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result(s) for
"Macdonald, R Loch"
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Spontaneous subarachnoid haemorrhage
by
Macdonald, R Loch
,
Schweizer, Tom A
in
Aneurysms
,
Cognitive ability
,
Genetic Predisposition to Disease
2017
Subarachnoid haemorrhage is an uncommon and severe subtype of stroke affecting patients at a mean age of 55 years, leading to loss of many years of productive life. The rupture of an intracranial aneurysm is the underlining cause in 85% of cases. Survival from aneurysmal subarachnoid haemorrhage has increased by 17% in the past few decades, probably because of better diagnosis, early aneurysm repair, prescription of nimodipine, and advanced intensive care support. Nevertheless, survivors commonly have cognitive impairments, which in turn affect patients' daily functionality, working capacity, and quality of life. Additionally, those deficits are frequently accompanied by mood disorders, fatigue, and sleep disturbances. Management requires specialised neurological intensive care units and multidisciplinary clinical expertise, which is better provided in high-volume centres. Many clinical trials have been done, but only two interventions are shown to improve outcome. Challenges that remain relate to prevention of subarachnoid haemorrhage by improved screening and development of lower-risk methods to repair or stabilise aneurysms that have not yet ruptured. Multicentre cooperative efforts might increase the knowledge that can be gained from clinical trials, which is often limited by small studies with differing criteria and endpoints that are done in single centres. Outcome assessments that incorporate finer assessment of neurocognitive function and validated surrogate imaging or biomarkers for outcome could also help to advance the specialty.
Journal Article
Pharmacological Prevention of Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage
2024
Background
Causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (aSAH) include early brain injury and delayed neurologic deterioration, which may result from delayed cerebral ischemia (DCI). Complex pathophysiological mechanisms underlie DCI, which often includes angiographic vasospasm (aVSP) of cerebral arteries.
Methods
Despite the study of many pharmacological therapies for the prevention of DCI in aSAH, nimodipine—a dihydropyridine calcium channel blocker—remains the only drug recommended universally in this patient population. A common theme in the research of preventative therapies is the use of promising drugs that have been shown to reduce the occurrence of aVSP but ultimately did not improve functional outcomes in large, randomized studies. An example of this is the endothelin antagonist clazosentan, although this agent was recently approved in Japan.
Results
The use of the only approved drug, nimodipine, is limited in practice by hypotension. The administration of nimodipine and its counterpart nicardipine by alternative routes, such as intrathecally or formulated as prolonged release implants, continues to be a rational area of study. Additional agents approved in other parts of the world include fasudil and tirilazad.
Conclusions
We provide a brief overview of agents currently being studied for prevention of aVSP and DCI after aSAH. Future studies may need to identify subpopulations of patients who can benefit from these drugs and perhaps redefine acceptable outcomes to demonstrate impact.
Journal Article
The critical care management of poor-grade subarachnoid haemorrhage
by
Marotta, Tom R.
,
Abrahamson, Simon
,
de Oliveira Manoel, Airton Leonardo
in
Brain - physiopathology
,
Brain Injuries - complications
,
Brain Injuries - prevention & control
2016
Aneurysmal subarachnoid haemorrhage is a neurological syndrome with complex systemic complications. The rupture of an intracranial aneurysm leads to the acute extravasation of arterial blood under high pressure into the subarachnoid space and often into the brain parenchyma and ventricles. The haemorrhage triggers a cascade of complex events, which ultimately can result in early brain injury, delayed cerebral ischaemia, and systemic complications. Although patients with poor-grade subarachnoid haemorrhage (World Federation of Neurosurgical Societies 4 and 5) are at higher risk of early brain injury, delayed cerebral ischaemia, and systemic complications, the early and aggressive treatment of this patient population has decreased overall mortality from more than 50 % to 35 % in the last four decades. These management strategies include (1) transfer to a high-volume centre, (2) neurological and systemic support in a dedicated neurological intensive care unit, (3) early aneurysm repair, (4) use of multimodal neuromonitoring, (5) control of intracranial pressure and the optimisation of cerebral oxygen delivery, (6) prevention and treatment of medical complications, and (7) prevention, monitoring, and aggressive treatment of delayed cerebral ischaemia. The aim of this article is to provide a summary of critical care management strategies applied to the subarachnoid haemorrhage population, especially for patients in poor neurological condition, on the basis of the modern concepts of early brain injury and delayed cerebral ischaemia.
