CASE REPORT
Coronary Atherosclerosis with Dual Coronary Artery Fistulas Hitoshi Hirose,1 Masatake Takagi,2 Naotaka Miyagawa,2 Hiroshi Hashiyada,2 Takafumi Yamada,2 Seiichi Tada2 and Toshiyasu Kugimiya2 From the 1Department of Cardiovascular Surgery, Shin-Tokyo Hospital, Chiba and 2Department of Cardiovascular Surgery, Nagasaki University School of Medicine, Nagasaki, Japan (Submitted January 14, 1998. Accepted for publication April 6, 1998)
Scand Cardiovasc J 32; 313–314, 1998 Coronary artery fistula (CAF) is an uncommon congenital anomaly. Bilateral CAFs, arising from both right and left coronary arteries are rare. Myocardial infarction is by far a less frequent complication of CAF than angina pectoris. Ligation of CAF and coronary artery bypass graft were performed in the treatment of coronary artery stenosis with CAF. Key words: coronary artery fistula, myocardial infarction, coronary artery disease, surgery. Hitoshi Hirose, MD, Shin-Tokyo Hospital, 473-1 Nemoto, Matsudo City, Chiba, 271-0077 Japan. Tel 81-47-360-9761. Fax 81-47-360-9761. E-mail:
[email protected]
Coronary artery fistula (CAF) is an uncommon congenital cardiac malformation. Fewer than 500 cases have been reported in the English literature (1, 2). The right coronary artery is frequently involved, and the fistula usually communicates with the right side of the heart (3). CAFs originating from both right and left coronary arteries are rare congenital errors at a separate site that would independently occur during the development of the coronary arteries (4). Angina is the most common symptom of the CAF, and myocardial infarction (MI) is infrequent (5). We encountered a patient with bilateral CAFs, involving both the right coronary artery (RCA) and the left anterior descending artery (LAD). The patient developed MI over 10 years, while the left-to-right shunt through the CAF had been almost stable or minimally increased. Long-standing coronary steal by the CAF may have contributed to increasing severity of the coronary artery disease. CASE REPORT A 54-year-old male demonstrated a heart murmur at 40 years of age. At that time, coronary angiography revealed CAF arising from both the RCA and LAD, with drainage into the pulmonary artery. The left-toright shunt ratio was 11.1%. No significant coronary arterial stenoses were observed. Other medical problems included hypertension, hyperlipidemia, and smoking. At age 50, he experienced acute onset of severe anterior chest pain and shortness of breath, and was 1998 Scandinavian University Press. ISSN 1401–7431
diagnosed as having acute myocardial infarction, for which he was treated medically. Repeated coronary angiography revealed a minimally increased left-toright shunt ratio (12.7%), and a significant stenotic lesion in the middle of the RCA (Fig. 1), which was successfully dilated by percutaneous transluminal coronary angioplasty. He was asymptomatic until age 53, when he suffered another angina attack. The left-to-right shunt ratio was slightly increased to 13.5%. Triple vessel coronary artery disease, demonstrated by coronary angiography, consisted of 99% stenosis in the proximal RCA, 75% stenosis in the middle RCA, 75% stenosis in the middle LAD, and 99% stenosis in the middle left circumferential artery (LCX). A coronary artery bypass graft (CABG), using the saphenous vein to the LCX, the left internal mammary artery to the LAD, and the right internal mammary artery to the RCA, was performed. During surgery, the CAFs originating from the RCA as well as the LCA were gathered together and dense branching networks were made on the anterior surface of the pulmonary artery. Thrills were palpable on the CAF. These fistulas were ligated using surgical clips on the pulmonary artery. His postoperative course was steady, and he has remained asymptomatic for 18 months. DISCUSSION Most CAFs are thought to be due to a continuous murmur, and diagnosed by coronary angiography. Scand Cardiovasc J 32
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Fig. 1. Coronary angiography of the patient. On the left, coronary artery fistulas (CAFs, large arrow) originating from the right coronary artery and draining into the pulmonary artery are observed along with a stenotic segment (small arrow) of the right coronary artery. On the right, CAFs (large arrow) arising from the left anterior descending artery and draining into the pulmonary artery are observed with atherosclerotic segments (small arrow) of the left coronary arteries.
