Adenosine-induced cardiac arrest during intraoperative cerebral aneurysm rupture

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.

Influence of Perioperative Three-Dimensional Computed Tomography (CT) Angiography and Surgical Clipping for Unruptured Cerebral Aneurysms on Renal Function in Patients with Chronic Kidney Disease

BACKROUND

Surgical clipping is a valuable treatment option for unruptured intracranial aneurysms in patients with chronic kidney disease (CKD). However, the comprehensive impact of clipping and perioperative three-dimensional computed tomography angiography (3D-CTA) on renal function remains unclear. This study aimed to evaluate the effects of perioperative 3D-CTA and surgical clipping on renal function in patients with CKD.

METHODS

We retrospectively analyzed 529 patients who underwent surgical clipping and perioperative 3D-CTA. An estimated glomerular filtration rate (eGFR) < 60 was defined as CKD. Patients were stratified according to their renal function (group 1: eGFR ≥60, group 2: 45 ≤ eGFR <60, group 3: 30 ≤ eGFR <45, group 4: eGFR <30 ml/min/1.73 m2), and eGFR was assessed preoperatively and 1 week and several months postoperatively.

RESULTS

Of the 529 patients, 442 did not have CKD and 87 had CKD. Hypertension, hyperlipidemia, and hyperuricemia were significantly more common in those with CKD. After the surgery and perioperative series of 3D-CTA, renal function deterioration was not observed in any group, whether in the acute or chronic postoperative period. Notably, eGFR significantly increased in groups 2 (66.7 ± 10.1, P < 0.01) and 3 (48.9 ± 9.2, P = 0.02) 1 week postoperatively, despite the CKD.

CONCLUSIONS

Surgical clipping of unruptured intracranial aneurysms and perioperative 3D-CTA with normal-dose contrast media did not impair renal function in patients with CKD. These results could be valuable in determining treatment strategies for those with CKD and intracranial aneurysms.

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.

Presurgical selection of the ideal aneurysm clip by the use of a three-dimensional planning system

Aneurysm occlusion rate after clipping is higher than after endovascular treatment. However, a certain percentage of incompletely clipped aneurysms remains. Presurgical selection of the proper aneurysm clips could potentially reduce the rate of incomplete clippings caused by inadequate clip geometry. The aim of the present study was to assess whether preoperative 3D image-based simulation allows for preoperative selection of a proper aneurysm clip for complete occlusion in individual cases. Patients harboring ruptured or unruptured cerebral aneurysms prior to surgical clipping were analyzed. CT angiography images were transferred to a 3D surgical-planning station (Dextroscope®) with imported models of 58 aneurysm clips. Intracranial vessels and aneurysms were segmented and the virtual aneurysm clips were placed at the aneurysm neck. Operating surgeons had information about the selected aneurysm clip, and patients underwent clipping. Intraoperative clip selection was documented and aneurysm occlusion rate was assessed by postoperative digital subtraction angiography. Nineteen patients were available for final analysis. In all patients, the most proximal clip at the aneurysm neck was the preselected clip. All aneurysms except one were fully occluded, as assessed by catheter angiography. One aneurysm had a small neck remnant that did not require secondary surgery and was occluded 15 months after surgery. 3D image-based preselection of a proper aneurysm clip can be translated to the operating room and avoids intraoperative clip selection. The associated occlusion rate of aneurysms is high.

Microsurgical Treatment of Deep and Eloquent AVMs

Over the past 30 years, the treatment of deep and eloquent arteriovenous malformations (AVMs) has moved away from microneurosurgical resection and towards medical management and the so-called minimally invasive techniques, such as endovascular embolization and radiosurgery. The Spetzler-Martin grading system (and subsequent modifications) has done much to aid in risk stratification for surgical intervention; however, the system does not predict the risk of hemorrhage nor risk from other interventions. In more recent years, the ARUBA trial has suggested that unruptured AVMs should be medically managed. In our experience, although these eloquent regions of the brain should be discussed with patients in assessing the risks and benefits of intervention, we believe each AVM should be assessed based on the characteristics of the patient and the angio-architecture of the AVM, in particular venous hypertension, which may guide us to treat even high-grade AVMs when we believe we can (and need to) to benefit the patient. Advances in imaging and intraoperative adjuncts have helped us in decision making, preoperative planning, and ensuring good outcomes for our patients. Here, we present several cases to illustrate our primary points that treating low-grade AVMs can be more difficult than treating high-grade ones, mismanagement of deep and eloquent AVMs at the behest of dogma can harm patients, and the treatment of any AVM should be tailored to the individual patient and that patient's lesion.

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.

