Background and purpose: In aneurysms that are adequately occluded 6 months after coiling, the risk of late reopening is largely unknown. We assessed the occurrence of late aneurysm reopening and possible risk factors.
Methods: From January 1995 to June 2005, 1808 intracranial aneurysms were coiled in 1675 patients at 7 medical centers. At 6 months, 1066 aneurysms in 971 patients were adequately occluded. At mean 6.0 years after coiling, of the 971 patients, 400 patients with 440 aneurysms underwent 3 Tesla magnetic resonance angiography to assess occlusion status of the aneurysms. Proportions and corresponding 95% CI of aneurysm reopening and retreatment were calculated. Risk factors for late reopening were assessed by univariate and multivariate logistic regression analysis, and included patient sex, rupture status of aneurysms, aneurysm size≥10 mm, and aneurysm location.
Results: In 11 of 400 patients (2.8%; 95% CI, 1.4-4.9%) with 440 aneurysms (2.5%; 95% CI, 1.0-4.0%), late reopening had occurred; 3 reopened aneurysms were retreated (0.7%; 95% CI, 0.2-1.5%). Independent predictors for late reopening were aneurysm size≥10 mm (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 late reopenings in the 143 anterior cerebral artery aneurysms.
Conclusions: For the vast majority of adequately occluded intracranial aneurysms 6 months after coiling (those<10 mm and not located on basilar tip), prolonged imaging follow-up within the first 5 to 10 years after coiling does not seem beneficial in terms of detecting reopened aneurysms that need retreatment. Whether patients might benefit from screening beyond the 5- to 10-year interval is not yet clear.