In Reply to: Case 0498_11 -- Management of massive pelvic AVM posted by Editor on April 02, 1998 at 14:04:13:
This is a very complex large AVM in which the outflow venous drainage is not well demonstrated. Because the varices are on the bladder it is assumed there are may be some form of pudendal or anterior abdominal venous outflow. However, from the single static images, it is difficult to ascertain that. Based on the final arteriogram (figure 5) significant residual AVM is noted. This suggests that the embolization procedures did not reach the nidus or at least did not reach a significant portion of the nidus. Such neovascular recruitment with revascularization of the nidus would not occur with a nidal emoblization. Frequently it is extremely difficult to determine what is nidus and what is inflow vessel and what is outflow vein. Confusion as to where the nidus is can lead to a proximal or too distal an occlusion. Thus the AVM nidus is intact, neovascular stimulation, vascular recruitment phenomenon, and recannalization can occur.
Regarding question #1, I would continue treatment before the neovascular recruitment phenomonen becomes more severe and may cause even more difficulty in AVM managment. This is a difficult and dangerous AVM
Question #2: My answer would be, if transvascular techniques are not an option then direct puncture techniques or retrograde vein approaches would be utlized. Again, ethanol, or possibly if single outflow vein physiology is demonstrated, ethanol and coils may be possible.
I must say this case is very well presented. However, to show a complete angiographic series of each study done would fill the entire web page and not help in the discussion. However, venous outflow issues and superselective placement documentation with angiography with pre-embolization would be important for even more comments to be made.
MR is much more sensitive to evaluating the AVM, gradient echo sequences in 3 orthgonal planes would be helpful despite previous coiling. SG and arterials should be placed to calculate the cardiac outputs, cardiac index, systemic vasular resistance and follow these numbers serially with each treatment. Further dramatic reduction and/or cure is possible in this patient.