1. Angiographic occlusion on follow‐up angiography during first year post‐treatment.

Number of participants per treatment	Extent of occlusion
	100%	90% to 100%	< 90%
ISAT 2002
Endovascular coiling: 881	584 (66%)	228 (26%)	69 (8%)
Neurosurgical clipping: 450	370 (82%)	55 (12%)	25 (6%)
Koivisto 2000
Endovascular coiling: 52	40 (77%)	10 (19%)	2 (4%)
Neurosurgical clipping: 57	49 (86%)	7 (12%)	1 (2%)
Total
Endovascular coiling: 933	624 (67%)	238 (26%)	71 (8%)
Neurosurgical clipping: 507	419 (83%)	62 (12%)	26 (5%)