Maternal and neonatal outcomes of women diagnosed with Placenta Accreta Spectrum Disorder managed by a standardized Multidisciplinary Team

doi:10.21203/rs.3.rs-3131845/v1

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Maternal and neonatal outcomes of women diagnosed with Placenta Accreta Spectrum Disorder managed by a standardized Multidisciplinary Team

https://doi.org/10.21203/rs.3.rs-3131845/v1

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Purpose

Placenta accreta spectrum disorder (PAS) is a pathological condition in which placenta abnormally adheres to or invades the myometrium. PAS has a high risk of complications, especially peripartum bleeding, which can be associated with several maternal and neonatal adverse outcomes. Our goal is to determine maternal and fetal outcomes in cases of PAS managed by a multidisciplinary team (MDT).

Methods

This is a retrospective cohort study that included all cases of PAS managed by a MDT between January 2016 and December 2022. Maternal and neonatal outcomes were analyzed for each case.

Results

There were 102 cases of PAS managed by a MDT during the study period. Maternal age average was 35.5 years, 75.4% had at least one prior cesarean section and 55.8% had placenta previa. 54.9% were diagnosed with placenta accreta, 20.5% with placenta increta and 24.5% with placenta percreta. Hysterectomy was performed in 55.8% of the cases, and in 87.7% of them placenta was left in situ. Blood products transfusion was necessary in 24.5% of the cases, with a mean number of 2 red blood cells concentrates. Intensive care unit admission rate after surgery was 8.8% and no maternal death occurred.

Conclusions

Although PAS is a condition associated with high morbidity and mortality, this study demonstrates lower rates of maternal complications than reported in literature. PAS management should be based in protocols, and pregnancy interruption should be performed in centers of excellence with an experienced and trained MDT, making it possible to reduce maternal morbidity and mortality.

placenta accreta spectrum disorder

multidisciplinary team

peripartum bleeding

maternal outcomes

maternal morbidity

Placenta accreta spectrum disorder (PAS) is a pathological condition in which spontaneous separation of the placenta does not occur, and it is not possible to remove it without causing abnormal or potentially fatal bleeding [1]. It is classified in three subtypes according to the depth of trophoblast invasion into the myometrium: placenta accreta, in which the villi is directly attached to the myometrium surface, without invading it; placenta increta, in which the villi is deeply penetrated into the myometrium up to the uterine serosa; and placenta percreta, in which the villous tissue penetrates and surpasses the serosa[2–4].

PAS incidence is increasing worldwide, most likely as a consequence of the rising rates of cesarean delivery - the most important risk factor for this condition [1]. The current incidence of PAS is 3.7 per 1000 births [5], and the most important risk factor is a previous uterine surgery.

Placenta previa is another important condition associated with PAS. Prevalence of PAS in women with placenta previa without prior cesareans is 3% [6], with a significant increase when both conditions are present [4,7].Several other risk factors for PAS are described, including advanced maternal age, multiparity, obesity, in vitro fertilization, prior uterine surgeries or curettage, manual delivery of placenta, postpartum endometritis, hysteroscopic surgery, endometrial ablation, uterine artery embolization, Asherman syndrome, bicornuate uterus, adenomyosis, submucous fibroids and myotonic dystrophy[2, 7, 8].

PAS is a potentially serious condition related to maternal outcomes such as severe bleeding - main cause of maternal death worldwide [9] - and need of blood transfusion, emergency surgeries and reintervention, intensive care unit (ICU) admission and even death. Multiple studies have demonstrated that maternal morbidity and mortality rates decrease when women with PAS are managed in “centers of excellence” [10–12]. There is no definitive evidence of what should constitute a “center of excellence”, although the following criteria are recommended by the International Society for Abnormally Invasive Placenta (IS-AIP): a center that can provide a multidisciplinary team (MDT) with experience in managing abnormally invasive placenta and can provide antenatal diagnosis and preoperative planning; rapid access to colorectal surgeon, vascular surgeon and hematologist in case of emergency; appropriate adult and neonatal intensive care facilities available; massive transfusion facilities; and intraoperative blood salvage services available [1]

The aim of this study is to describe maternal and fetal outcomes in cases of PAS handled by one MDT specialized in the management of PAS that acts in two hospital in Porto Alegre, Rio Grande do Sul, Brazil: Hospital de Clínicas de Porto Alegre and Hospital Moinhos de Vento.

