We performed a historical control study of patients with PAS from 1st March 2015 to 30th September 2016 in the Maternal and Child Care Hospital of Anhui Province. Written informed consent was obtained from each parturient before enrollment in the study according to the process of informed consent by the Institutional Ethics Committee of Anhui Women and Child Health Care Hospital. The study was approved by the Institutional Ethics Committee of Anhui Women and Child Health Care Hospital (2016(12)).
Forty-eight pregnant women were included in this trial, and the inclusion criteria were as follows:(1) clinical diagnosis of PAS by US or MRI; (2) gestational age > 31 weeks; and (3) elective or emergency caesarean delivery. The exclusion criteria were refusal by the parturient, antepartum bleeding, severe cardiac disease, aortic diseases and lack of complete information. The parturients were divided into two groups. Group A comprised 25 patients who underwent PAABO before CS. Group B comprised 23 patients who were not treated with PAABO: 10 did not undergo PAABO because they were hospitalized before October 2015, during which the PAABO technique was not available, and 13 declined the procedure.
In our pilot study, we found that compared with baseline values, the mean SBP level was elevated by 16.43 mmHg in Group A and 2.26 mmHg in Group B at T2 (1 min after balloon inflation). The standard deviations were 10.39 and 9.46, respectively. To achieve 90% power for the test, a minimum sample size was calculated by G*Power 3  software as 10 patients in each group if P < 0.05 was deemed to indicate a statistically significant difference.
For Group A, the prophylactic abdominal aorta balloon was implemented by the radiologist in a DSA operating room. The right femoral artery was punctured using a modified Seldinger technique. A 12-F sheath was inserted from the femoral artery to the infrarenal abdominal aorta. The 8-F pigtail occlusion balloon catheter was embedded and located below the level of the renal artery.
After foetal delivery and umbilical cord clamping, the balloon was inflated with 6 ~ 15 ml 0.9% saline solution if the placenta could not spontaneously be expelled or severe bleeding was present. Complete occlusion was defined as absent pulsation of the dorsalis pedis artery and a foot oxygen saturation of 0 . The longest single continuous balloon inflation time was 15 min, after which deflation was performed for 1 min. The duration of total occlusion was recorded for all patients. Once balloon inflation was achieved and a surgical field with less blood was obtained, the obstetricians set out to perform either conservative management or hysterectomy. When the operation was completed, the balloon was deflated for 1 min to check bleeding. If there was no recurrence of bleeding, the balloon remained deflating. If bleeding was observed, the balloon was re-inflated. Uterine artery embolization was carried out by the obstetrician. Subtotal hysterectomy was performed when necessary. If the placenta had penetrated the uterine wall and injured the bladder, the urologist might repair the bladder. Hysterectomy was carried out if the bleeding could not be controlled by the above operation. As soon as the operation was completed and there was no fresh uterine bleeding, the balloon catheter was pulled out, while the arterial sheath was removed after 6 h with compression bandaging of the femoral artery puncture sites.
In Group B, patients underwent CS and placenta evacuation without balloon occlusion of the abdominal aorta, followed by uterine artery ligation, local excision of the uterine wall, bladder repair, and even hysterectomy according to the placenta accreta location and depth. The intramuscular injection of uterotonic drugs ( 20 U of oxytocin and 100 µg of carbetocin or 250 µg of tromethamine) was given immediately after delivery of the baby and clamping of the umbilical cord.
Regarding the anaesthesia procedure, 24 parturients in Group A and 3 parturients in Group B were operated under general anaesthesia. General anaesthesia was performed with propofol (1.5 mg/kg), remifentanil (1.5 mg/kg), and succinylcholine (1.5 mg/kg) followed by tracheal intubation and mechanical ventilation just before skin incision. Midazolam (2 mg), sufentanil (0.3 µg/kg), and cisatracurium (0.15 mg/kg) were added after foetal delivery. Continuous pumping of propofol (6 mg/kg/h) and remifentanil (2 µg/kg/h) was performed to maintain the depth of anaesthesia. One parturient in Group A and 20 parturients in Group B were administered combined spinal and epidural anaesthesia. The patient’s vital signs, including blood oxygen saturation (SPO2), electrocardiogram (EKG), invasive arterial blood pressure (IBP), central venous pressure (CVP), and arterial blood gas analysis, were monitored in all parturients.
The primary outcomes were estimated blood loss (EBL), blood transfusion volume, incidence of hysterectomy, change in haemoglobin level after surgery, and vital parameters during surgery. EBL was calculated with the collection of blood in the suction bottle and the weight of the surgical swabs, subtracting the volume of amniotic fluid. Data on vital signs including systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were recorded at baseline (T0), 1 min before balloon inflation (T1), 1 min after balloon inflation (T2), 5 min after inflation (T3), 1 min after deflation (T4), and 5 min after deflation (T5).
The secondary outcomes included the operating time from the time of skin incision to skin closure, the balloon occlusion time, maternal balloon occlusion-related complications, neonatal outcomes including Apgar scores at 1 and 5 min, and a comparison of the outcomes in general anaesthesia versus regional anaesthesia.
Continuous variables were expressed as the mean ± standard deviation. Categorical variables are described as numbers and percentages. Data were analysed by using SPSS version 16.0. Normally distributed data, such as demographic data, EBL, change in haemoglobin levels and operating time, were analysed using independent samples t-tests. Abnormally distributed data, such as the volume of red blood cells transfused, were analysed using the Mann-Whitney U test. Categorical variables, such as hysterectomy, neurologic complications of the lower limbs, and gastrointestinal complications, were assessed using Fisher’s exact test. For laboratory data, paired t-tests were used to compare the preoperative and postoperative values, and two-sample t-tests were used to compare data from the two groups. Vital parameters including SBP were analysed by repeated measures ANOVA. P < 0.05 was considered statistically significant.