Ovarian artery

Fig. 9.1. Angiogram of the right uterine artery demonstrating Fig. 9.2. Selective angiogram of right ovarian artery feeding...

Apart from the classic pattern in which the uterine artery arises from the medial aspect of llA, there are many other variants that have been identified (please see Chap. 10.3). It may also arise from its anterior or lateral aspect of the IIA [18]. The origin of the uterine artery from the main IIA itself or from the aorta has also been described [18]. A common trunk between the uterine artery and vesical artery is another important variant that might lead to inadvertent vesical ischemia in cases of non-tar-geted embolization [19]. The uterine artery may also duplicate as illustrated by Redlich et al. [20]. The ovarian artery represents the second main vessel for PPH [21, 22]. The ovarian artery that participates in uterine blood supply could represent the major feeding vessel to the uterus as demonstrated in UFE literature [23] (Fig. 9.2). Recently, Saraiya et al. illustrated uterine artery replacement by the round ligament artery during embolization for leio-... 

Fig. 9.5. Final aortogram showed complete occlusion of uterine arteries. The patent ovarian arteries were demonstrated...

Razavi MK, Wolanske KA, Hwang GL, Sze DY, Kee ST, Dake MD (2002) Angiographic classification of ovarian artery-to-uterine artery anastomoses initial observations in uterine fibroid embolization. Radiology 224 707-712... 

Vascular anastomotic communications between the uterine and ovarian arteries provide a route by which embolization materials can affect the ovarian blood supply and ovarian function, either permanently or temporarily [71], One case report describes embolic microspheres found within the ovarian arterial vasculature of a pathological specimen following uneventful UAE [66]. Unintentional embolization of the ovarian arteries is theorized to cause ovarian failure. However, the incidence of ovarian failure post UAE is no different to hysterectomy [100]. In fact, it is not clear whether UAE has any effect on ovarian function at all. There are studies that support its lack of effect [3,17,99,100] and a few case reports that document transient or permanent amenorrhea [92,98]. 

It is thought that the ovarian arteries shrink with age leading to increased ovarian dependence upon uterine-tubal anastomoses [9]. This may explain an increased chance (from 0% incidence compared with 21%) of ovarian failure post UAE in patients aged 45 years or older [18]. A similar study looking at basal FSH after UAE showed a significantly increased risk of perimenopausal FSH levels in patients older than 45 years [84]. Thus, older women appear to be more at risk of losing their ovarian function than younger women. 

Nikolic B, Spies JB et al (1999) Ovarian artery supply of uterine fibroids as a cause of treatment failure after uterine artery embolization a case report. J Vase Interv Radiol 10 1167-1170... 

Payne JF, Robboy SJ et al (2002) Embolic microspheres within ovarian arterial vasculature after uterine artery embolization. Obstet Gynecol 100 883-886... 

The anatomy of uterine fibroids and uterine artery embolization (UAE) consists of the fibroids, their position in the uterus, and the vasculature associated with the uterus. The vasculature of the ovarian arteries is also important because of the potential for collateral blood flow from the ovarian arteries supplying the fibroids. Communication between the uterine arteries and the ovarian arteries are also important because of the risk of embolization of the ovaries through uterine-ovarian anastomoses. 

Intramural fibroids are the most common type of fibroids. Their blood supply comes from one or more nutrient arteries. As the fibroid increases in size, the nutrient artery, and the arcuate artery enlarge [4]. Submucosal fibroids also obtain their blood supply from the nutrient arteries. However, with subserosal fibroids, the fibroid may adhere to other structures, and derive blood supply from those adjacent structures [4], including the ovarian arteries. 

Variant anatomy of the ovarian arteries includes the gonadal artery originating from the renal artery in about 20% of individuals [2]. Very rarely the artery arises from the adrenal, lumbar, or iliac arteries [2]. In some cases, the right ovarian artery passes behind the cava and over the right renal vein. The left ovarian artery will occasionally also pass over the left renal vein [2], There is very rarely a common trunk of left and right gonadal arteries, and occasionally there are multiple gonadal arteries. 

