116 Chapter 7 Abstract Background and Purpose In a large multicenter study (the LOTUS study) the frequency of late recanalization of aneurysms more than five years after initially successful endovascular coiling was assessed, and possible risk factors for such recurrence were studied.1 In this chapter the data from the patients included by the Maastricht University Medical Centre (MUMC) are separately evaluated. The predictive value of the presence of a residual neck in a coiled aneurysm at six months follow-up, for late recanalization, is investigated. Methods From December 1997 to June 2005, 202 intracranial aneurysms were coiled in 180 patients in the MUMC. At 6 month angiographic follow-up, 150 aneurysms in 138 patients were judged to be still adequately occluded. After a mean period of 7.9 years after coiling, 62 of these 150 patients, harboring 72 aneurysms, underwent MR angiography (MRA) at 3T to assess the occlusion status of the aneurysms. Percentages and corresponding 95% confidence intervals (CI) of aneurysm recanalization and retreatment were calculated. Risk factors for late recanalization were assessed by univariable and multivariable logistic regression analysis, including patient gender, rupture status of aneurysms, initial aneurysm occlusion status, aneurysm size ш 10mm and aneurysm location. Occlusion status at six months follow-up was retrieved from patients treated in the MUMC and from the patients included in the LOTUS in whom this was documented according to the Roy and Raymond (R&) classification.2 Correlation between this classification and late recanalization was evaluated. Results In 3 of our 62 patients (4.8%, 95% CI: 1.3-14.4%) with 71 aneurysms (2.5%, 95% CI: 1.1-12.7%) late recanalization had occurred; none of these reopened aneurysms were retreated (0.0%, 95% CI: 0.0-6.4%). In the total group of 400 patients harboring 440 aneurysms, included in the LOTUS study, independent predictors for late recanalization were aneurysm size ш10mm (Odds Ratio (OR) 4.7, 95% CI: 1.3-16.3), and location on basilar tip (OR 3.9, 95% CI: 1.1-14.6). There were no cases of late recanalization in 143 anterior cerebral artery aneurysms.1 No correlation was found between residual neck at six months follow-up and late recanalization. Conclusions In patients with aneurysms that are adequately occluded at 6 months, the yield of long- term MRA follow-up for detection of recanalized aneurysms that require retreatment is very low. Longer-term follow -up may be considered in potential higher risk patients, such as patients with large or basilar tip aneurysms. Presence of a residual neck at six months follow-up has no predictive value for late recanalization.
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