Discussion
postpartum hemorrhage (PPH) is considered to be the leading cause (25%)
of maternal death, especially in developing
countries,1 that requires multidisciplinary
management, including gynecologists, anesthesiologists, and
interventional radiologists. Knowledge of the obstetrical and surgical
history of patients with PPH is required to anticipate the most probable
cause of PPH. In fact, visual estimation of blood loss (VEBL) was
described as the most common and practical way.2 Some
researchers noted that in spite of the relative accuracy of the weighing
method, it could not prevent the process of severe PPH. The key actions
to successful management of PPH are early recognition and prompt
treatment.3
AVF results from an abnormal connection between an artery and a vein
have been described in the pelvic vasculature and, more rarely, in the
uterus.4 A UAVF is a rare cause of congenital or
acquired-in-nature PPHs that represent 1% to 2% of all genital and
intraperitoneal hemorrhages and, as such, should be considered in any
postpartum female complaining of vaginal bleeding, particularly if the
patient has undergone instrumentation of the
uterus.5-8 Acquired UAVF has been attributed to
various causes, including malignancies, pregnancy-related, previous
uterine trauma from repeated D&E, surgery, infection, and
diethylstilbestrol exposure.5,6,9-14 Most reported
cases are acquired secondary to D&E but rarely to vaginal
delivery.15 A UAVF is most commonly identified when it
causes complications during pregnancy, typically in women between 20 and
40 years old, suggesting that hormonal changes during pregnancy and the
menstrual period may play a role in its
pathogenesis.16 The primary clinical manifestation of
a UAVF is paroxysmal massive vaginal bleeding that it potentially
life-threatening. The characteristics of vaginal bleeding in our case
were a massive gush of vaginal blood that suddenly stopped, possibly due
to the opening and closing of the blood sinus. The amount of vaginal
bleeding was difficult to estimate, but it was enough to cause severe
anemia, syncope, and unstable vital signs. This bleeding requires blood
transfusion in 30% of cases.17 While the true
incidence of a UAVF is unknown, and fewer than 150 cases have been
reported.18 O’Brien et al.19proposed a rough incidence of 4.5%, which would make its diagnosis an
even more critical issue for women with unexplained vaginal bleeding.
A UAVF is easily diagnosed now using color-Doppler ultrasonography
(CDUS).20 Other imaging modalities of importance
include pelvic magnetic resonance imaging (MRI) , hysteroscopy, and
DSA.21 While DSA is considered the gold standard
modality for diagnosing a UAVF,5 many authors have
found transvaginal ultrasound (TVUS) and CDUS more preferable diagnostic
methods in the last two decades because they are less
invasive.22 Grey scale imaging can reveal subtle
myometrial heterogeneities or anechoic spaces.19 CDUS
provides a more specific image and presents a color mosaic with
thickened vessels and flow reversals. Color-Doppler allows for the
identification and localization of increased vascularity, whereas
spectral flow Doppler generates a waveform from which systolic and
diastolic velocities may be measured. The spectral analysis of AVF
lesions reveals a tangle of vessels with a high-velocity flow; spectral
Doppler shows high-velocity and low-resistance flow, with low RI values
ranging from 0.25 to 0.55 and high PSV values in the range of 40-100
cm/s.19 In our case, a 78.5 cm/s PSV was recorded in
the mid-range, and the patient’s continued symptomatic status
necessitated a more aggressive approach.
The differential diagnosis of a UAVF comprises several conditions,
including hemangiomata, sarcoma of the uterus, trophoblastic disease,
and pelvic varicose veins. In the latter condition, the vessels do not
pulsate, and they are situated in the outer half of the
myometrium.21,22 In contrast to a real AVF with a
fistula, a non-AVF should be considered subinvolution of the placental
bed, which is defined as failure to obliterate the placental bed vessels
in the absence of retained placental tissues after cessation of
pregnancy or after abortion.22 A correct sonographic
diagnosis is, thus, very crucal.23 However, relying
only on Doppler measurements could result in the overdiagnosis of an
AVF, as increased vascularity in the endometrium, which resolves
spontaneously in 1-2 weeks, can also be noted immediately post
D&C.24 With DSA, hypertrophied uterine arteries
contributing to a large area of hypervascularity and rapid outflow into
pelvic venous channels indicate the presence of a
UAVF.25 Although contrast medium-enhanced DSA has been
the conventional criterion for standard diagnostic tests, its current
use is rare; it is now predominantly used during embolization therapy.
Failure to recognize a UAVF could lead to an improper treatment, a
life-threatening hemorrhage, and hysterectomy procedures. However while
a rapid, prompt, and precise recognition of a UAVF as the cause of
bleeding is critical because fistulas are life-threatening and uterine
instrumentation may aggravate the condition, the entity in the
postpartum must not be overdiagnosed, for many so-called UAVFs have
spontaneously resolved at follow-up imaging.15,23
A UAVF treatment is individualized based on clinical manifestations and
fertility requirements. Five main factors must be considered in the
planning and treatment of patients with a UAVF: these include
hemodynamic state, size and location of the lesions, degree of bleeding,
age, and the desire for future fertility.15Intervention options from conservative management to definitive surgical
hysterectomy are available to patients.8,11,26-28 DSA
is the gold standard for diagnosing an AVF and also an interventional
treatment technique. Because retaining fertility function and relieving
clinical symptoms are most important for these
women,29 bilateral UAE is regarded as a method that
effectively provides adequate symptomatic relief and retains fertility
with minimal side effects, lower complication rates, and major surgical
risks.12 Selective uterine artery embolization (UAE) ,
which has replaced surgery as the optimal treatment modality for
symptomatic UAVFs, has advantages that include a >95%
success rate, with a 4% complication rate in retrospective review
articles.30,31 UAE complications include
post-embolization syndrome in the form of severe pelvic pain and
radiation exposure, infection, embolization of nontarget organs,
impairment of ovarian function, intrauterine adhesions, and rebleeding
after blood recanalization. Several successful intrauterine pregnancies
after the UAE of UAVFs have been reported including a successful twin
pregnancy, which suggests that adequate collateral blood supply can
develop to support a full-term pregnancy.32 Peitsidis
et al. reported a 27 % pregnancy rate following bilateral
UAE.13 Women who become pregnant after UAE are at risk
of malpresentation, cesarean delivery, preterm birth, and
PPH.33 While the impact of UAE on future fertility and
pregnancy outcomes has been studied extensively, the subject remains
somewhat controversial.
Herein, we present a woman who suffered from secondary PPH following
vaginal delivery; her condition was diagnosed using DSA. This report
stresses the fact that the clinical suspicion of an acquired UAVF is
crucial to promptly diagnosing and treating secondary PPH. Still,
diagnosing and treating this condition is remains challenging for
physicians. By sharing this case report, we hope our experience will add
to what data exist already on UAVFs.