Stability of ruptured intracranial aneurysms treated with detachable coils: is delayed follow-up angiography warranted?

The optimal strategy for monitoring the stability of ruptured intracranial aneurysms following coil embolisation is unclear. The value of delayed follow-up angiography in detecting new recurrences or progression of residual lesions visualised on earlier angiographic studies was determined in the light of the increasing use of non-invasive imaging techniques such as time of flight magnetic resonance angiography (TOF-MRA) for the evaluation of intracranial aneurysm occlusion. Ninety-seven patients with 105 ruptured aneurysms treated with detachable coils in 2005 and 2006 were included. The presence of a residual neck or aneurysm was assessed on catheter angiograms performed at 6 months and 2 years using the Raymond criteria (Class I = completely occluded, class II = small residual neck, class III = aneurysm sac filling). At 6-month follow-up, 32% of class I aneurysms progressed to class II and 6% of these aneurysms required re-treatment. A further 2-year angiogram was obtained in 59 patients with 65 aneurysms. Ninety-six per cent of class I, 100% of the class II and class III aneurysms remained unchanged at 2 years compared to 6 months. In our series, most recurrences were apparent at 6-month follow-up. The vast majority of coiled ruptured aneurysms that were class I or II at 6 months remained stable at 2-year follow-up. In the absence of a residual lesion in the early angiographic study, a further delayed catheter angiogram may not be warranted. The use of non-invasive strategies such as TOF-MRA should be considered.