Complications and Neurological Outcome following Intraoperative Aneurysm Rupture in Adult Patients Undergoing Intracranial Aneurysmal Clipping: A Retrospective Study

Background  Intraoperative aneurysmal rupture (IAR) is a catastrophic complication; however, its impact on neurological outcome is debatable. We studied the effects of IAR on intraoperative and postoperative complications and neurological outcome. Methods  In this retrospective study, adult patients who underwent aneurysmal clipping over a period of 2 years were divided as follows: group R (with IAR) and group N (without IAR). Various perioperative parameters, intraoperative and postoperative complications were noted. Glasgow outcome scale (GOS) was noted at discharge from hospital and categorized as favorable (GOS IV and V) and unfavorable (GOS I, II and III). Collected data was statistically analyzed. Univariate and multiple logistic regression analyses were performed to identify predictors of IAR. A p value < 0.05 was considered significant. Results  Thirty-two out of 195 (16.41%) patients suffered IAR, with majority involving anterior communicating artery aneurysm (46.88%). Duration of temporary clipping ( p < 0.001), volume of blood loss, and fluid and blood transfusion were significantly more in group R. Postoperatively, significantly more patients in group R developed intracranial hematoma, cerebral infarct, and required prolonged ventilatory support (≥5 days). Unfavorable neurological outcome was observed more in group R ( p = 0.013). In univariate analysis, blood loss > 500 mL, use of colloids, and duration of surgery > 5 hours were found to be associated with IAR. After multiple logistic regression analysis, only use of colloids and duration of surgery > 5 hours were the most predictive variables for IAR. Conclusions  IAR is associated with serious intraoperative and postoperative complications and unfavorable neurological outcome.

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.

A literature review concerning contralateral approaches to paraclinoid internal carotid artery aneurysms

Ipsilateral approaches remain the standard technique for clipping paraclinoid aneurysms. Surgeons must however be prepared to deal with bony and neural structures restricting accessibility. The application of a contralateral approach has been proposed claiming that some structures in the region can be better exposed from this side. Yet, only few case series have been published evaluating this approach, and there is a lack of systematic reviews assessing its specific advantages and disadvantages. We performed a structured literature search and identified 19 relevant publications summarizing 138 paraclinoid aneurysms operated via a contralateral approach. Patient's age ranged from 19 to 79 years. Aneurysm size mainly varied between 2 and 10 mm and only three articles reported larger aneurysms. Most aneurysms were located at the origin of the ophthalmic artery, followed by the superior hypophyseal artery and carotid cave. All aneurysm protruded from the medial aspect of the carotid artery. Interestingly, minimal or even no optic nerve mobilization was required during exposure from the contralateral side. Strategies to achieve proximal control of the carotid artery were balloon occlusion and clinoid segment or cervical carotid exposure. Successful aneurysm occlusion was achieved in 135 cases, while 3 ophthalmic aneurysms had to be wrapped only. Complications including visual deterioration, CSF fistula, wound infection, vasospasm, artery dissection, infarction, and anosmia occurred in a low percentage of cases. We conclude that a contralateral approach can be effective and should be considered for clipping carefully selected cases of unruptured aneurysms arising from medial aspects of the above listed vessels.

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.

Microneurosurgical Management of Posterior Communicating Artery Aneurysm: A Contemporary Series from Helsinki

OBJECTIVE

The objectives of this study were to analyze microsurgical techniques and to determine correlations between microsurgical techniques and the radiographic findings in the microneurosurgical treatment of posterior communicating artery aneurysms (PCoAAs).

METHODS

We retrospectively analyzed radiographic findings and videos of surgeries in 64 patients with PCoAAs who underwent microsurgical clipping by the senior author from August 2010 to 2014.

RESULTS

From 64 aneurysms, 30 (47%) had acute subarachnoid hemorrhage (SAH) that necessitated lamina terminalis fenestration (odds ratio [OR], 67.67; P < 0.001) and Liliequist membrane fenestration (OR, 19.62; P < 0.001). The low-lying aneurysms significantly necessitated the coagulation of the dura covering the anterior clinoid process (ACP) (OR, 7.43; P = 0.003) or anterior clinoidectomy (OR, 91.0; P < 0.001). We preferred straight clips in 45 (83%) of 54 posterolateral projecting aneurysms (OR, 45.0; P < 0.001), but preferred curved clips for posteromedial projecting aneurysms (OR, 6.39; P = 0.008). The mean operative time from the brain retraction to the final clipping was 17 minutes and 43 seconds. Postoperative computed tomography angiography revealed complete occlusion of 60 (94%) aneurysms. Three (4.6%) patients with acute SAH suffered postoperative lacunar infarction.

CONCLUSIONS

For ruptured aneurysms, lamina terminalis and Liliequist membrane fenestration are useful for additional cerebrospinal fluid drainage. For low-lying aneurysms, coagulation of the dura covering the ACP or tailored anterior clinoidectomy might be necessary for exposing the proximal aneurysm neck. Type of clips depends on the direction of projection. The microsurgical clipping of the PCoAAs can achieve good immediate complete occlusion rate with low postoperative stroke rate.

