Vasodilation and neuroprotection: The magnesium saga in subarachnoid hemorrhage*:

Management of aneurysmal subarachnoid hemorrhage: State of the art and future perspectives

Background:

Aneurysmal subarachnoid hemorrhage (SAH) accounts for 5% of strokes and carries a poor prognosis. It affects around 6 cases per 100,000 patient years occurring at a relatively young age.

Methods:

Common risk factors are the same as for stroke, and only in a minority of the cases, genetic factors can be found. The overall mortality ranges from 32% to 67%, with 10–20% of patients with long-term dependence due to brain damage. An explosive headache is the most common reported symptom, although a wide spectrum of clinical disturbances can be the presenting symptoms. Brain computed tomography (CT) allow the diagnosis of SAH. The subsequent CT angiography (CTA) or digital subtraction angiography (DSA) can detect vascular malformations such as aneurysms. Non-aneurysmal SAH is observed in 10% of the cases. In patients surviving the initial aneurysmal bleeding, re-hemorrhage and acute hydrocephalus can affect the prognosis.

Results:

Although occlusion of an aneurysm by surgical clipping or endovascular procedure effectively prevents rebleeding, cerebral vasospasm and the resulting cerebral ischemia occurring after SAH are still responsible for the considerable morbidity and mortality related to such a pathology. A significant amount of experimental and clinical research has been conducted to find ways in preventing these complications without sound results.

Conclusions:

Even though no single pharmacological agent or treatment protocol has been identified, the main therapeutic interventions remain ineffective and limited to the manipulation of systemic blood pressure, alteration of blood volume or viscosity, and control of arterial dioxide tension.

Cerebral Vasospasm in Critically III Patients with Aneurysmal Subarachnoid Hemorrhage: Does the Evidence Support the Ever-Growing List of Potential Pharmacotherapy Interventions?

The occurrence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) is a significant event resulting in decreased cerebral blood flow and oxygen delivery. Prevention and treatment of cerebral vasospasm is vital to avert neurological damage and reduced functional outcomes. A variety of pharmacotherapy interventions for the prevention and treatment of cerebral vasospasm have been evaluated. Unfortunately, very few large randomized trials exist to date, making it difficult to make clear recommendations regarding the efficacy and safety of most pharmacologic interventions. Considerable debate exists regarding the efficacy and safety of hypervolemia, hemodilution, and hypertension (triple-H therapy), and the implementation of each component varies substantially amongst institutions. There is a new focus on euvolemic-induced hypertension as a potentially preferred mechanism of hemodynamic augmentation. Nimodipine is the one pharmacologic intervention that has demonstrated favorable effects on patient outcomes and should be routinely administered unless contraindications are present. Intravenous nicardipine may offer an alternative to oral nimodipine. The addition of high-dose magnesium or statin therapy has shown promise, but results of ongoing large prospective studies are needed before they can be routinely recommended. Tirilazad and clazosentan offer new pharmacologic mechanisms, but clinical outcome results from prospective randomized studies have largely been unfavorable. Locally administered pharmacotherapy provides a targeted approach to the treatment of cerebral vasospasm. However, the paucity of data makes it challenging to determine the most appropriate therapy and implementation strategy. Further studies are needed for most pharmacologic therapies to determine whether meaningful efficacy exists.

Pharmacologic Options for Prevention and Management of Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage

Background

Cerebral vasospasm and delayed cerebral ischemia continue to be major contributors to morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH).

Purpose

The purpose of this review was to evaluate the pharmacotherapy interventions for the prevention and management of cerebral vasospasm in patients with SAH.

Methods

A search of MEDLINE (January 1966-April 2012) and EMBASE (January 1974-April 2012) was conducted to retrieve relevant studies of pharmacotherapy options for prevention or treatment of cerebral vasospasm in SAH.

Results

Triple-H therapy (hypervolemia, hemodilution, hypertension) has been a widely accepted option by many clinicians for the management of cerebral vasospasm and delayed cerebral ischemia. However, implementation of Triple-H therapy varies considerably at individual institutions. Nimodipine and nicardipine have demonstrated the most dependable improvements in patient outcomes to date. High doses of intravenous magnesium have failed to show consistent benefits. Magnesium supplementation to prevent hypomagnesaemia should be employed. Statin therapy should be continued in patients who are taking statins prior to hospital admission. Use of statins in naive patients may be recommended when the results of an ongoing prospective study are available. Of the available locally administered pharmacologic therapies, nicardipine and thrombolytics appear to provide the most intriguing benefit-to-risk ratio. However, the data supporting the use of locally administered therapy are modest at best and require careful consideration prior to application.

Conclusions

Clinical studies have tested a variety of pharmacotherapy interventions for the prevention and treatment of cerebral vasospasm. Of available therapies, nimodipine has demonstrated consistent benefits and should be employed routinely. Demonstration of reduced cerebral vasospasm and improved neurological outcomes in larger prospective studies are needed for most pharmacologic therapy options prior to recommending their routine use.

Off-label use of drugs and devices in the neuroendovascular suite

SUMMARY

The off-label use of drugs and devices in neuroendovascular procedures is common. Neurointerventionalists should be well aware of the level of evidence available in support of the off-label use of drugs and devices in their practice and some of the potential adverse events associated with them. These uses are categorized as I or II if they have been evaluated as primary or ancillary interventions in prospective trials/registries of neuroendovascular procedures and III if they were evaluated in case series. Category IV use is based on evaluation as primary or ancillary interventions in prospective trials/registries of non-neuroendovascular procedures. Physicians are allowed to use off-label drugs and procedures if there is strong evidence that they are beneficial for the patient. The neurointerventional professional societies agree that off-label use of drugs and devices is an important part of the specialty, but practicing providers should base their decisions on sound evidence when using such drugs and devices.

Magnesium sulfate administration in subarachnoid hemorrhage

Magnesium offers theoretic vascular and neuroprotective benefits for patients with subarachnoid hemorrhage. An electronic literature search was conducted to identify original research studies describing intravenous magnesium treatment in patients with SAH published in English between January 1990 and October 2010. Seventeen articles were identified and reviewed, including one phase III randomized-controlled clinical trial and six phase II randomized-controlled trials. Study quality was low for most of the included studies, with the phase III trial considered to be of moderate quality. Due to inconsistently reported benefits and the occurrence of side effects, phase II data suggested that intravenous magnesium for SAH provided either no overall net benefit or uncertain trade-offs. Benefit was likewise not supported in the single phase III clinical trial.