Rolla Nuoman

Cerebral Ischemic Reperfusion Injury Following Recanalization of Large Vessel Occlusions.

Although stroke has recently dropped to become the nations fifth leading cause of mortality, it remains the top leading cause of morbidity and disability in the US. Recent advances in stroke treatment, including intravenous fibrinolysis and mechanical thromboembolectomy, allow treatment of a greater proportion of stroke patients than ever before. While intra-arterial fibrinolysis with recombinant tissue plasminogen is an effective for treatment of a broad range of acute ischemic strokes, endovascular mechanical thromboembolectomy procedures treat severe strokes due to large artery occlusions, often resistant to intravenous drug. Together, these procedures result in a greater proportion of revascularized stroke patients than ever before, up to 88% in 1 recent trial (EXTEND-IA). Subsequently, there is a growing need for neurointensivists to develop more effective strategies to manage stroke patients following successful reperfusion. Cerebral ischemic reperfusion injury (CIRI) is defined as deterioration of brain tissue suffered from ischemia that concomitantly reverses the benefits of re-establishing cerebral blood flow following mechanical or chemical therapies for acute ischemic stroke. Herein, we examine the pathophysiology of CIRI, imaging modalities, and potential neuroprotective strategies. Additionally, we sought to lay down a potential treatment approach for patients with CIRI following emergent endovascular recanalization for acute ischemic stroke.

Mechanical thrombectomy – is time still brain? The DAWN of a new era

Abstract Purpose: The purpose of this study is to review the history of treatments for acute ischemic stroke, examine developments in endovascular therapy, and discuss the future of the management of acute ischemic stroke. Methods: A selective review of recent clinical trials for the treatment of acute ischemic stroke was conducted. Results: We reviewed completed trials of the management of acute ischemic stroke including intravenous thrombolytics, intraarterial thrombolytics, and thrombectomy. We also assessed the future direction of research by reviewing ongoing clinical trials. Conclusions: The advancement of endovascular treatment for stroke has led to improved morbidity and mortality for patients. Future challenges include delivering these treatments to stroke centers worldwide.

Updates in the Management of Cerebral Infarctions and Subarachnoid Hemorrhage Secondary to Intracranial Arterial Dissection: A Systematic Review

OBJECTIVE Intracranial arterial dissection (IAD) is a rare cerebrovascular disease that is likely underdiagnosed because of the inherent difficulty of visualizing the subtle radiographic signs of the pathologic small intracranial arteries. No widespread consensus exists on the treatment of IAD, and thus it is often managed empirically because of the absence of major randomized controlled trials. In this study, we conducted a systematic review to evaluate the management and treatment options for IAD. METHODS We performed a systematic review in accordance with the PRISMA guidelines using the following databases: MEDLINE (PubMed) and Cochrane Library. Included studies were limited to human patients with dissections in intracranial vessels only. RESULTS A total of 82 studies were included in this systematic review. The most common complications of IAD were cerebral infarction and subarachnoid hemorrhage, and thus, patients with IAD can be subdivided into those presenting with either ischemia or hemorrhage, respectively. Those with ischemia were predominantly managed with antiplatelet therapy, whereas patients presenting with hemorrhage often were amenable to treatment with endovascular techniques. CONCLUSIONS Given these findings, clinicians should prescribe antiplatelet therapy for patients with IAD presenting with ischemia and consider endovascular treatment for those presenting with hemorrhage. However, further investigation is required given the heterogeneity of methods and reporting outcomes in the investigated studies.

Bailout Strategies and Complications Associated with the Use of Flow-Diverting Stents for Treating Intracranial Aneurysms

Background: Flow-diverting stents (FDS) have revolutionized the endovascular management of unruptured, complex, wide-necked, and giant aneurysms. There is no consensus on management of complications associated with the placement of these devices. This review focuses on the management of complications of FDS for the treatment of intracranial aneurysms. Summary: We performed a systematic, qualitative review using electronic databases MEDLINE and Google Scholar. Complications of FDS placement generally occur during the perioperative period. Key Message: Complications associated with FDS may be divided into periprocedural complications, immediate postprocedural complications, and delayed complications. We sought to review these complications and novel management strategies that have been reported in the literature.

