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.