Alkaline pH-Induced Extracellular Regulated Protein Kinase Activation in Brain Microvascular Endothelial Cells: Differential Effects of Tris and Lowered CO2

As it was previously reported that Tris-elevated pH acutely activated extracellular regulated protein kinase (ERK) in rat aorta smooth muscle cells, this study tested whether this finding could be extended to endothelial cells and, moreover, the relevance of this finding in brain microvascular endothelial cells with respect to respiratory-induced hypocapnic alkalosis. Exposure of bovine brain microvascular endothelial cells to pH 7.90 due to Tris for 15 and 30 min activated ERK twofold. In contrast, pH elevated to 7.75 and 7.90 by lowered percent CO2 failed to activate ERK (15, 30, and 60 min). These results suggest that respiratory alkalosis due to hypocapnia does not activate ERK in brain microvascular endothelial cells. The ability of Tris to activate ERK suggests a novel pathway, possibly independent of pH elevation, whereby Tris activates ERK.

Recent trends in the treatment of spontaneous intracerebral hemorrhage: analysis of a nationwide inpatient database

Object

Recently updated guidelines failed to reflect significant progress in the treatment of intracerebral hemorrhage (ICH). Using data from a nationwide hospital database, the authors identified recent trends in therapy and outcomes for ICH, as well as the effect of associated comorbidities and procedures, including surgery.

Methods

Data from the Nationwide Inpatient Sample hospital discharge database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality) for the period 1993–2005 was retrospectively reviewed. Multiple variables were categorized and subjected to statistical analysis for codes related to ICH from the International Classification of Diseases, 9th revision, Clinical Modification. Data linked by the Nationwide Inpatient Sample database to associated diagnoses and procedures were also retrieved and analyzed.

Results

The number of discharges remained constant for ICH. The mortality rate remained unchanged at an average of 31.6%, whereas routine discharges (home) steadily declined by 25%, and discharges other than home doubled (p < 0.01). By the end of the study, length of hospital stay decreased by 30% (p < 0.01), and mean hospital charges steadily increased to more than twice the original figures. Arterial hypertension was the most frequently associated comorbidity. Seizures were associated with longer hospital stays and higher mean hospital charges. Craniotomy was associated with decreased mortality rates but also with worse outcomes and lower rates of patients discharged home (p < 0.01). No geographic differences in treatment and outcomes were noted.

Conclusions

From 1993 to 2005, no significant progress in treatment and prevention of ICH was noted. There were no regional differences in the treatment and outcome of ICH. The role of surgery for ICH remains uncertain, and large-scale controlled studies are greatly needed to clarify this role.

The acetazolamide challenge: techniques and applications in the evaluation of chronic cerebral ischemia

The acetazolamide (ACZ) challenge test is a useful clinical tool and a reliable predictor of critically reduced perfusion. In patients with chronic steno-occlusive disease, the ability to maintain normal cerebral blood flow by reducing vascular resistance secondary to autoregulatory vasodilation is compromised. Identification of the presence and degree of autoregulatory vasodilation (reflecting the cerebrovascular reserve) is a significant prognostic factor in patients with chronic cerebrovascular disease. The pharmacologic challenge of a vasodilatory stimulus such as ACZ can also be used to optimize the treatment strategies for these patients. The pathophysiology, methods, and clinical applications of the ACZ challenge test are discussed in this article.

Eyelid approach to the anterior cranial base

Skull base approaches play a fundamental role in modern neurosurgery by reducing surgical morbidity. Increasing experience has allowed surgeons to perform minimally invasive approaches without straying from the premises of skull base surgery. The eyelid approach has evolved from the orbitopterional osteotomy into a more effective and targeted approach to disease of the anterior cranial fossa. In this technique, after an incision is made on the supratarsal fold, the orbicularis oculi muscle is incised, and a myocutaneous flap composed of the elements of the anterior lamella is elevated. Subperiosteal dissection is used to expose the superior and lateral walls of the orbit, the superior and lateral orbital rim, and the frontosphenoidal suture. A MacCarty bur hole is drilled, and a frontal osteotomy is fashioned medial to the supraorbital notch and extending through the orbital roof back toward the orbital half of the MacCarty bur hole, exposing the frontobasal brain. A conventional microsurgical technique is used to treat tumors and aneurysms of the anterior cranial fossa under the operative microscope.

Five patients were treated for unruptured aneurysms of the anterior circulation (3 anterior communicating artery aneurysms, 1 ophthalmic artery aneurysm, and 1 posterior communicating artery aneurysm) using the eyelid approach. The mean aneurysm size was 5 mm, and all aneurysms were approached from the right side. Three tumors in the anterior fossa (2 suprasellar pituitary adenomas and 1 craniopharyngioma) were also excised using this approach. There was no surgical morbidity. Three months after surgery all patients presented excellent cosmetic results. The eyelid approach may be considered as an effective, cosmetically beneficial, and minimally invasive skull base approach to selected aneurysms and tumors of the anterior circulation.

