Anaesthetic management of a parturient with an unrepaired coronary arteriovenous fistula for caesarean section

Coronary arteriovenous fistulas are an abnormal conduit between a coronary artery and another cardiovascular lumen, without an intervening capillary bed. The reported prevalence is 0.002–0.3%. Physiologic consequences such as congestive heart failure, coronary steal phenomenon and fistula aneurysm formation and rupture are possible. There are limited reports of symptomatic coronary arteriovenous fistulas in association with pregnancy. We describe a 19-year-old woman with symptomatic left circumflex artery to coronary sinus fistula, terminating into a large exophytic varix in the right atrium, presenting for an elective caesarean section at 37 weeks gestational age. Our anaesthetic management strategy aimed to optimise myocardial perfusion, maintain euvolemia, avoid right ventricular obstruction from exophytic varix and avoid sympathetic stimulation or sudden increases in pulmonary vascular resistance. A slowly titrated epidural was used as the primary anaesthetic. Our patient tolerated the procedure well and was discharged home on postoperative day two. Understanding of the potential physiologic consequence of coronary arteriovenous fistulas, and interaction with the physiologic changes of pregnancy and delivery, are essential for the management of these cases.