Uterine Pseudoaneurysm: From Clinical Suspicion to Treatment

Uterine Artery Pseudoaneurysm (UAP) is a severe complication associated with vascular damage caused by cesarean section or gynecological procedures. UAP is a pulsatile, repermeabilized, and encapsulated hematoma that communicates with the lumen of the damaged vessel and is subjected to systemic blood pressure, which leads to growth and rupture. It differs from true aneurysm because the latter has the three layers in the arterial wall. It is described as a rare but potentially life-threatening condition; however, there are increasing publications that highlight this complication and aim to raise awareness about the importance of early diagnosis. Determining its incidence is difficult, as some statistics only include those related to delivery, and depending on the sources consulted, it may vary from 2-3 to 5-6/1000 cases of postpartum hemorrhage [1].

Uterine Artery Pseudoaneurysm (UAP) is a rare complication that typically occurs after gynecological procedures, cesarean section [2], or instrumental delivery, but it has also been described after vaginal delivery, curettage, abortions, and even cerclage [1]. Clinical suspicion of this vascular anomaly usually begins when genital bleeding occurs, sometimes massive hemorrhage, in the context of secondary postpartum hemorrhage in cases occurring after childbirth. Hemorrhage results from the rupture of the UAP, although it can also be asymptomatic or thrombosed. UAP has been reported after hysteroscopy and subsequent polyp resection due to uterine artery damage during surgery, with subsequent formation of hematoma communicating with the arterial lumen, causing persistent bleeding [3]. This abnormal, abundant bleeding should alert healthcare providers to this complication. Although hysteroscopic surgery is common and considered safe for resection of polyps, fibroids, and other endometrial cavity pathologies [4] in order for a less invasive treatment to be considered it is important to be aware of the potential risks. 

Other gynecological procedures associated with the occurrence of UAP include conization [5], laparoscopic myomectomy [6], hysterectomy [7], or deep endometriosis diagnosis [8]. Additionally, a recent case has been published where UAP manifested as hemoperitoneum following a normal delivery [9], without genital bleeding, as the UAP ruptured into the abdominal cavity rather than into the uterine cavity. There are cases of UAP during pregnancy, and a published article reviews literature on cases after 2000, where UAP or uterine artery aneurysm occurred during pregnancy, excluding those from the postpartum period [10]. This review analyzed 18 cases that met these criteria, with the most significant symptoms being abdominal pain and bleeding. Most patients underwent UAE without any gestational complications related to the procedure. The risk of UAP rupture is high when it exceeds two centimeters and may be increased by hemodynamic overload, such as during pregnancy. Therefore, these cases should be evaluated by multidisciplinary teams to determine the best therapeutic option.

Two important points need to be highlighted when discussing UAP. One is that early clinical suspicion is essential for early diagnosis and to avoid complications. 

The second is that coordination with interventional radiologists is crucial to offer early diagnosis and a minimally invasive therapeutic procedure if necessary [11]. Such procedures also provide significant benefits for patient recovery and the potential preservation of fertility [4].

In the differential diagnosis of UAP, other vascular anomalies include uterine arteriovenous malformations, arteriovenous fistulas and uterine hemangiomas. Ultrasound is usually the first diagnostic tool in cases of vaginal bleeding. Its management is critical in any case of genital bleeding following obstetric or gynecological procedures. It helps to initiate differential diagnosis with other bleeding causes [12,13]. UAP can be identified on ultrasound as a hypoechoic mass with abundant turbulent flow in Doppler color [3], although some imaging studies suggest that depending on the UAP's developmental stage, a misdiagnosis of other pathologies might occur, as a small anechoic or hypoechoic mass may be observed without evidence of blood flow within the lesion [14]. However, given the relationship between UAP and the uterine artery and its branches, this diagnostic possibility should not be overlooked, especially when the clinical presentation or patient's history is compatible, or the patient's clinical evolution is not as expected with the initial diagnosis. In some cases, ultrasound can rule out the presence of vascular anomalies, but in others, further investigation with contrast-enhanced Computed Tomography (CT) is needed, which provides detailed images of uterine vascularization. This is useful for confirming the diagnosis and planning treatment [15]. 

Magnetic Resonance Imaging (MRI) is a less commonly used for diagnosis, but it can be useful when other imaging techniques are inconclusive. It offers high resolution but is usually less available. Treatment of UAP depends on the size, symptoms, and hemodynamic stability of the patient. Uterine Artery Embolization (UAE) is the initial therapeutic procedure of choice and is effective in stopping bleeding in 90% of cases, with artery occlusion confirmed in 98% through follow-up imaging tests [4]. Embolic agents such as particles, coils, or liquid substances are used. Interventional radiology techniques are increasingly available in centers treating these patients, following an early diagnosis of the UAP and treatment with embolization if indicated. However, some centers do not have the availability for UAE and uterine artery ligation, internal iliac artery ligation, or even hysterectomy may be performed to bleeding control [16]. 

Assessment of extravasation of ruptured UAP using contrast-enhanced ultrasonography during uterine balloon tamponade has been used, and blood extravasation can be identified at the bedside, compressing the bleeding point at the same time [17]. Conservative treatment is possible, particularly in asymptomatic patients with small UAPs, where strict clinical and ultrasound monitoring can be considered. However, there is no consensus on which cases would be candidates for a watching waiting strategy, as UAPs have a risk of rupture and bleeding due to the extraluminal turbulent blood flow that leads to the enlargement of the UAP. Probably, the aneurysm's size and the availability of urgent embolization might influence the decision to perform prophylactic treatment in asymptomatic cases.

UAP related to delivery and many gynecological procedures have been described. Although it is not a common complication, initial clinical suspicion of gynecologists and radiologists is essential for prompt treatment. Ultrasound is usually the first diagnostic tool performed in case of genital hemorrhage, but contrast-enhanced CT is useful for confirming diagnosis and planning a subsequent UAE as a first therapeutic option.

1. Sahoo B, Jena SK, Sethi P, Mitra S, Mishra S (2023) Uterine Artery Pseudoaneurysm after Cervical Cerclage: A Rare Case and Its Management Through Uterine Artery Embolization. J Obstet Gynaecol India 73: 264-267.
2. Melcer Y, Pekar-Zlotin M, Cherniavsky A, Levinsohn-Tavor O, Copel L, et al. (2024) Acquired uterine artery pseudoaneurysm: a rare iatrogenic complication following cesarean delivery at complete cervical dilatation. Arch Gynecol Obstet 310: 2267-2268.
3. Kakinuma K, Kakinuma T, Ueyama K, Okamoto R, Yanagida K, et al. (2024) Uterine artery pseudoaneurysm caused by hysteroscopic surgery: A case report. World J Clin Cases 12: 5968-5973.
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12. Baba Y, Matsubara S, Kuwata T, Ohkuchi A, Usui R, et al. (2014) Uterine artery pseudoaneurysm: not a rare condition occurring after non-traumatic delivery or non-traumatic abortion. Arch Gynecol Obstet 290: 435-440.
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