Every minute counts: a network meta-analysis comparing the effect of prophylactic endovascular procedures in abnormal placentation

Background: Preventing postpartum haemorrhage remains a high priority worldwide. We aimed to provide all available evidence comparing maternal and neonatal outcomes of different prophylactic endovascular procedures in patients with abnormal placentation. Methods: Pubmed, Embase and ClinicalTrials.gov databases were searched from inception to Nov, 2024, using relevant key words. Studies comparing outcomes of women undergoing or not prophylactic endovascular procedures in planned cesarean delivery in patients with antenatally suspected or confirmed PAS, placenta previa or both were included. An arm-based random effect frequentist network meta-analysis was performed. All available maternal and neonatal outcomes were evaluated. Results: Three randomized controlled trials and 59 observational studies were eligible reporting on 6973 women (42.9% did not undergo any endovascular procedure, 26.7% underwent aortic balloon occlusion, REBOA, 16.6%, internal iliac balloon occlusion, PBO-IIA, 5.8%, common iliac artery occlusion, PBO-CIA, placement, and 7.8% underwent uterine artery embolization, UAE). The pooled network analysis showed that all prophylactic endovascular procedures were associated with reduced perioperative blood loss, with proximal balloon occlusion (REBOA) having the strongest effect (SMD −1.80 L, 95%CI −2.38;-1.21; I2 = 97.2%). Also, peripartum hysterectomy rates were significantly lower in women undergoing prophylactic UAE and REBOA compared to the control group; moreover, patients with placenta previa without any prophylactic endovascular procedure had a 4 to fivefold increased risk of peripartum hysterectomy compared to the REBOA group (I2 = 20.6%). REBOA was associated with a significant decrease in massive transfusion rates (I2 = 0%), surgery-related complications (I2 = 0%), ICU admissions (I2 = 40.3%), and units of red blood cells transfused (I2 = 92.8%), compared to PBO-IIA and control groups. The control group versus women undergoing prophylactic UAE showed a significant increase in total operative time (I2 = 96.5%) and Clavien-Dindo grade IV post-operative complications (I2 = 26%), compared to REBOA. All prophylactic endovascular procedures had a comparable risk ratio in terms of units of platelets transfused, maternal mortality, and use of additional post-operative bilateral uterine artery embolization among the treatment groups. As for neonatal outcomes, no significant differences were detected. Conclusions: Although the preponderance of observational studies suggests caution in interpreting the results of this meta-analysis, our findings suggest that prophylactic endovascular interventional procedures, particularly aortic balloon occlusion, may substantially improve clinical outcomes in women with PAS, placenta previa or both. PROSPERO registration number: CRD4202457398.