Case series of patients with placenta percreta – pre-operative assessment and clinical experience in a tertiary care center

Introduction:

In patients with placenta percreta (PP), the placenta rather grows pushing the adjacent tissues apart than infiltrating these, often at the site of an iatrogenically pre-created niche. Blood perfusion of the PP is ensured by uterine vessels as well as vessels from neighboring organs, leading to one of the most challenging situations in obstetrics. Hysterectomy is mostly inevitable. The objective was to analyze clinical features of our patients with PP and to report our experience concerning preoperative assessment modalities, since correct preoperative preparation is of utmost importance.

Methods:

In this retrospective case-series, data from all patients with PP at the University Hospital Zurich between 2009 and 2018 were reviewed.

Results:

Twenty-three women with PP were identified, among these 14 patients with placenta previa. All patients but one had a previous cesarean section and the latter had a previous myomectomy. Hysterectomy was performed in all patients. All patients survived. The median blood loss was 3800 ml (IQR 3000 – 4500 ml) with transfusion of median 4 erythrocyte concentrates (IQR 2 – 5). Ureteral stents were preoperatively placed in 10 patients (43.5%) and aortic balloon catheters in 3 patients (13%).

Fig. 1

Preoperative imaging diagnosed a PP in 18 of the 23 cases. A tendency of improved preoperative imaging assessment was observed in the second half of the study period, where only one case of PP had been „missed“. Likewise, MRI in addition to ultrasound was increasingly performed in 8/11 patients in the last five years as compared to 4/12 patients in the first five years of the study period. In 4 cases the MRI and ultrasound diagnosis differed widely: in 3 cases the ultrasound described the intraoperative situs more accurately and in 1 case the MRI favored the diagnosis of a PP in contrast to the ultrasound which showed a placenta previa only.

Conclusions:

We assume that due to our interdisciplinary approach at our tertiary care center which involved detailed pre-operative planning as well as immediate interdisciplinary involvement in cases of unsuspected PP, maternal mortality was zero. Placental location in areas of prior uterine surgery (cesarean, myomectomy, curettage) is a risk factor for PP and demands accurate pre-surgery evaluation. MRI should be performed in case of uninformative ultrasound. Assessment and delivery in a specialized center is recommended if PP is suspected.