Anterio-Venous Malformations: From VEITHsymposium

This article is one of four stories that highlights the venous components covered at the November 2014 VEITHsymposium. Here are the remaining three articles that highlight what was covered at the symposium:

Anterio-Venous Malformations: From VEITHsymposium

by Wayne F. Yakes, MD, FSIR, FCIRSE

Vascular malformations comprise a vascular pathology that is extremely complex and challenging to effectively treat and eradicate. High-flow arteriovenous malformations (AVMs), low-flow venous malformations (VMs) and lymphatic malformations (LMs) are particularly challenging as they can involve any tissue and organ in the body. Endovascular embolization, surgery and combinations of these treatments were elaborately discussed during the Vascular Malformation Sessions during the VEITHsymposium. This is the second year that this topic was given its own formal session at the VEITHsymposium.

Various embolic agents have been used to embolize vascular malformations. In the AVM group of high-flow vascular malformations, particularly in the head and neck, Dr. Mollie Meek of the University of Arkansas for Medical Sciences in Little Rock, informed the attendees that all resected AVM specimens that were pre-operatively embolized with the polymerizing agent Onyx, demonstrated clear recanalizations of the resected embolized AVM specimens, particularly at one year post-embolization.

Onyx was first developed as a pre-operative brain AVM embolic agent. Using it outside the brain in other tissues with AVMs was done in the hopes that it could achieve a permanent treatment without necessitating a later resection. This lecture definitively removed this notion of permanence of Onyx as a primary form of therapy and reinforced its sole palliative potential at the histologic level.

Krassi Ivancev, MD, delivered an enlightening lecture focusing on Yakes’ AVM classification system, particularly the Yakes type IV infiltrating form of AVM and its treatment. This problematic AVM sub-type is not previously published in the literature. This type IV AVM diffusely involves a tissue, and intermingled with this AVM in the tissues are nutrient capillaries.

To embolize this infiltrating AVM with any embolic agent (e.g. particles, polymerizing agents and sclerosant liquid agents) would risk total tissue devitalization with the AVM and the admixed capillaries all being occluded, resulting in necrosis of that tissue. Dr. Ivancev demonstrated the successful curative potential of direct puncture into the AVM micro-fistulas themselves and embolizing them with pure ethanol, and when that could not be achieved, performing superselective catheterization and using a 50%-50% mixture of ethanol and non-ionic contrast that also was curative in occluding the AVM and sparing the capillaries. Thus, endovascular approaches using ethanol in these various ways proved a curative treatment and obviated amputation of the tissues, as was the only previous form of therapy.

Robert Vogelzang, MD, delivered a unique lecture describing the entire experience of vascular malformation treatment at Northwestern University Medical Center in Chicago, IL. It is rare that a complete experience of vascular malformation treatment is presented. This lecture accurately summarized the challenges vascular malformations pose and the curative potential of ethanol as an embolic agent in the treatment of all forms of AVMs, VMs and LMs. He also presented to the attendees the curative potential of retrograde vein dense coil-packing of a sub-type of AVM with an aneurysmal vein outflow (Yakes’ type IIIa & IIIb AVMs). Large inoperable AVMs were frequently cured by this technique alone at long-term arteriographic follow-up.

Francine Blei, MD, delivered an extremely informative lecture on the International Society for the Study of Vascular Anomalies (ISSVA) classification system. Dr. Blei was on the committee that further developed this ISSVA classification system. Based on the landmark work of John Mulliken, MD, and co-workers who first studied and reported at the cellular level the defining characteristics of vascular malformations, vascular tumors, pediatric hemangiomas, Kaposiform Hemangioendothelioma, and the like, is how this ISSVA classification system came about. This rational ISSVA classification system should be adopted by all workers in the realm of vascular anomalies to clear the current confusion rampant in the world’s literature with confusing terms of impressive clinical examples that leads to even more confusion. Now all clinicians can speak the “same language” regarding this often confused area of vascular medicine.