A Proposed Grading Scale Based on Radiographic Imaging for Wall Apposition to Estimate Neurologic Complications after Flow Diverter Treatment

BACKGROUND AND PURPOSE: The evaluation of wall apposition following flow diverter (FD) treatment remains poorly defined. This study aims to establish a radiographic grading scale for wall apposition after FD deployment and to investigate its association with FD-related neurologic complications.

MATERIALS AND METHODS: This retrospective study included patients treated with the Pipeline Embolization Device (PED). A wall apposition grading scale (grades I–IV) was developed based on radiographic imaging, incorporating anatomic location and the degree of malapposition: grade I, perfect wall apposition; grade II, mild malapposition; grade III, moderate malapposition; and grade IV, severe malapposition. Cases were categorized into 2 groups: complete wall apposition (grade I) and malapposition (grades II–IV). The association between malapposition and neurologic complications was further analyzed.

RESULTS: A total of 197 PED cases were included. Incomplete wall apposition was observed in 29 cases (14.7%), while 168 cases (85.3%) demonstrated complete wall apposition (grade I). In the malapposition group, 13 cases (6.6%) were classified as grade II, 11 cases (5.6%) as grade III, and 5 cases (2.5%) as grade IV. FD-related perioperative and follow-up neurologic complications occurred in 10.3% and 13.8% of the malapposition group, respectively, compared with 1.8% and 1.2% in the complete wall apposition group (P < .05). Multivariate logistic regression analysis identified malapposition as an independent risk factor for FD-related neurologic complications (P < .05). The Cochran-Armitage test revealed a significant trend of increasing neurologic complications with worsening malapposition from grade II–IV (P < .05).

CONCLUSIONS: The proposed grading scale is a feasible and practical tool for assessing wall apposition after FD treatment. Neurologic complications are significantly more likely in cases with moderate to severe malapposition (grades III and IV).