Endovascular Intervention Versus Surgery in Ruptured Intracranial Aneurysms in Equipoise

A Systematic Review

Chung Liang Chai, MD, MRes; Jin Pyeong Jeon, MD, PhD; Yi-Hsin Tsai, MD, PhD; Paula Whittaker, MBChB, MPH, MSc; R. Loch Macdonald, MD, PhD; Antti E. Lindgren, MD, PhD; Oliver G.S. Ayling, MD, MSc; Marcus André Acioly, MD, PhD; Aaron Cohen-Gadol, MD, MSc, MBA; Yu-Hua Huang, MD


Stroke. 2020;51(6):1703-1711. 

In This Article

Abstract and Introduction


Background and Purpose: The benefits of endovascular intervention over surgery in the treatment of ruptured aneurysms of anterior circulation remains uncertain. Recently, published studies did not find superiority of endovascular intervention, challenging earlier evidence from a clinical trial. The earlier evidence also had a higher than average proportion of patients in good clinical status, leading to uncertainty about external validity of earlier trials.

Methods: We performed a systematic review of studies after 2005 under a protocol published in the International Prospective Register of Systematic Reviews. Primary outcomes were posttreatment rebleeding and adverse events (procedural complications). Secondary outcomes were dependency at 3 to 6 and 12 months, delayed cerebral ischemia, and seizures.

Results: Rebleeding was more frequent after endovascular intervention (Peto OR, 2.18 [95% CI, 1.29–3.70]; 3104 participants; 15 studies; I2=0%, Grading of Recommendations, Assessment, Development and Evaluation: very low certainty of evidence). Fewer adverse events were reported with the endovascular intervention (RR, 0.71 [95% CI, 0.53–0.95]; 1661 participants; 11 studies; I2=14%, Grading of Recommendations, Assessment, Development and Evaluation: low certainty of evidence). Three to six months dependency (RR, 0.82 [95% CI, 0.73–0.93]; 4081 participants; 18 studies; I2=15%, Grading of Recommendations, Assessment, Development and Evaluation: low certainty of evidence) and 12-month dependency (RR, 0.76 [95% CI, 0.66–0.86]; 1981 participants; 10 studies; I2=0%, Grading of Recommendations, Assessment, Development and Evaluation: low certainty of evidence) were lower after endovascular intervention.

Conclusions: This study found consistent results between recent studies and the earlier evidence, in that endovascular intervention results in lower chance of dependency compared with surgery for repair of ruptured anterior circulation aneurysms. A lower proportion of patients in good clinical status in this review supports the application of the earlier evidence.

Registration: URL: https://www.crd.york.ac.uk/PROSPERO. Unique identifier: CRD42018090396.


Endovascular intervention and surgery are the standard treatments for ruptured intracranial aneurysms. Previous evidence supporting a better outcome from endovascular intervention was based on the ISAT (International Subarachnoid Aneurysm Trial)[1] and a systematic review[2] that was also predominantly based on ISAT. After the publication of ISAT[1] in 2002, numerous studies, mostly nonrandomized studies (NRS), compared both interventions in terms of functional outcome. Many NRS, including the 2 largest cohorts[3,4] found no statistically significant differences between the 2 treatments. Also, a pseudorandomized trial reported that the long-term clinical outcome was similar for endovascular or surgical aneurysm repair.[5]

The external validity of ISAT has been questioned because it included a lower proportion of patients with poor neurological grades than the general population of ruptured aneurysm cases.[6,7] Approximately 6% of patients in ISAT were poor grade.[1,8] In addition, aneurysms in ISAT were on average small and narrow-necked and endovascular repair has since been applied to a broader range of aneurysms and using endovascular devices that were not used in ISAT.[9]

Rebleeding is another issue of significance within the neurovascular community as the fundamental role of endovascular intervention or surgical clipping of a ruptured intracranial aneurysm is to prevent rebleeding. In ISAT, the risk for rebleeding in patients after coiling was 2.5× higher than in those after clipping.[1,6] Recent data concerning rebleeding were not available at the time of writing and is therefore needed.

The objective of this study is to address the above criticisms by systematically identifying the differences in outcomes between the 2 interventions. This review is not an all-encompassing comparison in all types of aneurysms and date of publication. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines,[10] Methodological Expectations of Cochrane Intervention Reviews,[11] and the Institute of Medicine of the United States.[12]