Placenta Accreta Spectrum

Prenatal identification of invasive placentation using ultrasound in women with placenta previa and prior cesarean delivery

OBJECTIVE

To evaluate the performance of ultrasound for antenatal identification of invasive placentation in women with placenta previa in the setting of prior cesarean delivery.

STUDY DESIGN

This was a multicenter, retrospective, cohort study. Singleton pregnancies at risk of placenta accreta because of persistent placenta previa in the setting of prior cesarean delivery who delivered at four centers, from January 2010 to May 2020, were included in the study. For this study, pregnancies with diagnosis of accreta, increta, or percreta were considered under the umbrella term of placenta accreta. All women with placenta previa identified in the second trimester had a follow-up ultrasound at 32-34 weeks. Only those with prior cesarean delivery were considered at risk of placenta accreta. Women were considered with suspected accreta in case of suspected prenatal ultrasound. Women with suspected placenta accreta had delivery planned via cesarean hysterectomy at 34+0 - 35+6 weeks, without any attempt to remove the placenta. The primary endpoint of the study was the performance of ultrasound for antenatal identification of invasive placentation. The following ultrasound signs were evaluated: placenta lacunae; loss of clear space; increased vascularity between myometrium and placenta; intracervical lake; rail sign; uterovesical hypervascularity; increased vascularity in the inferior part of the lower uterine segment potentially extending into the parametrial region; and disruption of bladder-myometrial interface.

RESULTS

180 singleton pregnancies with placenta previa in the setting of prior cesarean delivery were identified. Of them, 155 (86.1%) had antenatal suspected placenta accreta based on ultrasound, having at least one sign of invasive placentation. Of the 155 suspected cases, 99 had confirmed placenta accreta at the time of delivery. Among the 99 cases of confirmed placenta accreta, all of them had at least one sign of invasive placentation at ultrasound. Among the 81 cases with placenta previa, prior cesarean delivery, without placenta accreta, 25/81 (30.9%) had ultrasound scan negative for sign of invasive placentation, and 56/81 (69.1%) had at least one sign of invasive placentation). In particular, 12/81 (14.8%) had placenta lacunae, 16/81 (19.8%) had loss of clear space, 20/81 (24.7%) had increased vascularity between myometrium and placenta, 9/81 (11.1%) had intracervical lake, 14/81 (17.3%) had rail sign, 14 (17.3%) had uterovesical hypervascularity, 5/81 (6.2%) had increased vascularity in the inferior part of the lower uterine segment potentially extending into the parametrial region, 8/81 (9.9%) had disruption of bladder-myometrial interface. In the group of women with confirmed placenta accreta, the most common sign recorded was the disruption of bladder-myometrial interface, being recorded in 88/99 women. Disruption of bladder-myometrial interface had the highest sensitivity in detection placenta accreta. Women with disruption of bladder-myometrial interface at ultrasound had 73-fold increase in the risk of placenta accreta compared to those who did not.

CONCLUSION

Prenatal ultrasound has an excellent diagnostic accuracy in identifying invasive placentation in women with placenta previa and prior cesarean delivery.

MR Evaluation of Placenta Accreta Spectrum: Concordance Rates and Effect of Structured Reporting on Patient Outcomes

OBJECTIVE

To examine the concordance rate of MRI findings with intraoperative and pathologic findings in patients with Placenta Accreta Spectrum (PAS), as well as the use of structured reporting, and their relationship to clinical outcomes.

METHODS

An IRB approved retrospective chart review was performed for patients with a history of cesarean delivery, a diagnosis of PAS on post-operative pathology report, and a placental MRI prior to delivery between 2008-2022. Concordance rates were calculated between final MRI, ultrasound, operative, and pathologic diagnoses, as well as impact on clinical outcomes. Quantitative variables were analyzed using a t-test. Categorical variables were analyzed using chi-squared and Fischer's exact tests.

RESULTS

A total of 59 patients met initial inclusion criteria. Of these 59 patients, 8 (13.6%) were interpreted using structured reporting. Discordance between preoperative imaging, operative findings and final pathology diagnoses were associated with increased blood loss, blood transfusion, ICU admission, and postpartum length of stay. Structured reporting was found to significantly reduce the amount of diagnostic discordance (p=.017) and was associated with decreased ICU admissions when utilized (p=.045).

CONCLUSIONS

Use of structured reporting in the interpretation of placental MRI may decrease the amount of discordance between imaging and intraoperative or pathologic diagnoses, which in our study is associated with improved patient outcomes including decreased blood loss and amount of blood transfused. Radiologists must be cognizant of key imaging features of PAS on MRI, as interpretation provides an opportunity to positively impact the quality and safety of patient care.

Gynaecological Causes of Acute Pelvic Pain: Common and Not-So-Common Imaging Findings

In female patients, acute pelvic pain can be caused by gynaecological, gastrointestinal, and urinary tract pathologies. Due to the variety of diagnostic possibilities, the correct assessment of these patients may be challenging. The most frequent gynaecological causes of acute pelvic pain in non-pregnant women are pelvic inflammatory disease, ruptured ovarian cysts, ovarian torsion, and degeneration or torsion of uterine leiomyomas. On the other hand, spontaneous abortion, ectopic pregnancy, and placental disorders are the most frequent gynaecological entities to cause acute pelvic pain in pregnant patients. Ultrasound (US) is usually the first-line diagnostic technique because of its sensitivity across most common aetiologies and its lack of radiation exposure. Computed tomography (CT) may be performed if ultrasound findings are equivocal or if a gynaecologic disease is not initially suspected. Magnetic resonance imaging (MRI) is an extremely useful second-line technique for further characterisation after US or CT. This pictorial review aims to review the spectrum of gynaecological entities that may manifest as acute pelvic pain in the emergency department and to describe the imaging findings of these gynaecological conditions obtained with different imaging techniques.

