Temporary Vascular Occlusion During Cerebral Aneurysm Surgery

Risk Factors for Cerebral Infarction After Microsurgical Clipping of Hunt-Hess Grade 0-2 Single Intracranial Aneurysm: A Retrospective Study

OBJECTIVE

The study aimed to explore risk factors for cerebral infarction after microsurgical clipping in patients with Hunt-Hess grade 0-2 single intracranial aneurysms.

METHODS

A total of 137 patients with Hunt-Hess grade 0-2 single intracranial aneurysms treated with microsurgical clipping between March 2017 and December 2020 were retrospectively enrolled. Patients were divided into 2 groups on the basis of the occurrence of cerebral infarction after surgery.

RESULTS

Of 137 enrolled patients, 14 (10.22%) showed cerebral infarction symptoms after surgery. Univariate analysis indicated that ruptured aneurysm status, aneurysm rupture during surgery, history of transient ischemic attack (TIA)/stroke, aneurysm size ≥7 mm, temporary clipping, intraoperative systolic hypotension (IOH), and occurrences of intraoperative motor-evoked potentials change were significantly related to postoperative cerebral infarction (PCI). However, using multivariate regression, only history of TIA/stroke (odds ratio = 0.124; 95% confidence interval [CI] = 0.021-0.748, P = 0.023) and IOH (odds ratio = 0.032; 95% CI = 0.005-0.210, P < 0.001) were independent predictors for PCI. Receiver operating characteristic curve analysis showed that the critical duration of temporary clipping and IOH that minimized the risk of PCI was 5.5 minutes and 7.5 minutes, respectively.

CONCLUSIONS

Our study identified history of TIA/stroke and IOH as independent risk factors for cerebral infarction after microsurgical clipping.

Artificial Neural Network for Predicting the Safe Temporary Artery Occlusion Time in Intracranial Aneurysmal Surgery

BACKGROUND

Temporary artery clipping facilitates safe cerebral aneurysm management, besides a risk for cerebral ischemia. We developed an artificial neural network (ANN) to predict the safe clipping time of temporary artery occlusion (TAO) during intracranial aneurysm surgery.

METHOD

We devised a three-layer model to predict the safe clipping time for TAO. We considered age, the diameter of the right and left middle cerebral arteries (MCAs), the diameter of the right and left A1 segment of anterior cerebral arteries (ACAs), the diameter of the anterior communicating artery, mean velocity of flow at the right and left MCAs, and the mean velocity of flow at the right and left ACAs, as well as the Fisher grading scale of brain CT scans as the input values for the model.

RESULTS

This study included 125 patients: 105 patients from a retrospective cohort for training the model and 20 patients from a prospective cohort for validating the model. The output of the neural network yielded up to 960 s overall safe clipping time for TAO. The input values with the greatest impact on safe TAO were mean velocity of blood at left MCA and left ACA, and Fisher grading scale of brain CT scan.

CONCLUSION

This study presents an axillary framework to improve the accuracy of the estimated safe clipping time interval of temporary artery occlusion in intracranial aneurysm surgery.

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.

Analysis of the relationship between different bleeding positions on intraoperative rupture anterior circulation aneurysm and surgical treatment outcome

BACKGROUND

It is well recognized that intraoperative aneurysm rupture (IAR) is a serious event that is difficult to manage and has a relatively serious influence on a patient's prognosis. The aim of this study was to evaluate the prognostic value of different bleeding positions of IAR in patients, and to describe the technique that the authors have used to clip the ruptured aneurysms.

METHODS

From May 2009 to March 2012, a total of 148 aneurysms in 135 consecutive patients in our institution underwent clipping surgeries, and 31 IARs occurred in 30 patients. The clinical data of all patients were retrospectively analyzed. Statistics analysis was performed to analyze possible factors of different bleeding positions of IARs, to assist observation.

RESULTS

Outcome was estimated by Glasgow outcome scale via following up or calling back within 1, 3, and 6 months after surgery: 94 patients were 5', 23 patients were 4', nine patients were 3', two patients were 2' and eight patients were 1'. There was no significant difference between the outcome of IAR and that of no intraoperative aneurysm rupture (NIAR) in Hunt-Hess groups 0-III (P = 0.802) and Hunt-Hess groups IV-V (P = 0.229), and the different bleeding positions were shown to be an important factor that significantly influences the patients' prognosis (P = 0.001).

