Purpose To determine if AVM angioarchitecture characteristics resulting in a classification system can be predictive and direct specific curative endovascular procedures accurately and consistently to treat high-flow malformations.
Materials and Methods Angiographic analysis of high-flow vascular malformations determined 4 major angioarchitectures.
Type I: Direct arterial/arteriolar to vein/venule connection; e.g., as commonly seen in pulmonary AVF, congenital renal AVF, etc.
Type IIa Arterial/arteriolar connections to a “nidus” that then have several out-flow veins with no intervening capillary beds in any of the vascular interconnections.
Type IIb AVM nidus with single aneurysmal vein out-flow drainage.
Type IIIa Arterial/arteriolar connections to an aneurysmal vein (“nidus” is the vein wall) that drains into a dominant out-flow vein with no intervening capillary bed in these connections.
Type IIIb Same angioarchitecture as Type IIIa, except that there are more than one (several) out-flow veins.
Type IV: “Infiltrative” form of AVM whereby innumerable micro-arteriolar branches fistulize through a tissue (e.g., ear) totally infiltrating it, shunting into multiple out-flow veins. Capillary beds also exist in the tissue and are mixed with the innumerable AVFs. Without the capillaries the tissue could not be viable, therefore must be present.
Results Type I: Can be effectively treated with mechanical devices; e.g., coils, Amplatzer Plugs, etc.
Type IIa Can be effectively treated with ethanol embolization.
Type IIb Can be cured with transarterial ethanol embolization of the nidus or coil embolization of the vein aneurysm.
Type IIIa Can be effectively treated by transcatheter ethanol, retrograde vein catheter access or direct puncture access of the aneurysmal vein and treatment with ethanol and coils, or even by coils alone.
Type IIIb Can be effectively treated as above, but can be more challenging by the vein route as more veins (not a single out-flow vein) require closure.
Type IV: Can be effectively treated by transcatheter or direct puncture of the innumerable microfistulous AVFs by embolization with 50%–50% ethanol non-ionic contrast mixture, or by direct puncture into the AV connections and pure ethanol injected into the AVFs.
Conclusion This never before reported classification system has a direct impact on determining the curative endovascular and direct puncture embolization procedures and also determines the embolic agents that will successfully treat complex AVMS in the body and head and neck anatomies.
Disclosures W. Yakes: None.
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