This is a seven years retrospective cohort study that included 102 cases of PAS who were managed between January, 2016 and December, 2022 in HCPA - a hospital which provides mainly public health assistance - and HMV - a private hospital which provides assistance through supplementary health care system. Both institutions are located in Porto Alegre, a state’s capital in southern Brazil. This study describes the first seven years of a MDT that intended to develop training and expertise in the management of PAS and ended up becoming a reference group, acting in both centers. Diagnosis of PAS was made preoperatively by imaging and postoperatively by direct visual and histopathological examination.

The MDT includes obstetricians and anesthesiologists specialized in high complexity obstetrics; gynecologists specialized in oncologic surgery; gynecologists specialized in fetal medicine and radiologists with expertise in placental imaging; urologist; interventional radiologists; obstetric nurses; experts in adult and neonatal intensive care; and vascular surgeon, colorectal surgeon, and hematologist on-call. Both centers provided surgical facilities and materials, blood bank, adult and neonatal intensive care units. Patients were managed according to a flowchart and a checklist developed by the authors (J.V., C.C.S. and P.V.T.). One or more meetings for surgical planning were held, according to characteristics and severity of each case. Decisions about gestational age of planned delivery, setting (surgical or obstetric unit), skin and uterine incision, expected surgical procedure (conservative techniques or hysterectomy), use of ureteral stents and arterial balloons, blood products reserve, and different necessary resourced were made beforehand and discussed with the patients. Appropriate informed consent was obtained from each woman. The MDT protocol is described in Box 1 and is constantly being improved, aiming to provide a more systematic and evidence-based approach.

Data was collected by electronic medical records review and compiled into a database. Information regarding gynecological and obstetric characteristics, additional exams, surgical procedures and maternal and neonatal outcomes were included. Data is presented in absolute numbers, percentages, and frequencies. Continuous variables are presented as mean ± standard deviation or as median and interquartile range according to data distribution. Categorical variables are presented as frequencies. Variables were described as absolute (n) and relative frequencies (n%) or standard deviation (SD).

The study was approved by the Research Ethics Committee of Gynecology and Obstetrics Research and Postgraduate Group (GPPG-GO) and is registered in Plataforma Brasil (Certificate of Presentation of Ethical Appreciation: 19927919.0.0000.5327).

There were 102 cases of PAS managed by the MDT during the study period. 63 cases were admitted in HCPA and 39 in HMV. The MDT was implemented in 2015; data collecting and review began in 2016, when 6 cases occurred. After that, there were 13 cases in 2017, 14 in 2018, 24 in 2019, 19 in 2020, 17 in 2021 and 9 in 2022. The cases were respectively classified as placenta accreta, increta and percreta in 55%, 20.5% and 24.5%.The study flowchart is presented in Fig. 2.

Most women presented at least one prior cesarean section and placenta previa, and maternal age average was 35.5 years. At HMV, 74.4% of the women were 35 years or older and at HCPA 52.4%. The assessed main characteristics are described in Table 1.

Table 1

Characteristics of 102 women with placenta accreta spectrum disorder (PAS)
	Total (n = 102)
Age (years ± SD)	35.5 ± 4.9
Placenta previa	57 (55.8%)
One prior cesarean section	32 (31.3%)
Two or more prior cesarean sections	27 (26.4%)
Prior uterine curettage	25 (24.5%)
In vitro fertilization	14 (13.7%)
Uterine malformation	6 (5.8%)
Placenta accreta	56 (54.9%)
Placenta increta	21 (20.5%)
Placenta percreta	25 (24.5)

Average gestational age at delivery was 35.1 weeks and in 79 cases (77.4%) pregnancy interruption was planned. Regarding surgical settings, 68.6% of the cesarean sections took place in the surgical center and 31.4% in the obstetric unit. Median incision was performed in 46% of the cesarean sections. Ureteral stents and arterial balloons for occlusion of the hypogastric arteries were placed in 61.7% and 44.1% of women, respectively. Nearly half of the cases (55,8%) ended in hysterectomy; in 87,7% of those, placenta was left in situ, with no efforts made to remove it. Surgical time was counted starting from birth time until the end of surgery. Table 2 presents surgical characteristics subdividing the 102 cases in different time lapses.