(1, 4). CAFs usually originate from a single coronary artery; right coronary trees are involved in 50% of CAFs and left coronary trees in 42% of CAFs (6). Dual CAFs involving both right and left coronary artery trees are uncommon and account for only 5% of all CAFs (4, 6). Drainage sites of the CAFs are the right ventricle (41%), the right atrium (26%), the pulmonary artery (17%), the coronary sinus (7%), the left atrium (5%), and the left ventricle (3%) (6). The pulmonary artery is the most common drainage site for bilateral CAFs, whereas right cardiac chambers are the most usual drainage sites for single CAFs (4). The common symptoms of CAFs are angina, congestive heart failure, dyspnea, palpitations, and endocarditis (3, 5). Other rarer complications of CAFs include MI, aneurysm formation, and rupture of CAF (5). Despite the frequent occurrence of angina, MI is not a usual clinical manifestation in patients with CAF (7, 5). The largest series of CAF by Urrutia et al. demonstrated MI in only 3.4% (2/58) of patients, compared with angina in 22% (13/58) (5). Smaller studies by Lowe (28 cases of CAF), Baim (19 cases of CAF), or Leberthson (13 cases of CAF) reported no cases of MI (3, 4, 8). A proposed mechanism of coronary ischemia is the “coronary artery steal phenomenon” by CAF, where blood flow is diverted from the high-resistance distal coronary arteries into the low-resistance fistula (4–6). Patients with CAFrelated angina may not have severe coronary artery stenosis; thus, these symptoms may disappear after simple surgical closure of CAF without CABG (4, 6). However, even though minor coronary atherosclerosis is present, the patient’s symptoms of angina may be potentiated by CAF shunting of blood flow out of the main coronary arteries. The shunt size of CAF as well as the frequency of the
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symptoms are correlated to the patient’s age (8). Younger patients with CAF are generally asymptomatic, but older patients develop symptoms more frequently. Our patient developed accelerated atherosclerotic coronary artery disease over a decade even though shunt size was relatively stable. CAF could be a risk factor for coronary artery disease. Thus we recommend early surgical correction of all symptomatic patients as well as all asymptomatic patients with CAF, to prevent future development of symptoms and complications. REFERENCES 1. Bauer EP, Piepho A, Klo¨vekorn WP. Coronary arteriovenous fistula: surgical correction of a rare form. Thorac Cardiovasc Surgeon 1994; 42: 237–239. 2. Bishop JO, Mathur VS, Guinn GA. Congenital coronary artery fistula with myocardial infarction. Chest 1974; 65: 233–264. 3. Lowe JE, Oldham Jr HN, Sabiston Jr DC. Surgical management of congenital coronary artery fistulas. Ann Surg 1981; 194: 373–380. 4. Baim DS, Kline H, Silverman FJ. Bilateral coronary artery-pulmonary artery fistulas, report of five cases and review of the literature. Circulation 1982; 65: 810–815. 5. Urrutia-S CO, Falaschi G, Ott DA, Cooley DA. Surgical management of 56 patients with congenital coronary artery fistulas. Ann Thorac Surg 1983; 35: 300–307. 6. Levin DC, Fellows KE, Abrams HL. Hemodynamically significant primary anomalies of the coronary arteries: angiographic aspects. Circulation 1978; 58: 25–33. 7. Rittenhouse EA, Dorty DB, Ehrenhaft JL. Congenital coronary artery-cardiac chamber fistula. Ann Thorac Surg 1975; 20: 468–485. 8. Leberthson 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; 59: 849– 854.
