Endovascular Coiling Versus Neurosurgical Clipping for Patients With Aneurysmal Subarachnoid Hemorrhage
Section Editor: Graeme J. Hankey MD, FRCP
Patients who have had an aneurysmal subarachnoid hemorrhage (SAH) are at very high risk of rebleeding if the aneurysm is not treated. The standard treatment for several decades has been surgical clipping of the neck of the aneurysm. In recent years, an alternative, the introduction of detachable coils to occlude the aneurysm, has become more common.
The goal was to compare the effects of endovascular coiling versus neurosurgical clipping in patients with aneurysmal SAH.
We searched the Cochrane Stroke Group Trials Register (last searched in February 2005). In addition, we searched MEDLINE (1966 to January 2004) and EMBASE (1980 to January 2004) and contacted trialists.
We included randomized trials in which endovascular coiling of aneurysms was compared with neurosurgical clipping in patients with SAH who have proven aneurysm.
Data Collection and Analysis
Two authors independently extracted the data and assessed trial quality. Trialists were contacted to obtain missing information. The primary analyses were based on the intention-to-treat results of the individual trials, for “poor outcome” (death or dependence), and for case fatality.
We identified 3 randomized trial1,2 (Brilstra and Lusseveld E, unpublished data, 2002). The trials included a total of 2272 patients (2143, 109, and 20 patients per trial, respectively). Most of the patients were in good clinical condition and had an aneurysm on the anterior circulation. After 1 year of follow-up, the relative risk of poor outcome for coiling versus clipping was 0.76 (95% CI, 0.67 to 0.88; Figure). The absolute risk reduction was 7% (95% CI, 4% to 11%). This means that if 14 (95% CI, 10 to 25) patients are coiled instead of clipped, 1 poor outcome is prevented. In the worst case scenario analysis (in which, for patients with missing follow-up data, those in the coil strategy were assigned a poor outcome and those in the clip strategy a good outcome) for poor outcome, the relative risk for coiling versus clipping was 0.81 (95% CI, 0.70 to 0.92) and the absolute risk reduction was 6% (95% CI, 2% to 10%). For patients with anterior circulation aneurysm, the relative risk of poor outcome was 0.78 (95% CI, 0.68 to 0.90), and the absolute risk decrease was 7% (95% CI, 3% to 10%). For those with a posterior circulation aneurysm, the relative risk was 0.41 (95% CI, 0.19 to 0.92), and the absolute decrease in risk was 27% (95% CI, 6% to 48%).
The evidence comes mainly from 1 large trial. For patients in good clinical condition with ruptured aneurysms of either the anterior and posterior circulation, we have firm evidence that if the aneurysm is considered suitable for surgical clipping and endovascular treatment, coiling is associated with a better outcome.
For patients in poor clinical grades, there is no reliable randomized evidence comparing the risks and benefits of coiling versus clipping. Because coiling is less invasive than surgery, also in patients with poor clinical condition, coiling seems the preferred option. A disadvantage of coiling is that aneurysms are more often incompletely treated (90% to 100% obliteration) and carry a risk for reopening. The long-term follow-up (>1 year after SAH) of coiled patients, with regard to renewed filling of the aneurysm, is an unknown but important issue that needs further study.
- Received September 23, 2005.
- Accepted October 11, 2005.
Molyneux AJ, Kerr RS, Yu LM, Clarke M, Sneade M, Yarnold JA, Sandercock P; International Subarachnoid Aneurysm Trial (ISAT) Collaborative Group. International subarachnoid aneurysm trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, and aneurysm occlusion. Lancet. 2005; 366: 809–817.
Koivisto T, Vanninen R, Hurskainen H, Saari T, Hernesniemi J, Vapalahti M. Outcomes of early endovascular versus surgical treatment of ruptured cerebral aneurysms. A prospective randomized study. Stroke. 2000; 31: 2369–2377.