Effects of Various Therapeutic Agents on Vasospasm and Functional Outcome After Aneurysmal Subarachnoid Hemorrhage-Results of a Network Meta-Analysis

Pharmacological Prevention of Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

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.

The efficacy of different nimodipine administration route for treating subarachnoid hemorrhage: A network meta-analysis

BACKGROUND

A systematic review and network meta-analysis (NMA) were conducted to explore the optimal administration route of nimodipine for treatment subarachnoid hemorrhage.

METHODS

Electronic databases (Pubmed, Embase, Web of Science and Cochrane databases) were systematically searched to identify randomized controlled trials evaluating different administration route of nimodipine (intravenous and enteral) versus placebo for treatment subarachnoid hemorrhage. Outcomes included case fatality at 3 months, poor outcome measured at 3 months (defined as death, vegetative state, or severe disability), incidence of delayed cerebral ischemia (DCI), delayed ischemic neurological deficit. A random-effect Bayesian NMA was conducted for outcomes of interest, and results were presented as odds ratios (ORs) and 95% credible intervals. The NMA was performed using R Software with a GeMTC package. A Bayesian NMA was performed and relative ranking of agents was assessed using surface under the cumulative ranking (SUCRA) probabilities.

RESULTS

Nine randomized controlled trials met criteria for inclusion and finally included in this NMA. There was no statistically significant between intravenous and enteral in terms of case fatality, the occurrence of DCI, delayed ischemic neurologic deficit and poor outcomes (P > .05). Both intravenous and enteral could reduce case fatality, the occurrence of DCI, delayed ischemic neurologic deficit and poor outcomes (P < .05). The SUCRA shows that enteral ranked first, intravenous ranked second and placebo ranked the last for case fatality, the occurrence of DCI and poor outcomes. The SUCRA shows that intravenous ranked first, enteral ranked second and placebo ranked the last for delayed ischemic neurologic deficit.

CONCLUSIONS

It is possible that both enteral and intravenous nimodipine have comparable effectiveness in preventing poor outcomes, DCI, and delayed ischemic neurological deficits. However, further investigation may be necessary to determine the exact role of intravenous nimodipine in current clinical practice.

A Comparison Between Enteral and Intravenous Nimodipine in Subarachnoid Hemorrhage: A Systematic Review and Network Meta-Analysis

Our objective was to compare the effectiveness of intravenous and enteral nimodipine in preventing poor outcome from delayed cerebral ischemia in patients with subarachnoid hemorrhage. We performed a systematic search and a network meta-analysis using the following databases: PubMed, Scopus, the Cochrane Central Register of Controlled Trials, and Google Scholar. Risk of Bias 2 tool was used to assess risk of bias of included studies. A ranking among methods was performed on the basis of the frequentist analog of the surface under the cumulative ranking curve. Published studies that met the following population, intervention, comparison, outcomes and study (PICOS) criteria were included: patients with subarachnoid hemorrhage aged 15 years or older (P); nimodipine, intravenous and oral formulation (I); placebo or no intervention (C); poor outcome measured at 3 months (defined as death, vegetative state, or severe disability), case fatality at 3 months, delayed cerebral ischemia, delayed ischaemic neurologic deficit, and vasospasm measured with transcranial Doppler or digital subtraction angiography (O); and randomized controlled trials (S). No language or publication date restrictions were applied. Ten studies were finally included, with a total of 1527 randomly assigned patients. Oral and intravenous nimodipine were both effective in preventing poor outcome, delayed cerebral ischemia, and delayed ischaemic neurological deficit. Neither treatment was effective in improving case fatality. Evolving clinical protocols over a 30-year period and the risk of bias of the included studies may limit the strength of our results. Enteral and intravenous nimodipine may have a similar effectiveness in terms of preventing poor outcome, delayed cerebral ischemia, and delayed ischaemic neurological deficit. More research may be needed to fully establish the role of intravenous nimodipine in current clinical practice.