Communications between the ovarian artery and the uterine artery has two potential adverse outcomes, it may allow continued blood supply to the fibroid, leading to failure of the procedure, and alternatively it can lead to permanent ovarian failure following embolization. Because of these potential problems, there has been considerable interest in how best to evaluate the ovarian arteries. Flush arteriography has been an approach to evaluating the ovarian arteries to determine if there is enlargement of the ovarian artery and supply to the fibroid [23]. In one study [23] of 294 aortograms, 75 ovarian... 

CiciNELLi et al. [5] described an interesting pattern of collateral flow between the uterine and ovarian arterial supply to the uterus. In doing measurements of blood flow in premenopausal women, this group found there is more blood flow to the uterus from the ovarian artery during the follicular phase, whereas in the luteal phase most of the uterus is supplied from the uterine artery. Whether this change in blood flow patterns is changed in patients with fibroids is not clear. No studies of the effect of the phase of the menstrual cycle on the effectiveness of uterine artery embolization have been performed at this point. 

Since the communications between the uterine artery and the ovarian arteries have been measured at 500 microns, particle sizes larger than 500 pm should help avoid having particles cross the anastomoses to enter the ovaries [9,30,34]. 

My technique for embolization of uterine fibroids starts with placing a flush catheter that allows a contralateral approach (VCF or Omni Flush catheter) into the aorta and positioning it just below the level of the renal arteries. The image intensifier is centered over the pelvis and a angiogram is performed which allows for visualization of ovarian artery collaterals, and provides visualization of the iliac anatomy (Fig. 10.3.6a). The flush catheter is then positioned... 

If large ovarian arteries are found, they maybe embolized with relatively large embolic particles, PVA 500-700 pm or spherical embolic particles 700-900 pm (Fig. 10.3.9a,b). Alternatively many... 

Fig. 10.3.7. Preliminary aortogram demonstrating bilateral enlarged ovarian arteries...

Fig. 10.3.8. Patient with recurrent symptoms following uterine artery embolization. MRA demonstrating large right ovarian artery...

Fig. 10.3.9. a Right ovarian artery supplying fibroid, b Post embolization, stasis in ovarian artery and no supply to fibroid... 

Pelage JP, Walker WJ, Le Dref 0, Rymer R (2003) Ovarian artery angiographic appearance, embolization and relevance to uterine fibroid embolization. Cardiovasc Intervent Radiol 26 227-233... 

Binkert CA, Andrews RT, Kaufman JA (2001) Utility of non-selective abdominal aortography in demonstrating ovarian artery collaterals in patients undergoing uterine artery embolization for fibroids. J Vase Interv Radiol 12 841-845... 

Several theories, however, have been proposed to serve as possible explanations for this complication. Small embolization particles administered within the uterine arteries can potentially make their way into the ovarian arterial circulation through patent uterine-to-ovarian anastomoses, increasing the risk of reduced ovarian perfusion and subsequent ischemia [6, 71]. This theory is supported by the demonstration of angiographically visible anastomoses between these two arterial beds in up to 10% of cases [71]. In addition, several reports described the presence of embolization particles in the ovarian arterial vasculature, within an oophorectomy specimen obtained after UFE [7, 72]. Microspheres smaller than 500 pm in diameter can pass within the ovarian arterial circulation after uterine artery embolization performed in sheep, which may offer some guidance as to particle size selection for this procedure [47]. 

Ryu RK, Siddiqi A, Omary RA et al. (2003b) Sonography of delayed effects of uterine artery embolization on ovarian arterial perfusion and function. Am J Roentgenol 181 89-92... 

Ryu RK, Chrisman HB, Omary RA et al. (2001) The vascular impact of uterine artery embolization prospective sonographic assessment of ovarian arterial circulation. J Vase Interv Radiol 12 1071-1074... 

There are some important anatomic variations associated with failure. These include tortuous artery, small uterine artery in one or both sides, absence of uterine arteries, ovarian artery supply of the fibroids and other less common variants such as a round ligament artery supply [7]. 

The role of ovarian arteries as a cause of failure is well known. Ovarian arteries may feed the fibroids through different pathways. The visualization of an ovarian artery is not systematically associated with failure. In one study, 25% of patients had large ovarian arteries before embolization [8]. Only arteries that directly participate in feeding the uterus cause failure. In cases of a small uterine artery or absence of one or both arteries, the ovarian artery supply should be suspected (Fig. 10.5.3). However, additional supply to the fibroids may come from the ovarian arteries, even if large sized bilateral uterine arteries are present [9, 10]. 

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