Effect of clot removal on cerebrovascular contraction after subarachnoid hemorrhage in the monkey: pharmacological study

The supraorbital endoscopic approach for aneurysms

OBJECTIVE

To review our surgical experience in minimally invasive transcranial endoscope-assisted microsurgical treatment of intracranial aneurysms, using the supraorbital keyhole craniotomy.

METHODS

The supraorbital keyhole approach was performed through an eyebrow skin incision in 793 cases for treatment of 989 intracranial aneurysms. Of patients, 474 were operated on after subarachnoid hemorrhage, and 319 were operated on under elective conditions. After lateral frontobasal burr hole trephination, a limited subfrontal craniotomy was created. To achieve adequate intraoperative exposure through the limited approach, endoscopes were used routinely. Surgical outcome was assessed using the modified Rankin scale.

RESULTS

The transcranial endoscope-assisted microneurosurgery technique was used routinely via a supraorbital approach. In 152 operations (19.1%), the endoscope provided important visual information in the vicinity of the aneurysm, revealing subsequent clip repositioning. The results of incidental aneurysms were excellent with a modified Rankin scale score ≤2 in 96.52%. The overall outcome of ruptured aneurysms was good with a modified Rankin scale score ≤2 in 72.2% of patients. There were no approach-related intraoperative or postoperative complications.

CONCLUSIONS

The minimally invasive supraorbital keyhole approach allowed safe surgical treatment of intracranial aneurysms, including after subarachnoid hemorrhage. The markedly improved endoscopic visualization increased the assessment of clip placement with ideal control of surrounding vessels including perforators for identification of incorrect clip position.

Cerebral vasospasm after aneurysmal subarachnoid hemorrhage and traumatic brain injury

OPINION STATEMENT

Cerebral vasospasm (cVSP) consists of the vasoconstriction of large and small intracranial vessels which can lead to cerebral hypoperfusion, and in extreme cases, delayed ischemic deficits with stroke. While most commonly observed after aneurysmal subarachnoid hemorrhage (aSAH), cVSP can also occur after traumatic brain injury (TBI) as we have described in detail in this review. For the past decades, the research attention has focused on cVSP because of its association with delayed cerebral ischemia, which is the largest contributor of morbidity and mortality after aSAH. New discoveries in the cVSP pathophysiology involving multifactorial complex cascades and pathways pose new targets for therapeutic interventions in the prevention and treatment of cVSP. The goal of this review is to demonstrate the commonalities and differences in epidemiology and pathophysiology of both aSAH and TBI-associated cVSP, and highlight the more recently discovered pathways of cVSP. Finally, the latest cVSP surveillance methods and treatment options are illustrated.

Treatment modality and vasospasm after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Vasospasm is the leading source of neurological morbidity after aneurysmal subarachnoid hemorrhage. Our objective was to evaluate the impact of treatment modality on vasospasm, delayed cerebral infarction, and clinical deterioration caused by delayed cerebral ischemia (CD-DCI).

METHODS

We reviewed an institutional cohort, comparing rates of vasospasm, delayed cerebral infarction, and CD-DCI between patients managed with only microsurgical clipping and those treated with only endovascular coiling within 72 hours of rupture. Age, sex, smoking status, Hunt-Hess grade, and Fisher grade were adjusted for in a multivariate regression model.

RESULTS

Two hundred three patients were treated with clipping and 52 with coiling. There was no significant difference in patient age, sex, smoking status, aneurysm location, and presenting clinical (Hunt-Hess) and radiographic (Fisher) grade between these two groups. Sixty-percent of patients had moderate or severe vasospasm after clipping compared with 38% after coiling (Multivariate odds ratio [OR] 2.32, 95% confidence interval [95% CI] 1.21-4.47, P = 0.01). Clipping was associated with a greater number of territories with vasospasm (mean of 3.1 vs. 2.3, P = 0.03 after multivariate analysis). Delayed radiographic cerebral infarction was more common in the clipping group (17% vs. 6%, multivariate OR 3.66, 95% CI 1.06-12.71, P = 0.04). For CD-DCI, a trend was seen as 16% of patients treated with clipping had CD-DCI compared with 6% of patients treated with coiling (multivariate OR 3.11, 95% CI 0.89-10.86, P = 0.07).

CONCLUSION

We demonstrate significantly lower rates of vasospasm and delayed infarction after endovascular coiling of ruptured aneurysms.

