Novel subtype of atonic postpartum hemorrhage: dynamic computed tomography evaluation of bleeding characteristics and the uterine cavity

Abstract

Background: Uterine atony is the leading cause of severe postpartum hemorrhage (PPH); however, the underlying cause of intractable atonic PPH unresponsive to conventional treatments (such as uterotonics and intrauterine balloon tamponade) remains unclear.Objectives: The aim of this study was to investigate whether intractable atonic PPH is associated with the type of bleeding (arterial or nonarterial) and its location, along with variations in the size and shape of the uterine cavity after delivery.Study design: This retrospective study included women who had undergone a dynamic computed tomography (CT) scan for the management of severe PPH at Kyoto University Hospital between April 2011 and March 2017. Patients’ electronic medical records were reviewed, and relevant clinical information was collected. The presence of contrast extravasation (CE) on CT images in the early phase (40 s) was regarded as active arterial bleeding. Bleeding sites and size of the uterine cavity were evaluated using an xyz coordinate system. The size of the uterine cavity was compared between groups with CE into the upper and lower parts of the uterine body.Results: Of the 60 women assessed for eligibility, 30 were included in the current analysis. Contrast extravasation was detected in 19 women, with 14 showing CE in the early phase. The presence of CE in the early phase was significantly associated with the need for transarterial embolization (Fisher’s exact test, p = .0017). The upper and lower parts of the uterine cavity were 97.4 ± 2.7 mm (mean ± standard error of the mean) and 87.2 ± 3.5 mm in length, respectively. The maximum anteroposterior diameters of the upper and lower parts of the uterine cavity were 23.1 ± 2.6 and 76.0 ± 3.0 mm, respectively, and the largest transverse diameters were 67.3 ± 1.9 and 81.1 ± 2.3 mm, respectively. The group that showed CE into the upper uterine cavity had significantly larger qualitative parameters of the upper uterine cavity compared to the group with CE into the lower uterine cavity. The gate from the lower uterine cavity toward the upper uterine cavity was narrow (anteroposterior diameter of 22.6 ± 2.0 mm, transverse diameter of 40.7 ± 3.3 mm), and the intrauterine balloon was always found in the lower uterine cavity on the CT scan. The upper uterine body was characterized by a flat oval-shaped cavity (xy plane), thick uterine wall, and lack of uniformity among bleeding sites (z = 62.4 ± 14.8 mm). In contrast, the lower uterine cavity was a circular shape (xy plane) with thin walls, and bleeding sites were located at lateral sides around the level of the internal os (z = −18.8 ± 4.9 mm).Conclusions: Atonic PPH has a significant subtype, named “PRACE,” which is characterized by PPH, resistance to treatment, and arterial CE. The need for embolization can be predicted by the presence of arterial bleeding and its location, along with the shape of the uterine cavity.