Hiroyasu Nakamura

Uterine artery pseudoaneurysm: its occurrence after non-traumatic events, and possibility of “without embolization” strategy

OBJECTIVES Uterine artery pseudoaneurysm (UAP) has been considered to occur very rarely after traumatic delivery/abortion, and is usually detected after its rupture, yielding massive bleeding. Our hypothesis is: some UAP may be undetected without massive bleeding and may spontaneously resolve, and, thus, may not require transarterial embolization (TAE). We attempted: (1) to detect both ruptured and non-ruptured UAP, thereby characterizing candidates of spontaneously resolving UAP, and (2) to confirm that UAP is not rare and not always associated with traumatic events. STUDY DESIGN This was a retrospective observational study of 50 women with angiographically confirmed UAP and treated by TAE. Angiograms and medical charts were retrieved to examine the associations among symptoms, ultrasound findings, and extravasation. Gray-scale ultrasound was performed for all women after delivery or abortion as our routine practice. RESULTS UAP occurred in 3-6/1000 deliveries and 40% occurred after non-traumatic deliveries/abortion. While 36% had active vaginal bleeding at admission, 64% did not. While 100% of patients with current active bleeding showed extravasation from the pseudoaneurysmal sac, patients without it showed a varied incidence of extravasation depending on the bleeding pattern/history and ultrasound findings. Interestingly, all patients with current bleeding (-), bleeding history (+), and ultrasound-discernable-intrauterine low echoic mass (-) were devoid of extravasation, suggesting that UAP may show progression to thrombosis and, thus, resolve spontaneously. CONCLUSIONS UAP may not be so rare and not associated with traumatic delivery/abortion. Some UAP may resolve, and, thus, may not require TAE, at least immediately.

Uterine artery pseudoaneurysm hidden behind septic abortion: Pseudoaneurysm without preceding procedure

Uterine artery pseudoaneurysm (UAP) can occur after cesarean section or traumatic delivery, usually manifesting as postpartum hemorrhage. Here we report a patient with UAP possibly caused by septic abortion. She had high fever and bleeding with positive urine pregnancy test. We diagnosed this condition as septic abortion. Ultrasound revealed an intrauterine echogenic mass and color Doppler revealed swirling blood flow within the mass. Contrast‐enhanced computed tomography showed a heterogeneously enhanced intrauterine mass. Selective internal iliac artery angiography revealed contrast medium within the mass immediately after medium injection. Bilateral uterine artery embolization was performed, after which medium no longer accumulated in the uterus, and hemostasis was achieved, confirming the diagnosis as UAP. Antibiotic treatment ameliorated the infection and the uterine content was expelled and absorbed. UAP can occur even without preceding procedures and may manifest abortive, and not postpartum, hemorrhage. UAP may be hidden behind septic abortion.

Postpartum hemorrhage: is angiographically detectable “sac” mandatory for diagnosis of ruptured pseudoaneurysm?

Postpartum hemorrhage (PPH) continues to threaten mothers’ lives: articles in this journal repeatedly dealt with this issue [1]. Rupture of a uterine artery pseudoaneurysm (UAP) causes PPH. Contradictory to previous belief, UAP can occur more frequently (2–3/1000 deliveries) [2] and can no less frequently occur after non-traumatic than traumatic deliveries [2], and, thus, UAP has attracted wider attention. The symptoms and signs of UAP change in patient-by-patient manner, deceiving obstetricians [3], leading our team to refer to UAP as ‘‘chameleon’’ in obstetric practice [4]. Although ultrasound and enhanced computed tomography facilitates a pretreatment diagnosis, pelvic angiography is a gold standard for diagnosing ‘‘ruptured’’ UAP, namely, a parent artery (usually the uterine artery), narrow connecting portion, pseudoaneurysmal sac, and extravasation from the sac: many obstetricians consider this as a ‘‘typical’’ angiographic image of ruptured UAP. Actually, Lipere et al. [5] recently reported PPH caused by uterine artery injury showing ‘‘extravasation without sac’’, with a context that this was a new clinical entity and not ruptured UAP. The presence of angiographically detectable ‘‘sac’’ may be considered mandatory for ruptured UAP diagnosis. We are concerned about ‘‘too much’’ emphasis being placed on the presence of a sac. In UAP rupture, a sac may not be as evident as expected. In our previous analysis of 22 consecutive angiographically confirmed UAP cases [2], some had only a small ‘‘sac’’, and at its extreme end, ‘‘no discernable sac’’ may be the result. We consider four scenarios regarding the relationship between the presence/absence of a sac and extravasation in ruptured UAP. First, a pseudoaneurysmal sac is initially occupied only by swirling blood flow. If it ruptures, the round ‘‘sac’’ and extravasation from it may be visible on angiography, showing a typical ruptured pseudoaneurysm, with which obstetricians are well accustomed. Second, with the time course, an intra-sac thrombus may be formed: centripetal formation of an intra-sac thrombus has already been demonstrated in a femoral artery pseudoaneurysm [6]. If rupture occurs at this stage, the sac, partly occupied by the thrombus, may become irregularly shaped and angiography may not show the typical image of a ‘‘round sac with extravasation’’. Third, at the extreme end of this phenomenon, the aneurysmal sac may mostly become occupied by the thrombus and there remains a small free blood-flow space. When a pseudoaneurysm ruptures at this stage, angiography may indicate extravasation without a sac. Fourth, the thrombosed sac may be broken and detached altogether at the rupture: the aneurysmal structure may no longer exist and, thus, it is undiscernable. In the latter two scenarios, angiography may show ‘‘extravasation without sac’’, similarly to in Lipere et al.’s patient [5]. & Shigeki Matsubara matsushi@jichi.ac.jp

Letter to the Editor on the article “Clinical evaluation of balloon occlusion of the lower abdominal aorta in patients with placenta previa and previous cesarean section: A retrospective study on 43 cases.”: The drier the surgical field, the better?

