Coronary artery fistulas: A case presentation and literature review

Abstract

Coronary fistulas are rare anomalies that connect the coronary artery to either a cardiac chamber (coronary cameral fistula) or vein (arteriovenous fistula). They arise due to abnormalities in embryologic development and are often coincidental findings. The exact incidence is estimated to be between 0.1-0.2 percent of the general population. There are no consensus guidelines for management of these fistulas. We present a patient with a large fistula and will review the literature and management decisions for this clinical abnormality.A 66-year-old man with diabetes, hypertension and a prior bioprosthetic aortic valve presented to the Loma Linda VA Hospital with shortness of breath. An echocardiogram revealed moderate to severe prosthetic aortic stenosis, and an angiogram showed 80% mid left anterior descending (LAD) obstruction with a large arteriovenous fistula. The fistula extended from the circumflex artery to coronary sinus. He was referred for redo open heart surgery with aortic valve replacement, coronary bypass grafting and repair of the fistula. There are multiple case reports of these malformations causing symptoms of angina, coronary steal or heart failure based on various testing modalities.  However, in 31 individuals with incidental findings of coronary fistulas from a small case series, no adverse effects on cardiac function were noted based on physical exam or functional testing.  If treatment is deemed beneficial, surgery is the most available option and another study of 41 symptomatic patients reported low post-operative morbidity and mortality after nine-year follow-up.  The authors believe that large fistulas found incidentally should be further evaluated for ischemia and monitored for symptoms. For individuals with small fistulas, conservative management is a viable strategy as there is a high incidence of spontaneous closure. If a fistula is determined to be symptomatic, operative repair is well tolerated.