Introduction 1 3 Patients and methods Patients From January 1998 to September 2005, 817 aneurysms were coiled. The starting point of the study was chosen because of installation of a new biplane angiographic unit (Integris 3000 BN Neuro, Philips Medical Systems, Best, The Netherlands) at the end of 1997. 4 5 6 7 8 Statistical analysis 7 8 t Results 1 Fig. 1 Procedural times in minutes for 642 coiling procedures displayed as number of procedures in 15-min time periods  1 2 Table 1 Procedural times for all 642 aneurysms in relation to patient and aneurysm characteristics Variable No. of aneurysms Procedural time (min) Median Mean Range Standard deviation Aall aneurysms 642 57.3 52.0 15–158 24.1 Use of supportive device 60 80.5 80.2 35–150 30.7 Procedural morbidity 40 72.5 75.6 28–158 30.7 Aneurysm size in upper quartile (10–55 mm) 163 64 70.5 25–158 26.4 Age more than median 52 years 321 55 60.7 17–158 25.0 Hunt and Hess grade III–V 186 54 59.2 18–122 22.6 Ruptured aneurysm 523 52 58.1 16–158 24.6 Male gender 182 55 60.4 17–131 23.8 Procedural rupture 26 50 53.8 16–107 21.3 Aneurysm location  Middle cerebral artery 46 53 61.8 19–131 26.8  Posterior circulation 154 54 61.7 22–146 27.1  Anterior cerebral artery 246 53.5 57.1 16–112 21.2  Carotid artery 196 48 53.1 15–158 23.9 Implementation of 3-D angiography  Before 167 52 58.6 18–158 25.5  After 475 52 56.9 15–146 23.7 Table 2 Odds ratios with 95% confidence intervals for different variables for the upper quartile of procedural times (70–158 min) Variable Odds ratio 95% CI Use of supportive device 5.40 3.11–9.34 Procedural morbidity 4.49 2.33–8.64 Aneurysm size in upper quartile (10–55 mm) 3.03 2.06–4.45 Age more than median age 1.47 1.02–2.10 Hunt and Hess grade III–V 1.32 0.88–1.97 Ruptured aneurysm 1.41 0.87–2.30 Male gender 0.79 0.54–1.16 Procedural rupture 0.73 0.27–1.98 Aneurysm location  Middle cerebral artery 1.81 0.97–3.40  Posterior circulation 1.30 0.87–1.95  Anterior cerebral artery 0.93 0.65–1.35  Carotid artery 0.68 0.46–1.02 Implementation of 3D angiography 1.11 0.74–1.66 t P Discussion In this study, the mean procedural time for coiling was 57 min. Most procedures were performed within 1 h. Procedural time was defined as the time between the first and the last angiographic run, since this time period could easily be assessed from time prints on the images. The time for patient preparation, anesthetic care, insertion of angiographic sheet and catheterization of the first vessel were not included in the procedural time. In our department, this additional time is usually between 30 and 45 min. This means that the typical time needed for coiling of an intracranial aneurysm is around one and a half hours, varying from one to two hours. 6 It is of note that no difference in procedural time was found between the earlier and later procedures, despite the technical advances in microcatheters and guidewires and increased experience. In both groups, there was no difference in mean aneurysm size (8.7 versus 7.2 mm), use of a supportive device (both 30) or occurrence of morbidity (both 20). We did not include the first 3 years of coiling in our hospital because the time was not printed on the images by the angiographic equipment used during that period. The mean procedural time may have been longer on the steep side of the learning curve during those first 3 years. In our high-volume department, logistics have been optimized. In patients scheduled for coiling, an intravenous line and urinary catheter are placed on the ward, the treating endovascular team is experienced, a biplane angiographic unit with 3DRA is available, all catheters and devices needed are available in the angiography room, microcatheters and guidewires are prepared by technicians, and in recent years the puncture site is closed with a dedicated device. For coiling of large and giant aneurysms, we use for the most part mechanically detachable coils 50 cm long. All anesthetists involved in coil procedures were experienced, with no residents in training. Our time slot for anesthesia is in the afternoon from 1300 to 1600 hours with a “deadline” at 16.30, after which time an anesthetist on call has to be notified to take over care. With these logistics we normally plan two patients, and regularly treat three patients within this time slot. Both of the senior authors (M.S. and W.J.v.R) have performed many coil procedures in four other hospitals in The Netherlands. The procedural time may differ greatly between centers, depending on many factors such as availability of single- or biplane angiographic equipment and 3DRA, the experience of the operator, supporting technicians and anesthetic team, and local preferences such as liberal or restricted use of supportive devices. Conclusion With optimal logistics, coiling of most intracranial aneurysms can be performed in one to two hours, including patient handling before and after the actual coiling procedure.