Tuesday, December 4, 2012
The placenta accreta spectrum involves abnormal placental implantation. Placenta accreta is implantation of the chorionic villi in the myometrium while increta and percreta refer to implantation through the myometrium and in the serosa respectively. The incidence of placenta accreta is one in 2500 deliveries. Prior history of cesarean section and advanced maternal age are considered risk factors. Placenta accreta is associated with massive blood loss during delivery which could be fatal.
Techniques to minimize intraoperative blood loss focus on reducing arterial flow to the uterus and include extraluminal ligation of the pelvic arteries or endovascular occlusion of the iliac arteries with or without embolization.
Endovascular iliac artery occlusion is performed prior to planned cesarean section and involves puncture of the bilateral femoral arteries with placement of balloon catheters in each internal iliac artery, preferably in its anterior trunk. After the umbilical cord is clamped, the balloons are inflated and remain so until skin closure, occluding the internal iliac arteries and reducing blood flow to the uterus. If endovascular balloon occlusion is not successful at controlling intraoperative hemorrhage, embolization with gelatin sponge particles can be performed. The latter is associated with greater radiation doses to the fetus.
To present date, there are few studies (each with small sample sizes) showing the efficacy of endovascular balloon occlusion techniques in the perioperative management of placenta accreta. However, the existing data demonstrates it to be a safe technique to prevent blood loss in these patients.
Tan CH, Tay KH, Sheah K, et al. Perioperative endovascular internal iliac artery occlusion balloon placement in the management of placenta accreta. AJR Am J Roentgenol 2007;189:1158-63.