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.

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.

Transfusion Frequency of Red Blood Cells, Fresh Frozen Plasma, and Platelets During Ruptured Cerebral Aneurysm Surgery

BACKGROUND

The use of blood products after subarachnoid hemorrhage (SAH) is common, but not without controversy. The optimal hemoglobin level in patients with SAH is unknown, and data on perioperative need for red blood cell (RBC), fresh frozen plasma (FFP), or platelet transfusions are limited. We studied perioperative administration of RBCs, FFP, and platelets and the impact of red blood cell transfusions (RBCTs) on outcome in patients undergoing surgery for ruptured a cerebral arterial aneurysm.

METHODS

A retrospective analysis was performed of 488 patients with aneurysmal SAH during the years 2006-2009 at Helsinki University Central Hospital. Patients who received RBC, FFP, or platelet concentrates perioperatively were compared with a cohort of patients from the Helsinki database of aneurysmal SAH who did not receive transfusions. A multiple regression model was created to identify factors related to transfusion and outcome.

RESULTS

RBC, FFP, or platelet concentrates were given in 7.6% (37 of 488), 3.1% (15 of 488), and 1.2% (6 of 488) of patients intraoperatively and in 3.5% (17 of 486), 1.6% (8 of 488), and 0.9% (4 of 488) of patients postoperatively. Of 37 intraoperative RBCTs, 26 were related to intraoperative rupture of the aneurysm. Intraoperative RBCTs were associated with lower preoperative hemoglobin concentration, higher World Federation of Neurosurgical Societies classification, and intraoperative rupture of an aneurysm. In multivariate analysis, intraoperative RBCT (odds ratio = 5.13, 95% confidence interval = 1.53-17.15), worse World Federation of Neurosurgical Societies classification and Fisher grade (odds ratio = 1.97, confidence interval = 1.64-2.36 and odds ratio = 1.89, confidence interval = 1.23-2.92, respectively), and increasing age (odds ratio = 1.07, confidence interval = 1.04-1.10) independently increased the risk of poor neurologic outcome at 3 months.

CONCLUSIONS

Transfusion frequencies of RBCs, FFP, and platelets were relatively low. Intraoperative RBCT was strongly related to intraoperative rupture of the aneurysm in patients with poor-grade SAH. The observed association between poor outcome and RBCT in patients with SAH warrants further study.

Contralateral Approach to Internal Carotid Artery Ophthalmic Segment Aneurysms: Angiographic Analysis and Surgical Results for 30 Patients

BACKGROUND

Contralateral aneurysm clipping can be applied to bilateral intracranial aneurysms of the anterior circulation and to selected aneurysms on the medial wall of the internal carotid artery (ICA).

OBJECTIVE

To identify anatomic and radiological parameters that would favor a contralateral microsurgical approach to ICA-ophthalmic segment (ICA-opht) aneurysms.

METHODS

For the period January 1957 to December 2012, we retrospectively analyzed 268 patients with ICA-opht aneurysms treated in our institution. Of these patients, 30 underwent a contralateral approach; 15 patients (50%) had multiple intracranial aneurysms, and 15 patients had a single aneurysm on the contralateral side of the craniotomy.

RESULTS

Thirty saccular aneurysms located on the contralateral ICA were treated. Six aneurysms (20%) were present in patients with a subarachnoid hemorrhage due to associated aneurysms, whereas 24 aneurysms (80%) had no history of bleeding. Contralateral aneurysms were smaller than 14 mm and showed no wall irregularities, calcifications, or secondary pouches. Projections of the aneurysms were superomedial (n = 23, 77%), medial (n = 4, 13%), and superior (n = 3, 10%). The median prechiasmatic distance was 5.7 mm (range, 3.4-8.7 mm), the median interoptic distance was 10.5 mm (range, 7.6-15.9 mm), and the median distance between both ICAs was 14.7 mm (range, 10.4-21.4 mm).

CONCLUSION

The contralateral approach for ICA-opht aneurysms remains a treatment option for intracranial aneurysms. Its feasibility depends on specific anatomic parameters related to the aneurysm itself and to the prechiasmatic distance, interoptic distance, and relationship of the ICA with the anterior clinoid process.

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.

Controversies in the anesthetic management of intraoperative rupture of intracranial aneurysm

Despite great advancements in the management of aneurysmal subarachnoid hemorrhage (SAH), outcomes following SAH rupture have remained relatively unchanged. In addition, little data exists to guide the anesthetic management of intraoperative aneurysm rupture (IAR), though intraoperative management may have a significant effect on overall neurological outcomes. This review highlights the various controversies related to different anesthetic management related to aneurysm rupture. The first controversy relates to management of preexisting factors that affect risk of IAR. The second controversy relates to diagnostic techniques, particularly neurophysiological monitoring. The third controversy pertains to hemodynamic goals. The neuroprotective effects of various factors, including hypothermia, various anesthetic/pharmacologic agents, and burst suppression, remain poorly understood and have yet to be further elucidated. Different management strategies for IAR during aneurysmal clipping versus coiling also need further attention.

