Peter Adamczyk

Medical Management of Cerebral Vasospasm following Aneurysmal Subarachnoid Hemorrhage: A Review of Current and Emerging Therapeutic Interventions.

Cerebral vasospasm is a major source of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). Evidence suggests a multifactorial etiology and this concept remains supported by the assortment of therapeutic modalities under investigation. The authors provide an updated review of the literature for previous and recent clinical trials evaluating medical treatments in patients with cerebral vasospasm secondary to aSAH. Currently, the strongest evidence supports use of prophylactic oral nimodipine and initiation of triple-H therapy for patients in cerebral vasospasm. Other agents presented in this report include magnesium, statins, endothelin receptor antagonists, nitric oxide promoters, free radical scavengers, thromboxane inhibitors, thrombolysis, anti-inflammatory agents and neuroprotectants. Although promising data is beginning to emerge for several treatments, few prospective randomized clinical trials are presently available. Additionally, future investigational efforts will need to resolve discrepant definitions and outcome measures for cerebral vasospasm in order to permit adequate study comparisons. Until then, definitive recommendations cannot be made regarding the safety and efficacy for each of these therapeutic strategies and medical management practices will continue to be implemented in a wide-ranging manner.

Mechanical Thrombectomy in Acute Stroke: Utilization Variances and Impact of Procedural Volume on Inpatient Mortality

BACKGROUND An increasing number of endovascular mechanical thrombectomy procedures are being performed for the treatment of acute ischemic stroke. This study examines variances in the allocation of these procedures in the United States at the hospital level. We investigate operative volume across centers performing mechanical revascularization and establish that procedural volume is independently associated with inpatient mortality. METHODS Data was collected using the Nationwide Inpatient Sample database in the United States for 2008. Medical centers performing mechanical thrombectomy were identified using International Classification of Diseases, 9th revision codes, and procedural volumes were evaluated according to hospital size, location, control/ownership, geographic characteristics, and teaching status. Inpatient mortality was compared for hospitals performing ≥10 mechanical thrombectomy procedures versus those performing<10 procedures annually. After univariate analysis identified the factors that were significantly related to mortality, multivariable logistic regression was performed to compare mortality outcome by hospital procedure volume independent of covariates. RESULTS Significant allocation differences existed for mechanical thrombectomy procedures according to hospital size (P<.001), location (P<.0001), control/ownership (P<.0001), geography (P<.05), and teaching status (P<.0001). Substantial procedural volume was independently associated with decreased mortality (P=.0002; odds ratio 0.49) when adjusting for demographic covariates. CONCLUSIONS The number of mechanical thrombectomy procedures performed nationally remains relatively low, with a disproportionate distribution of neurointerventional centers in high-volume, urban teaching hospitals. Procedural volume is associated with mortality in facilities performing mechanical thrombectomy for acute ischemic stroke patients. These results suggest a potential benefit for treatment centralization to facilities with substantial operative volume.

The artery of percheron and etiologies of bilateral thalamic stroke.

he artery of Percheron (AOP) is a unique vessel that originates from the posterior cerebral artery (PCA) to supply the T bilateral thalami. Recognition of this anatomic variant should be of practical interest to clinicians, as occlusion of the AOP remains an important cause of bilateral thalamic strokes. The first published report of bilateral thalamic infarctions has been attributed to Beauvois and Lhermitte in 1975 (1). Since then, there has been increasing acknowledgment and association of the AOPwith bilateral thalamic injury. However, this ischemic presentation still remains uncommon. A review of the literature in 2009 identified only 51 cases of AOP involving bilateral thalamic infarcts (17). Similar stroke patterns have also been recognized with other vascular etiologies, such as “top of the basilar” syndrome, as well as cerebral venous thrombosis. Therefore, distinguishing AOP occlusion from other vascular pathologies requires a thorough understanding of the anatomic, clinical, and radiographic differences in order to provide optimal therapeutic management.

Matrix Metalloproteinases in Cerebral Vasospasm following Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral vasospasm is a significant cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). While the cellular mechanisms underlying vasospasm remain unclear, it is believed that inflammation may play a critical role in vasospasm. Matrix metalloproteinasees (MMPs) are a family of extracellular and membrane-bound proteases capable of degrading the blood-rain barrier (BBB). As such, MMP upregulation following SAH may result in a proinflammatory extravascular environment capable of inciting delayed cerebral vasospasm. This paper presents an overview of MMPs and describes existing data pertinent to delayed cerebral vasospasm.

A Persistent Primitive Hypoglossal Artery Arising from the External Carotid Artery Associated with Subarachnoid Hemorrhage

BACKGROUND A persistent primitive hypoglossal artery (PHA) is a rare congenital caroticobasilar anastomosis with a reported prevalence of 0.027%-0.26%. Intracranial aneurysms occur with a frequency of approximately 26% in the setting of PHAs. CASE DESCRIPTION PHAs typically originate from the proximal cervical internal carotid artery. To date, however, six cases of PHAs originating from the external carotid artery have been reported. We present the first case of a PHA originating from the external carotid artery associated with subarachnoid hemorrhage. CONCLUSION We review the literature and discuss anatomic implications with respect to the extreme lateral infrajugular transcondylar exposure for clip ligation of a ruptured posterior inferior cerebellar artery aneurysm in the setting of a PHA.