Table 2

Surgical characteristics in pregnant women with placenta accreta spectrum disorder (PAS)
	2016–2017 (n = 19)	2018–2019 (n = 38)	2020–2022 (n = 45)	Total (n = 102)
Gestational age (weeks; median, p25-p75)	35.4 [34–36.6]	35.1 [34.1–36.2]	35.7 [33.3–36.8]	35.3 [34–36.4]
Surgical time (minutes; median, p25-p75)	82 [52.5–119.5]	84.5 [61–115]	75 [55–96]	79 [55–110]
Setting: surgical unit	14 (73.6%)	23 (60.5%)	33 (73.3%)	70 (68.6%)
Median incision	8 (42.1%)	19 (50.0%)	20 (44.4%)	47 (46.0%)
Ureteral stents	10 (52.6%)	24 (63.1%)	29 (64.4%)	63 (61.7%)
Arterial balloons in hypogastric arteries	11 (57.8%)	13 (34.2%)	21 (46.6%)	45 (44.1%)
Hysterectomy	11 (55.0%)	22 (57.8%)	24 (53.3%)	57 (55.8%)
Hysterectomy with Placenta left in situ (n = 57)	7 (63.6%)	19 (86.3%)	24 (100%)	-

During the study period, 102 alive babies were born, 98 from single pregnancies and 4 from twin pregnancies.

Blood transfusion was needed in 25 cases, from which 18 received only red blood cells concentrates and 7 received other blood products as well. Massive transfusion was performed in only 2 cases, both in HCPA. One of them, occurred in 2020, presented invasion of iliac vessels by placenta percreta and demanded transfusion of 18 units of red blood cells concentrates, 28 units of platelet concentrates, 16 units of fresh frozen plasma and 1 unit of cryoprecipitate. The other case, managed in 2021, presented placenta percreta with important bladder invasion, requiring transfusion of 17 units of red blood cells concentrates and 2 units of fresh frozen plasma. Due to severity and special characteristics of these cases, they were not included in the analysis of the mean number of blood products transfusion.

Most cases of bladder injury during surgery presented some degree of placental invasion of the organ. Maternal death, thromboembolic events, intestine injury and reintervention did not occur. Table 3 depicts the maternal and neonatal outcomes assessed in the present study.

Table 3

Maternal and neonatal outcomes in pregnancies with placenta accreta spectrum disorder (PAS)
	2016–2017 (n = 19)	2018–2019 (n = 38)	2020–2022 (n = 45)	Total (n = 102)
Maternal Outcomes
Transfusion of blood products	2 (10.5%)	12 (31.5%)	11 (24.4%)	25 (24.5%)
Red blood cells concentrates (n = 25) (units, median, p25-p75)	-	2.0 [1–3]	2.0 [2–3]	2.0 [1–3]
Postoperative wound infection	1 (5.2%)	4 (10.2%)	2 (4.4%)	7 (6.8%)
Bladder injury	-	7 (17.9%)	7 (15.5%)	14 (13.7%)
Maternal ICU admission	-	3 (7.8%)	6 (13.3%)	9 (8.8%)
Neonatal Outcomes
Neonatal ICU admission	13 (68.4)	27 (69.2)	29 (65.9%)	69 (67.6%)
Sepsis	-	3 (7.6%)	8 (18.1%)	11 (10.7%)
Jaundice	4 (21.0%)	15 (38.4%)	20 (45.4%)	39 (38.2%)
Respiratory failure	11 (57.8%)	22 (56.4%)	26 (59.0%)	59 (57.8%)

PAS is an obstetric disorder with rising incidence that requires appropriate management by expert professionals. It is one of the main causes of postpartum hemorrhage and is associated with a 40% chance of needing massive transfusion, contributing to high mortality rates [13]

Studies show that management by a MTD reduces PAS morbidity, which includes prenatal diagnosis and prenatal care by experienced professionals. A standardized planning prior to labor is mandatory, as well as preparation for performing an elective cesarean section, followed by an immediate hysterectomy if necessary [14–15].

Another recent retrospective cohort study demonstrated that antenatally diagnosed PAS and MDT management reduced blood loss and blood transfusion. Median blood loss of women with suspected PAS was 2000 mL versus 4000 mL (p < 0.001) compared to those with unexpected PAS; median number of red blood cells transfusion was four versus nine units (p < 0.001), respectively. In women managed by a MDT compared to usual care, median red blood cells transfusion was of one versus six units (p = 0.04) [5].

