INTRODUCTION: Coronary arteriovenous fistulas (CAVF) are an abnormal connection between a coronary artery and one of the cardiac chambers or an adjacent low-pressure vein. Although rare, these anomalies are found in 0.002% of the general population and 0.25% of cardiac catheterizations. Even more fascinating is that only 5% of all CAVFs are bilateral. We present a case of a patient who presented with chest pain and was found to have bilateral CAVFs.
CASE PRESENTATION: A 55-year-old Caucasian male presented to the emergency department with chest pressure. The first episode happened while he was shoveling snow. The chest pressure radiated to the back, left arm, and neck. It lasted twenty minutes and was relieved by rest. The next two episodes had similar characteristics but happened at rest. His past medical history was significant for hypertension, hyperlipidemia and history of tobacco use. Given multiple risk factors for atherosclerosis, patient was admitted with a working diagnosis of acute coronary syndrome. Investigations including d-dimer, electrocardiogram, chest x-ray, serial troponins and echocardiogram were normal. Right and left cardiac catheterization with coronary angiography was performed and was significant only for bilateral CAVFs. One fistula was from proximal left main coronary artery to pulmonary artery (PA), a unique variation of an already rare anomaly and the second was between right coronary artery (RCA) and PA. There was no significant left to right shunt. During cardiac rehabilitation the patient did not have recurrence of chest pain. He was discharged on aspirin, atenolol, pravastatin and lisinopril. Patient was seen in follow-up and has not had recurrent symptoms.
DISCUSSIONS: CAVFs are most commonly congenital. 20% of CAVFs are associated with other congenital heart diseases including Tetralogy of Fallot, atrial septal defect, patent ductus arteriosus, and ventricular septal defect. The "steal phenomenon" and the location of the termination of the fistula determine their clinical significance. The mechanism of coronary "steal phenomenon" is related to the diastolic pressure gradient and runoff from the high pressure coronary vasculature to a low resistance receiving cavity, potentially leading to ischemia. The location of fistula termination is also crucial. If the fistula terminates in the venous side of the circulation, a left-to-right shunt results and if large enough, volume overload of both ventricles can occur. Alternately, if the fistula drains into the left atrium or the pulmonary vein, the left heart can potentially become volume overloaded due to left-to-left shunt. Surgical obliteration or coil embolization is indicated in young patients with CAVFs that cause a significant shunt or "steal phenomenon" causing ischemia or associated with another congenital heart disease. In our patient, we elected for conservative therapy as the shunt was not hemodynamically significant and there was no evidence that CAVFs was the cause of chest pain. In addition the location of the origin of a fistula in the proximal left main could increase the risk of systemic embolization of a coil during insertion.
CONCLUSION: We present a case of a patient with bilateral CAVFs with chest pain without evidence of hemodynamically significant shunt. Based on the available literature and clinical findings we decided that closing the fistulas would not be significantly beneficial for the patient. Although infrequent, CAVFs should be kept in mind as a potential cause of cardiac symptoms. There is a strong consensus that CAVFs causing steal phenomenon or significant shunt should be closed in younger patients. However, there is no consensus as to the management of CAVFs without significant hemodynamic steal, especially in the elderly. We propose that while conservative management is appropriate, close follow-up is necessary as these patients are at increased risk for complications described above.
DISCLOSURE: Elizabeth Hurd, No Financial Disclosure Information; No Product/Research Disclosure Information