Novel minimally invasive multi-modality monitoring modalities in neurocritical care

Elevated intracranial pressure (ICP) following brain injury contributes to poor outcomes for patients, primarily by reducing the caliber of cerebral vasculature, and thereby reducing cerebral blood flow. Careful monitoring of ICP is critical in these patients in order to determine prognosis, implement treatment when ICP becomes elevated, and to judge responsiveness to treatment. Currently, the gold standard for monitoring is invasive pressure transducers, usually an intraventricular monitor, which presents significant risk of infection and hemorrhage. These risks made discovering non-invasive methods for monitoring ICP and cerebral perfusion a priority for researchers. Herein we sought to review recent publications on novel minimally invasive multi-modality monitoring techniques that provide surrogate data on ICP, cerebral oxygenation, metabolism and blood flow. While limitations in various forms preclude them from supplanting the use of invasive monitors, these modalities represent useful screening tools within our armamentarium that may be invaluable when the risks of invasive monitoring outweigh the associated benefits.

Novel management strategies for medically-refractory vasospasm following aneurysmal subarachnoid hemorrhage

Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) is an important cause of further morbidity and mortality after an already devastating condition. Though traditionally attributed to vasospasm of large capacitance arteries and the resulting down-stream disruption of cerebral blood flow, the pathogenesis of DCI has proven to be more complex with early brain injury, blood-brain barrier disruption, microthrombosis, cortical spreading depolarizations, and the failure of cerebral autoregulation as newly elucidated factors. Vasospasm is a known consequence of SAH. The standard of care includes close monitoring for neurological deterioration, most often with serial clinical examinations, transcranial Doppler ultrasonography, and vascular imaging (crucial for early detection of DCI and allows for prompt intervention). Nimodipine continues to remain an important pharmacological strategy to improve functional outcomes in patients with SAH at risk for developing vasospasm. The paradigm for first line therapy in patients with vasospasm of induced hypertension, hypervolemia, and hemodilution has recently been challenged. Current American Heart Association guidelines recommend targeting euvolemia and judicious use of the pharmacologically induced hypertension component. Symptomatic vasospasm patients who do not improve with this first line therapy require rescue intervention with mechanical or chemical angioplasty and optimization of cardiac output and hemoglobin levels. This can be escalated in a step-wise fashion to include adjunct treatments such as intrathecal administration of vasodilators and sympatholytic or thrombolytic therapies. This review provides a general overview of the treatment modalities for DCI with a focus on novel management strategies that show promising results for treating vasospasm to prevent DCI.

Multimodality Monitoring in Neurocritical Care: Decision-Making Utilizing Direct And Indirect Surrogate Markers

Substantial progress has been made to create innovative technology that can monitor the different physiological characteristics that precede the onset of secondary brain injury, with the ultimate goal of intervening prior to the onset of irreversible neurological damage. One of the goals of neurocritical care is to recognize and preemptively manage secondary neurological injury by analyzing physiologic markers of ischemia and brain injury prior to the development of irreversible damage. This is helpful in a multitude of neurological conditions, whereby secondary neurological injury could present including but not limited to traumatic intracranial hemorrhage and, specifically, subarachnoid hemorrhage, which has the potential of progressing to delayed cerebral ischemia and monitoring postneurosurgical interventions. In this study, we examine the utilization of direct and indirect surrogate physiologic markers of ongoing neurologic injury, including intracranial pressure, cerebral blood flow, and brain metabolism.

Chemical angioplasty for medically refractory reversible cerebral vasoconstriction syndrome

Abstract Purpose: Medically refractory reversible cerebral vasoconstriction syndrome (RCVS), a rare variant of RCVS, poses a significant therapeutic challenge. Herein we describe a case of medically refractory RCVS that required treatment with intra-arterial (IA) verapamil and subsequent nimodipine, resulting in both angiographic and clinical improvement after failing to respond to hemodynamic augmentation. We also supplement a description of our case with a review of other case studies and case series in which IA calcium channel blockers were used to treat RCVS. We propose that the case we outline below demonstrates that neurointerventional management with IA verapamil is appropriate and effective as an early intervention of medically refractory RCVS. Methods and Materials: Using PubMed and Google Scholar, we performed a search of the English language literature with several combinations of the keywords “intra-arterial”, “calcium channel blockers”, “reversible cerebral vasoconstriction syndrome”, “RCVS”, “nimodipine”, “verapamil”, “milrinone”, and “nicardipine” to identify studies in which RCVS was treated with IA calcium channel blockers. Results: We identified eight case studies and case series that met our inclusion criteria. Eighteen patients are encompassed in these eight studies. Conclusions: IA administration of calcium channel blockers has been shown to return cerebral vessels to their normal caliber in patients with medically refractory RCVS. However, there are no randomized controlled trials of the treatment of RCVS, and further studies are needed to elucidate the optimal treatment protocol for medically refractory RCVS.