Coronary arteriovenous fistula
Although a CAVF, in the strictest sense of the term, implies a communication between the coronary arteries and coronary venous system, the term has been adopted and accepted to refer to any communication between the coronary arteries and other cardiac or vascular structures 1. Furthermore, large CAVFs have sometimes been known as ‘cor medusae’ in the literature 2.
CAVFs are rare, being present in approximately 0.002% of the population 3,4.
Patients may be asymptomatic 1,3-5, but may also have a range of clinical features:
- angina, especially on exertion 1,3-5
- dyspnoea, especially on exertion 1,3-5
- cardiac murmur heard continuously in systole and diastole, decreases in intensity during inspiration 1,3-5
The most common origins for the CAVF are the RCA (50%) and LAD (42%) while the most common drainage sites are the relatively low-pressure right ventricle (41%), right atrium (26%), or pulmonary artery (17%) 3,4. However, any coronary artery may be an origin and the fistula may less commonly drain into the coronary sinus, superior vena cava, or left-sided cardiac chambers 3,4.
Due to the most common drainage sites being in the right side of the cardiac circulation, CAVFs often cause a left-to-right shunt and result in the ‘coronary artery steal’ phenomenon 3-5. This coronary artery steal results in less blood being delivered to the myocardium at the origin of the fistula causing continual myocardial ischaemia and the development of the aforementioned clinical presentation 3-5.
CAVFs are most commonly congenital, but can also be rarely acquired 3,4. Risk factors and aetiologies for acquired CAVFs include 4:
- pathology-related: acute myocardial infarction, hypertrophic cardiomyopathy, dilated cardiomyopathy, coronary artery aneurysm rupture into adjacent structures 4
- iatrogenic: percutaneous coronary intervention, coronary artery bypass grafting, cardiac transplant, pacemaker placement 4
- chest trauma 4
Imaging can demonstrate not only the CAVF, but also the numerous complications (as listed below).
Coronary artery angiography is an invasive imaging modality for evaluating CAVFs and has long been considered to be the gold-standard 3,4,6,7. Angiography is able to provide details regarding the origin, drainage, size, and course of CAVFs 3,4,6,7.
Electrocardiographically-gated CT is able to not only detect the same characteristics of CAVFs as demonstrated by coronary artery angiography, but also has the additional benefit of being easily accessible and non-invasive 3,7. Thus, CT is increasingly considered to be the ideal imaging modality for evaluating CAVFs instead of angiography 3,7.
Treatment and prognosis
Although there have been reports of spontaneous closure of the fistula due to thrombus, generally symptomatic patients require closure via either transcatheter embolisation or surgical ligation 4. Patients with known CAVFs should also receive prophylactic anti-platelet therapy and antibiotic prophylaxis against bacterial infective endocarditis 4.
Patients who have undergone a closure procedure tend to have an excellent prognosis 4.
- 1. Steinberg I, Baldwin JS, Dotter CT. Coronary Arteriovenous Fistula. Circulation. 17 (3): 372. doi:10.1161/01.CIR.17.3.372 - Pubmed
- 2. Challoumas D, Pericleous A, Dimitrakaki IA, Danelatos C, Dimitrakakis G. Coronary arteriovenous fistulae: a review. The International journal of angiology : official publication of the International College of Angiology, Inc. 23 (1): 1-10. doi:10.1055/s-0033-1349162 - Pubmed
- 3. Zenooz NA, Habibi R, Mammen L, Finn JP, Gilkeson RC. Coronary artery fistulas: CT findings. Radiographics : a review publication of the Radiological Society of North America, Inc. 29 (3): 781-9. doi:10.1148/rg.293085120 - Pubmed
- 4. Challoumas D, Pericleous A, Dimitrakaki IA, Danelatos C, Dimitrakakis G. Coronary arteriovenous fistulae: a review. The International journal of angiology : official publication of the International College of Angiology, Inc. 23 (1): 1-10. doi:10.1055/s-0033-1349162 - Pubmed
- 5. Engle MA, Goldsmith EI, Holswade GR, Goldberg HP, Glenn F. Congenital coronary arteriovenous fistula. Diagnostic evaluation and surgical correction. The New England journal of medicine. 264: 856-8. doi:10.1056/NEJM196104272641705 - Pubmed
- 6. Fujise K, Sherman W. Images in clinical medicine. Coronary arteriovenous fistula on coronary angiography. The New England journal of medicine. 331 (19): 1265. doi:10.1056/NEJM199411103311904 - Pubmed
- 7. Kacmaz F, Isiksalan Ozbulbul N, Alyan O, Maden O, Demir AD, Atak R, Senen K, Erbay AR, Balbay Y, Olcer T, Ilkay E. Imaging of coronary artery fistulas by multidetector computed tomography: is multidetector computed tomography sensitive?. Clinical cardiology. 31 (1): 41-7. doi:10.1002/clc.20286 - Pubmed