The Source for Neurovascular News and Education

June 13, 2024

Over 7-year follow-up, there was a significantly higher rate of retreatment after endovascular coiling than surgical clipping.


Among patients with unruptured intracranial aneurysms, a treatment strategy of either surgical clipping or endovascular coiling results in similar long-term rates of all-cause mortality, according to a South Korean study published online in the Journal of NeuroInterventional Surgery. The study also found that while there was no significant difference in rupture rates after treatment between the groups, coiling was associated with greater need for retreatment.

The American Heart Association has published guidelines on the management of patients with unruptured intracranial aneurysms, but the guidelines do not address long-term outcomes of surgical clipping compared with endovascular coiling.

Based on the results of this Korean study, Young Deok Kim, MD, of Seoul National University College of Medicine, and colleagues say it is reasonable to conclude that both procedures are “reasonably safe modalities for preventing aneurysm rupture.”

In the retrospective claims data-based study, Kim and colleagues use the Korean Health Insurance Review and Assessment Service to look at mortality among patients who underwent surgical clipping or endovascular coiling for unruptured intracranial aneurysms between 2008 and 2014. The primary outcome was all-cause mortality at 7 years.

In all, 26,411 patients underwent either clipping (11,777 patients) or coiling (14,634 patients). After adjustment, all-cause mortality rates at 7 years were similar between the two groups (3.8% for coiling vs 3.6% for clipping; HR 1.05; 95% CI 0.61-1.34).

The rate of periprocedural rupture also was not significantly different, occurring in 1.6% of patients in both treatment groups (RR 1.06; 95% CI 0.87-1.30).

Differences were seen between the treatment groups for some of the study’s secondary outcomes, however. Thromboembolic events requiring endovascular thrombolysis or mechanical thrombectomy occurred more commonly in patients who underwent endovascular coiling vs clipping (0.4% vs < 0.1%; P < 0.001), while transfusion of red blood cells was more common n the surgical clipping group (24.0% vs 2.6%; P < 0.001).

The median length of hospital stay was almost three times longer in patients who underwent surgical clipping compared with coiling (11 days vs 4 days; P < 0.001).

Finally, the unadjusted probability of retreatment was 5.4% for coiling compared with 3.2% for clipping (P < 0.001). After adjustment there was still a significant difference in probability of retreatment between the two groups.

“We confirmed this result, but one should interpret these results with caution because they included recanalization of treated aneurysms and de novo formation and growth of the observed aneurysm,” the researchers write.



Kim YD, Bang JS, Lee SU, et al. Long-term outcomes of treatment for unruptured intracranial aneurysms in South Korea: clipping versus coiling. J NeuroIntervent Surg. 2018;Epub ahead of print.



Kim reports no relevant conflicts of interest.