Adenosine for Temporary Flow Arrest During Intracranial Aneurysm Surgery: A Single-Center Retrospective Review

Safety of Adenosine-assisted Clipping Surgery for Unruptured Cerebral Aneurysms: Interim Results of a Single-center, Single-arm Study

The aim of this single-center, single-arm study was to evaluate the safety of adenosine-assisted clipping surgery for unruptured cerebral aneurysms. Five patients underwent aneurysmal clipping during adenosine-induced hypotension at ≤60 mmHg. The mean age of patients was 63.4±8.5 years, and the mean aneurysm size was 5.3±1.1 mm. The prevalence of patients with modified Rankin Scale scores of zero 30 days after surgery was 100%. The degree of aneurysm obliteration was complete in 4 patients and residual dome in 1 patient. The mean total dosage of adenosine was 37.4±18.8 mg. The mean duration of systolic blood pressure at ≤60 mmHg was 64.2±28.3 secs. No patients exhibited paroxysmal atrial fibrillation within 24 hours after adenosine administration or elevation of high-sensitivity cardiac troponin T on postoperative day 1. There was no reduction in either motor-evoked or somatosensory-evoked potential amplitude during surgery. Adenosine-induced hypotension is a safe procedure in clipping surgery for unruptured cerebral aneurysms.

Efficacy and safety of adenosine, rapid ventricular pacing and hypothermia in cerebral aneurysms clipping: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Cerebral aneurysms in complex anatomical locations and intraoperative rupture can be challenging. Many methods to reduce blood flow can facilitate its exclusion from the circulation. This study evaluated the safety and efficacy of using adenosine, rapid ventricular pacing, and hypothermia in cerebral aneurysm clipping.

METHODS

Databases (PubMed, Embase, and Web of Science) were systematically searched for studies documenting the use of adenosine, rapid ventricular pacing, and hypothermia in cerebral aneurysm clipping and were included in this single-arm meta-analysis. The primary outcome was 30-day mortality. Secondary outcomes included neurological outcomes by mRs and GOS, and cardiac outcomes. We evaluated the risk of bias using ROBIN-I, a tool developed by the Cochrane Collaboration. OpenMetaAnalyst version 2.0 was used for statistical analysis and I2 measured data heterogeneity. Heterogeneity was defined as an I2 > 50%.

RESULTS

Our systematic search yielded 10,100 results. After the removal of duplicates and exclusion by title and abstract, 64 studies were considered for full review, of which 29 were included. The overall risk of bias was moderate. The pooled proportions of the adenosine analysis for the different outcomes were: For the primary outcome: 11,9%; for perioperative arrhythmia: 0,19%; for postoperative arrhythmia: 0,56%; for myocardial infarction incidence: 0,01%; for follow-up good recovery (mRs 0-2): 88%; and for neurological deficit:14.1%. In the rapid ventricular pacing analysis, incidences were as follows: peri operative arrhythmia: 0,64%; postoperative arrhythmia: 0,3%; myocardial infarction: 0%. In the hypothermia analysis, the pooled proportion of 30-day mortality was 11,6%. The incidence of post-op neurological deficits was 35,4% and good recovery under neurological analysis by GOS was present in 69.2%.

CONCLUSION

The use of the three methods is safe and the related complications were very low. Further studies are necessary, especially with comparative analysis, for extended knowledge.

Combined endoscopic endonasal and transcranial approach for internal carotid artery aneurysms: usefulness and safety of endonasal proximal control

It is necessary to secure both the proximal and distal sides of the parent artery to prevent premature rupture when clipping cerebral aneurysms. Herein, we describe four cases in which the proximal internal carotid artery (ICA), affected by a paraclinoid aneurysm, was secured using an endoscopic endonasal approach. We used various tools, including a surgical video, cadaver dissection picture, artist's illustration, and intraoperative photographs, to elucidate the process. No patient experienced postoperative complications at our institution. Compared to the cervical or cavernous ICA, the ICA adjacent to the clivus (paraclival ICA) can be anatomically safely and easily exposed using an endoscopic endonasal approach because there is no need to consider cerebrospinal fluid leakage or hemorrhage from the cavernous sinus. Securing the proximal side of the parent artery using an endoscopic endonasal approach may be a viable method for clipping selected ICA aneurysms, such as paraclinoid aneurysms especially for upward or outward aneurysms of the C2 portion.

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.

