Large Coronary Arteriovenous Fistula to the Main Pulmonary Artery

Abstract

A 50-yr-old woman with hyperlipidemia was generally well until 2000, when she felt intermittent chest tightness, palpitation, nausea, and diaphoresis. These symptoms worsened with progressive exertional dyspnea and mild paroxysmal nocturnal dyspnea over 3 mo before admission. Diagnostic evaluation with transthoracic echocardiography (TTE) demonstrated an atrial septal defect (ASD) with large left-to-right shunt. The patient was scheduled for closure of the ASD. Intraoperative transesophageal echocardiography performed at the time of surgery confirmed the ASD but also revealed increased left main coronary artery size and flow (Fig. 1) with some turbulent flow in the main pulmonary artery (Fig. 2; also please see video loop available at www.anesthesia-analgesia.org). The diagnosis of coronary artery arteriovenous fistula (CAVF) from the left main coronary artery to the left posterior main pulmonary artery was confirmed by surgical inspection. The patient underwent an uncomplicated repair of the ASD and ligation of the CAVF and was discharged 5 days later.Figure 1.: Transesophageal echocardiography, mid-esophageal aortic valve view. The enlarged left main coronary artery (arrow) with flow in the fistula (arrowhead) can be clearly seen.Figure 2.: Two-dimensional (Fig. 2A) and color flow mapping (Fig. 2B) of the multiplane transesophageal echocardiography of the main pulmonary artery (MPA) and pulmonary valve (PV), mid-esophageal ascending aortic short-axis view. The coronary arteriovenous fistula on the left posterior side of the MPA is shown (arrow).Congenital CAVF occurs in 1% to 2% of the population, and in 15% to 30% of cases the fistula connects with the pulmonary artery. More than 90% of CAVF open into right heart chambers and the most frequent drainage site is the right ventricle (40%) (1). Coexisting congenital or acquired heart disease is found in 40% of patients; however, no associated lesion was found to have a specific relationship with CAVF (1). Presenting symptoms include fatigue, exertional dyspnea, angina, and myocardial infarction in some patients as a result of coronary steal. Transthoracic echocardiography could be used to diagnose CAVF, but poor acoustic penetration and low preoperative suspicion may prevent the identification of this uncommon coronary artery anomaly (2). In this case, intraoperative transesophageal echocardiography was useful in demonstrating a previously unknown CAVF and in directing surgical intervention.