The Importance of Coil Packing Keigo Osuga, MD, PhD Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine
Keigo Osuga, M.D., Ph.D. No relevant financial relationship reported
VAAs: When Packing Indicated? The anatomy is favorable for packing - Narrow-neck, not too large (<3cm) The anatomy is unsuitable for isolation - Short distance to vital branch to preserve Parent artery should be preserved to avoid organ ischemia (esp. kidney) - Angulation of parent a. precludes covered stenting Vital artery < to 3cm preserve Angulation of parent artery Too short Parent artery Parent artery Vital organ to protect
Ryu CW et al. Neuroradiology 2011;53:883-889 UCAS Japan investigators.nejm 2012;366:2474-2482 Sluzewski, et al. Radiology 2004;231:653-658 What We Learned from Packing Intracranial Aneurysms Risk factors for rupture - Aneurysm size >7mm, higher height/neck ratio Morphology unsuitable for tight packing - Wide-neck (Neck diameter > 4mm, dome/neck ratio < 2) - Irregular shape or daughter sac - Giant > 25mm - Intramural thrombosis -- coil may migrate in thrombus Compaction or recanalization rates: 26-28% Intramural thrombus Compaction less likely at packing density (PD) >24% Height Neck Dome Neck
Little is Known for Packing VAA! No established data for natural history or the risk of rupture. Few studies evaluate the optimal PD to prevent compaction or recanalization? Tight packing is technically difficult compared to intracranial aneurysms: Larger aneurysm size Wide-neck Irregular dome shape Branches from dome
Yasumoto et al. JVIR 2013;24:1798-1807 Osaka Multi-center Study Retrospective study to assess relationship between PD and incidence of compaction/recanalization of true VAAs. 42 pts. with 46 unruptured true VAAs in 2004-2012 - M:F=19:23, mean age 61.4 yo (range 35-86) - 16 splenic, 11 pancreatoduodenal, 8 renal, 6 hepatic, & 5 others Aneurysm was packed as tightly as possible with bare detachable coils (IDC, GDC, Detach, Cerecyte): - Mean aneurysm size 19 mm (5-40 mm) - Mean PD 19% (5-42 %) - Mean f/u 37 mo (11-80 mo) - Coil compaction n=2 (4 %) - Recanalization n=12 (26 %)
Packing Density (%) Yasumoto et al. JVIR 2013;24:1798-1807 Compaction / Recanalization Occur at Lower PD Compaction/Reca nalization Mean 12% Mean 22% Yes No PD was significantly lower in aneurysms with compaction/racanalization
Yasumoto et al. JVIR 2013;24:1798-1807 Aneurysms 20mm Are Prone To Compaction / Recanalization Aneurysm size < 20mm (n=28) 20mm (n=18) P-value Packing density (%) 22 ± 8 15 ± 6 0.045 Incidence of compaction/recanalizatio n (%) 21 33 0.039 Aneurysms 20mm showed significantly lower PD and higher incidence of compaction/recanalization
Packing density (%) No Compaction / Recanalization at PD >24% 16/46=34.8% >3cm Cut-off PD=24% compaction/recanalization No Yes Aneurysm size (mm) PD>24% was achieved in only 35% of patients. If aneurysm >3cm, it is difficult to achieve by the standard bare platinum coil. Yasumoto et al. JVIR 2013;24:1798-1807
Case: Late Compaction at 8% PD Φ 37 mm, PD 8% f/u +46mo Yasumoto et al. JVIR 2013;24:1798-1807
Technical Considerations for Tight Packing of VAAs Assessment of 3D-aneurysm sizes, morphology, and related anatomy using 3D-CT or rotational angio. Microcatheter positioning and coil arrangement should be monitored with optimal projection Detachable coils with 3D and/or 2D configurations - Controllability and retrievability Adjunctive techniques for larger, wide-neck aneurysms: - Neck-remodeling technique - Double microcatheter technique - Newer generation coils to increase packing density
Real-Time PD Calculation 14 coils 430cm PD 29.5%
Newer Coils for Tighter Packing Fibered detachable coils Retracta (Cook) Interlock (Boston Scientific) - To increase thrombogenecity Bioactive coils Cerecyte (Codman) - PGA polymer suture inside the coil Hydrogel coils AZUR (Terumo) - 0.032 (if hydrogel fully expanded) Large volume coils Ruby (Penumbra) - 0.020 (up to 60cm length) Delta design Deltamaxx, Deltapaq (Codman) - Flexibility to deflect to fill open space
Osuga & Yasumoto. Endovascular Today, August 2014 Case: GDA aneurysm Aneurysm size: 24 x 22 x 19 mm Ruby standard 24-18 mm x 60-57cm soft: 10-5 mm x 30-9 cm Extra-soft: 4-3 mm x 8-6 cm 19 coils 709cm PD 27.4%
Osuga & Yasumoto. Endovascular Today, August 2014 Case: GDA aneurysm + 24mo No coil compaction or recanalizataion
Case: L-Renal Artery Aneurysm Ruby: 28-16 mm x 60-57 cm Azur: 8-4 mm x 20-5 cm 14 coils 557 cm PD 34%
Case: L-Renal Artery Aneurysm +1M +6M +12M +18M X-rays demonstrate coil compaction around neck CE-MRA shows reperfusion through neck
Case: Hepatic Artery Aneurysm Intramural thrombus
Case: Hepatic Artery Aneurysm Aneurysm size: 26 x 25 x 22 mm Ruby: 24-10 mm x 60-35 cm Azur: 4 mm x 20 cm 20 coils 875 cm PD 21.8%
Case: Hepatic Artery Aneurysm + 3mo Coil compaction due to coil migration into thrombus
Case: Hepatic Artery Aneurysm + 5mo
Case: Hepatic Artery Aneurysm + 8mo No reperfusion
Conclusion Currently, tight packing is the only predictor for long-term occlusion of saccular VAAs. Aneurysms 20 mm or PD < 24% are prone to compaction or recanalization. Real-time calculation of PD and careful imaging follow-up are important for successful outcomes. Use of newer generation coils and adjunctive techniques can be considered especially for large or wide-neck aneurysms.
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