Mechanisms of acute brain injury after subarachnoid hemorrhage

Brain injury after subarachnoid hemorrhage (SAH) is a biphasic event with an acute ischemic insult at the time of the initial bleed and secondary events such as cerebral vasospasm 3 to 7 days later. Although much has been learned about the delayed effects of SAH, less is known about the mechanisms of acute SAH-induced injury. Distribution of blood in the subarachnoid space, elevation of intracranial pressure, reduced cerebral perfusion and cerebral blood flow (CBF) initiates the acute injury cascade. Together they lead to direct microvascular injury, plugging of vessels and release of vasoactive substances by platelet aggregates, alterations in the nitric oxide (NO)/nitric oxide synthase (NOS) pathways and lipid peroxidation. This review will summarize some of these mechanisms that contribute to acute cerebral injury after SAH.

Aneurysmal subarachnoid hemorrhage models: do they need a fix?

The discovery of tissue plasminogen activator to treat acute stroke is a success story of research on preventing brain injury following transient cerebral ischemia (TGI). That this discovery depended upon development of embolic animal model reiterates that proper stroke modeling is the key to develop new treatments. In contrast to TGI, despite extensive research, prevention or treatment of brain injury following aneurysmal subarachnoid hemorrhage (aSAH) has not been achieved. A lack of adequate aSAH disease model may have contributed to this failure. TGI is an important component of aSAH and shares mechanism of injury with it. We hypothesized that modifying aSAH model using experience acquired from TGI modeling may facilitate development of treatment for aSAH and its complications. This review focuses on similarities and dissimilarities between TGI and aSAH, discusses the existing TGI and aSAH animal models, and presents a modified aSAH model which effectively mimics the disease and has a potential of becoming a better resource for studying the brain injury mechanisms and developing a treatment.

The importance of early brain injury after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a medical emergency that accounts for 5% of all stroke cases. Individuals affected are typically in the prime of their lives (mean age 50 years). Approximately 12% of patients die before receiving medical attention, 33% within 48 h and 50% within 30 days of aSAH. Of the survivors 50% suffer from permanent disability with an estimated lifetime cost more than double that of an ischemic stroke. Traditionally, spasm that develops in large cerebral arteries 3-7 days after aneurysm rupture is considered the most important determinant of brain injury and outcome after aSAH. However, recent studies show that prevention of delayed vasospasm does not improve outcome in aSAH patients. This finding has finally brought in focus the influence of early brain injury on outcome of aSAH. A substantial amount of evidence indicates that brain injury begins at the aneurysm rupture, evolves with time and plays an important role in patients' outcome. In this manuscript we review early brain injury after aSAH. Due to the early nature, most of the information on this injury comes from animals and few only from autopsy of patients who died within days after aSAH. Consequently, we began with a review of animal models of early brain injury, next we review the mechanisms of brain injury according to the sequence of their temporal appearance and finally we discuss the failure of clinical translation of therapies successful in animal models of aSAH.

Timing of symptomatic vasospasm in aneurysmal subarachnoid hemorrhage: the effect of treatment modality and clinical implications

A better prediction of the time course of symptomatic vasospasm (SVSP) might have a significant impact on the management and prevention of delayed neurologic ischemic deficit (DIND). We studied the influence of the treatment for ruptured aneurysm on SVSP timing. We retrospectively analyzed data of consecutive patients with aneurysmal subarachnoid hemorrhage (aSAH) admitted in our center between 1999 and 2005, treated within 72 hours of the rupture by surgical clipping or endovascular coiling and in accordance with our neuroscience unit protocol. We analyzed the presence of SVSP and recorded the timing of occurrence after the aneurysmal repair intervention. Data on demographics, premorbid conditions, time elapsed from the subarachnoid hemorrhage onset and intervention, and clinical and radiologic characteristics at admission were collected. The first occurrence of postintervention SVSP was recorded and compared between the 2 treatment groups using a proportional hazards regression model, including significant covariates. Of the 67 patients analyzed, 21 (31%) underwent endovascular coiling and 46 (69%) underwent surgical clipping. The baseline variables were similar in the 2 groups. The median time from the procedure to clinical vasospasm was 4 days in the coiled patients and 7 days in the clipped patients. In a proportional hazards model regression analysis including age, sex, Fisher and Hunt-Hess grades, time between onset to procedure, and intervention type, only intervention type emerged as a significant predictor of time to SVSP after intervention (likelihood ratio chi2 = 16.8; P < .00). Treatment modality of ruptured intracranial aneurysm may influence the timing of SVSP occurrence.

