OC30.06: Proposal for ultrasound staging of placenta accreta spectrum disorders

Abstract

Objectives: To develop an ultrasound(US) staging system for placenta accreta spectrum disorders (PAS) and to ascertain whether it may stratify the risk of surgical outcome before birth. Methods: We propose the following classification of PAS based upon the distribution of the different US signs in women with placenta previa:PAS0:Placenta previa with no US signs of invasion or placenta previa with placental lacunae. PAS1:Presence of at least two US signs among:placental lacunae,loss of the clearzone or bladder wall interruption. PAS2:PAS1 +uterovescical hypervascularity.PAS3:PAS1/PAS2+evidence of increased vascularity in the inferior part of the lower uterine segment potentially extending in the parametrial region.We explored whether this US staging system was correlated with surgical outcomes and depth of placental invasion. We assessed the correlation between the present US and the FIGO clinical grading system proposed. Results: 259 women were included in the analysis. There was a increase in the mean units of FFP, PRBC transfused and mean EBL with increasing severity of US staging of PAS. Women with PAS3 on US had a significantly higher PLT transfused. Mean surgical time was longer in women PAS3 compared to PAS1-2. Women with PAS3 had a longer LOS in the hospital compared to PAS0, PAS1 and PAS2. Increase severity in US staging for PAS was independently associated with a significant increase in EBL,units of PRBC,PLT transfused,surgical time and length of in hospital stay.Logistic regression analysis, increase in PAS severity was independently associated with surgical complications while only PAS3 was associated with admission to NICU.All women labelled as PAS0 on US were stage 1 according to FIGOgrading system. Of the women presenting with PAS1 on US,64.1%were classified as stage 3, 35.9% as stage 4 according to FIGOgrading system. All women with PAS2 were categorized as stage 5 and all those with PAS3as stage 6 according to the FIGO classification. Conclusions: US staging of PAS disorders is feasible and correlates with surgical outcome,depth of invasion and FIGO clinical grading system.