Focused opening of the sylvian fissure for microsurgical management of MCA aneurysms

BACKGROUND

A wide sylvian opening, with either a proximal or distal start, has been standard for microsurgical management of middle cerebral artery (MCA) aneurysms. However, extensive sylvian dissection is potentially associated with increased incidence of iatrogenic injury to the brain and neurovascular structures. The aim of the present study was to describe the technique of focused opening of the sylvian fissure for microsurgical management of MCA aneurysms with additional tips on handling difficulties which may be encountered with this technique.

METHOD

A 3D image-based anatomic orientation, clipping field-focused surgical planning, slack brain, and high magnification are the basic requirements for this approach. A 10-15 mm sylvian opening is placed so that it allows safe access and a good surgical view of the MCA aneurysm clipping field. Under proximal control of the MCA, the aneurysm neck can be dissected and clipped effectively and safely, in this small surgical field.

RESULTS

The presented technique has been developed and refined by the senior author during the surgery of 1,097 aneurysms over the last 13 years. It has proved to be safe, and effective for clipping of both ruptured and unruptured MCA aneurysms. Its greatest advantages are a shorter operative time and less brain and vessel manipulation compared to more extensive approaches.

CONCLUSION

The focused sylvian opening is a less-invasive alternative to the classical wide sylvian opening for the microsurgical management of most MCA aneurysms.

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.

Rapid Ventricular Pacing for Flow Arrest During Cerebrovascular Surgery: Revival of an Old Concept

BACKGROUND:

Intraoperative rupture of a cerebral aneurysm can be a devastating event that increases operative morbidity and mortality. Rapid ventricular pacing (RVP) is a technique used in interventional cardiology to obtain flow arrest for short periods of time.

OBJECTIVE:

To present our experience using RVP for flow arrest during cerebrovascular surgery.

METHODS:

We used RVP to produce flow arrest for periods of 40 seconds in 12 patients who underwent craniotomy for a cerebrovascular disorder (11 aneurysms and 1 arteriovenous malformation).

RESULTS:

During RVP, there was an immediate and significant reduction of blood pressure in each patient. The maximum degree of hypotension was obtained 3.2 ± 0.7 seconds (mean ± SD) after the start of RVP. When RVP was terminated, normal sinus rhythm returned instantaneously, along with recovery of indexes of hemodynamic function. Subjectively, the decrease in blood pressures facilitated dissection, and during clipping, the aneurysm sac felt softer and was easier to manipulate. No complications related to RVP occurred.

CONCLUSION:

Rapid ventricular pacing during cerebrovascular surgery is an effective method for lowering the arterial blood pressure in a controlled and directly reversible manner. Advances in cardiology now make RVP a promising and safe technique that can facilitate complex cerebrovascular surgery.

Microsurgery for Previously Coiled Aneurysms: Experience With 81 Patients

BACKGROUND:

Residual and recurrent intracranial aneurysms after endovascular treatment with Guglielmi detachable coils may necessitate a microsurgical occlusion.

OBJECTIVE:

To analyze the microsurgical technique and describe how the location, morphology, and appearance of the coiled aneurysm affect the technique.

METHODS:

We retrospectively analyzed 81 patients with 82 previously coiled aneurysms treated microsurgically at 2 Finnish neurosurgical university hospitals in Helsinki and Kuopio between July 1995 and August 2009. Seven videos were selected to demonstrate the microsurgical strategy in various locations.

RESULTS:

Fifty-eight aneurysms (71%) were located at anterior circulation and 24 (29%) at posterior circulation. Fifteen patients were operated on within the first month (early surgery) after coiling, whereas 66 were treated later (late surgery). Complete or partial removal of coils during surgery may facilitate clipping, but is significantly (P &lt; .001) more difficult to accomplish in late surgery. Removal of coils may also increase the chance of poor outcome. Chance of poor outcome also increased with intraoperative aneurysm rupture, size of the aneurysm, and posterior circulation location. Good clinical outcome (same or better clinical condition 3 months after surgery) was achieved in 71 patients (88%). After microsurgery, 4 patients were severely disabled and 6 patients died, 3 of them because of poor clinical condition.

CONCLUSION:

Complete microsurgical occlusion of the residual aneurysm is possible. However, in large or giant aneurysms direct microsurgery is a challenging high-risk procedure, and we recommend that these patients be referred to a dedicated neurovascular center to minimize surgical complications. Even in experienced hands, use of different bypass procedures may be the best option for demanding growing lesions, especially those in the posterior circulation.