Coronary artery fistula case
Coronary artery fistulae are anomalous communications with either another coronary artery, or a cardiac chamber (coronary-cameral fistula). They could be single or multiple, and most commonly arise from the right coronary system.
Coronary cameral fistulae can be classified according to their insertion into either cardiac chamber, fistulae are classified as arterio-luminal (direct communication with the cardiac chamber) or arterio-sinusoidal (communication via sinusoidal network).
Coronary-cameral fistulae are mostly diagnosed as incidental finding in asymptomatic patients. Symptoms depend on the flow within the fistula and the degree of shunting in symptomatic patients. Other infrequent presentations include myocardial ischemia due to steel syndrome, infective endocarditis, aneurysmal dilation, and rupture.
In this paper, we present an interesting presentation of a patient diagnosed with infective endocarditis, with a coronary cameral fistula connecting the right coronary artery (RCA) to the superior vena cava (SVC) being identified as the source of infection.
A 34-year-old male patient with no significant past medical history, presented to the emergency department for constant generalized headache, subjective feeling of warmth and generalized fatigue. In the emergency department (ED), the patient was febrile at 102.9 F, and vital signs were otherwise within normal limits. Physical examination did not reveal any murmurs, and the examination was otherwise non-revealing. Laboratory results showed normal white blood cell count, normal basic metabolic panel, negative urine analysis, negative urine toxicology screen, and low ethanol blood levels. Two sets of blood cultures were drawn. Chest Xray did not show any evidence of consolidations or pleural effusion, with normal cardiac borders and absence of cardiomegaly. His electrocardiogram showed normal sinus rhythm
The patient received a dose of intravenous Cefepime and Vancomycin, and intravenous fluids. Due to resolution of his symptoms, it was thought his symptoms are due to viral illness due to which patient was discharged home.
On the next day, patient’s two sets of blood cultures grew Streptococcus Gordonii, a bacterium that resides in oral flora. Patient was called back to the hospital and was admitted for further investigations and management.
He underwent an echocardiogram to evaluate for possible infective endocarditis. His echocardiogram revealed no evidence of valvular heart disease or vegetations, dilated right ventricle with normal systolic function, and a continuous flow doppler signal visualized throughout through the cardiac cycle, which appears to originate from a systemic cardiac chamber and drains into the right atrium (RA).
[Include TTE images]
Streptococcus Gordonii was sensitive to cefazolin, for which patient’s antibiotics were switched to intravenous cefazolin.
Patient underwent transesophageal echocardiogram (TEE), which revealed an RCA coronary cameral fistula draining to the right atrium. The RCA was aneurysmal and dilated, with a tortuous branch artery originating from its proximal-to-mid segment, coursing posteriorly and terminating into the proximal SVC. Calculation of left to right shunting was performed by calculating the ratio of the flow between the right ventricular outflow (Qp) and the left ventricular outflow (Qs) and it was 1.7 (Qp:Qs = 1.7). The right ventricle was dilated with normal systolic function. No valvular pathology or vegetation was demonstrated.
[Include TEE images]
Cardiothoracic surgery team was consulted. Due to significant shunting and presentation with infective endocarditis, patient was deemed a candidate for surgical correction once he completes his treatment for his infective endocarditis and preoperative workup.
Perioperative workup included a coronary CT angiogram (CTA) to delineate the fistulous tract. Coronary CTA demonstrated a fusiform aneurysmal dilation of the proximal part of the RCA measuring up to 1.7 cm, coursing posteriorly between the aortic root and RA, and draining to the SVC above the level of the cavo-atrial junction.
[include coronary CT-A images]
A coronary angiogram was also planned to assess for any existing coronary artery disease prior to any surgical intervention.
Upon discussion with the patient, he decided to have a peripherally inserted central catheter (PICC) line placed, and to be discharged home to complete his antibiotic therapy for infective endocarditis, and to follow up as outpatient for the preoperative workup. Patient was then lost to follow up.
Coronary artery fistulae (CAF) are anomalous communications with either another coronary artery, or a cardiac chamber (coronary-cameral fistula).
CAF is present in 0.002% of the general population and represents 0.4% of all cardiac malformations.
CAF are commonly congenital; however, it could be acquired.
Congenital CAF may arise due to persistence of sinusoidal connections between the lumens of the primitive tubular heart that supply myocardial blood flow in the early embryologic period. In the primitive heart.[2
Congenital coronary artery-pulmonary artery fistula are thought to be remnants of the splanchnic vascular system that regress normally during fetal life during the development of the pulmonary circulation.
Acquired CAF can occur secondary to infection, trauma, as a complication of Kawasaki disease or iatrogenic injury. Reported iatrogenic etiologies of CAF were intracardiac congenital heart operations, myocardial biopsy, or coronary angioplasty.