Management of Intraoperative Rupture of Intracranial Aneurysms: Agony and Ecstasy

Intraoperative rupture (IOR) of an intracranial aneurysm is a serious complication, often with catastrophic consequences that are difficult to manage even by the best hands. Like most surgical complications, this one is better to avoid than to treat, but any vascular neurosurgeon should know how to deal with IOR of an aneurysm, because it is bound to occur. The aims of this study were to evaluate the incidence and factors associated with IOR during clipping of intracranial aneurysms, to analyze strategies for controlling hemorrhage in such cases, and to assess outcomes. Overall, 911 cases of intracranial aneurysms, which were treated surgically by the author during 26 years of his professional career, were reviewed. IOR was never noted during clipping of an unruptured intracranial aneurysm (65 cases) but was encountered in 49 of 846 cases (5.8%) presenting with subarachnoid hemorrhage. This complication occurred most often in cases of internal carotid artery aneurysms (22 cases; 45%), followed by anterior communicating artery aneurysms (12 cases; 24%), distal anterior cerebral artery aneurysms (6 cases; 12%), middle cerebral artery aneurysms (6 cases; 12%), and posterior circulation aneurysms (3 cases; 6%). IOR was mostly encountered during early surgery (within 3 days) after the ictus (26 cases; 53%) and most frequently occurred during dissection of the aneurysm (26 cases; 53%). Overall, 22 patients (45%) had good outcome, 18 (37%) had variable morbidity, and 9 (18%) died. Fatal consequences of IOR were noted only in cases of big or multilobulated internal carotid artery aneurysms. Detailed planning of the surgical procedure, application of meticulous microdissection techniques, and anticipation of possible intraoperative incidents during intervention aimed at clipping of an intracranial aneurysm can reduce the risk of IOR, as well as the associated morbidity and mortality.

Avoiding Complications in Aneurysm Ligation: Operative Tips and Tricks

Preventing possible complications during brain aneurysm surgery is mandatory to ensure a better outcome for patients. Currently, it is possible to rely on some technologic innovations such as motor evoked potential, endoscope-assisted surgery, dye with indocyanine green, and video angiography capable of supporting the surgeon's work. The innovation process has mainly assisted the endovascular technique compared with surgery. The latter, apart from some new technical expedients, always requires anatomic knowledge and optimal technical preparation. A careful patient selection, adequate surgical exposure, use of microsurgical techniques in expert hands, and meticulous postoperative management represent the key to success for the surgical treatment of cerebral aneurysms.

Selective arterial temporary flow arrest with balloons during transvenous embolization for the treatment of brain arteriovenous malformations: a feasibility study with MRI-monitored adverse events

BACKGROUND

The technique of endovascular transvenous embolization for brain arteriovenous malformations (AVMs) has emerged in the last 8 years as a very promising therapeutic alternative for otherwise incurable cases. Selective temporary flow arrest during transvenous endovascular embolization (TFATVE) is a novel adaptation of our previously described transvenous approach, which employs hyper-compliant balloons intra-arterially for the selective occlusion of arterial feeders during ethylene vinyl copolymer (EVOH) injection, in order to reduce intra-nidal pressure and increase nidi occlusion rates.

METHODS

We performed a feasibility study of the TFATVE technique between January 2016 and April 2020. Consecutive patients were included. All patients had at least one axial brain MRI or CT in the first 48 hours following intervention, and at least one brain MRI scan within the first postoperative month, in order to detect both silent and clinically evident adverse events. Patients' demographics, angio-architectural characteristics, total injection and procedure times, angiographic and clinical outcomes were analyzed.

RESULTS

22 patients underwent TFATVE during transvenous endovascular treatment of brain AVMs. Among them, 86.4% were high Spetzler-Martin's grade. Good clinical outcome (modified Rankin Scale <2) was achieved in 95.5% of the cases, with 0% of procedure-related mortality and 4.5% of clinically significant, procedure-related morbidity. Total occlusion of the nidus was achieved in >90% of the cases at the end of the procedure and angiographic stability was achieved in all cases; 100% of the cases had angiographic cure at follow-up.

CONCLUSIONS

TFATVE seems a safe and effective technique when conducted in carefully selected patients in highly specialized centers.

Rapid Ventricular Pacing as a Safe Procedure for Clipping of Complex Ruptured and Unruptured Intracranial Aneurysms

Surgical treatment of intracranial aneurysm requires advanced technologies to achieve optimal results. Recently, rapid ventricular pacing (RVP) has been described to be an elegant technique that facilitates clip reconstruction of complex unruptured intracranial aneurysm (uIA). However, there is also a growing need for intraoperative tools to ensure safe clip reconstruction of complex ruptured intracranial aneurysm (rIA). We conducted a retrospective analysis of 17 patients who underwent RVP during surgical reconstruction of complex aneurysms. Nine patients had uIA while eight patients underwent surgery for rIA suffering from consecutive subarachnoid hemorrhage (SAH). Hemodynamic data, critical events, laboratory results, and anesthesia-related complications were evaluated. No complications were reported concerning anesthesia induction and induction times were similar between patients exhibiting uIA or rIA (p = 0.08). RVP induced a significant decline of median arterial pressure (MAP) in both groups (p < 0.0001). However, median MAP before and after RVP was not different in both groups (uIA group: p = 0.27; rIA group: p = 0.18). Furthermore, high-sensitive Troponin T (hsTnT) levels were not increased after RVP in any group. One patient in the rIA group exhibited ventricular fibrillation and required cardiopulmonary resuscitation, but has presented with cardiac arrest due to SAH. Otherwise, no arrhythmias or complications occurred. In summary, our data suggest RVP to be feasible in surgery for ruptured intracranial aneurysms.