CONCLUSIONS

Different bleeding positions of IAR have a significant impact on surgical outcome; IAR of the neck is the most devastating complication. If surgeons take appropriate measures according to different bleeding positions, the efficiency, accuracy and security of the operation will be improved.

The impact of temporary artery occlusion during intracranial aneurysm surgery on long-term clinical outcome: Part II. The patient who undergoes elective clipping

BACKGROUND

Temporary artery occlusion (TAO) during intracranial aneurysm surgery is a key element in facilitating aneurysm dissection and clipping. Despite its significance, knowledge of its effects on long-term clinical outcome in patients undergoing elective clipping for unruptured aneurysms is limited. This study evaluated the safety of this technique in this patient population by 1 surgeon.

METHODS

Patients managed for an intracranial aneurysm were followed from 2000-2009. This study included a cohort of patients found to have unruptured intracranial aneurysms who underwent TAO during their elective clipping procedure. Potential risk factors to affect outcome were considered. Effects of TAO on long-term clinical outcome were evaluated using the Glasgow Outcome Scale (GOS) obtained retrospectively by analyzing medical records at the last follow-up visit or discharge. Analyses included descriptive statistics, binary logistic regression, and ordinal logistic regression.

RESULTS

Inclusion criteria were met by 246 patients (75.2% female, age 54 years±10.9) with electively clipped, unruptured aneurysms. Mean follow-up was 53 months±67.5. Mean temporary artery clipping time was 16.1 minutes±14.7. Of patients, 86% had a good outcome and made a complete recovery at last follow-up (GOS 5); 9% of patients were moderately disabled (GOS 4); 5% of patients were severely disabled (GOS 3), were in a vegetative state (GOS 2), or had died (GOS 1). TAO time had no effects on overall long-term clinical outcomes (P=0.59). Although patients with posterior circulation aneurysms had a worse outcome compared with patients with anterior circulation aneurysms (P=0.008), age (P=0.176) and aneurysm size (P=0.497) were not significantly associated with clinical outcome.

CONCLUSIONS

This study did not demonstrate any relationship between limited duration of TAO and clinical outcome. Posterior circulation aneurysms are associated with worse long-term clinical outcomes in patients with electively clipped, unruptured aneurysms.

Anesthetic considerations for intraoperative management of cerebrovascular disease in neurovascular surgical procedures

Despite new surgical methods and interventions a considerable number of patients who undergo neurovascular procedures emergently or electively have substantial mortality, morbidity, and disability. Sound knowledge of pathophysiology of cerebral hypoperfusion, reliable and timely information from monitoring devices, and appropriate choice of therapeutic intervention is essential for successful anesthetic management of these patients. The management of perioperative vasospasm and temporary ischemia during aneurysm clipping require an understanding of cerebral vascular pathophysiology and neuroprotective measures.

Use of intraoperative monitoring of somatosensory evoked potentials to prevent ischaemic stroke after surgical exclusion of middle cerebral artery aneurysms

OBJECTIVE

The aim of this study was to assess the value of monitoring somatosensory evoked potentials (SEP) in the prevention of ischaemic stroke occurring during surgical exclusion of middle cerebral artery aneurysms.

METHODS

SEP monitoring was performed during the surgical exclusion of 131 aneurysms in 122 patients. All SEP variations over 30% were notified to the surgeon and those over 50% were considered as highly significant. If this happened, and in concert with the conduct of the operation, a return to the basal level was systematically sought.

RESULTS

Post-operative ischemic stroke was observed after 15 (11.4%) operations, leading to a permanent neurological deficit in 12 (9.2%). During nine (6.9%) operations there was a highly significant SEP change that persisted, or was only partially reversed, after corrective procedure. Nine of these patients had a post-operative ischaemic stroke. In 25 (19%), operations there was a highly significant SEP change followed by complete recovery. Of these 25 patients, 2 suffered a post-operative ischemic stroke. Following 49 operations (37.4%) with less significant SEP modifications, 4 patients suffered a post-operative stroke (8%). A stroke did not occur in the 48 (36.6%) operations during which there was not a variation in SEP. The strokes were related to temporary clipping in 9 patients to definitive clipping in 3 to sylvian fissure opening in 1 to brain retraction in and to dissection of the aneurysm in 1 (1 case).