Multidrug-resistant, progressive, invasive diffuse spinal aspergillosis: case report and review of the literature

The authors describe a 65-year-old man who, after 7 years of complete remission from lung cancer, was found on routine oncologic follow imaging to have lesions on several vertebral bodies. Open biopsy of the affected thoracic vertebrae and surrounding soft tissue were negative for neoplasia. Bacteriology cultures revealed colonies of aspergillus fumigatus in all bone samples. Unlike most reported cases in which vertebral compromise rarely extends to more than two adjacent vertebrae, our patient had extensive compromise of the thoracic spine. This infection progressed despite treatment with antifungal regimens known to be effective, even in immunocompromised patients. Invasive aspergillosis of the spine is a rare and typically occurred in terminal patients. However, the spectrum of hosts and clinical presentations of invasive aspergillosis are increasing, due in part to better medical treatments that prolong the survival of patients with cancer, severe infections, and organ failure. In reviewing the literature, the authors discuss the currently available therapies for such infections of the spine, and highlight the growing incidence these and other formerly rare infections.

Recent trends in the treatment of cerebral aneurysms: analysis of a nationwide inpatient database

Object

The most appropriate treatment for cerebral aneurysms, both ruptured and unruptured, is currently under debate, and updated guidelines have yet to be defined. The authors attempted to identify trends in therapy for cerebral aneurysms in the US as well as outcomes.

Methods

The authors retrospectively reviewed data from the Nationwide Inpatient Sample hospital discharge database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality) for the period 1993–2003. Multiple variables were categorized and subjected to statistical analysis for International Classification of Diseases, 9th Revision, Clinical Modification codes related to subarachnoid hemorrhage (SAH), unruptured aneurysm, and clipping and endovascular treatment of cerebral aneurysm.

Results

During the study period, the numbers of discharges remained stable for SAH but doubled for unruptured aneurysms. Concomitantly, the number of aneurysms treated with clip placement remained stable, and the number treated by means of endovascular procedures doubled. By the study's end, the mortality rates had decreased 20% for SAH and 50% for unruptured aneurysms. Increasing age was associated with increased mortality rates, mean length of hospital stay (LOS), and mean charges (p < 0.01). Endovascular treatment was used more often in older patients (p < 0.01). Teaching status and larger hospital size were associated with higher charges and longer hospital stays (although the association was not statistically significant) and with better outcomes (p < 0.05) and lower mortality rates (p < 0.05), especially in patients who underwent aneurysm clipping (p < 0.01). Endovascular treatment was associated with significantly higher mortality rates in small hospitals (p < 0.001) and steadily increasing morbidity rates (45%). Morbidity rates, mean LOS, and mean charges were higher for aneurysm clipping (p < 0.01).

Conclusions

From 1993 to 2003, endovascular techniques for aneurysm occlusion have been increasingly used, while the use of surgical clipping procedures has remained stable. Toward the end of the study period, better overall outcomes were observed in the treatment of cerebral aneurysms, both ruptured and unruptured. Large academic centers were associated with better results, particularly for surgical clip placement.

Use of radial artery grafts in extracranial-intracranial revascularization procedures

Cerebral revascularization procedures have been used in the clinical management of actual or threatened cerebral ischemic states and unclippable cerebral aneurysms. An alternative to a low-flow bypass graft (for example, with the superficial temporal artery) is the use of high-flow grafts created using the saphenous vein (SV) or radial artery (RA). These high-flow grafts are particularly useful when otherwise adequate collateral flow is insufficient to enable sacrifice of the parent vessel without the risk of cerebral ischemia. In their clinical series of 13 patients who underwent high-flow bypass with an RA graft, the authors describe 8 women and 5 men whose ages ranged from 44 to 69 years (mean 57.84 +/- 9.05 years). Indications for RA graft bypass were unclippable aneurysms in 10 patients and occlusive cerebrovascular disease in 3 patients. The authors review the properties of the 2 most common conduits, the SV and RA grafts. They present the technique of high-flow extracranial-intracranial bypass produced using RA grafts in the management of occlusive atherosclerotic disease and complex intracranial aneurysms that are not otherwise amenable to either clip ligation or coil occlusion.