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.

Adenosine-induced transient circulatory arrest in transvenous embolization of cerebral arteriovenous malformations

Due to advances in interventional techniques, the transvenous approach may present an effective treatment option for embolization of brain arteriovenous malformations (AVMs). Contrary to the transarterial method, the transvenous approach can only be utilized in a specific subset of patients and is not suitable as a standard procedure for all AVM lesions. While this technique can be helpful in certain patients, careful patient selection to ensure patient safety and favorable clinical outcomes is important. However, especially in high-flow AVMs, targeted deposition of embolic materials through a transvenous access can be challenging. Therefore, a temporary flow arrest may prove helpful. Transient cardiac arrest by use of adenosine has been applied in cerebrovascular surgery but is not common for endovascular embolization. Adenosine-induced arrest and systemic hypotension may be a feasible, safe method to reduce flow and help endovascular transvenous embolization of certain AVMs. Our study evaluated the efficiency and safety of adenosine-induced circulatory arrest for transvenous embolization of cerebral AVMs.

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.

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.

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)

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

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.

A Case of High-dose Adenosine Usage for Anterior Communicating Artery Aneurysm Clip Ligation: What is the Dose Limit for a Resistant Response?

Intraoperative adenosine is used to induce asystole to facilitate clip ligation of intracranial aneurysms. Typically, 5–10 mg doses are used per administration and approximately 30 mg is used for a given case. An obvious concern with using adenosine is that the patient can remain in asystole or that prolonged hypotension can result in cerebral or cardiovascular ischemia. The upper limit of adenosine administration remains unclear. We present a case of a patient with a large anterior communicating artery aneurysm requiring large doses of adenosine, far exceeding previously reported cases. The patient received a 90 mg dose of adenosine to achieve 5 s of asystole as well as 30 s of hypotension that facilitated vessel dissection and clip application. Moreover, in order to successfully clip his aneurysm, he received a total of 744 mg of adenosine. After each administration of adenosine, his heart rate and blood pressure returned to baseline without the need for chest compressions or other interventions. He tolerated the procedure and had a good neurological outcome. This case is the first report of using such a high dose of adenosine in intracranial aneurysm surgery and suggests that more aggressive administration of adenosine during aneurysm clipping is feasible. Transient hypotension, as seen in this report, can provide surgeons the crucial moments they need to safely secure an aneurysm from circulation.

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.

Direct Repair of Iatrogenic Internal Carotid Artery Injury During Endoscopic Endonasal Approach Surgery With Temporary Endovascular Balloon-Assisted Occlusion: Technical Case Report

BACKGROUND AND IMPORTANCE

Iatrogenic internal carotid artery (ICA) injuries during endoscopic endonasal approach (EEA) surgeries are associated with a high morbidity and mortality, with few acceptable methods described for repair.

CLINICAL PRESENTATION

A 13-year-old girl with a large anterior and central skull base osteoblastoma incurred an iatrogenic cavernous ICA injury during a staged EEA approach. Intraoperative angiogram was performed with balloon-assisted EEA primary microsurgical repair of the lacerated ICA.

CONCLUSION

By integrating current techniques commonly used in open aneurysm surgeries and in endovascular procedures, we developed a rapid, safe technique to repair an EEA-associated iatrogenic ICA injury.

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.

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.

Guidelines for the Management of Patients With Unruptured Intracranial Aneurysms: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

PURPOSE

The aim of this updated statement is to provide comprehensive and evidence-based recommendations for management of patients with unruptured intracranial aneurysms.

METHODS

Writing group members used systematic literature reviews from January 1977 up to June 2014. They also reviewed contemporary published evidence-based guidelines, personal files, and published expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulated recommendations using standard American Heart Association criteria. The guideline underwent extensive peer review, including review by the Stroke Council Leadership and Stroke Scientific Statement Oversight Committees, before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with unruptured intracranial aneurysms. The guidelines address presentation, natural history, epidemiology, risk factors, screening, diagnosis, imaging and outcomes from surgical and endovascular treatment.