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High-dose steroids prevent placental dysfunction after fetal cardiac bypass
J F Sabik1, M K Heinemann, R S Assad
1Department of Cardiovascular Surgery, Children's Hospital of Boston, Harvard Medical School, Mass.
The Journal of Thoracic and Cardiovascular Surgery
|January 1, 1994
Summary
Fetal cardiac bypass requires placental support. Indomethacin and steroids prevent increased placental resistance during bypass, suggesting prostaglandins cause this issue, enabling safer fetal heart surgery.
Area of Science:
- Cardiovascular Surgery
- Fetal Medicine
- Pharmacology
Background:
- In utero surgical repair of congenital heart defects offers potential advantages over postnatal interventions.
- Successful fetal cardiac surgery necessitates effective fetal circulation support during the procedure.
- Previous attempts at fetal cardiac bypass failed due to increased placental vascular resistance, leading to fetal demise.
Purpose of the Study:
- To investigate the mechanisms by which indomethacin prevents adverse placental vascular changes during fetal cardiac bypass.
- To evaluate the role of prostaglandins and leukotrienes in regulating placental vascular resistance during fetal cardiac bypass.
- To assess the efficacy of high-dose steroids in preventing placental vasoconstriction during fetal cardiac bypass.
Main Methods:
- Fourteen fetal lambs underwent surgical procedures simulating fetal cardiac bypass.
- Groups received indomethacin (cyclooxygenase inhibitor), high-dose steroids (inhibiting both prostaglandin and leukotriene synthesis), or served as controls.
- Placental blood flow and vascular resistance were measured before, during, and after the bypass period.
Main Results:
- Indomethacin administration prevented the increase in placental vascular resistance and maintained placental blood flow.
- High-dose steroid administration similarly prevented elevated placental vascular resistance and preserved placental blood flow.
- These findings suggest that prostaglandin production is the primary cause of increased placental vascular resistance post-fetal cardiac bypass.
Conclusions:
- Pharmacological interventions like indomethacin and steroids can mitigate adverse placental circulatory effects during fetal cardiac bypass.
- The study implicates prostaglandin synthesis as the key mediator of placental vasoconstriction following fetal cardiac bypass.
- These findings support the development of safer fetal cardiac surgical procedures by addressing placental circulatory complications.