Efficacy of low extra-abdominal aortic block in cesarean section for placenta accreta spectrum disorders and its effect on the expression of MDA and SOD

Abstract

Objectives: Placenta accreta spectrum disorders (PAS) refers to a group of abnormalities in placental adhesion and invasion, which may lead to serious complications such as intractable postpartum hemorrhage. The use of low-level extra-abdominal aortic temporary block during cesarean section may reduce intraoperative bleeding in patients with PAS, but it may also cause ischemia-reperfusion injury. In this study, we intend to investigate the efficacy of low extra-abdominal aortic block in cesarean section for placental implantation disease and its effect on malondialdehyde (MDA) level and superoxide dismutase (SOD) activity, and analyze the severity of ischemia-reperfusion injury caused by them.

Methods: Pregnant women with invasive placenta accreta spectrum disorders who delivered in the Department of Obstetrics and Gynecology of the Third Xiangya Hospital of Central South University from July 2017 to July 2021, were selected, and they were divided into 2 groups. Group A consisted of those who underwent low extra-abdominal aortic block during cesarean section (n=15) and group B consisted of those who did not undergo extra-abdominal aortic block (n=15). The intraoperative bleeding, blood transfusion, hysterectomy and complication rate, postoperative hospital stay and hospitalization expenses were compared between the 2 groups to analyze the efficacy of abdominal aortic block. The biochemical indexes related to ischemia-reperfusion, MDA content and total superoxide dismutase (T-SOD) activity, were measured at the corresponding time points in both groups. The time points of each test were: in group A, before the block of the low extra-abdominal aorta after delivery (A0), 0 h (A1, when the myometrium was started to be sutured), 0.5 h (A2), 2 h (A3), and 4 h (A4) after the open block; in group B, after delivery of the fetus (B0), 0 h (B1), 0.5 h (B2), 2 h (B3), and 4 h (B4) after the myometrium was started to be sutured. Total duration of abdominal aortic block in group A was also recorded. Both groups were observed for sings of edema, ischemia, necrosis and infection in the limbs after surgery. The severity of ischemia-reperfusion injury caused by abdominal aortic block were determined by detecting the relevant biochemical indexes at different moments of reperfusion.

Results: The intraoperative bleeding and blood transfusion in group A were less than those in group B, and the difference was statistically significant (P<0.05). There was no significant difference in postoperative hospital stay and hospitalization expenses between the 2 groups (P>0.05). Surgical complications: in group A, the uterus was preserved in all cases, there was 1 bladder injury and 2 pelvic infections; while in group B, there was 1 hysterectomy, 3 bladder injuries, and 3 pelvic infections. Changes in T-SOD and MDA values: compared with A0 before block, the MDA level was significantly elevated in blood at time points A1, A2, and A3, while SOD activity was significantly decreased (P<0.05), and the 2 observed indexes basically returned to A1 level (ischemic period) at 4 h after open block (A4). There was no significant difference in the changes of T-SOD and MDA in group B (P>0.05). Comparison of T-SOD and MDA levels between group A and B: the difference of the 2 indexes was not statistically significant between A0 and B0 (P>0.05), MDA level was not statistically significant between A1 and B1, T-SOD activity at A1 was lower than B1, the difference was statistically significant, at the rest of the same time point, MDA level in group A were higher than that in group B, T-SOD activity in group A were lower than that in group B, the difference was statistically significant (P<0.05). No postoperative limb edema, ischemia, necrosis, or infection occurred in both groups.

Conclusions: Low-level extra-abdominal aortic block effectively reduces bleeding and transfusion during cesarean section for placenta accreta spectrum disorders, resulting in a transient MDA elevation and a decrease of SOD activity, which means causing transient ischemia-reperfusion injury without complications such as limb edema, ischemia, necrosis, and infection.

Keywords: low extra-abdominal aortic block; placenta accreta spectrum disorders; severe postpartum hemorrhage.

Figure 1. A 14-gauge disposable rubber catheter is used as the blocking band and wrapped around the abdominal aorta for 2 laps