Silent thromboembolic events associated with the treatment of unruptured cerebral aneurysms by use of Guglielmi detachable coils: Prospective study applying diffusion-weighted imaging

BACKGROUND AND PURPOSE: Aneurysm embolization using Guglielmi detachable co ils (GDC) is gaining increasing acceptance as a viable alternative to surge ry in the treatment of cerebral aneurysms. Although recent reports describe a significant rate of symptomatic thromboembolic complications with GDC us e, many of the neurologic deficits are transient. We sought to determine th e incidence of silent thromboembolic events with the use of diffusion-weigh ted imaging and to correlate radiologic findings with the results of neurol ogic examinations. METHODS: Diffusion-weighted MR imaging was performed within 48 hours in 14 consecutive elective GDC aneurysm treatments. Embolizations were performed under systemic heparinization; all flush solutions were heparinized, and bo th guiding catheters and microcatheters were placed for continuous heparini zed infusions. Neurologic examination, including the National Institutes of Health Stroke Scale determination, was performed by a stroke neurologist b efore the coiling procedures were performed, immediately after the procedur es were performed, and before discharge. MR imaging examinations were revie wed by a stroke neurologist and an interventional neuroradiologist, with de termination and characterization of diffusion-weighted imaging abnormalitie s. RESULTS: Small areas of restricted diffusion, presumed to represent procedu re-related embolic infarctions, were noted on the images of eight of 14 pat ients. All except one of the areas were located ipsilateral to the side of the catheterization. Six patients had evidence of multiple infarcts. Most l esions were small (<2 mm); one patient with coil stretch and herniation int o the parent vessel had numerous infarcts with a dominant posterior frontal infarct, Pre- and post-treatment National Institutes of Health Stroke Scal e scores were unchanged for 13 of 14 patients. Overall, the rate of asympto matic emboli was 61% (eight of 13 treatments) in uncomplicated treatments. Strokes occurred independently of the number of coils used; the mean number of coils used for patients with strokes was 7.6 (range, two to 13) and for patients without evidence of infarcts was 10.2 (range, one to 30), This wa s not a significant difference (P > .5). CONCLUSION: Silent thromboembolic events related to the use of the GDC syst em are a common occurrence, despite meticulous technique and systemic antic oagulation, Although clinical sequelae are rare, the high rate of occurrenc e suggests that alterations in the technique, such as the addition of antip latelet agents, should be considered.