Case Report

Severe Myocardial Ischemia due to a Large Vascular Malformation of the Left Anterior Descending Coronary Artery

Uzoma N. Ibebuogu, MD, Deepak Kapoor, MD, Vincent J.B. Robinson, MD Author Affiliations: From the Section of Cardiology, Medical College of Georgia, Augusta, Georgia. The authors report no conflicts of interest regarding the content herein. Manuscript submitted June 30, 2008 and accepted August 29, 2008. Address for correspondence: Uzoma N. Ibebuogu, MD, Section of Cardiology, Medical College of Georgia, 1120 15th Street (BBR 6518), Augusta, GA 30912. E-mail: ibebuogu@yahoo.com
Uzoma N. Ibebuogu, MD, Deepak Kapoor, MD, Vincent J.B. Robinson, MD Author Affiliations: From the Section of Cardiology, Medical College of Georgia, Augusta, Georgia. The authors report no conflicts of interest regarding the content herein. Manuscript submitted June 30, 2008 and accepted August 29, 2008. Address for correspondence: Uzoma N. Ibebuogu, MD, Section of Cardiology, Medical College of Georgia, 1120 15th Street (BBR 6518), Augusta, GA 30912. E-mail: ibebuogu@yahoo.com
Author Affiliations: From the Section of Cardiology, Medical College of Georgia, Augusta, Georgia. The authors report no conflicts of interest regarding the content herein. Manuscript submitted June 30, 2008 and accepted August 29, 2008. Address for correspondence: Uzoma N. Ibebuogu, MD, Section of Cardiology, Medical College of Georgia, 1120 15th Street (BBR 6518), Augusta, GA 30912. E-mail: ibebuogu@yahoo.com

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J INVASIVE CARDIOL 2009;21:E1-E2

With a Fistulous Connection from the Right Coronary Artery

Coronary artery fistulae (CAF) are rare, mostly congenital abnormalities in which coronary blood bypasses the myocardial capillary network and is shunted into a great vessel or cardiac chamber. They represent a persistence of embryonic intertrabecular spaces and sinusoids1,2 and occur in 1 out of 50,000 of the general population.3 Most CAF are small and usually asymptomatic. However, hemodynamically significant fistulae may result in adverse clinical outcomes if untreated.4 The usual origin of CAF are the right or left coronary arteries, with the major termination sites occurring in low-pressure structures, which include the right-sided cardiac chambers, pulmonary artery, superior vena cava or coronary sinus.1 A fistula connecting two coronary arteries has not been previously reported. We report the first case in the literature of a symptomatic right coronary artery to left coronary artery fistula in a 58-year-old female who was successfully treated with a single-vessel bypass surgery. Case Report. A 58-year-old black female with a history of hypertension was referred for the evaluation of severe, cramping, nonradiating exertional chest pain after starting an exercise program. The only abnormal finding on physical examination was an elevated blood pressure of 148/98. Her resting electrocardiogram (ECG) showed anterolateral and inferior T-wave inversions (Figure 1), and her peak exercise ECG showed inferior and anterolateral 3 mm ST-segment depression (Figure 2), which was suggestive of ischemia. Myocardial perfusion study revealed a large reversible 50% myocardial volume perfusion defect involving the apical, anterior, anteroseptal and inferior segments of the left ventricle. Transient local ischemic dilatation of the left ventricular cavity was also noted on stress imaging. Subsequent cardiac catheterization showed a left ventricular end-diastolic pressure of 25 mmHg and an ejection fraction of 70%, with no wall motion abnormalities. However, coronary artery angiography revealed an intramyocardial proximal left anterior descending artery (LAD) with a large, grape-like vascular malformation with a fistulous drainage from a dominant right coronary artery (RCA) (Figures 3 and 4). The patient underwent a single-vessel coronary bypass graft of her LAD with the left internal mammary artery inserted distal to the vascular malformation and fistulous connection. The RCA fistula was not amenable to ligation. Her postoperative recovery was complicated by pulmonary embolism which was adequately managed with anticoagulation. On subsequent follow-up visits, the patient had improved exercise tolerance with no anginal symptoms. A repeat myocardial perfusion study performed 6 months after surgery showed normal perfusion with no significant defects. Discussion. Communications between the coronary arteries and the cardiac chambers or great vessels are mostly due to deviations from normal embryologic development. During fetal development, the myocardium consists of blood-filled sinusoids, that communicate with the cardiac chambers. Persistence of these sinusoids after the 6th week of gestation leads to abnormal communication between the coronary arteries and the cardiac chambers or great vessels, known as coronary-cameral fistulae and coronary artery arteriovenous malformations, respectively.1,2 CAF arise mostly from the right (50%) and left coronary arteries (42%) and terminate in low-pressure structures such as the right ventricle (41%), right atrium (26%) and the pulmonary artery (17%).1 The coronary sinus, left atrium, left ventricle and superior vena cava account for 7%, 5%, 3% and 1%, respectively, of the termination sites.1 CAF connecting two coronary arteries have not been previously reported to the best of our knowledge. Most CAF are asymptomatic due to their small size and are incidentally found during coronary angiography.5 When symptoms occur, they are due to hemodynamically significant blood shunts that may occur with these fistulae. Termination into the right-sided structures and less commonly in the left-sided structures may give rise to pulmonary hypertension, congestive heart failure, subacute bacterial endocarditis, chronic myocardial ischemia or infarction due to coronary steal or rupture of an aneurysmal dilation of the CAF.4,6–10 Our patient had a previously unreported coronary artery-to-coronary artery fistula that caused coronary steal during exertion from the vascular malformation and fistulous connection of the LAD. This coronary steal resulted in severe myocardial ischemia of the myocardial segments perfused by the LAD distally and gave rise to our patient’s symptoms. This rare variant of CAF was successfully treated with single-vessel coronary artery bypass surgery. The fistulous connection was not amenable to surgical ligation. Our patient also had an elevated left ventricular end-diastolic pressure (25 mmHg), which may be due to volume overload resulting from coexisting small vascular connections between the LAD vascular malformation and the left ventricular cavity. This occurs in 3% of cases with CAF.1 In conclusion, to the best of our knowledge, we report the first case in literature of a coronary artery-to-coronary artery fistula successfully treated with a single-vessel bypass graft. Acknowledgment. The authors gratefully acknowledge the excellent assistance of Michael Konomos with the images.
References

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