perioperative cardiac arrhythmias).

RESULTS:

The study groups were statistically similar except for a difference in the size and location of cerebral aneurysms and the incidence of coronary artery disease. The primary composite outcome occurred in 4.6% and 9.4% of patients in the nonadenosine and adenosine groups, respectively (P = .13). After adjustment for differences in the incidence of coronary artery disease between the 2 groups, the odds of the primary outcome were not significantly different between the groups (adjusted odds ratio = 2.12; 95% confidence interval, 0.76-5.93; P = .15). There were also no significant differences in the durations of hospital and intensive care unit stay between the study groups.

CONCLUSION:

Our results suggest that adenosine-assisted intracranial aneurysm surgery is not associated with an increase in perioperative cardiac complications or mortality in patients with low risk of coronary artery disease and may be considered a safe technique to assist clipping of complex aneurysms.