BLISTER-LIKE ANEURYSMS OF THE ANTERIOR COMMUNICATING ARTERY

OBJECTIVE

Blood blister-like aneurysms are small hemispherical bulges from the dorsomedial wall of the internal carotid artery that resemble berry aneurysms but differ in their clinical and surgical features. On the basis of our literature review, blister-like aneurysms have been reported to occur only at nonbranching sites of the dorsomedial internal carotid artery. In this report on our series of five patients, we describe blister-like aneurysms of the anterior communicating artery (AComA) and discuss important diagnostic and therapeutic aspects unique to them.

METHODS

In our retrospective review of 719 patients with nontraumatic subarachnoid hemorrhage admitted to our service from 1998 to 2003, 181 (25.17%) patients harbored AComA aneurysms. Five (2.76%) patients (four women, one man) had blister-like aneurysms that were recognized at the time of surgery.

RESULTS

Initial digital subtraction angiography was diagnostic in only one patient. A second digital subtraction angiogram was diagnostic in one patient but failed to reveal an aneurysm in the remaining three patients; these were eventually diagnosed by computed tomographic angiography. All aneurysms were clipped. At the time of surgery, the aneurysms arose from the horizontal portion of the AComA without any involvement of the branches of the anterior cerebral artery. All presented as blister-like aneurysms that were thin-walled and lacking a surgical neck. On dissection, two of the lesions ruptured. All lesions were treated with straight fenestrated clips through the A1–AComA junction, thus remodeling the AComA. No delayed rupture was noted at the time of the last follow-up evaluation. At the time of discharge, outcomes were good in two patients, fair in two, and poor in the remaining patient.

CONCLUSION

Blister-like aneurysms constitute technically challenging lesions that may occur at the AComA. Computed tomographic angiography is valuable in diagnosis. Blister-like aneurysms should be suspected when digital subtraction angiography findings are negative for subarachnoid hemorrhage.

Subarachnoid hemorrhage: effect on cerebral blood flow and cerebral metabolism

Alterations in cerebral blood flow and metabolism after subarachnoid hemorrhage (SAH) are well known and have been extensively described. Many techniques exist in the intensive care setting to monitor for these alterations. Ranging from classic neurological exam to novel imaging studies a variety of modalities are available for intensive monitoring. Early identification of cerebral vasospasm is the key to prevention of its long term complications and as such the role of genetics and biochemical markers are currently being investigated. The dynamics of cerebral blood flow and metabolism following SAH are unique and require additional studies before any monitoring technique can be used as stand alone modality and supplant the DSA as the gold standard for detection of cerebral vasospasm.

REPRINT

Purpose— The aim of this statement is to present current and comprehensive recommendations for the diagnosis and treatment of acute spontaneous intracerebral hemorrhage.

Methods— A formal literature search of Medline was performed through the end date of August 2006. The results of this search were complemented by additional articles on related issues known to the writing committee. Data were synthesized with the use of evidence tables. The American Heart Association Stroke Council’s Levels of Evidence grading algorithm was used to grade each recommendation. Prerelease review of the draft guideline was performed by 5 expert peer reviewers and by the members of the Stroke Council Leadership Committee. It is intended that this guideline be fully updated in 3 years’ time.

Results— Evidence-based guidelines are presented for the diagnosis of intracerebral hemorrhage, the management of increased arterial blood pressure and intracranial pressure, the treatment of medical complications of intracerebral hemorrhage, and the prevention of recurrent intracerebral hemorrhage. Recent trials of recombinant factor VII to slow initial bleeding are discussed. Recommendations for various surgical approaches for treatment of spontaneous intracerebral hemorrhage are presented. Finally, withdrawal-of-care and end-of-life issues in patients with intracerebral hemorrhage are examined.

Acute cocaine induces endothelin-1-dependent constriction of rabbit basilar artery

It has been postulated that ischemic stroke due to acute cocaine usage involves constriction of the cerebral vasculature. However, the mechanism underlying the constriction remains unclear. This study tested whether cocaine constriction was mediated via endothelin-1. Cocaine suffusion induced maintained constriction in the rabbit basilar artery in situ. The constriction was relaxed by PD145065, an endothelin A and B receptor antagonist. These results support the hypothesis that constriction of the cerebral vasculature due to acute cocaine exposure is via endothelin-1 release. Endothelin receptor antagonists may be of therapeutic benefit in cerebrovascular pathophysiologies involving cocaine constriction.

Guidelines for the Management of Spontaneous Intracerebral Hemorrhage in Adults

PURPOSE

The aim of this statement is to present current and comprehensive recommendations for the diagnosis and treatment of acute spontaneous intracerebral hemorrhage.

