Role of Placenta Accreta Index for Diagnosis of Placenta Accreta Spectrum in High-Risk Patients.

Background: Antenatal diagnosis of placenta accreta spectrum (PAS) can ensure multidisciplinary management at center of excellence which can reduce maternal and fetal complications. This can be established by a scoring system which provides a standardized criterion for the diagnosis and management. The objective of our study was to assess the placenta accreta index (PAI) and its individual parameters for diagnosis of PAS in high-risk patients.
Methods: A prospective study was conducted on 71 pregnant women with placenta previa and previous cesarean section. After informed consent, history was taken and ultrasonography was used to calculate the PAI for each patient. Definitive diagnosis was made clinically during cesarean section or by histopathology for those requiring hysterectomy. The data were evaluated using the latest version of Statistical Package for the Social Sciences software.
Results: All ultrasound parameters of placenta accreta index were statistically significant for predicting PAS (p value < 0.001). ROC curve with AUC of 0.87 95% CI of 0.77-0.94 showed that a score of 4.75 was the best cutoff value to diagnose PAS. Out of the 30 patients found to have placental invasion, 22 had a PAI score of more than 4.75. The score was found to have a sensitivity of 73.3%, specificity 95.1%, positive predictive value 91.7%, negative predictive value 83% and diagnostic accuracy 85.9%. Conclusions: Women with placenta previa and history of previous CS should undergo screening by PAI, and a cutoff value of ≥ 4.75 should be viewed with high index of suspicion for the presence of PAS. © Federation of Obstetric & Gynecological Societies of India 2021.