Journal Article
Delayed neurological deterioration after subarachnoid haemorrhage
2014
Key Points
The two main effects of subarachnoid haemorrhage (SAH) are early brain injury and delayed cerebral ischaemia (DCI)
The pathogenesis of DCI is hypothesized to be multifactorial and includes angiographic vasospasm, cortical spreading ischaemia, microthrombosis and microcirculation constriction
Early brain injury, which refers to the acute effects of subarachnoid blood and the transient global ischaemia that may accompany aneurysm rupture, has also been suggested to contribute to DCI
Risk of DCI is increased by volume, density and persistence of the subarachnoid thrombus, early brain injury, factors that reduce brain oxygen and glucose supply and, probably, pre-existing hypertension
Treatments that reduce the risk of DCI include nimodipine, rescue therapy consisting of balloon or pharmacological angioplasty, and induced hypertension
Drugs under investigation for DCI include intrathecal dihydropyridines, magnesium, albumin, sodium nitrite, statins, dantrolene and cilostazol
Subarachnoid haemorrhage (SAH) has a high case fatality. In addition to neurological injury occurring at the time of haemorrhage, delayed neurological deterioration can occur days later owing to processes such as cerebral vasospasm and microthrombosis, which culminate in delayed cerebral ischaemia. R. Loch Macdonald reviews the pathophysiology of these delayed complications of SAH, and outlines existing treatments and drugs in development for this indication.
Subarachnoid haemorrhage (SAH) causes early brain injury (EBI) that is mediated by effects of transient cerebral ischaemia during bleeding plus effects of the subarachnoid blood. Secondary effects of SAH include increased intracranial pressure, destruction of brain tissue by intracerebral haemorrhage, brain shift, and herniation, all of which contribute to pathology. Many patients survive these phenomena, but deteriorate days later from delayed cerebral ischaemia (DCI), which causes poor outcome or death in up to 30% of patients with SAH. DCI is thought to be caused by the combined effects of angiographic vasospasm, arteriolar constriction and thrombosis, cortical spreading ischaemia, and processes triggered by EBI. Treatment for DCI includes prophylactic administration of nimodipine, and current neurointensive care. Prompt recognition of DCI and immediate treatment by means of induced hypertension and balloon or pharmacological angioplasty are considered important by many physicians, although the evidence to support such approaches is limited. This Review summarizes the pathophysiology of DCI after SAH and discusses established treatments for this condition. Novel strategies—including drugs such as statins, sodium nitrite, albumin, dantrolene, cilostazol, and intracranial delivery of nimodipine or magnesium—are also discussed.
Journal Article
Effect of pharmaceutical treatment on vasospasm, delayed cerebral ischemia, and clinical outcome in patients with aneurysmal subarachnoid hemorrhage: A systematic review and meta-analysis
by
Etminan, Nima
,
Vergouwen, Mervyn DI
,
Macdonald, R Loch
in
Biological and medical sciences
,
Brain Ischemia - complications
,
Brain Ischemia - prevention & control
2011
As it is often assumed that delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) is caused by vasospasm, clinical trials often focus on prevention of vasospasm with the aim to improve clinical outcome. However, the role of vasospasm in the pathogenesis of DCI and clinical outcome is possibly smaller than previously assumed. We performed a systematic review and meta-analysis on all randomized, double-blind, placebo-controlled trials that studied the effect of pharmaceutical preventive strategies on vasospasm, DCI, and clinical outcome in SAH patients to further investigate the relationship between vasospasm and clinical outcome. Effect sizes were expressed in pooled risk ratio (RR) estimates with corresponding 95% confidence intervals (CI). A total of 14 studies randomizing 4,235 patients were included. Despite a reduction of vasospasm (RR 0.80 (95% CI 0.70 to 0.92)), no statistically significant effect on poor outcome was observed (RR 0.93 (95% CI 0.85 to 1.03)). The variety of DCI definitions did not justify pooling the DCI data. We conclude that pharmaceutical treatments have significantly decreased the incidence of vasospasm, but not of poor clinical outcome. This dissociation between vasospasm and clinical outcome could result from methodological problems, sample size, insensitivity of clinical outcome measures, or from mechanisms other than vasospasm that also contribute to poor outcome.
Journal Article
Development and validation of outcome prediction models for aneurysmal subarachnoid haemorrhage: the SAHIT multinational cohort study
by
Etminan, Nima
,
Pickard, John
,
Macdonald, R Loch
in
Aneurysm
,
Aneurysm, Ruptured - complications
,
Aneurysms
2018
AbstractObjectiveTo develop and validate a set of practical prediction tools that reliably estimate the outcome of subarachnoid haemorrhage from ruptured intracranial aneurysms (SAH).DesignCohort study with logistic regression analysis to combine predictors and treatment modality.SettingSubarachnoid Haemorrhage International Trialists’ (SAHIT) data repository, including randomised clinical trials, prospective observational studies, and hospital registries.ParticipantsResearchers collaborated to pool datasets of prospective observational studies, hospital registries, and randomised clinical trials of SAH from multiple geographical regions to develop and validate clinical prediction models.Main outcome measurePredicted risk of mortality or functional outcome at three months according to score on the Glasgow outcome scale.ResultsClinical prediction models were developed with individual patient data from 10 936 patients and validated with data from 3355 patients after development of the model. In the validation cohort, a core model including patient age, premorbid hypertension, and neurological grade on admission to predict risk of functional outcome had good discrimination, with an area under the receiver operator characteristics curve (AUC) of 0.80 (95% confidence interval 0.78 to 0.82). When the core model was extended to a “neuroimaging model,” with inclusion of clot volume, aneurysm size, and location, the AUC improved to 0.81 (0.79 to 0.84). A full model that extended the neuroimaging model by including treatment modality had AUC of 0.81 (0.79 to 0.83). Discrimination was lower for a similar set of models to predict risk of mortality (AUC for full model 0.76, 0.69 to 0.82). All models showed satisfactory calibration in the validation cohort.ConclusionThe prediction models reliably estimate the outcome of patients who were managed in various settings for ruptured intracranial aneurysms that caused subarachnoid haemorrhage. The predictor items are readily derived at hospital admission. The web based SAHIT prognostic calculator (http://sahitscore.com) and the related app could be adjunctive tools to support management of patients.