Comparison between clipping and coiling on the incidence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

Cerebral vasospasm is one of the most important complications of aneurysmal subarachnoid hemorrhage. The effect of aneurysm occlusion technique on incidence of vasospasm is not exactly known. The objective was to analyze surgical clipping versus endovascular coiling on the incidence of cerebral vasospasm and its consequences. Using the MEDLINE PubMed (1966-present) database, all English-language manuscripts comparing patients treated by surgical clipping with patients treated by endovascular coiling, regarding vasospasm incidence after aneurysmal subarachnoid hemorrhage, were analyzed. Data extracted from eligible studies included the following outcome measures: incidence of total vasospasm, symptomatic vasospasm, ischemic infarct vasospasm-induced and delayed ischemic neurological deficit (DIND). A pooled estimate of the effect size was computed and the test of heterogeneity between studies was carried out using The Cochrane Collaboration's Review Manager software, RevMan 4.2. Nine manuscripts that fulfilled the eligibility criteria were included and analyzed. The studies differed substantially with respect to design and methodological quality. The overall results showed no significant difference between clipping and coiling regarding to outcome measures. According to the available data, there is no significant difference between the types of technique used for aneurysm occlusion (clipping or coiling) on the risk of cerebral vasospasm development and its consequences.

A murine model of subarachnoid hemorrhage-induced cerebral vasospasm

Cerebral vasospasm remains a major cause of morbidity and mortality after subarachnoid hemorrhage (SAH). The availability of a mouse model of SAH that is simple, replicable and has low mortality would provide a powerful approach for understanding cellular and molecular mechanisms contributing to post-SAH pathologies. The present study characterizes a mouse model of experimental SAH, which produces consistent constriction of large cerebral arteries. Adult mice received injections of autologous blood into the cisterna magna, and the diameters of large intracranial vessels were measured 1 h to 7 days post-SAH. A diffuse blood clot was evident in both the anterior and posterior circulations after SAH. Vascular wall thickening, lumenal narrowing and corrugation of the internal elastic lamina were observed. Both acute (6-12 h) and delayed (1-3 days) phases of vasoconstriction occurred after SAH. Overall mortality was only 3%. A reproducible, low mortality model of SAH-induced cerebral vasospasm in mice is described. This mouse model should facilitate the delineation of cellular and molecular mechanisms of SAH-induced pathologies because of the widespread availability of various technologies for this species (e.g. genetically-altered animals and gene expression arrays). This model also represents a replicable and inexpensive approach for screening therapeutic candidates.

Ultra-early surgery for aneurysmal subarachnoid hemorrhage: outcomes for a consecutive series of 391 patients not selected by grade or age

OBJECT

This study was undertaken to determine the outcomes in an unselected group of patients treated with semiurgent surgical clipping of aneurysms following subarachnoid hemorrhage (SAH).

METHODS

A clinical management outcome audit was conducted to determine outcomes in a group of 391 consecutive patients who were treated with a consistent policy of ultra-early surgery (all patients treated within 24 hours after SAH and 85% of them within 12 hours). All neurological grades were included, with 45% of patients having poor grades (World Federation of Neurosurgical Societies [WFNS] Grades IV and V). Patients were not selected on the basis of age; their ages ranged between 15 and 93 years and 19% were older than 70 years. The series included aneurysms located in both anterior and posterior circulations. Eighty-eight percent of all patients underwent surgery and only 2.5% of the series were selectively withdrawn (by family request) from the prescribed surgical treatment. In patients with good grades (WFNS Grades I-III) the 3-month postoperative outcomes were independence (good outcome) in 84% of cases, dependence (poor outcome) in 8% of cases, and death in 9%. In patients with poor grades the outcomes were independence in 40% of cases, dependence in 15% of cases, and death in 45%. There was a 12% rate of rebleeding with all cases of rebleeding occurring within the first 12 hours after SAH; however, outcomes of independence were achieved in 46% of cases in which rebleeding occurred (43% mortality rate). Rebleeding was more common in patients with poor grades (20% experienced rebleeding, whereas only 5% of patients with good grades experienced rebleeding).

CONCLUSIONS

The major risk of rebleeding after SAH is present within the first 6 to 12 hours. This risk of ultra-early rebleeding is highest for patients with poor grades. Securing ruptured aneurysms by surgery or coil placement on an emergency basis for all patients with SAH has a strong rational argument.