This study was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (registration number: 2021–059). We retrospectively analyzed the clinical data of PAS patients with placenta previa who underwent cesarean section from October 2018 to October 2020. The inclusion criteria were patients with PAS combined with placenta previa diagnosed by color Doppler ultrasound or magnetic resonance imaging (MRI) and were further confirmed during the operation, with a history of caesarean section, and without other obstetric diseases. In addition, patients with abnormal coagulation function, anemia, and bleeding before surgery are not included. Emergency cesarean section surgery was not included in this study. Based on the results of ultrasound or magnetic resonance examinations, combined with clinical features, obstetricians pre-place abdominal aortic balloons for patients who need to. For economic reasons or other special reasons, the patient may refuse to install an abdominal aortic balloon. In patients with a balloon, if there is no obvious bleeding during the operation, the balloon will not be inflated. Data collection was accomplished by the authors by review of medical records.
This study was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (registration number: 2021–059). We retrospectively analyzed the clinical data of PAS patients with placenta previa who underwent cesarean section from October 2018 to October 2020. The inclusion criteria were patients with PAS combined with placenta previa diagnosed by color Doppler ultrasound or magnetic resonance imaging (MRI) and were further confirmed during the operation, with a history of caesarean section, and without other obstetric diseases. In addition, patients with abnormal coagulation function, anemia, and bleeding before surgery are not included. Emergency cesarean section surgery was not included in this study. Based on the results of ultrasound or magnetic resonance examinations, combined with clinical features, obstetricians pre-place abdominal aortic balloons for patients who need to. For economic reasons or other special reasons, the patient may refuse to install an abdominal aortic balloon. In patients with a balloon, if there is no obvious bleeding during the operation, the balloon will not be inflated. Data collection was accomplished by the authors by review of medical records.
Treatment methods
The process of Cesarean section for patients without balloon placement. 20 U of oxytocin was injected in the myometrium. If the placenta cannot be peeled off automatically, it needs to be peeled off manually. If the placenta invaded up to one-third of the myometrial layer, we excised a section of the placenta, simultaneously ligated the bleeding vessels, and applied a ∞-shaped suture to the placental bed. After the placenta had separated, we examined the placental bed and the depth of myometrial invasion. Choose to use ergonovine and Hemabate according to the condition of uterine contraction. Uterine compression sutures, uterine gauze packing, uterine tamponade, uterine artery ligation, or uterine artery embolization are selected according to the blood loss on the wound. Hysterectomy was performed when the bleeding could not be controlled.
The procedure of Cesarean section for patients with abdominal aortic balloon. In the DSA operating room, the abdominal aortic balloon was placed before the Cesarean section. With the help of contrast agent, the catheter position is positioned below the renal artery. Choose an appropriate size cuff, fill the cuff with contrast agent, and record the dose of the contrast agent. After the balloon placement is complete, the patient is sent to the operating room for Cesarean section. Choose to inflate or deflate the cuff according to the bleeding during the placenta dissection. If there is no obvious bleeding, the balloon is released to restore blood supply. The wound was carefully observed. If there is heavy bleeding, inflate the balloon to block the abdominal aorta, and take the following measures: suture the bleeding area, cervix pull-up suture, uterine artery ligation (or uterine artery embolization), uterine compression sutures, uterine cavity gauze packing or balloon tamponade. The surgeon will choose gauze packing or balloon tamponade for compression according to their own habits or experience. If the bleeding cannot be controlled, a hysterectomy is performed. The abdominal aortic balloon can be blocked intermittently during the operation to determine the hemostatic effect.
Investigated clinical characteristics
The primary outcome of this study was the occurrence of postpartum massive bleeding.
Other clinical related indicators that need to be collected: the amount of red blood cell transfusion, uterus resection, maternal ICU admission and other indicators. We also reviewed the neonatal outcome including neonatal gender and birth weight. To evaluate some of the mother’s clinical characteristics, including the mother’s age, body mass index, gestational age at delivery, history of cesarean section, history of curettage, and number of pregnancy.
Ultrasound-related indicators that need to be collected: ultrasound examination before surgery to determine the exact location of the placenta, and at the same time to verify the exact location of the placenta in the postoperative medical records. It also includes the placental hypervascularity, the thickness of the placenta, and the length of the cervical canal.
PAS (formerly called morbidly adherent placenta) is a broad term that includes: Placenta accreta – Anchoring placental villi attach to the myometrium (rather than decidua). Placenta increta – Anchoring placental villi penetrate into the myometrium. Placenta percreta – Anchoring placental villi penetrate through the myometrium to the uterine serosa or adjacent organs. Placental hypervascularity can be divided into the following four levels, including visible blood flow, relatively rich blood flow, rich blood flow and extremely rich blood flow. The position of the placenta is mainly divided into the following three situations. First, if the placenta mainly covers the anterior wall of the uterus, it is called an anterior position. Second, if the main position of the placenta is anterior and posterior, the position of the placenta is anterior and posterior. Third, if the location of the placenta is mainly in the posterior wall of the uterus, the location of the placenta is posterior.
Statistical analysis
All statistical analyses were conducted using the SPSS 22.0 software (IBM, Armonk, NY, USA). The categorical data were expressed as number/proportion and analyzed by x2-test, Fisher’s exact test. The continuous variables were expressed as mean ± SD and analyzed by t-test. P<0.05 was considered statistically significant.
The association between the ultrasound and clinical characteristics and postpartum massive bleeding was analyzed by univariable and multivariable logistic regression analysis. Univariate and multivariable logistic regression analyses were used to test the association between massive bleeding and maternal age, degree of previa, history of abortion, gestational age at delivery, cervical canal length, placenta thickness, placental implant area, placental hypervascularity, and inflation of the abdominal aortic balloon.