Journal Article
The critical care management of spontaneous intracranial hemorrhage: a contemporary review
by
de Oliveira Manoel, Airton Leonardo
,
Abrahamson, Simon
,
Turkel-Parrella, David
in
Critical care
,
Critical Care Medicine
,
Development and progression
2016
Spontaneous intracerebral hemorrhage (ICH), defined as nontraumatic bleeding into the brain parenchyma, is the second most common subtype of stroke, with 5.3 million cases and over 3 million deaths reported worldwide in 2010. Case fatality is extremely high (reaching approximately 60 % at 1 year post event). Only 20 % of patients who survive are independent within 6 months. Factors such as chronic hypertension, cerebral amyloid angiopathy, and anticoagulation are commonly associated with ICH. Chronic arterial hypertension represents the major risk factor for bleeding. The incidence of hypertension-related ICH is decreasing in some regions due to improvements in the treatment of chronic hypertension. Anticoagulant-related ICH (vitamin K antagonists and the newer oral anticoagulant drugs) represents an increasing cause of ICH, currently accounting for more than 15 % of all cases. Although questions regarding the optimal medical and surgical management of ICH still remain, recent clinical trials examining hemostatic therapy, blood pressure control, and hematoma evacuation have advanced our understanding of ICH management. Timely and aggressive management in the acute phase may mitigate secondary brain injury. The initial management should include: initial medical stabilization; rapid, accurate neuroimaging to establish the diagnosis and elucidate an etiology; standardized neurologic assessment to determine baseline severity; prevention of hematoma expansion (blood pressure management and reversal of coagulopathy); consideration of early surgical intervention; and prevention of secondary brain injury. This review aims to provide a clinical approach for the practicing clinician.
Journal Article
Phase 1, randomized, crossover study comparing intravenous GTX-104 to oral nimodipine in healthy human subjects
by
Kumar, Amresh
,
D'Andrea, Carrie
,
Kohli, Prashant
in
Administration, Intravenous
,
Administration, Oral
,
Adult
2025
Enterally-administered nimodipine is the only approved drug formulation available in the United States for treatment of patients with aneurysmal subarachnoid hemorrhage. Intravenous nimodipine is available in other countries but it contains a high concentration of ethanol that is irritating to the vasculature, can alter the effects of other medications, impair neurological assessments and is potentially harmful to the liver. We developed a sterile aqueous solution of nimodipine solubilized in polysorbate 80 micelles (GTX-104) that circumvents these problems. GTX-104 has been administered to 168 healthy human volunteers in 2 studies. We report the second study here, a phase 1, single center, randomized, 2-period cross over study that assessed the pharmacokinetics of GTX-104 and oral nimodipine capsules, which is the reference standard, in 58 healthy human volunteers. GTX-104 was administered for 72 hours as a continuous infusion of 0.15 mg/hour with a 30 minute bolus infusion of 4 mg every 4 hours. Nimodipine capsules were administered orally at a dose of 60 mg every 4 hours for 72 hours. The maximum plasma concentrations (geometric least square means) after the first dose of each formulation were similar (GTX-104: 63 ng/mL, n = 57 versus nimodipine capsules: 69 ng/mL, n = 56, ratio and 90% confidence interval [CI] of geometric LSmeans: 92% [90% CI: 82-104%]). The areas under the concentration-time curves on the 3rd day at steady state also were the same (GTX-104: 492 ng*h/mL, n = 56 versus nimodipine capsules: 462 ng*h/mL, n = 55, ratio and 90% CI of geometric LSmeans: 106% [90% CI: 99-114%]). The secondary pharmacokinetic parameters (daily maximum concentration at steady-state and time to maximum concentration) were also similar for the 2 formulations. The variability in PK parameters was less for GTX-104 compared to nimodipine capsules. The average oral bioavailability for nimodipine capsules was 7%. These results enabled a Phase 3 safety study of GTX-104 in humans with aneurysmal subarachnoid hemorrhage.
Journal Article