Intracranial atherosclerotic disease associated with moyamoya collateral formation: histopathological findings.

Atherosclerotic disease has been suspected as a cause of moyamoya disease in some patients but has not, to the authors' knowledge, been confirmed by pathological studies. The authors present the histopathological findings in a patient with moyamoya collateral formation associated with atherosclerotic occlusive disease of the distal internal carotid artery (ICA). Typical atheromatous changes were evident in the distal ICA and proximal middle cerebral artery. In addition, intimal thickening, fibrosis, and abnormal internal elastic lamina were present in these vessels. These findings are common in moyamoya but not in atherosclerotic disease. Proliferation and enlargement of the lenticulostriate arteries in the basal ganglia was also identified. Moyamoya phenomenon secondary to atherosclerotic disease has similar histopathological features to idiopathic moyamoya phenomenon, both in the affected large basal arteries and lenticulostriate collaterals. These findings support the hypothesis advanced by Peerless that moyamoya is a 2-step process involving an obliterative vasculopathy of the terminal ICA and a secondary proliferative response

Effect of High-Dose Simvastatin on Cerebral Blood Flow and Static Autoregulation in Subarachnoid Hemorrhage

Statins may promote vasodilation following subarachnoid hemorrhage (SAH) and improve the response to blood pressure elevation. We sought to determine whether simvastatin increases cerebral blood flow (CBF) and alters the response to induced hypertension after SAH

Cerebellum as the Normal Reference for the Detection of Increased Cerebral Oxygen Extraction

Hemispheric ratios of oxygen extraction fraction (OEF), a proven methodology for the detection of severe hemodynamic impairment and stroke risk, are not sensitive for detecting bilateral hemispheric increases in OEF. The aim of this study was to investigate the use of cerebellum as the reference normal. We analyzed positron emission tomographic (PET) measurements of count-based OEF and clinical data from 57 patients with unilateral atherosclerotic carotid occlusion and 13 controls enrolled in a prospective study of stroke risk. The ipsilateral, contralateral, and total cerebellum were each evaluated as possible reference regions, and the ratios of the middle cerebral artery (MCA) hemispheric OEF counts against those in each reference region were determined. A statistically significant correlation (P<0.0001) was observed with all three MCA-to-cerebellar ratios when compared with the gold standard of ipsilateral-to-contralateral MCA hemispheric ratio. Kaplan–Meier analyses showed all MCA-to-cerebellar ratios to be predictive of stroke. By using the total cerebellum method, 7 strokes were found to have occurred in 20 patients with increased OEF (P=0.0007), compared with 7 strokes out of 16 patients with elevated OEF using the ipsilateral or contralateral cerebellum methods (P<0.0001). These methods may be useful for categorizing the hemodynamic status of patients with bilateral cerebral occlusive diseases, including atherosclerosis and moyamoya, to determine the association with the risk of subsequent stroke

Recruitment in Acute Stroke Trials: Challenges and Potential Solutions

Randomized clinical trials of acute stroke have led to major advances in acute stroke therapy over the past decade. Despite these successes, recruitment in acute trials is often difficult. We outline challenges in recruitment for acute stroke trials and present potential solutions, which can increase the speed and decrease the cost of identifying new treatments for acute stroke. One of the largest opportunities to increase the speed of enrollment and make trials more generalizable is expansion of inclusion criteria whose impact on expected recruitment can be assessed by epidemiologic and registry databases. Another barrier to recruitment besides the number of eligible patients is availability of study investigators limited to business hours, which may be helped by financial support for after-hours call. The wider use of telemedicine has accelerated quicker stroke treatment at many hospitals and has the potential to accelerate research enrollment but requires training of clinical investigators who are often inexperienced with this approach. Other potential solutions to enhance recruitment include rapid prehospital notification of clinical investigators of potential patients, use of mobile stroke units, advances in the process of emergency informed consent, storage of study medication in the emergency department, simplification of study treatments and data collection, education of physicians to improve equipoise and enthusiasm for randomization of patients within a trial, and clear recruitment plans, and even potentially coenrollment, when there are competing trials at sites. Without successful recruitment, scientific advances and clinical benefit for acute stroke patients will lag

Surgical results of the carotid occlusion surgery study: Clinical article

The Carotid Occlusion Surgery Study (COSS) was conducted to determine if STA-MCA bypass, when added to best medical therapy, would reduce subsequent ipsilateral stroke in patients with complete ICA occlusion and an elevated OEF in the cerebral hemisphere distal to the carotid occlusion. A recent publication reported the methodology of COSS in detail and briefly outlined the major findings of the trial.29 The surgical results of COSS are described in detail in this report

Lower stroke risk with lower blood pressure in hemodynamic cerebral ischemia

OBJECTIVE: To determine whether strict blood pressure (BP) control is the best medical management for patients with symptomatic carotid artery occlusion and hemodynamic cerebral ischemia. METHODS: In this prospective observational cohort study, we analyzed data from 91 participants in the nonsurgical group of the Carotid Occlusion Surgery Study (COSS) who had recent symptomatic internal carotid artery occlusion and hemodynamic cerebral ischemia manifested by ipsilateral increased oxygen extraction fraction. The target BP goal in COSS was ≤130/85 mm Hg. We compared the occurrence of ipsilateral ischemic stroke during follow-up in the 41 participants with mean BP ≤130/85 mm Hg to the remaining 50 with higher BP. RESULTS: Of 16 total ipsilateral ischemic strokes that occurred during follow-up, 3 occurred in the 41 participants with mean follow-up BP of ≤130/85 mm Hg, compared to 13 in the remaining 50 participants with mean follow-up BP >130/85 mm Hg (hazard ratio 3.742, 95% confidence interval 1.065-13.152, log-rank p = 0.027). CONCLUSION: BPs ≤130/85 mm Hg were associated with lower subsequent stroke risk in these patients. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that control of hypertension ≤130/85 mm Hg is associated with a reduced risk of subsequent ipsilateral ischemic stroke in patients with recently symptomatic carotid occlusion and hemodynamic cerebral ischemia (increased oxygen extraction fraction)

A review of technological innovations leading to modern endovascular brain aneurysm treatment

Tools and techniques utilized in endovascular brain aneurysm treatment have undergone rapid evolution in recent decades. These technique and device-level innovations have allowed for treatment of highly complex intracranial aneurysms and improved patient outcomes. We review the major innovations within neurointervention that have led to the current state of brain aneurysm treatment