Timing of delivery for placenta accreta spectrum: the Pan-American Society for the Placenta Accreta Spectrum experience

BACKGROUND

The Society for Maternal-Fetal Medicine recommends cesarean delivery with potential hysterectomy scheduled in the late preterm period between 34 0/7 and 35 6/7 weeks of gestation for prenatally suspected placenta accreta spectrum.

OBJECTIVES

We aimed to investigate clinical compliance with the recommended delivery timing window for placenta accreta spectrum and its impact on maternal and neonatal outcomes.

STUDY DESIGN

We performed a retrospective multicenter review of data from referral centers within the Pan-American Society for Placenta Accreta Spectrum. Patients with placenta accreta spectrum with both antenatal diagnosis and confirmed histopathologic findings were included. We investigated adherence to the Society for Maternal-Fetal Medicine-recommended gestational age window for delivery, and compliance was further stratified by scheduled and unscheduled delivery. We compared the outcomes for patients with scheduled delivery within vs immediately 2 weeks outside the recommended window.

RESULTS

Among 744 patients with a prenatal diagnosis of placenta accreta spectrum and placental histopathologic confirmation, 488 (66%) had scheduled delivery. Among all prenatally diagnosed placenta accreta spectrum patients, 252 (39%) delivered within the recommended window of 34 0/7 and 35 6/7 weeks gestation. For the subgroup of patients who underwent scheduled delivery (n=426), 209 (49%) had delivery in this window, 120 (28%) delivered before 34 weeks, and 97 (23%) delivered at or later than 36 weeks. In the patients with scheduled delivery, 27% of placenta accreta spectrum patients with accreta delivered in the 2 weeks immediately after the recommended window (36 0/7-37 6/7 weeks), and 22% of placenta accreta spectrum pregnancies with increta/percreta delivered in the 2 weeks immediately before the recommended delivery (32 0/7-33 6/7 weeks). The maternal outcomes among those who delivered within the recommended range vs those delivering 2 weeks before and after the recommended range were similar, regardless of placenta accreta spectrum severity.

CONCLUSION

Less than half of placenta accreta spectrum patients had scheduled delivery within the recommended gestational age of 34 0/7 to 35 6/7 weeks. The reasons for deviation from recommendations and the risks and benefits of individualized timing of delivery on the basis of risk factors and predicted outcomes warrant further investigation.

Importance of the gynecologic oncologist in management of cesarean hysterectomy for Placenta Accreta Spectrum (PAS)

OBJECTIVE

Placenta Accreta Spectrum (PAS) is an invasive placental disorder characterized by significant maternal and fetal morbidity. Utilization of multidisciplinary teams has been shown to optimize patient outcomes. Our objective was to assess the impact of cesarean hysterectomy performed by gynecologic oncologists versus Ob/Gyn specialists in maternal morbidity.

METHODS

A retrospective cohort study was performed of singleton, non-anomalous pregnancies complicated by PAS University of Texas Health San Antonio Placenta Accreta program from 2010 to 2021. Our primary outcome was a maternal morbidity composite of any of the following: estimated blood loss >2 L, ICU admission, intraoperative acidosis and post-operative length of stay >4 days. In addition, demographic and pregnancy data were obtained. Univariate and multivariate analyses were performed to identify the individual impact of variables such as general anesthesia, episodes of vaginal bleeding, uterine artery embolization, emergent delivery and placenta percreta pathology.

RESULTS

122 pregnancies complicated by PAS who underwent cesarean hysterectomy were identified from 2010 to 2021. Gynecologic oncologists were the primary surgeons for 62 (50.8%) of these cases. The involvement of gynecologic oncologists increased over the time period from 16% to 80%. Gynecologic oncologists were more like to be involved in cases with an antenatal diagnosis of placenta percreta (11.7 vs 37.1%, p = 0.001) and these cases were characterized by increased composite maternal morbidity (65 vs 83.9%, p = 0.02). These cases were also significantly longer (151 vs 271 min, p < 0.0001), involved greater usage of urinary stents (36.7 vs 66.1%, p = 0.002) and had longer post-operative lengths of stay (3 vs 4 days, p < 0.0001). PAS cesarean hysterectomies by gynecologic oncologists were less likely to be supracervical (25 vs 3.2%, p = 0.0005). Multivariate analysis controlling for placenta percreta, uterine artery embolization, vaginal bleeding and emergent delivery showed no difference in composite maternal morbidity (aOR = 0.95, 95%CI [0.35-2.52]) and lower rates of intraoperative acidosis (aOR = 0.36, 95%CI [0.14-0.93]) or post-operative length of stay >4 days (aOR = 0.37, 95%CI [0.15-0.91]).

CONCLUSIONS

Gynecologic oncologists play a critical role in the surgical management of PAS cesarean hysterectomies. When compared to Ob/Gyn specialists, gynecologic oncologists are more likely to act as primary surgeons in complex cases similar morbidity and greater post-operative outcomes.