Uterine artery embolization during pregnancy

Abstract

Uterine artery pseudoaneurysms are very rare but serious malformations that can occur during pregnancy or postpartum. It is crucial to identify and treat them due to the morbid consequences associated with rupture. We present a case of a 27-year-old primigravid at 22 weeks 4 days with placenta previa and recent right salpingo-oophorectomy who presented with hematuria and right lower quadrant pain. A left uterine artery pseudoaneurysm was found on computed tomography, which grew from 1.3 to 1.8 cm over 2 days. During therapeutic endovascular embolization, the pseudoaneurysm was identified and the uterine artery was successfully embolized. The fetus was carried to 34 weeks 4 days. There is no medical treatment for pseudoaneurysms and the risk of rupture vs complication of embolization must be weighed on an individual basis. As shown in this case, interventions are generally recommended to prevent harm to both mother and fetus.

Uterine artery pseudoaneurysms are rare but serious malformations that can form during pregnancy or in the postpartum period. The formation of pseudoaneurysms is related to arterial wall disruption. They are typically formed after local surgery or trauma such as childbirth.¹ Diagnosing a pseudoaneurysm is critical, especially during pregnancy when the uterine arteries are receiving up to 20% of cardiac output.² Diagnosing them is a challenge, as they are rare and can be asymptomatic or present with vague symptoms such as pelvic pain and bleeding.¹ We present a case of incidentally discovered uterine artery pseudoaneurysm during pregnancy to discuss its treatment and potential complications.

CASE PRESENTATION

A 27-year-old primigravid with placenta previa presented at 22 weeks 4 days gestation for right lower quadrant pain and hematuria. Ten days before, the patient underwent diagnostic laparoscopy and right salpingo-oophorectomy due to hemoperitoneum. Multiple serosal tears and clot were present on the left lateral, posterior uterus/parametrium with a dusky appearance. She was placed on therapeutic enoxaparin postoperatively for deep vein thrombosis. As part of her workup, a contrast computed topography (CT) scan was performed showing possible left uterine artery pseudoaneurysm, measuring up to 1.3 cm. Two days later, follow-up CT displayed the same hyperdense nodule, now measuring 1.8 cm (Figure 1a). Interventional radiology was consulted for therapeutic evaluation, and endovascular embolization was planned. The pseudoaneurysm was identified fluoroscopically (Figure 1b), and an attempt to glue embolize the pseudoaneurysm was made. However, the sac ruptured (Figure 1c), and the uterine artery was quickly coiled in a distal to proximal fashion across the sac’s origin. Subsequent angiography showed complete stasis upon completion of the procedure (Figure 1d). She then developed a submassive pulmonary embolism requiring thrombectomy and inferior vena cava filter placement. The patient was discharged in stable condition and followed up as an outpatient. She underwent cesarean hysterectomy at 34 weeks 4 days gestation as a large area of necrosis was discovered on the posterior uterus with active bleeding. Both mother and baby are healthy, and she is undergoing a hematology workup for her hypercoagulability.

Figure 1.

(a) Contrast CT scan showing a hyperdense nodule on the left posterolateral to the uterus concerning for pseudoaneurysm. (b) Angiogram of the left internal iliac artery showing a pseudoaneurysm without extravasation off the left uterine artery. (c) Post–glue embolization angiography showing active extravasation. (d) Post–coil angiography showing complete stasis with coils located distal and proximal to the pseudoaneurysm neck.

DISCUSSION

Uterine artery pseudoaneurysms are rare in pregnancy, occurring in about 3 to 6 of 1000 pregnancies.³ The gold standard for diagnosis is transvaginal ultrasound and identifying the ‘yin-yang’ sign.² On contrast-enhanced CT, uterine artery pseudoaneurysms appear as hyperdense nodules adjacent to arteries.

The major risk factors for pseudoaneurysm formation are trauma and surgery. Our patient had two recent surgeries, but they were performed in the right adnexa with minimal disruption of the left. Other potential etiologies in this case include regional inflammatory processes or a vasculitis. This patient was unique as she had coexisting hypercoagulability.

Historically, pseudoaneurysms have been treated with open laparotomy and vessel ligation. These had high rates of morbidity and mortality, leading to adoption of transcatheter arterial embolization, a much safer procedure.⁴ There is some controversy on whether to treat or adopt a “watch and wait” philosophy since pseudoaneurysms could resolve spontaneously.³ However, the hormonal and hemodynamic changes during pregnancy are associated with increased risk of rupture.⁵ In addition, size over 2 cm is an indication for immediate treatment.⁵ While few adverse effects have been published, there are few reports of term deliveries following a uterine artery embolization. In this case, the embolization was an unlikely cause of preterm delivery. The mother’s suspected underlying hypercoagulable disorder as evidenced by the pre-existing ischemia discovered during her surgery was likely a contributing factor.

Unfortunately, complications and future fertility after uterine artery embolization are not well reported in the literature.⁶ Our patient was found to have partial uterine necrosis at the time of cesarean section leading to hysterectomy. To our knowledge, this has not been reported as an outcome of uterine artery embolization in the past. Due to the patient’s underlying hypercoagulability, we cannot be certain whether it is an outcome of the procedure or if she had thrombosis earlier.

While efforts should be made to embolize the pseudoaneurysm sac itself, previous reports indicate it is safe for the existing pregnancy to occlude one uterine artery.⁴ Further studies are required to determine the long-term effects and complications of embolization, as uterine necrosis may be a potential risk. Nevertheless, the benefit of prolonging the pregnancy with minimal to no fetal defects is important to consider. Routine outpatient follow-up is essential after this procedure to ensure proper fetal growth and detect any complications.