The Source for Neurovascular News and Education

October 27, 2021

These risk factors were independent predictors of poor outcome even in a recent cohort mostly treated with coiling.


Researchers from the United Kingdom have identified independent predictors of poor outcome in a series of patients with aneurysmal subarachnoid hemorrhage predominantly treated with endovascular coiling. Two risk factors emerged in this analysis that have the potential to be addressed: preoperative rebleeding and delayed cerebral ischemia.

“Although several factors have been identified as important in predicting outcome, poor presentation grade, increasing age, preprotection aneurysm rebleeding, and delayed cerebral ischemia (DCI) are the only consistently identified independent predictors of a negative outcome in patients presenting with [an aneurysmal subarachnoid hemorrhage],” lead author James P. Galea, PhD (University of Manchester, England), and colleagues write in their paper published earlier this month in Stroke.

They point out that previous studies examining prognostic factors have been limited by focusing on a single center, including a preponderance of patients treated with open microsurgery, or using only selected groups of patients randomized to clinical trials. In addition, analyses of outcomes over a long period of time fail to take into account recent improvements, calling into question whether the prognostic factors identified remain relevant.

To give an updated look, Galea and colleagues analyzed prospectively collected data on 3,341 patients with aneurysmal subarachnoid hemorrhage treated at 14 centers in the United Kingdom between September 2011 and September 2015.

Patients’ median age was 55, and 68.5% were female. Most presented in World Federation of Neurological Surgeons (WFNS) grade 1 or 2 (70%), and the majority (75%) were treated with endovascular coiling.


The independent predictors of an unfavorable outcome—defined as a Glasgow Outcome Scale score of 1 to 3—were increasing age, WFNS grade, preoperative rebleeding, need for cerebrospinal fluid (CSF) diversion, and DCI.

Predictors of Unfavorable Outcome



95% CI

Increasing Age



WFNS Grade



Preoperative Rebleeding



Need for CSF Diversion







Patients who underwent any type of treatment tended to be less likely to have an unfavorable outcome (OR 0.20; 95% CI 0.64-1.08).

The authors point out that among the risk factors identified, preoperative rebleeding and DCI should be given special attention, given that both are potentially modifiable.

“Early treatment of ruptured aneurysm is now considered the norm to reduce rebleeding, and this is reflected in this series where the median time to treat was 1 day,” they write. “Ultra-early treatment strategies have been proposed by several [aneurysmal subarachnoid hemorrhage] treating specialists, although this has not been shown to be any better than a more pragmatic treat as early as possible approach in some studies.”

The authors add that prevention of preoperative rebleeding requires a good understanding of the population in which it occurs. “Rebleed in poor-grade patients may be the result of a purposeful treatment strategy driven by the clinical presentation and acute pathophysiological changes,” they write.

Most rebleeds occur within 6 hours of aneurysm rupture, they note. Given that many patients require transfer to specialized centers during this time period, a pharmacological approach to prevention of rebleeding may be most useful.

With regard to DCI, they write, only nimodipine has been shown in phase III clinical trials to attenuate its ill effects.

The authors also deem it valuable to explore why the need for CSF diversion is associated with poorer outcomes.

Aditya S. Pandey, MD (University of Michigan, Ann Arbor, MI), agrees that the study highlights the need to focus on prevention of preoperative rebleeding. “We need to treat these patients as soon as possible to prevent a rebleed,” he told Neurovascular Exchange in an email. He also suggested that smoking cessation could be another way to help optimize outcomes, since smoking has been linked with both aneurysmal growth and bleeding.

“This is a great example of how accumulation of large clinical data is essential in understanding how clinical outcomes are changing with time, as well as an opportunity to evaluate factors that could lead to an improvement in clinical outcome,” Pandey concluded. He added, however, that the findings may not relate to systems of care for subarachnoid hemorrhage outside of the United Kingdom.




Galea JP, Dulhanty L, Patel HC, et al. Predictors of outcome in aneurysmal subarachnoid hemorrhage patients: observations from a multicenter data set. Stroke. 2017;Epub ahead of print.



Galea reports no relevant conflicts of interest.