临床适应症
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子宫肌瘤栓塞
Concerns:
- Target perifibroid plexus (500-800μm)
- Minimize myometrial damage & passage through U-O anastomosis
Conventional
- PVA (Contour) 355-500, 500-710μm
- Gelatin particles 1-2mm
Microspheres
- Embosphere ≥500-700μm
- limited (pruned tree)
- Others ≥700-900μm
- near stasis
X Soft spherical-PVA (Contour SE)
- incomplete infarction
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| 术前 | 术后3个月 |
Caution for Small Microspheres
H&N, MSK, bronchial, GI, etc.
Deep penetration has risks:
- Inadvertent cerebral or spinal artery embolization via dangerous anastomosis
- Systemic (paradoxical) embolization through AV shunts
- Ischemic damage of mucosa or bronchial wall
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Dog small bowel / Embosphere 100-300
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Kishimoto K, et al. J Vasc Interv Radiol 2014; 25:1767–1773
Tips & pitfalls (especially for microspheres)
Microspheres Are Not the Same
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Round
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Round | Expand & deform |
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flattened
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Final Location Depends on Mechanical Property
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Elasticity / compressibility
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High |
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Middle |
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Low |
Redistribution of Microspheres
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Aggregation
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Re-check after 5-10min
Redistribution
Recanalization
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Adequate Dilution & Slow Injection
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Especially when
Using small size
In small arteries
In slow-flow condition
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Homogeneous suspension
1mL-luer lock syringe
Very slow injection
Under “free-flow”
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New concepts (WIP)
可吸收微球 Resorbable microspheres
Rationale:
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作为异物，微粒在栓塞后不再被需要 As foreign body, particles are not needed after the effect is obtained.
- 在理想的情况下，伴随有控制的吸收时间，和有限的炎症，血管的完整性和药物荷载能力重新恢复
Products or WIP (few clinical data):
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| 当天 | 3天 | 9天 | 14天 |
血管完整性恢复 Restoration of Vessel Integrity
ResMic
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| 0天 | 7天 |
Occlusin 503
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Owen RJ, et al. CVIR2012;35:636-644；Maeda N, et al. JVIR 2013;24:1391-98
可视微球 Visible (radiopaque) microspheres
- 微球的可见性将有助于实时监测微粒释放的情况，并应用CT或MRI下评估它们的分布。
Visibility of microspheres would help for real-time monitoring of delivery and also evaluation of distribution under CT or MRI.
- WIIP
Polyzene-F coated with barium sulfate 硫酸钡包裹的聚锌-F
MRI visible amonafide-eluting arginate microspheres etc. MRI可见氨奈菲特了（抗肿瘤药）洗脱精氨酸微球等。
Sharma KVJ, et al. JVIR 2010;21:865-876
Stampfl U, et al. JVIR 2012;23:1225-1231
Kim DH, et al.Theranostics 2015;5:477-488
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HepaSphere 150-200
(expanded size 600-800)
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术前 | 术后 |
Real-time monitoring of particle distribution or passage through the nidus
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| 术前 | 术后6个月 |
总结
用味道管的微粒栓塞，广泛应用于各种器官或靶向部位，Microparticles are widely used in various organs or locations for targeted embolization with a microcatheter.
了解每一种所选择栓塞微粒的物理特性和表现都很重要。It is important to understand each physical property and behavior in choice of materials.
熟悉正确的处理方法，包括稀释，注射和大小选择。Be familiar with correct handling including dilution, injection, and size selection.