140: Placenta accreta index predicts placenta accreta spectrum severe enough to result in hysterectomy

Abstract

To validate the Placenta Accreta Index (PAI) for prenatal diagnosis of placenta accreta spectrum (PAS) at time of delivery in women with prior cesarean deliveries. Using an ultrasound (US) database, pregnancies complicated by third trimester placenta previa or low-lying placenta in the setting of prior cesarean delivery (CD) between 1/2012 and 12/2018 were identified. Images from the third trimester US most immediately preceding delivery were read by two physicians who were blinded to US reports, pregnancy outcomes, and clinical outcomes. A PAI calculation was calculated. This calculation includes number of prior cesareans, placental location, lacunae, bridging vessels, and smallest myometrial thickness. PAS was diagnosed based on histology of degree of placenta invasion (accreta, increta, or percreta). Clinical outcomes were obtained. Statistical analysis included Wilcoxon rank-sum test with P < 0.05 considered significant. 194 pregnancies met inclusion criteria. Cesarean hysterectomy was performed in 93 (48%), repeat CD in 94 (48%), and vaginal delivery in 7 (4%). Of those who underwent hysterectomy, 79 had histologic confirmation of PAS. The median PAI score was significantly different according to need for hysterectomy with the diagnosis of PAS (p < 0.001). Of the remaining 14 who underwent hysterectomy, but did not have histologic confirmation of PAS, 12 had clinically suspected invasion and 11 had bleeding complications. The PAI is useful in the prenatal diagnosis of PAS at the time of delivery and provides a standardized approach to US diagnosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)