CONCLUSION

Changes in the SEP correlated well with the occurrence of post-operative stroke. This early detection of ischemia directs attention to the need for measures such as withdrawal of temporary clipping or identification of another factor (e.g. release of brain retraction or repositioning of an occlusive clip) so that the risk of post-operative is reduced.

Does intraoperative aneurysm rupture influence outcome? Analysis of 169 patients

OBJECTIVES

The aim of this study was to evaluate the prognostic value of intraoperative aneurysm rupture (IAR) in patients with subarachnoid hemorrhage (SAH) undergoing surgery for cerebral aneurysms.

PATIENTS AND METHODS

Between July 1997 and April 2000, 292 consecutive patients were admitted to our institution with SAH due to ruptured intracranial aneurysms. Of these, 169 patients were treated surgically according to standard microsurgical procedures and were included in this study. Mean age was 47 years. Initial clinical state was graded according to the classification of Hunt and Hess (HH). Outcome was classified according to the Glasgow Outcome Scale as favorable (grades IV and V) and unfavorable (grades I-III). Outcome of patients with intraoperative ruptured and non-ruptured aneurysms was analyzed in correlation to the preoperative clinical state and with respect to the time of surgery and to aneurysm localization.

RESULTS

Different rupture rates were observed with respect to the localization of the aneurysm: anterior circulation (n=69) 39.1%, middle cerebral artery (n=46) 34.8%, internal carotid artery (n=48) 31.2%, and posterior circulation (n=6) 16.7%. Patients with HH-grades I-III showed a favorable outcome in 72.2% (61 of 84 patients) without intraoperative rupture and in 71.7% (33 of 46 patients) with intraoperative aneurysm rupture. The corresponding values for patients with HH-grades IV/V were: favorable outcome in 34.6% (9 of 26 patients) and 23.1% (3 of 13 patients), respectively. Poor initial clinical condition (HH IV and V) as well as the initial Fisher grades III and IV were strongly associated with poor clinical outcome.

CONCLUSIONS

Intraoperative aneurysm rupture has no impact on the outcome, neither in patients with good initial condition nor for poor grades patients.

Protective effect of C1 esterase inhibitor on reperfusion injury in the rat middle cerebral artery occlusion model

OBJECTIVE

The complement system is thought to play a major role in initiating some of the inflammatory events that occur during reperfusion injury. The aim of this study was to assess the effects of C1 esterase inhibitor (C1-INH) on ischemic injury in the rat model of middle cerebral artery suture occlusion and reperfusion.

METHODS

Thirty-six male Wistar rats were used. Intraluminal middle cerebral artery occlusion was performed for 60 minutes. Just before reperfusion, C1-INH (50 international units/kg) (C1-INH group, n = 19) or saline solution (control group, n = 17) was administered. Physiological parameters (arterial blood gas values, mean arterial blood pressure, and heart rate) and local cerebral blood flow were recorded during the experiment. Forty-eight hours after reperfusion, all rats were killed, and assessments of leukocyte infiltration with a myeloperoxidase activity assay and histological analyses with 2,3,5-triphenyl tetrazolium chloride staining were performed.

RESULTS

The physiological parameters and local cerebral blood flow values were not significantly different in the two groups. The infarction volume was significantly smaller and the myeloperoxidase activity was significantly lower in the C1-INH group (84.9 +/- 69.1 mm(3) and 0.40 +/- 0.29 units/g, respectively) than in the control group (202.3 +/- 98.3 mm(3) and 1.41 +/- 0.44 units/g, respectively) (P < 0.01). Myeloperoxidase activities were strongly correlated with infarction volumes (r = 0.73, P < 0.01).

CONCLUSION

The results of this study indicated that C1-INH reduced polymorphonuclear leukocyte accumulation and neuronal damage in focal ischemia and reperfusion.