Ruptured Intracranial Aneurysms and the Timing of Embosurgery

Abstract

Among the many variables that influence outcomes in acute subarachnoid hemorrhage resulting from a ruptured cerebral aneurysm (aSAH), the three most consistent predictors of a dismal outcome are poor initial clinical presentation, advanced age, and aneurysm rebleeding (1,2). As a result, the management of aSAH is focused largely on securing the culprit aneurysm from future rehemorrhage. Craniotomy with clipping and endovascular coil embolization (embosurgery) are both effective in this regard, although the landmark International Subarachnoid Aneurysm Trial demonstrated superior short- and long-term outcomes for embosurgery (3,4). Becauserebleeding representsthemajor preventivecauseof death and disability, obliterating the aneurysm in a timely fashion would therefore appear prudent. Unfortunately, unfavorable cofactors often exist to delay surgery, including worsening clinical grade and developing hydrocephalus. Most surgeons are loath to operate on patients who are likely to die despite their efforts; therefore, waiting a day or more to stabilize the patient is a common reason frequently invoked for delaying surgery, especially in the elderly and poorer clinical grade patients with aSAH. Compounding this clinical caveat, a substantial body of research has repeatedly found that the timing of clipping surgery is critical in avoiding additional patient morbidity (5,6). Specifically, clipping during days 0‐2 or after day 10 following aSAH has better outcomes compared to surgery performed between days 4‐6. This reflects the influence of cerebral arterial vasospasm, which typically occurs in the 4- to 10-day window, and which exacerbates operative ischemia because of retraction and anesthesia. Because of this temporal nuance, important questions are raised in the post-International Subarachnoid Aneurysm Trial era. First, does the timing of embosurgery improve patient outcomes by eliminating aneurysm rebleeding if performed within 24 hours? Second, could the timing of embosurgery introduce an unanticipated risk