Acquired Uterine Vascular Anomaly: Experience from a tertiary care centre in Pakistan.

The present study was conducted as a retrospective analysis at the Aga Khan University Hospital (AKUH), Karachi, Pakistan. Patients who underwent UAE from January 2010 to May 2020 were identified from the radiology database of the hospital. After excluding patients with known uterine tumours, retained products of conception, gestational trophoblastic disease and postpartum haemorrhage, 15 cases were identified in which UVAs were suspected clinically and/or on imaging. A pre-structured pro forma was used to record patient demographics, including age, parity, pattern and volume of vaginal bleeding, history of uterine surgery or dilatation and curettage (D&C), time interval since the intervention, findings on imaging and angiography and patient outcome. The duration of hospital stays, post-procedure complication, follow-up ultrasound findings and post-embolisation fertility/pregnancy were also recorded. The patients’ imaging was reviewed using the picture archiving and communication system, Rogan Delft View Pro-X (Rogan-Delft BV, Veenendaal, Utrecht, Netherlands), while additional data was collected from the Health Information Management Services. The pre-angiography imaging modality was chosen at the discretion of the referring physician and included ultrasonography with colour Doppler imaging, pelvic MRI and CT, either by itself or in combination. The referring physician decided on embolisation after consultation with the interventional radiologist who performed the embolisation procedures in the angiographic suite of the present hospital. The patients underwent the procedure on a flat panel monoplane digital subtraction angiography machine, Axiom-Artis (Siemens Healthineers, Erlangen, Germany), under local anaesthesia. The femoral artery was punctured and a 4F vascular access sheath was inserted. A 4Fr Simmons 1 catheter (Cordis, Santa Clara, California, USA) or a Cobra 1 angiographic catheter (Cordis) was advanced over a 0.035-inch guide wire. An angiographic run was performed after selective catheterisation of the uterine artery. It was followed by super-selective cannulation using a Progreat® microcatheter (Terumo Interventional Systems, Tokyo, Japan), which was placed coaxially as near as possible to the feeder vessel. The embolisation materials used were polyvinyl alcohol particles (PVA) that were 355–500 μm in size, gel foam, glue and coil, either in combination or in isolation. In a few cases, the ovarian artery was also embolised. Clinical success was defined as the resolution of vaginal bleeding and/or abnormal imaging findings on post-embolisation follow-up. The Statistical Package for the Social Sciences (SPSS), Version 20.0 (IBM Corp., Armonk, New York, USA) was used for statistical analysis. All quantitative data were expressed as mean ± standard deviation and qualitative data were expressed using frequencies and percentages. A descriptive analysis was conducted for all the variables, including the demographic and the other categorical variables and frequencies, proportions and percentages were reported. The benefits and risks of the embolisation procedure were explained to the patients and it was performed only after their consent was obtained. Ethical approval for the study was obtained from the Ethical Review Committee of AKUH (ERC #2020-3690-10189).

The mean patient age was 28.2 years (range: 20–35 years). A total of 14 patients had undergone a prior uterine procedure, 12 had a prior D&C, one had a repair of a uterine rupture and one had a C-section. The patient without prior D&C or surgery had a history of medical termination of the pregnancy. The main presenting complaint was abnormal pervaginal bleeding. It was considered mild in case of only spotting, moderate in case of continuous bleeding without clots and severe in case of passage of clots. The mean time interval of patient presentation following the intervention was 64.6 days (range: 1–365 days) [ Table 1 ]. All patients underwent a pre-embolisation ultrasound except one, who underwent only an MRI examination. The greyscale ultrasound identified an abnormal area in the myometrium in 12 patients (85.7%) and an abnormal area in the endometrium in two patients. On Doppler imaging, eight patients showed mixed arterial/venous flow. Following angiography, six of the eight patients were confirmed to have AVM, while the other two showed only uterine hyperaemia [ Figure 1 ]. Four patients showed focal increased vascularity within the myometrium, one was found to be an AVM on angiography and the remaining three patients only showed uterine artery hyperaemia. Two patients showed pseudoaneurysms on Doppler, which were confirmed through a pre-embolisation CT and angiography [ Figure 2 ]. Two other patients had abnormal focal vascularity on arterial phase, with prominent veins on the pre-embolisation CT suggesting AVM. Of these two cases, one proved to be AVM on angiography [ Figure 3 ], while the other showed only uterine hyperaemia. Six out of the 15 patients underwent pre-embolisation MRI. The MRI findings demonstrated abnormal signal intensity areas in either the myometrium or endometrium, with abnormal enhancement and multiple flow voids suggesting AVM. Three of these were confirmed as AVM on angiography, while the other three showed enlarged, prominent uterine arteries [ Figure 4 ]. The most frequently used embolisation material for the procedure (13 out of the 15 cases) was PVA particles. It was the sole embolic agent in 10 cases, while it was used in combination with gel foam in one case and in combination with histoacryl glue and coil in two other cases. Gel foam was used as the sole embolic agent in one case. One patient with a right uterine artery pseudoaneurysm was embolised with cyanoacrylate glue [ Table 2 ]. The embolisation procedure was technically successful in all 15 patients, none of whom required a repeat embolisation or post-embolisation transfusion. None of the patients had an on-table procedure-related or puncture site complication. The mean duration of hospital stay was 2.73 days (range: 2–4 days). Nine out of the 15 patients had mild bleeding at the time of discharge from the hospital, which resolved by the next clinic visit. Two patients had an episode of pervaginal bleeding a month later, which resolved in response to conservative management. A total of 12 patients underwent follow-up ultrasound examinations. The mean time interval for the follow-up ultrasound was 40.6 days (range: 15–90 days) after embolisation. In five patients, the follow-up ultrasound was completely normal. On the other hand, five patients showed persistent greyscale findings, although the abnormal vascularity had resolved. One patient showed a decrease in size of the abnormal area on ultrasound, with persistent mild vascularity, although she was asymptomatic. In another patient, abnormality was demonstrated on both greyscale and Doppler ultrasound on initial follow-up, but it resolved completely on repeat ultrasound two months later. Three patients did not have any follow-up imaging but were clinically asymptomatic. Seven patients (46.7%) had normal pregnancies that were carried to term after the procedure. The mean time interval between the procedure and the pregnancy was 15.7 months (range: 4–28 months). The remaining eight did not conceive to the best of the authors’ knowledge.