• Aortic balloon occlusion can reduce bleeding during abnormally-invasive-placenta surgery, but depending on the situation.

Letter to ‘Novel approach to uterine artery pseudoaneurysm embolization for delayed post‐partum hemorrhage’: Thrombin really necessary?

Parker et al. used transarterial-thrombin-embolization for a uterine artery pseudoaneurysm (UAP), concluding ‘intra-arterial catheter-directed thrombin injection should be considered a viable option for pseudoaneurysm embolization’. We have a question. Our question regards the reason why they chose superselective embolization. Use of the catheter tip was attempted in order to ‘access the pseudoaneurysm neck.’ Parker et al. used the 1.5-Fr Marathon microcatheter (eV3), which is flow-directed and suitable for superselective embolization, usually used with liquid embolic agents, such as N-butyl-2-cyanoacrylate (NBCA) or thrombin rather than gelatin sponge. Embolization should be as selective as possible to achieve hemostasis; this may reduce the possibility of ischemic adverse events. Theoretically, thrombin is less likely to cause ischemic events than NBCA, a permanent embolic agent. Thus, we consider the following scenario: attempting superselective embolization in the setting of tortuous vessels requires this microcatheter, which then requires a liquid embolic agent, forcing the choice between NBCA versus thrombin – thrombin was used considering safety. Parker et al. made ‘multiple attempts with various microcatheters’. The introduction of interventional radiology as an obstetric hemorrhage treatment has created ‘room’ to devise new techniques. We respect Parker et al.’s effort; however, an orthodox embolization procedure, for example, 2.4-Fr Progreat with gelatin sponge, may be sufficient. Which is better: ‘after failed multiple attempts at coil embolization, attempt with thrombin for the first time’ or make ’one attempt with an established gelatin sponge’? This consideration is much more important in an emergency setting, which is often encountered in daily obstetrics. We have employed the latter technique with no significant ischemic adverse events. The more selective, the less adverse events, but the more time/experience required, showing a trade-off relationship. The procedure is optimal if the physician is well experienced with it, leading to good results. We do not argue against Parker et al.’s procedure, which may be an option depending on the situation. Preferably, however, procedures should be ‘universally achievable’ and applicable, even by less experienced physicians. This issue should be more fully discussed.

Recurrent postpartum haemorrhage following transcatheter arterial permanent embolisation using N-butyl cyanoacrylate requiring repeat embolisation with transient gelatine sponge: Lessons for clinical practice

Transcatheter arterial embolisation (TAE) is an effective treatment option for postpartum haemorrhage (PPH), in which two categories of embolic agent are used: permanent vs. transient. N-butyl cyanoacrylate (NBCA) or gelatine sponge represents the former and latter, respectively (Matsubara et al. 2011; Nagayama et al. 2015). Both merits and demerits of a transient vs. permanent embolic agent have been discussed (Yonemitsu et al. 2010; Igarashi et al. 2011; Matsubara et al. 2011; Woo et al. 2013). A transient embolic agent (gelatine sponge) induces thrombus formation around the embolic material (Igarashi et al. 2011): it has generally been considered to be easier to use, and its plugging effect is ‘transient’, with accompanying ischaemic adverse events expected to be less frequent (Igarashi et al. 2011; Woo et al. 2013). Its haemostatic effect relies on the thrombus-forming capacity and, thus, in the presence of severe coagulopathy, its haemostatic effect is limited (Yonemitsu et al. 2010). Contrarily, a permanent embolic agent (NBCA) undergoes rapid polymerisation and hardening in an ionic fluid: NBCA physically plugs the vessels not depending on the thrombus formation at the site (Igarashi et al. 2011; Kim et al. 2013). TAE using a permanent embolic agent (NBCA) is generally considered to require more experience to apply it (Igarashi et al. 2011) and it occludes the artery ‘permanently’: it has been assumed that this may more frequently cause ischaemic adverse events (Igarashi et al. 2011). Since its haemostatic effect is less reliant on the host’s thrombus-forming capacity as described, it can be used even in cases of severe coagulopathy (Igarashi et al. 2011; Matsubara et al. 2011). Therefore, NBCA is considered more effective than a transient embolic agent, i.e., a ‘last resort’ in TAE (Yonemitsu et al. 2010; Matsubara et al. 2011). Since NBCA-TAE is classified, and, thus, referred to, as ‘permanent’ embolisation, obstetricians may reduce their caution against re-bleeding after NBCA-TAE. We report a coagulopathic patient with PPH, in whom NBCA-TAE stopped bleeding once but re-bleeding occurred, which required re-embolisation. Case report

Endovascular Embolization of an Aberrant Bronchial Artery Originating from the Internal Mammary Artery in a Patient with Hemoptysis.

Massive hemoptysis is a life threatening respiratory emergency with high mortality and the bronchial artery (BA) is its most frequent source. Herein, we report a case of a 76-year-old man with recurrent hemoptysis due to an aberrant right BA arising from the right internal mammary artery (IMA), an extremely rare origin, that was clearly depicted on pretreatment computed tomography angiography (CTA). The patient was treated successfully by transcatheter bronchial artery embolization (BAE) of the aberrant BA and the hemoptysis has since been controlled for 9 months. Knowledge of the detailed BA anatomy is essential for performing BAE, especially in cases of aberrant BA. CTA is a promising tool for pretreatment planning of emergency BAE in patients with hemoptysis.