Pre-labor recognition of PAS cases prevents inappropriate attempts of placental removal, a procedure that is potentially harmful and can culminate with maternal death. A retrospective cohort study showed that women who were managed by the MDT had less attempts of manual removal of the placenta compared to those managed by usual care (p < 0,001) [13].

Planned cesarean section followed by hysterectomy is considered the ideal management for most critical cases. This approach presents better clinical outcomes when compared to emergency surgery due to an unplanned labor[13,16,18]. PAS management by a MDT reduced the need of emergency surgeries (14), an important aspect due to the high risk associated with these procedures. Thus, proper prenatal diagnosis of PAS is a cornerstone of the management of the disorder.

MDT management provides a larger number of prenatal diagnoses (44 [79%] versus 12 [37%], respectively (p < 0,001)) [13]. Ultrasound (US) examination and magnetic resonance imaging (MRI) interpretation for accurate antenatal diagnosis should be done by an experienced radiologist. US is usually the first imaging modality for the prenatal diagnosis of PAS and can be highly accurate when performed by a provider with expertise [19]. MRI is usually performed when PAS is suspected by US studies mostly with the aim of evaluating the extent of placental invasion, specially for those cases of posterior lying placenta. A study published by this research group analyzing diagnostic performance of radiologists with different levels of experience in the interpretation of MRI of PAS shows the most experienced professionals had higher sensitivity, negative predictive value and accuracy [20].

Cohort studies comparing outcomes before and after the implementation of a MDT and specific protocols show a reduction in blood loss and in blood products transfusion, and an increase in surgical time due to additional procedures [13, 21]. Intraoperative hemodynamic instability is common in cases of PAS and is potentially catastrophic, with consequences such as intravascular disseminated coagulation, kidney failure, acute respiratory distress syndrome and death. Therefore, an increase in surgical time is worthwhile if these outcomes can be prevented due to a more stable and safe clinical condition during surgery [21–22].

Different studies suggest there is a reduction in morbidity of women diagnosed with PAS managed in regional centers when compared to those managed in local hospitals [16]. Since the MDT was implemented, HCPA and HMV became reference hospitals for the management of PAS in the state of Rio Grande do Sul, Brazil. Similarly to other institutions that have implemented a MDT [23], the protocol used in HCPA and HMV enables early diagnosis of PAS, proper surgical planning - avoiding emergency surgeries - and a set of special standardized procedures (described above). Studies evaluating performance of MDT in the management of PAS show improved outcomes over time, with increasing experience of the professionals [24]. In the present study, as the team acquired more experience over years, there were progressively fewer attempts of placental removal before hysterectomy, less need for transfusion and shorter surgical time.

Studies suggest that a standardized approach carried out by a specific MTD for patients with PAS can be probably associated with mortality reduction [13]. No deaths were reported in the present study. It is not possible to determine if this reflects the effectiveness of MTD approach, or if it is due to lack of enough patients. PAS is an infrequent disorder and the number of cases described is still small. Nevertheless, this report describes one of the larger published case series until the present moment [13, 17–21].

Even though PAS is associated with a high risk of morbidity and mortality, in the present study we identified lower rates of complications than reported in literature. Unfortunately, comparisons of outcomes with a control group before the introduction of the MDT were not possible to perform, as HCPA and HMV have become reference centers for PAS only after the MDT was implemented, with few cases being referred to them before 2015. It is expected that in years to come, with an increasing number of cases and progressive acquisition of experience, it will be possible to obtain more data and conclusions on this very important topic.

Author Contribution

J Vettorazzi: Project development, Data Collection, Manuscript writing, Data analysis

LP Farenzena: Project development, Data Collection, Manuscript writing, Data analysis

AV Perez: Data Collection, Manuscript writing

MAJ dos Reis: Data Collection

PV Teichmann: Manuscript writing, Data analysis

Ts Garcia: Project development

CC Salazar: Project development, Data Collection, Manuscript writing, Data analysis

LA Scaffaro: Project development

CLA Ghezzi: Project development

EM Arlindo: Project development

DV Vettori: Project development, Data Collection

EG Valerio: Project development, Data Collection

Statements & Declarations

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

The authors have no relevant financial or non-financial interests to disclose.

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Maternal and neonatal outcomes of women diagnosed with Placenta Accreta Spectrum Disorder managed by a standardized Multidisciplinary Team

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Abstract

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Introduction

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Box 1

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