study reported in abstract form they found a very favor­able embolization result as compared to the myomec­

tomy result.Several very important studies are as yet unpublished

and/or unfinished. These include the Canadian Multi­center Clinical trial, the Boston Scientific Corporation'ssponsored uterine artery emboJization versus myomec­tomy trial, the Biosphere sponsored uterine artelY em­bolization versus hysterectomy trial, and the nationaluterine artery embolization registry. Although resultsfrom these studies are not currently available resultsshould be available by the time of the spring SIR meet­

ing.

1:45 p.m.Award:GBYIA WifUler Presentation

1:50 p.m.Failures and Recurrences: Why They Occur and

How to Manage Them

James B. Spies, MDGeorgetown University Medical CenterWashington, DC

The growing acceptance of uterine artery embolization(UAE) as a treatment for leiomyomata has led to its usein many centers across the country and the world. Thepublished case series suggest that the short and midtermoutcome from treatment is very good, with 80o/<r-95% ofpatients having improved symptoms after treatment (1­

10).With several years experience with this treatment in

this country, sufficient data are now available to allowsome perspective of the outcome from this procedure.One thing we have learned is that not every patientimproves after treatment: if 90% of patients are symp­tomatically improved, then 10% are not. The reasons forthese failures are now becoming clearer as researchadvances.

Defming FailureBefore one can analyze the reasons for failure, the firststep is to define failure. From a technical perspective,failure is when the fibroids do not infarct after the em­bolization. The goal of the embolization is to causeischemic infarction of the fibroids and from both apathologic perspective (11,12) and an imaging perspec­tive (13-15); this is what occurs after a successful embo­lization. WhiJe in the short term a partially infarctedfibroid may not affect outcome, over the longer term, thefibroid is likely to regrow and symptoms regrow. Even ininstances when the uterine volume decreases and the

.dominant fibroid shrinks, recurrence can be predictedwhen other substantial fibroids don't infarct. Thus thetechnical goal of the procedure is to embolize suffi­cient.ly to infarct the fibroids, while not injuring thenormai uterus or adjacent organs. This is a key area to

focus research; how may we improve the technical suc­

cess of the procedure?

Understanding the Causes of FaUureFor nearly all patient.s, bilateral embolization is necessaryfor the procedure to succeed. In most operators' expe­rience, fibroids usually derive a portion of their vascularsupply from both uterine arteries and if onJy one arteryis embolized, it is likely that a least a portion of thefibroids will not infarct. Rarely a patient will have all theapparent blood supply to the fibroids from one side anda unilateral embolization is all that is necessary, but therehas been no study published to corroborate this opinion.

Based on the preceding discussion, an obvious causeof a technical faiJure is the failure to catheterize theuterine artery, either on one or both sides. With experi­ence, this type of catheterization faiJure is very unusual,occurring in about 1% of the patient.s. However, failureswill occur early in the experience of most physicians.Embolization should not be performed unless the uter­ine artery has been selectively catheterized and test in­jections ensure that embolization can proceed withoutreflux into other branches. A failure is better than acomplication from misembolization.

Beyond the inability to catheterize a uterine arterythat is present, the artery may in fact be tiny or evenabsent on one or both sides. This may be iatrogenic froma prior myomectomy and the opposite uterine arterymay provide aJI the supply to the uterus. In this setting,a unilateral embolization may be effective. However,there mayaiso be ovarian flow in addition to uterineflow and these arteries should be surveyed to detect anyadditional collateral flow. Very commonly, absence ofthe uterine artery indicates replacement of that flow bythe ipsilateral ovarian altery or the opposite uterine ar­tery. We have aiso seen one patient in whom the uterineartery arose from the inferior epigastric artery (16). Theremayaiso be rare cases of multiple uterine alteries, nonelarge enough to cannulate to allow embolization.

The most common secondary source of blood supplyto fibroids is from the ovarian arteries (17,18). This likelyoccurs in about 5% of patient.s. The degree of ovariansupply varies, but in aur experience, a potential predic­tor of a failed procedure is the presence of the ovariansupply not just to the uterus, but rather to fibroids orpOI"tions of fibroids not supplied by the uterine aIteries.If the ovarian artery is enlarged but merely joins the mainuterine artery trunk and together they feed the fibroids,uterine artery embolization may be completely success­ful, with the ovarian contribution of flow helping to carrythe particles further out into fibroid feeding vessels. Toassess this risk, we perform an abdominal aortogramafter the embolization but prior to catheter removal tolook for aberrant supply, particularly for ovarian supply.Usually, we do not embolize any ovarian arteries on theday of the initial procedure. If the patient's symptomsdon't improve and fibroids in the distribution of theovarian supply don't infarct, ovarian embolization may

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