Coils or clips in subarachnoid haemorrhage?

Abstract

In this issue of the Journal of Cerebrovascular Diseases and Stroke, the International Subarachnoid Aneurysm Trial (ISAT) collaborators report their multicenter randomized trial comparing the safety and efficacy of endovascular coiling versus neurosurgical clipping in patients with a ruptured intracranial saccular aneurysm. Both the ISAT report and this editorial were previously published in The Lancet. The primary outcome measure was the proportion of patients dead or disabled, defined by a modified Rankin scale (mRS) score between 3 and 6, at 1 year. Recruitment was halted after randomization of 2143 eligible patients selected from 9278 patients with subarachnoid hemorrhage (SAH). A planned interim analysis demonstrated a relative risk reduction of 22.6% and an absolute risk reduction of 6.9% of dependency or death at 1 year with endovascular treatment. The patients randomized in ISAT represent a selected subgroup of patients with SAH seen in clinical practice. Eighty-eight percent were of good clinical status, 93% of the target aneurysms were 10 mm or smaller in diameter, and 97% of target aneurysms were in the anterior circulation. These three characteristics have historically been thought to predict a good neurological outcome after neurosurgical clipping. The better neurological outcome after endovascular coiling in ISAT is thus noteworthy. Despite no prospective study demonstrating superior safety of one treatment over another, a relatively small number of assessed patients were randomized in ISAT. Apparently, clinical equipoise did not exist in 80% of 9278 patients with aneurysmal SAH assessed for eligibility. Almost thirty percent (2737) of the patients were considered to be better candidates for endovascular coiling, 3615 patients for neurosurgical clipping, and 1064 were treated in some other unknownmanner. Any pre-existing bias is likely to be multifactorial, including personal experiences at the individual centers, knowledge of the results of previous retrospective reviews of treatment of aneurysms with particular characteristics, patient’s preference, and clinical status after SAH. Given that so many patients were deemed ineligible for randomization by the participating interventional neuroradiologists and neurosurgeons, it is difficult to generalize the results of this study to the entire population of patients with aneurysmal SAH. Application to practice must be limited to those whose characteristics match those randomized in ISAT. The clinical follow-up data are limited. Dependency and death were assessed by postal questionnaire. The differences in outcome between treatments were mainly in the mRS3 (significant restriction in lifestyle) and mRS2 (some restriction in lifestyle) groups, and there was no difference in mortality between treatments. The ability of a questionnaire to reliably differentiate moderate from moderately severe functional disability is uncertain. Activities-of-daily-living, or deficit-delineation scales were not reported. Evaluation of cognitive outcome is an important contributor to assessment of disability after surgery for unruptured aneurysm. The comprehensive neuropsychometric data collected on a subset of the ISAT patients will greatly help to clarify cognitive outcomes after aneurysmal SAH treatment. In the neurosurgical group, 23 patients rebled before the first procedure, compared with 14 in the endovascular group. This result may be secondary to the small but statistically significant difference in the time between randomization and the first procedure (1.7 days for neurosurgery compared with 1.1 days for endovascular), and underscores the importance of early treatment of ruptured cerebral aneurysms. More than 3% (3.4%) of neurosurgical cases and 13.0% of endovascular cases required a second procedure—higher than might be expected given the characteristics of the patients. In those patients allocated to endovascular treatment, 5 who had failed endovascular coiling rebled while awaiting neurosurgical clipping. The ongoing debate about what constitutes definitive treatment of a ruptured cerebral aneurysm and durability of treatment remains unanswered. If definitive treatment is defined as prevention of post-treatment rebleeding, then definitive treatment was not attained in 2.4% (26/ 1048) of endovascular cases and in 1.0% (10/994) of those treated surgically, as indicated by target aneurysm rebleeding within a year. These data suggest an increased early rebleeding risk among endovascularly treated patients. The early rebleeding rates in this study for both endovascularly and surgically treated patients are higher From the *Departments of Radiology, †Neurology, and Neurologic Surgery, Mayo Clinic, Rochester, MN. Reprinted from The Lancet 360:1262-1263, 2002; copyright by Elsevier Science Ltd. All rights reserved. Address reprint requests to: Douglas A. Nichols, MD, Department of Radiology, Mayo Clinic, Rochester, MN 55905. Copyright © 2002 by National Stroke Association 1052-3057/02/1106-0001$35.00/0 doi:10.1053/jscd.2002.130389