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The Natural History of Coiled Cerebral Aneurysms Stratified by Modified Raymond-Roy Occlusion Classification
Stephen K Mendenhall1, Daniel H Sahlein1, Christopher D Wilson1
1Department of Neurological Surgery, Indiana University School of Medicine, Goodman Campbell Brain and Spine, Indianapolis, Indiana, USA.
Insights
The Modified Raymond-Roy Classification (MRRC) grade independently predicts the long-term durability of Guglielmi detachable coil (GDC) embolization for cerebral aneurysms. Achieving complete occlusion (MRRC grade 1) is crucial for sustained GDC durability.
Area of Science:
- Neurosurgery
- Interventional Radiology
- Vascular Neurology
Background:
- The long-term efficacy and natural history of Guglielmi detachable coil (GDC) embolization for cerebral aneurysms remain incompletely understood.
- The Modified Raymond-Roy Classification (MRRC) is used to assess aneurysm occlusion post-embolization.
Purpose of the Study:
- To investigate the long-term durability of GDC embolization for cerebral aneurysms.
- To determine if the MRRC stratification correlates with the durability of GDC-treated aneurysms.
Main Methods:
- Retrospective review of first-time GDC-embolized cerebral aneurysms (2004-2015).
- Loss of durability (LOD) defined by changes in aneurysm size or patency on serial imaging.
- Kaplan-Meier analysis and multivariate Cox regression used to assess durability and associated factors.
Main Results:
- Of 443 aneurysms, 89 (21%) experienced LOD.
- Higher MRRC grades (especially 3b) were associated with significantly worse durability compared to grade 1.
- Initial MRRC grade was the only factor significantly associated with treatment durability (P < 0.001).
Conclusions:
- MRRC grade is an independent predictor of GDC embolization durability in cerebral aneurysms.
- Complete occlusion (MRRC grade 1) is strongly associated with superior long-term GDC durability.
- While most incomplete occlusions remain stable, MRRC may lack sensitivity for long-term morphological changes.
Objective:
The natural history and long-term durability of Guglielmi detachable coil (GDC) embolization is still unknown. We hypothesize a stepwise decrease in durability of embolized cerebral aneurysms as stratified by the Modified Raymond-Roy Classification (MRRC).
Methods:
First-time GDC-embolized cerebral aneurysms were retrospectively reviewed from 2004 to 2015. Loss of durability (LOD) was defined by change in aneurysm size or patency seen on serial radiographic follow-up. Kaplan-Meier survival analysis was performed to evaluate embolization durability. Multivariate Cox regression modeling was used to assess baseline aneurysm and patient characteristics for their effect on LOD.
Results:
A total of 427 patients with 443 aneurysms met the inclusion criteria. Overall, 89 (21%) aneurysms met LOD criteria. Grade 1 aneurysms had statistically significantly greater durability than did all other MRRC grades. Grade 3b aneurysms had significantly worse durability than did all other aneurysm grades. There was no difference in durability between grade 2 and 3a aneurysms. Of aneurysms with LOD, 26 (29%) experienced worsening of MRRC grade. Thirty-five (24%) initial MRRC grade 2, 72 (45%) initial MRRC grade 3a, and 6 (22%) initial MRRC grade 3b aneurysms progressed to MRRC grade 1 without retreatment. In our multivariate analysis, only initial MRRC grade was statistically significantly associated with treatment durability (P < 0.001).
Conclusions:
MRRC grade is independently associated with first-time GDC-embolized cerebral aneurysm durability. Achieving MRRC grade 1 occlusion outcome is significantly associated with greater long-term GDC durability. Although few aneurysms experience further growth and/or recanalization, most incompletely obliterated aneurysms tend to remain stable over time or even progress to occlusion. Grading scales such as the MRRC are useful for characterizing aneurysm occlusion but may lack sensitivity and specificity for characterizing changes in aneurysm morphology over time.
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