Abstract
Background and Purpose Fresh thrombus formation at the coil–parent artery interface around the neck of aneurysms
is sometimes observed during coil embolization of cerebral aneurysms. We retrospectively
analyzed the factors associated with local acute thrombus formation from the data
of patients treated over a period of 5 years at our institute.
Methods Between November 2004 and March 2009, 242 patients harboring 250 aneurysms were treated
with endovascular coil embolization at our institute. The patients were divided into
two groups: Group A included 107 patients who were treated and followed up during
the initial 29 months of the study, and group B included 135 patients who were treated
and followed up during the later 24 months of the study. Clinical and angiographic
variables of the procedures were statistically tested for correlation with thrombus
formation in the parent arteries.
Results Fresh thrombus formation occurred in six patients with unruptured aneurysms (15%)
and 11 patients with ruptured aneurysms (14%) in group A. Among the patients with
unruptured aneurysms, the dome-to-neck ratio and location of the aneurysms were independently
associated with the risk of thrombus formation, whereas among patients with ruptured
aneurysms, a higher World Federation of Neurological Surgeons (WFNS) grade and longer
interventional duration were significantly associated with thrombus formation. However,
fresh thrombus formation occurred in only two patients with unruptured aneurysms (2.9%)
and three patients with ruptured aneurysms (4.4%) in group B. There were no factors
that were significantly associated with thrombus formation in all Group B patients.
Conclusions With regard to coil embolization treatment, anatomical and morphological factors
seem to be related to intraprocedural thrombus formation in patients with unruptured
aneurysms, whereas duration of the intervention and preoperative status are associated
factors in patients with ruptured aneurysms. Careful comparison of the thrombus with
control angiograms is important to prevent thrombembolic complications. Moreover,
the rate of fresh thrombus formation during coil embolization has decreased over the
past 5 years at our institute, suggesting the possibility of lowering the incidence
of these complications by early detection and treatment.
Keywords
Guglielmi detachable coils - embolization - thrombembolic complications - fresh thrombus
formation