High-output heart failure due to a renal arteriovenous fistula in a pregnant woman with suspected preeclampsia.

A 29-year-old nulliparous woman had development of hypertension, proteinuria, and congestive heart failure during the third trimester of her pregnancy. Her symptoms and cardiovascular changes were consistent with congestive heart failure and severe preeclampsia. The underlying pathophysiology was believed to be caused by the high-output state of pregnancy and by the increased peripheral vascular resistance of preeclampsia. The patient underwent an elective cesarean section, but her cardiovascular symptoms did not resolve. Soon after delivery, the patient was found to have an arteriovenous fistula of the right renal artery that caused the high-output cardiac state. Embolization and surgical removal of the arteriovenous fistula resulted in complete resolution of the patient's high-output heart failure. All previously reported cases of renal arteriovenous fistulas and malformations that have occurred during pregnancy are reviewed.