Does Coiling Beat Clipping for Ruptured Aneurysms?

Megan Brooks

December 31, 2012

For endovascular treatment of ruptured intracranial aneurysm, coiling yields a better clinical outcome than clipping, with the benefit greatest in patients with a good preoperative grade, according to a new meta-analysis of relevant studies.

However, there is a greater risk of rebleeding with coiling, particularly for patients with poor preoperative grade, the study team concludes.

"For patients with poor preoperative condition, further evaluation should be made, considering its greater risk of rebleeding, higher cost and uncertain benefit of postoperative outcome and 1 year mortality," Ying Peng, MD, PhD, Department of Neurology, Sun Yat-sen Memorial Hospital, Guangzhou, Guangdong Province, China, told Medscape Medical News.

The study was published online December 13 in Stroke.

To Clip or Coil?

In recent years, coiling has gained acceptance as an alternative to clipping for treatment of ruptured subarachnoid hemorrhage (SAH). Yet, it's still uncertain how coiling compares with clipping in terms of outcomes.

Dr. Peng and colleagues performed a meta-analysis of 4 randomized controlled trials (RCTs) and 23 observational studies to evaluate the efficiency, safety, and potential advantages of coiling vs clipping. The goal was to "inform the decision-making process in choosing which procedure to perform in patients with aneurysmal SAH," Dr. Peng said. Altogether, the trials had 11,568 participants.

Pooled data from the RCTs showed that coiling was associated with a better outcome at 1 year (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.24 - 1.76; P < .00001). However, the data from non-RCT observational studies showed only a small benefit with coiling that did not reach statistical significance (OR, 1.11; 95% CI, 0.96 - 1.28; P = .17).

In a subgroup analysis, coiling yielded better outcomes for patients with good preoperative grade (OR, 1.51; 95% CI, 1.24 - 1.84) than for those with poor preoperative grade (OR, 0.88; 95% CI, 0.56 - 1.38).

The researchers say the incidence of rebleeding was higher after coiling (OR, 0.43; 95% CI, 0.28 - 0.66), corresponding to a better complete occlusion rate of clipping (OR, 2.43; 95% CI, 1.88 - 3.13).

Mortality at 1 year was not significantly different with coiling vs clipping (OR, 1.07; 95% CI, 0.88 - 1.30).

Vasospasm was more common after clipping (OR, 1.43; 95% CI, 1.07 - 1.91), but there were no marked differences between techniques in terms of ischemic infarct (OR, 0.74; 95% CI, 0.52 - 1.06), shunt-dependent hydrocephalus (OR, 0.84; 95% CI, 0.66 - 1.07), and procedural complication rates (OR, 1.19; 95% CI, 0.67 - 2.11).

More Study Needed

This systematic review and meta-analysis "covers the most recent data and controversies in relation to safety and efficiency of aneurysmal ablation by coiling versus clipping," Philip B. Gorelick, MD, MPH, medical director of the Hauenstein Neuroscience Center at Saint Mary's Healthcare and professor in the Department of Translational Science and Molecular Medicine at Michigan State University College of Human Medicine in Grand Rapids, told Medscape Medical News. Dr. Gorelick was not involved in the study.

The analysis, however, is subject to several study limitations, Dr. Gorelick said. "For example, there were only 4 clinical trials that could be included in the overview, and one, the International Subarachnoid Aneurysm Trial (ISAT), had the largest number of study patients and accounted for the vast majority of cases in the clinical trial data sub-analysis."

"Importantly," Dr. Gorelick points out, "ISAT has been criticized for the high proportion of cases that were ineligible for study challenging its generalizability."

Dr. Peng echoed this point. "The results of ISAT have continued to generate some criticism, mainly because of its selection bias," he told Medscape Medical News. "The question has arisen: ISAT was designed as a pragmatic trial, but can we generalize the results of a study where > 80% of the patients were excluded to the entire body of patients with aneurysmal SAH?"

Another limitation to the current analysis, cited by both Dr. Gorelick and the authors, is that the nonrandomized data was not adjusted for potential confounding variables. "In these observational studies, the choice to submit a patient to aneurysmal ablation by coiling or clipping was based on physician preference and other key variables that could influence the outcomes of interest," Dr. Gorelick noted.

He said the authors "rightly conclude that more inclusive and well-designed RCTs are needed to better clarify their conclusions. Until then, the science of ablation of ruptured intracranial aneurysm will continue to advance, but the art of treatment will continue to weigh-in substantially in clinical decision making of whether to clip or coil a ruptured intracranial aneurysm."

The authors and Dr. Gorelick have disclosed no relevant financial relationships.

Stroke. Published online December 13, 2012. Abstract