Typically, uterine artery embolization has been performed as a unilateral femoral puncture. It is fair to say that unilateral access has been by far the most common approach for patients undergoing uterine artery embolization (UAE) and it has been successful for many. Most likely, this approach is based primarily on a tradition of single puncture used for most arteriographic interventions.
Early in our experience at Georgetown University, we recognised that UAE is one of the few interventional radiology procedures that routinely requires the embolization of two vessels on opposite sides of the body. With this recognition, we began to explore the possibility of successful embolization using both femoral punctures. We felt that this approach might have advantages both in shortening the procedure and in the use and radiation dose by being able to perform bilateral and simultaneous embolizations rather than sequential unilateral embolization, one followed by the other. From about the 15th patient on at our institution, we have employed a bilateral approach. At that early stage, we did studies that demonstrated that there was likely a significant reduction in the radiation dose associated with this. However, those studies were not randomised and there were a number of different factors related to the newer approach that might have confounded the results.
Other groups have been interested in this as well, and Michael Bratby, Anna-Maria Belli and others, working in London, published a paper in CVIR at the end of 2007, (Bratby MJ, et al. Prospective study of elective bilateral versus unilateral femoral arterial puncture for uterine artery embolization. Cardiovasc Intervent Radiology 2007;30:1139-1143.), which demonstrated that there was a reduction of fluoroscopy time and procedure time using a bilateral femoral approach. However, this was a small study and was not randomised.
Here at Georgetown, we have just completed a randomised trial which we hope to report at the annual meeting of the SIR in 2010, and that has been submitted for publication. Our findings are similar to those of Bratby’s and continue to support our belief that bilateral femoral puncture has an advantage.
Regardless of the time and radiation dose associated with a bilateral puncture, there are other technical considerations that give an advantage to this method. With two catheters in place, we have the ability to visualise the entire uterus with a single initial arteriogram and to better plan an approach to embolization. For example, if we find a patient has significant spasm on one side with very limited flow and there is good flow on the opposite, embolization can be performed on the side with the best flow, and this often will result in increased flow from the side with spasm. This is due to dilation of the cross-uterine collaterals. This will allow a safer and easier embolization on the side that had previously had spasm. In addition, at the end of the procedure we usually wait five minutes to be certain that we have a stable endpoint. This certainly is easier to do when you have two catheters in place, because we only have to wait once. We then can choose whether we need to embolize one side additionally or the other. Finally, two catheters help to detect collateral blood supply more easily. When one does a bilateral embolization, you can more easily see if there is a defect within the uterine contour that would suggest the presence of ovarian artery supply. This allows the selective use of aortography and perhaps the better use of resources in that regard.
There are some negatives to the two-punctures technique as well. If the procedure is done simultaneously, two vascular sheaths, catheters and micro-catheters are required for each case, which is an increase in resource use. It also requires two operators to inject embolic simultaneously, although one operator injecting intermittently between one side to the other can be done. Finally, because there are two punctures, there is twice the risk of a puncture site complication. However, in this young and otherwise healthy patient population, this risk is tiny in our experience.
In summary, we have adapted to the bilateral femoral puncture and, although in certain circumstances will consider unilateral puncture, feel that this is the best approach for us. It is worth consideration for other practices as well.
James B Spies is Chair and Chief of Service (Radiology), Georgetown University Hospital, Washington, USA