Feasibility of intraventricular nicardipine prolonged release implants in patients following aneurysmal subarachnoid haemorrhage
ABSTRACT Intracisternal nicardipine prolonged release implants (NPRI) have been shown to be effective in the prophylaxis of cerebral vasospasm (VS). However, they cannot be used in patients following coil occlusion of the aneurysm. As a certain dissemination of nicardipine within the cerebrospinal fluid (CSF) has been described, we examined the feasibility of intraventricular use of NPRI in patients that underwent clip and coil occlusion of their aneurysms following aneurysmal subarachnoid haemorrhage (aSAH). By comparison with an historical control group, an estimation of their effectivity in regard to angiographic vasospasm and the development of cerebral infarction has been performed.
Thirty-one patients suffering from aSAH were prospectively included in this trial. Study participants received prior to clipping (n = 17) or coiling (n = 14) 6 (n = 15) or 10 NPRI (n = 16) into the lateral ventricles. Physiological data were collected, proximal and global VS were determined using pre-operative and day 8 ± 1 angiography, and incidence of hydrocephalus and VS related infarcts were evaluated and compared to a historical control group consisting of 16 operated patients without NPRI implantation.
Intraventricular NPRI were tolerated well. There were no adverse side effects detectable, physiological variables such as heart rate (HR), mean arterial blood pressure (MAP), intracranial pressure (ICP) and electrolytes showed no difference compared to control. There was no difference in the proportion of patients that required CSF shunting. A significant positive angiographic effect could only be observed in clipped patients (proximal vessel diameters: control, 80 ± 30%; NPRI 90 ± 24%; incidence of moderate/severe global VS: control, 73%; NPRI, 41%).
The use of intraventricular NPRI seems to be safe and tolerated well. There is preliminary evidence for effectivity on angiographic VS for clipped patients only. A further increase of the effective dose might also exert efficacy in the subset of patients following coil occlusion.
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ABSTRACT: Nimodipine is a widely used medication for treating delayed cerebral ischemia (DCI) after subarachnoid hemorrhage. When administrated orally or intravenously, systemic hypotension is an undesirable side effect. Intracranial subarachnoid delivery of nimodipine during aneurysm clipping may be more efficient way of preventing vasospasm and DCI due to higher concentration of nimodipine in cerebrospinal fluid (CSF). The risk of systemic hypotension may also be decreased with intracranial delivery. We used animal models to evaluate the feasibility of surgically implanting a silica-based nimodipine releasing implant into the subarachnoid space through a frontotemporal craniotomy. Concentrations of released nimodipine were measured from plasma samples and CSF samples. Implant degradation was followed using CT imaging. After completing the recovery period, full histological examination was performed on the brain and meninges. The in vitro characteristics of the implant were determined. Our results show that the biodegradable silica-based implant can be used for an intracranial drug delivery system and no major histopathological foreign body reactions were observed. CT imaging is a feasible method for determining the degradation of silica implants in vivo. The sustained release profiles of nimodipine in CSF were achieved. Compared to a traditional treatment, higher nimodipine CSF/plasma ratios can be obtained with the implant.BioMed Research International 01/2015; 2015. DOI:10.1155/2015/715752 · 2.71 Impact Factor
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ABSTRACT: Aneurysmal subarachnoid hemorrhage- (aSAH-) associated vasospasm constitutes a clinicopathological entity, in which reversible vasculopathy, impaired autoregulatory function, and hypovolemia take place, and lead to the reduction of cerebral perfusion and finally ischemia. Cerebral vasospasm begins most often on the third day after the ictal event and reaches the maximum on the 5th-7th postictal days. Several therapeutic modalities have been employed for preventing or reversing cerebral vasospasm. Triple "H" therapy, balloon and chemical angioplasty with superselective intra-arterial injection of vasodilators, administration of substances like magnesium sulfate, statins, fasudil hydrochloride, erythropoietin, endothelin-1 antagonists, nitric oxide progenitors, and sildenafil, are some of the therapeutic protocols, which are currently employed for managing patients with aSAH. Intense pathophysiological mechanism research has led to the identification of various mediators of cerebral vasospasm, such as endothelium-derived, vascular smooth muscle-derived, proinflammatory mediators, cytokines and adhesion molecules, stress-induced gene activation, and platelet-derived growth factors. Oral, intravenous, or intra-arterial administration of antagonists of these mediators has been suggested for treating patients suffering a-SAH vasospam. In our current study, we attempt to summate all the available pharmacological treatment modalities for managing vasospasm.01/2013; 2013:571328. DOI:10.1155/2013/571328
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ABSTRACT: In this manuscript a comprehensive coverage of recent developments in the drug therapy of vasospasm while providing the background information that neuroscientists need to understand its rationale. The range of new agents available for treatment of cerebral vasospasm is expanding rapidly along with rapid advances in pharmacology and physiology that are uncovering the mechanisms of this disease. Although there are many publications for treatment of cerebral vaso-spasm, most are focusing on different aspects of vasospasm treatment and many have limited value due to insufficient quality. Moreover, the complexity of this, in many cases deleterious condition, is enormous and the information needed to understand drug effects is accordingly often not readily available in a single source. A number of pharmacological and medical therapies are currently in use or being investigated in an attempt to reverse cerebral vasospasm, but only a few have proven to be useful. Current research efforts promise the eventual production of new medical therapies. At last, recommendations for the use of different treatment stages based on currently available clinical data are provided.Open Journal of Modern Neurosurgery 01/2013; 03(04). DOI:10.4236/ojmn.2013.34016