METHODS

A formal literature search of Medline was performed through the end date of August 2006. The results of this search were complemented by additional articles on related issues known to the writing committee. Data were synthesized with the use of evidence tables. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. Prerelease review of the draft guideline was performed by 5 expert peer reviewers and by the members of the Stroke Council Leadership Committee. It is intended that this guideline be fully updated in 3 years' time.

RESULTS

Evidence-based guidelines are presented for the diagnosis of intracerebral hemorrhage, the management of increased arterial blood pressure and intracranial pressure, the treatment of medical complications of intracerebral hemorrhage, and the prevention of recurrent intracerebral hemorrhage. Recent trials of recombinant factor VII to slow initial bleeding are discussed. Recommendations for various surgical approaches for treatment of spontaneous intracerebral hemorrhage are presented. Finally, withdrawal-of-care and end-of-life issues in patients with intracerebral hemorrhage are examined.

Exposure of the cervical internal carotid artery: surgical steps to the cranial base and morphometric study

OBJECTIVE

Several studies have reported on approaches to increase exposure of the distal cervical internal carotid artery (ICA), but these studies have neither systematically addressed the anatomic aspects nor quantified the additional exposure of each maneuver. We describe surgical steps to expose the ICA region, quantify the additional exposure of each operative step, and discuss ways to minimize surgical morbidity.

METHODS

The ICA was exposed in 10 formalin-fixed cadaveric heads using the following four steps: 1) anterior sternocleidomastoid approach, 2) retroparotid dissection and division of the digastric muscle, 3) section of the styloid apparatus, and 4) mandibulotomy. After completion of each step, the most distal level of ICA exposure was marked with a hemoclip and segment lengths were measured between each clip.

RESULTS

Sectioning of the digastric muscle and sectioning of the styloid apparatus provided the most significant exposure of the ICA (14.15 and 15.08 mm, respectively) with minimal risks. Mandibulotomy added 10.20 mm in length and 20.65 degrees in width, but is a maneuver that must be weighed against the heightened risk of morbidity.

CONCLUSION

Surgical exposure of the distal cervical ICA is associated with relatively high morbidity that increases with higher levels of exposure. Staged maneuvers have been shown to increase ICA exposure, especially in our systematic approach. The number of steps required varies depending on the level of lesion. Complete understanding of the surgical anatomy is essential to minimize surgical morbidity and to develop surgical expertise.

Evidence for the improved exposure of the ophthalmic segment of the internal carotid artery after anterior clinoidectomy: morphometric analysis

BACKGROUND

Although resection of the anterior clinoid process (ACP) is valuable in the surgical treatment of aneurysms of the ophthalmic (C6) segment of the internal carotid artery (ICA), quantitative assessment of this adjunct is incomplete. Our morphometric study assesses the effectiveness of the anterior clinoidectomy for exposure of the C6 segment of the ICA.

METHODS

Ten formalin-fixed adult cadaveric heads were dissected bilaterally and pterional craniotomies were performed bilaterally. Measurements before and after resection of the ACP included the length of C6 segment of the ICA on its lateral aspect; C6 segment length on its medial aspect; and medial length of the optic nerve from the optic chiasm to falciform ligament (before ACP resection) then to the annulus of Zinn (after ACP resection).

FINDINGS

Height and width of the intradural ACP were 8.67 +/- 2.63 and 6.57 +/- 1.68 mm, respectively. After clinoidectomy, mean length of the lateral C6 segment of the ICA increased 60% and mean exposure of the medial C6 segment of the ICA increased 113% (p < 0.001). Exposure of the optic nerve increased 150% (p < 0.001) after clinoidectomy and sectioning of the falciform ligament. No correlations were found between the lengths of the ACP and entire C6 segment, or the ACP size and amount of the C6 segment covered by the clinoid.

CONCLUSIONS

Exposure of the C6 segment of the ICA is markedly increased by increase of the mobility of the optic nerve with clinoidectomy and section of the falciform ligament.

Subdural hemorrhage in the posterior fossa caused by a ruptured cavernous carotid artery aneurysm after a balloon occlusion test

✓Given the relatively benign natural history of cavernous carotid artery aneurysms and based on anecdotal reports in the literature of subarachnoid hemorrhage (SAH) or subdural hemorrhage (SDH) from these aneurysms, observation is warranted and typically recommended. In this case report, the authors describe a woman who harbored a partially thrombosed, giant cavernous aneurysm that ruptured after she underwent a balloon occlusion test (BOT) and predominately led to an SDH. The authors believe that this occurrence is the first such report in the English literature. They discuss possible mechanisms for this event and the literature related to SAH or SDH from cavernous aneurysms, including why cavernous aneurysms cause such hemorrhages. The authors also recommend that attention be paid to such lesions regarding the possibility of aneurysmal rupture following a BOT.