Inferior mesenteric artery collaterals to the uterus during uterine artery embolization: Prevalence, risk factors, and clinical outcomes

Purpose To evaluate the prevalence of inferior mesenteric artery (IMA) collaterals to the uterus found during uterine artery embolization (UAE), associated risk factors, and clinical outcomes. Materials and Methods The records of 559 women who underwent UAE during the period 2008-2011 for uterine fibroids or adenomyosis found on magnetic resonance imaging were retrospectively analyzed. If IMA collaterals to the uterus were suspected on aortography performed after embolization, selective angiography was performed. Risk factors for IMA collaterals to the uterus were analyzed, including the presence of adenomyosis, baseline uterine volume, or prior pelvic surgery. Results Collaterals to the uterus were found from the ovarian artery (n = 21; 3.8%), IMA (n = 7; 1.3%), round ligament artery (n = 1; 0.2%), and internal pudendal artery (n = 1; 0.2%). IMA collaterals were found in seven patients. Of 185 patients, 6 (3.2%) had adenomyosis, with or without fibroids, which was significantly more frequent than the 1 (0.27%) of 374 patients who had fibroids only (P =.006). On multiple logistic regression analysis, the presence of adenomyosis (odds ratio, 19.556; P =.0168) and uterine volume (odds ratio, 1.003; P =.0069) were independent factors for the presence of IMA collaterals. Of the seven patients with IMA collaterals, embolization was not attempted in six, resulting in clinical failure in four. One patient who underwent IMA embolization with coils experienced clinical improvement. Conclusions The IMA was the second most common (1.3%) source of collaterals to the uterus. IMA collaterals were more frequent in patients with adenomyosis than in patients with fibroids only, resulting in high frequency of treatment failure.