They most commonly arise from the right coronary system (55% of the cases) but can originate from the left side (35%) or bilaterally (5%).
CAFs can be classified according to their origin (Sakakibara classification), drainage site, or complexity; the number of fistulous tracts; or the presence of accompanying anomalies.
CAFs are usually asymptomatic and are diagnosed incidentally. Symptomatic CAFs present due to significant shunting from high-pressure coronary arterial blood flow drains into a low-resistance venous circuit resulting in right heart fluid overload, right ventricular failure, reduction in left ventricular output. bypassing myocardial arterioles and capillary networks (distally to the origin of CAF) resulting in myocardial ischemia by steal phenomenon.
Complications of CAF appear due to acute intrinsic changes within the fistula and include fistula thrombosis with distal embolization, dissection, or rupture causing hemopericardium and tamponade. Extension of these changes to the native vessel can cause acute coronary syndrome. CAF can be infected causing infective endarteritis, which our patient presented with.
Historically, coronary angiography has been considered the gold standard for diagnosis. Recently, with advances in noninvasive cardiac imaging, CAF has been more commonly diagnosed with multimodal imaging, including collaboration of TTE, TEE, coronary CTA, and cardiac MRI. 
Asymptomatic incidentally discovered fistulae with minimal shunting are usually managed conservatively with regular follow up. 
Management is indicated for large CAFs; regardless of the symptoms, and for small to moderate-size fistulas with symptoms. Symptoms include myocardial ischemia, arrhythmia, ventricular dysfunction, and endarteritis, as in our patient. Treatment options include surgical ligation and percutaneous transcatheter closure. 
Choice of management modality depends on presence of symptoms, degree of shunting, anatomical complexity, and presence for another indication for surgical intervention. 
Surgical methods are associated with low mortality and morbidity; however, there is a risk of myocardial infarction postoperatively and a risk of recurrence of the fistula. Risks of fistula closure with devices include myocardial infarction, with the risk being the highest for CAF originating from the proximal portion of the native coronary artery, and migration of closure devices. [1,5]
CAF are increasingly recognized due to recent advancement in cardiac imaging modalities. Better understanding of CAF natural course, pathophysiology, and management option are required to promote appropriate intervention and management for CAF.
 Boyle S, Jesuthasan LSB, Jenkins C, Challa P, Ranjan S, Dahiya A. Coronary-Cameral Fistula. Circ Cardiovasc Imaging. 2019 May;12(5):e008691. doi: 10.1161/CIRCIMAGING.118.008691. PMID: 31088151.
 Dimitrakakis G, Von Oppell U, Luckraz H, Groves P. Surgical repair of triple coronary-pulmonary artery fistulae with associated atrial septal defect and aortic valve regurgitation. Interact Cardiovasc Thorac Surg. 2008 Oct;7(5):933-4. doi: 10.1510/icvts.2008.181388. Epub 2008 Jun 10. PMID: 18544587.
 Liberthson RR, Sagar K, Berkoben JP, Weintraub RM, Levine FH. Congenital coronary arteriovenous fistula. Report of 13 patients, review of the literature and delineation of management. Circulation. 1979 May;59(5):849-54. doi: 10.1161/01.cir.59.5.849. PMID: 428095.
 Mangukia CV. Coronary artery fistula. Ann Thorac Surg. 2012 Jun;93(6):2084-92. doi: 10.1016/j.athoracsur.2012.01.114. Epub 2012 May 5. PMID: 22560322.
 Yun G, Nam TH, Chun EJ. Coronary Artery Fistulas: Pathophysiology, Imaging Findings, and Management. Radiographics. 2018 May-Jun;38(3):688-703. doi: 10.1148/rg.2018170158. Epub 2018 Mar 30. Erratum in: Radiographics. 2018 Nov-Dec;38(7):2214. PMID: 29601265.
 Reddy G, Davies JE, Holmes DR, Schaff HV, Singh SP, Alli OO. Coronary artery fistulae. Circ Cardiovasc Interv. 2015 Nov;8(11):e003062. doi: 10.1161/CIRCINTERVENTIONS.115.003062. PMID: 26510560.
 Warnes CA, Williams RG, Bashore TM, Child JS, Connolly HM, Dearani JA, Del Nido P, Fasules JW, Graham TP Jr, Hijazi ZM, Hunt SA, King ME, Landzberg MJ, Miner PD, Radford MJ, Walsh EP, Webb GD. ACC/AHA 2008 Guidelines for the Management of Adults with Congenital Heart Disease: Executive Summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to develop guidelines for the management of adults with congenital heart disease). Circulation. 2008 Dec 2;118(23):2395-451. doi: 10.1161/CIRCULATIONAHA.108.190811. Epub 2008 Nov 7. PMID: 18997168.
Garly Ste Croix