Results:
Thirty articles were initially retrieved from literature search. Eleven
articles were excluded as duplicates. Out of 19 remaining abstracts, 7
articles were excluded for irrelevance, 7 articles were review articles,
and 1 article was a conference paper. Eventually, 4 studies with, a
total of 399 patients, were eligible for this review (3, 19-21).
Selection process and quality assessment of included studies are
illustrated in Figure 1 and Figure 2, respectively.
All studies were conducted in China. Three of them were retrospective
(3, 20, 21), and one study was prospectively designed (19). Selection
criteria were highly consistent in all studies and were confined to
clinically stable women with imaging-based diagnosis of PAS, and a
residual placental tissue greater than 3 cm. Included women were highly
motivated to preserve their uteri and their baseline hemoglobin level
was above 70 g/l. Eligibility was confined to women delivered vaginally
in one study (19). Otherwise, both women delivered vaginally or by
cesarean section were included. Women with active postpartum hemorrhage,
genital infection, or extensive abdominal scarring were excluded.
Patients with a large residual placental mass occupying more than half
of the uterus cavity were not eligible in one study (19), and
non-vascularized retained placenta was excluded from another study (20).
Study characteristics and selected population are summarized (Table S1).
Diagnosis of PAS was verified by color Doppler ultrasound and magnetic
resonant imaging (MRI) findings, which were conducted before and after
the procedure in all studies. Average placental volume was 61.74
cm3 (range: 6.01 to 339 cm3) (3, 19,
20). Treatment was delivered in one session in all studies except one
study where treatment was delivered in a 3-day course (20). Sonication
time ranged between 200 to 2500 seconds (median time ranged between 600
to 701 seconds) (3, 20, 21). In all studies, HIFU was combined with
uterine curettage/hysteroscopic resection, at one or more sessions, to
remove residual tissue or necrotic debris. Methotrexate was considered
in some patients in one study if baseline β-HCG was greater
than100mIU/mL (20).
In all studies, HIFU was associated with decrease in size and
vascularity by ultrasound, and reduced signal intensity and degree of
enhancement by MRI. Normal menstruation recovered after 48.8 days on
average (range: 15-150 days) (3, 19, 20). Average time for β-HCG to
normalize was 16.5 (1-82) days (3, 20). No major complications were
encountered in all studies. One patient experienced significant vaginal
bleeding requiring uterine evacuation. Skin burn and hyperpyrexia were
reported in one patient each (0.25%). Majority of patients (393,
98.5%) had no pain or low pain scores ≤ 3. A summary of management and
outcomes of included studies is shown in Table S2.
Sixty-one studies were retrieved from CON-PAS registry on common
modalities of conservative management of PAS (Figure 3). Uterine artery
embolization (UAE) was evaluated in 23 studies with a total of 453
patients. Uterine preservation was reported in 83.7%, and complications
were encountered in 19.6% of patients. Prophylactic internal
iliac/aortic balloon placement was assessed in 15 studies (651
patients); success and complication rate were 92.9% and 6.8%,
respectively. Compression sutures were addressed in 10 studies (265
patients). Uterus was preserved in 87.9%, and complications were
described in 16.6% of study cohort. Leaving placenta in situ, with or
without systemic methotrexate treatment, was assessed in 7 studies.
Management was successful in 85.2% of 122 patients, and 18.6%
experienced perioperative complications. Finally, six studies expatiate
uterine wall excision and reconstruction. Among 488 patients managed by
this technique, uterine preservation was achieved in 79.3% of patients.
The rate of complications was 27.5% (Table S3).