CLINICAL ARTICLE J Neurosurg 129:684–690, 2018 D uring cerebral aneurysm clipping, a common tech- nique for reducing intraaneurysmal pressure and preventing premature aneurysm rupture is tem- porary clipping (TC) of the feeding arteries. However, its use has some limitations such as timing-related cerebral ischemia, thromboembolic stroke, and vessel injury, espe- cially in atherosclerotic vessels. TC is not feasible in some circumstances: for example, when treating a large or deep- seated aneurysm for which visualization of the proximal artery is diffcult or impossible. Accordingly, adenosine- induced cardiac arrest (AiCA) has slowly gained interest as an alternative option for the decompression of an aneu- rysm in such situations prior to permanent clip application. Several studies have determined the safety of AiCA on perioperative and immediate postoperative outcome. 3,4,16 However, the impact of AiCA on the use of TC, intraoper - ative aneurysm rupture (IAR), and radiographic outcome remains unclear. The aims of the study were to compare the TC time, postoperative cerebral infarction rate, and IAR rate be- tween patients treated with and without AiCA during in- tracranial aneurysm surgery. ABBREVIATIONS ACA = anterior cerebral artery; AiCA = adenosine-induced cardiac arrest; IAR = intraoperative aneurysm rupture; ICA = internal carotid artery; MCA = middle cerebral artery; TC = temporary clipping. SUBMITTED September 27, 2016. ACCEPTED May 8, 2017. INCLUDE WHEN CITING Published online October 27, 2017; DOI: 10.3171/2017.5.JNS162469. Adenosine-induced cardiac arrest as an alternative to temporary clipping during intracranial aneurysm surgery Patcharin Intarakhao, MD, 1,2 Peeraphong Thiarawat, MD, 1,3 Behnam Rezai Jahromi, MB, 1 Danil A. Kozyrev, MD, 1 Mario K. Teo, MD, FRCS(SN), 4 Joham Choque-Velasquez, MD, 1 Teemu Luostarinen, MD, PhD, 5 and Juha Hernesniemi, MD, PhD 1 1 Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland; Departments of 2 Anesthesiology and 3 Surgery, Naresuan University, Phitsanulok, Thailand; 4 Department of Neurosurgery, Bristol Institute of Clinical Neuroscience, North Bristol University Hospital, Bristol, United Kingdom; and 5 Department of Anesthesiology, Intensive Care, Emergency Care and Pain Clinic, University of Helsinki and Helsinki University Hospital, Helsinki, Finland OBJECTIVE The purpose of this study was to analyze the impact of adenosine-induced cardiac arrest (AiCA) on temporary clipping (TC) and the postoperative cerebral infarction rate among patients undergoing intracranial aneurysm surgery. METHODS In this retrospective matched-cohort study, 65 patients who received adenosine for decompression of aneurysms during microsurgical clipping were identifed (Group A) and randomly matched with 65 selected patients who underwent clipping but did not receive adenosine during surgery (Group B). The matching criteria included age, Fisher grade, aneurysm size, rupture status, and location of aneurysms. The primary outcomes were TC time and the postoper- ative infarction rate. The secondary outcome was the incidence of intraoperative aneurysm rupture (IAR). RESULTS In Group A, 40 patients underwent clipping with AiCA alone and 25 patients (38%) received AiCA combined with TC, and in Group B, 60 patients (92%) underwent aneurysm clipping under the protection of TC (OR 0.052; 95% CI 0.018–0.147; p < 0.001). Group A required less TC time (2.04 minutes vs 4.46 minutes; p < 0.001). The incidence of post- operative lacunar infarction was equal in both groups (6.2%). There was an insignifcant between-group difference in the incidence of IAR (1.5% in Group A vs 6.1% in Group B; OR 0.238; 95% CI 0.026–2.192; p = 0.171). CONCLUSIONS AiCA is a useful technique for microneurosurgical treatment of cerebral aneurysms. AiCA can mini- mize the use of TC and does not increase the risk of IAR and postoperative infarction. https://thejns.org/doi/abs/10.3171/2017.5.JNS162469 KEY WORDS adenosine-induced cardiac arrest; temporary clipping; postoperative lacunar infarction; intracranial aneurysm surgery; vascular disorders J Neurosurg Volume 129 • September 2018 684 ©AANS 2018, except where prohibited by US copyright law