Ultrasound is the first-line imaging modality employed for the diagnosis of UVAs. It has high specificity for pseudoaneurysms but lacks specificity for AVMs. It is important to consider placental bed sub-involution when diagnosing AVMs on non-invasive imaging among patients with a history of a recent miscarriage. The findings from the current study demonstrate that UAE is a safe and effective management option for intractable severe bleeding in patients with UVAs post instrumentation and it does not appear to limit future pregnancy outcomes.

The present retrospective study conducted at a tertiary referral centre, reviewed a spectrum of imaging findings in patients with suspected acquired UVA. Additionally, the outcomes of super-selective UAE were also studied. True AVMs were observed in seven cases, including one arteriovenous fistula. Additional anomalies observed include uterine hyperaemia and pseudo-aneurysm. Timmerman et al . studied 30 cases of suspected uterine vascular malformations, out of which eight underwent angiography. 16 Their study showed true AVMs in three patients, while the rest had only an abnormal arterial blush. Occasionally, the number of AVMs is found to be purportedly higher on (conventional) angiography. Hugues et al . studied 26 cases of suspected uterine AVMs, of which about a quarter showed uterine hyperaemia, while true AVMs were observed in the remaining cases. 17 Furthermore, a study of iatrogenic uterine arterial injuries, which were treated by UAE, found AVMs in the majority of cases (15 out of 24), either alone or in combination with a pseudoaneurysm. 2 All of the cases considered in the present study showed abnormalities on both greyscale and colour Doppler ultrasound examinations. The two cases of pseudoaneurysms were accurately identified. Pseudoaneurysms appear as cystic spaces on greyscale ultrasound and exhibit swirling multidirectional flow on colour Doppler, with varying degrees of turbulence; hence they allow for accurate identification in most cases. 1 , 2 The greyscale appearances of AVMs, on the other hand, are non-specific, ranging from subtle myometrial inhomogeneity to linear, anechoic spaces in the myometrium, which show colour filling on Doppler interrogation with a mosaic pattern. 12 , 19 The specificity is increased by duplex ultrasound/spectral analysis that reveals high-velocity and low-resistance arterial flow. 16 Unfortunately, the spectral analysis findings were not available in all the cases considered for the present study as mostly only greyscale and colour Doppler evaluations were conducted. It has been observed that low-resistance abnormal vascularity often persists in the myometrium at the site of trophoblast or placental implantation and takes time to resolve. 1 , 10 This is referred to as sub-involution of the placental bed and may account for abnormal findings on ultrasound and MRI, as observed in some of the patients included in the present study who subsequently demonstrated only uterine hyperaemia on angiography with no AVM. Nevertheless, angioembolisation was justified since these patients presented with moderate to severe bleeding that had been resistant to conservative management. The symptoms resolved completely following a single session of embolisation with no discernible adverse effects. Although digital subtraction angiography (DSA) is currently the gold standard for the diagnosis of UVA, its use is not justified unless DSA is utilised as the precursor to an embolisation. The management of UVAs depends on the clinical presentation as well as the severity of the anomaly. Patients who show minimal symptoms and/or are haemodynamically stable may be followed-up clinically and by ultrasound. Bleeding usually resolves spontaneously within weeks to months in milder cases. 19 UAE is offered to patients with severe intractable or recurrent bleeding. It helps to avoid hysterectomy, thereby preserving chances of future fertility. UAE may theoretically result in reduced vascular supply to the uterus; however, the presence of rich collaterals prevents uterine infarction. 12 Many case reports and studies have shown successful pregnancy outcomes post angioembolisation. 12 , 19 , 20 Almost half of the cases considered in the present study had post-embolisation pregnancies that were carried to term. It is known that the reported complication rate of pelvic artery embolisation is low. 21 Several embolic agents have been used for the treatment of UVAs, including gel foam, PVA particles, glue, coil or a combination of these agents. 12 , 14 , 15 , 17 , 21 , 22 In the present study, PVA particles were the most frequently used embolisation material, employed in 13 out of the 15 cases. Minor complications such as puncture site pain or haematoma, fever and transient lower limb and buttock claudication are more frequent than severe complications such as iatrogenic rupture of a pelvic artery, sloughing of perineal skin, vesicovaginal fistula or major distal ischemia. 12 , 21 , 22 No major post-procedural complications were encountered in the present study. Only three patients experienced mild abdominal pain, which did not require any treatment, while fever was observed in two patients, which resolved before discharge.