High intensity focused ultrasound in management of placenta accreta spectrum: A systematic review

Background: High intensity focused ultrasound (HIFU) is a non-invasive procedure that has been recently studied in management of placenta accreta spectrum (PAS). Objective: To appraise efficacy and safety of HIFU in management of PAS and to highlight restrictions of transitioning uterus-preserving studies to clinical practice. Search Strategy: A search on Scopus, Cochrane, PubMed and Web of Science was conducted from date of database inception to January 31st, 2020. Selection Criteria: Studies on use of HIFU in management of PAS were eligible. Review articles, conference papers, animal studies, and case reports were excluded. Data Collection and Analysis: A standardized data collection sheet was used to abstract data from eligible studies. CON-PAS registry was used to include studies on other conservative modalities of management of PAS. Results: Out of 30 studies, four were eligible (399 patients). Average residual placental volume was 61.74 cm3 (6.01-339). Treatment was successful in all patients. Normal menstruation recovered after 48.8 days (15-150). Average time for normalization of β-HCG was 16.5 (1-82) days. No major complications were encountered. Sixty-one studies were retrieved from CON-PAS registry; uterine artery embolization (23 studies), Prophylactic balloon placement (15), compression sutures (10), leaving placenta in situ (7), and uterine wall excision (6) were successful in 83.7% 92.9% 87.9%, 85.2%, and 79.3% of patients, respectively. Conclusions: HIFU yields promising success and safety profile in management of PAS in certain clinical situations. A global research strategy is recommended to incorporate conservative approaches in selected patients within a comprehensive protocol to manage PAS.