Changes in Modified Raymond–Roy Classification Occlusion Classes and Predictors of Recurrence-Free Survival in Patients with Intracranial Aneurysms after Endovascular Coil Embolization

Purpose To assess changes in modified Raymond–Roy classification (MRRC) occlusion classes and recurrence rates over time and evaluate recurrence-free survival after coil embolization and its predictors. Materials and Methods During 2007–2016, 201 patients (mean age, 57.1 ± 13.4 years; 75.5% women) with 240 aneurysms treated with coil embolization were enrolled. MRRC Class I (n = 210), Class II (n = 14), Class IIIa (n = 10), and Class IIIb (n =6) closures were assessed. Recurrence was defined as recanalization in MRRC Class I closures or an increase of at least 20% in any of the dimensions of the remnants of the other classes. Recurrence-free survival and its predictors were analyzed using survival analysis. Results Most changes in MRRC class occurred in the first year after treatment. MRRC Class I closures had a slightly lower probability of change than that associated with other classes within 1–5 years, whereas Class IIIb closures remained unchanged. Rates of recurrence or regression for all classes were highest within the first year. The median recurrence-free survival times among patients with Class IIIa and Class IIIb closures were 11.56 and 5.55 months, respectively. Significant predictors of recurrence included aneurysm size of 13–24 mm, ruptured or wide-necked aneurysms, and MRRC Class IIIa or IIIb closures. Conclusions Class changes and recurrence rates for all MRRC classes were highest in the first year. MRRC Class IIIb closures had the highest recurrence rate and the shortest recurrence-free survival. Recurrence risk increased in Classes IIIa and IIIb and with large, ruptured or wide-necked aneurysms.