Coronary Fistulas Can Develop Collateral Vessels: Angiographic Follow-up of an Embolized Giant Right Coronary Artery-Superior Vena Cava Fistula in a Patient with Variant Angina

ABSTRACT: A 54-year-old man was transferred to our emergency department because of acute inferior myocardial infarction. However, ST-segment elevation resolved after intravenous nitrate administration on admission and coronary angiography revealed a nonobstructive atherosclerotic plaque at the mid-portion of the circumflex artery and a giant tortuous fistula from the right sinus of Valsalva to the superior vena cava. The patient was diagnosed with variant angina and coronary arteriovenous fistula after vasodilator treatment and maximal treadmill stress test. After effective medical treatment of variant angina and successful percutaneous coil embolization of the fistula, the patient had not experienced any angina episodes for 1 year. However, control coronary angiography revealed partial persistence of fistula flow because of new collateral vessels, bridging distal and proximal parts of the occluded segment. We present the first coexistence of coronary to superior vena cava fistula and variant angina in the literature. This report also shows the ability of coronary fistulas to develop collateral vessels, like coronary arteries.

Coronary artery fistula (CAF), an anomalous connection between a coronary artery and major vessel or cardiac chamber, was first described in 1841. The incidence of coronary anomalies is about 1.34% in patients attending the catheterization laboratory and coronary fistulae constitute only 4.8% of them.¹ In a retrospective study reviewing catheterization database between 1987 and 2004 at the Mayo Clinic, CAF was found in 30 patients. Superior vena cava was the site of CAF drainage in only 1 patient.²

On the other hand, variant angina was first defined by Prinzmetal and colleagues in 1959.³ Ischemic chest pain and ST-segment elevation at rest due to transient vasospasm of epicardial or large septal coronary arteries constitute the main characteristics of this syndrome. Atherosclerosis is the most common reason for spasm, even if it is not visible on conventional coronary angiography at the spasmodic segment.⁴

In this study, we present effective medical- and catheter-based treatment of a patient who had both variant angina and a large congenital coronary fistula.

Case Report. A 54-year-old man was transferred in the early morning hours to our emergency department because of chest pain and ST-segment elevation in leads II, III and aVF as well as ST-segment depression in leads aVL and V1–V3 (Figure 1A). In our emergency department, his complaints resolved after administration of intravenous nitrate; at that time, electrocardiogram (ECG) was completely normalized (Figure 1B). He recounted the same complaints a few times during the past week at rest during the morning hours. Hypertension and cigarette smoking in his medical history were risk factors for atherosclerosis. Physical examination was normal. Transthoracic echocardiography showed hypokinesia of the inferior wall of the left ventricle, but cardiac enzymes did not reach pathologic levels during follow-up in the Coronary Care Unit. Control transthoracic echocardiography showed completely normal systolic function of the left ventricle 2 days later. Coronary angiography was performed. It revealed a nonobstructive atherosclerotic plaque at the mid-portion of the circumflex artery and a giant tortuous fistula from the right sinus of Valsalva to the right atrium or superior vena cava (Figure 2A). Size and function of the right heart chambers were normal. 64-slice multidetector coronary computed tomography was performed to better delineate the anatomy; it confirmed a large tortuous fistula arising from the right sinus of Valsalva, giving a rudimentary right coronary artery and draining into the superior vena cava (Figures 2B and 2C). As variant angina was considered to be the most plausible diagnosis, treatment with calcium-channel blockers and long-acting nitrates was initiated. A treadmill stress test was performed 3 weeks later to show possible steal phenomenon, but there were no symptoms or ischemic ECG changes during maximal effort (12.8 METs) in the Bruce protocol. The patient was diagnosed with variant angina and a giant fistula between the sinus of Valsalva and superior vena cava. Although the patient had not experienced any ischemic episodes under medical treatment during 2 months, coil embolization of fistula was planned to prevent hemodynamic effects of a left-to-right shunt and to avoid fistula rupture and possible steal phenomenon during vasospastic episodes. Coil embolization of fistula using 4 coils (2 IMWCE-6,5-PDA5 and 2 IMWCE-8-PDA5, Cook Inc., Bloomington, Indiana) was performed successfully without any complications. Control coronary angiography performed 12 months later showed persistence of occlusion, but multiple tiny collaterals bridging the proximal and distal parts of the occluded segment were present (Figure 2C). Residual shunt was negligible.

Discussion. Our patient, who was a heavy smoker, experienced typical anginal pain in typical hours for variant angina. ECG demonstrating ST-segment elevations was documented during one of these episodes. Disappearance of the pain and resolution of ST-segment elevation rapidly after nitrate administration, as well as non-critical lesion present in the circumflex artery on coronary angiography are all compatible with variant angina. On the other hand, cardiac enzymes did not increase beyond the upper range defined for myocardial infarction and serial TTE examinations showed recovery of left ventricular wall motion abnormality present during pain. Maximal stress ECG failed to provoke angina or ischemic changes under vasodilator treatment, so we excluded the possibility of ‘steal phenomenon’ by the fistula. The final diagnosis was variant angina and a bystander asymptomatic giant aorta–superior vena cava fistula.

Coronary arteriovenous fistulae are relatively rare. Most commonly, they involve the right coronary artery and drain to the right ventricle, right atrium, and pulmonary artery, left atrium in descending order and rarely to the coronary sinus, bronchial veins or superior vena cava.⁵

Mainstay therapy of variant angina is medical treatment, including calcium-channel blockers, long-acting nitrates and life style changes such as smoking cessation. Medical treatment is the first choice in variant angina as most patients respond well. However, there is no consensus regarding the optimal management of CAF. Hemodynamically significant fistulae, especially those causing heart failure, require intervention but optimal management of small and/or asymptomatic fistula remains controversial. Intervention can be achieved surgically through ligation or percutaneously. There is no agreement on the superiority of one technique over the other, but surgical closure of the fistula may be recommended in cases with extreme tortuosity of the fistulous tract, aneurysm formation, coronary branches at the site of optimal device positioning and the presence of additional complex heart disease requiring surgery.⁶ Small residual leaks after either type of procedure appear to be present in 10% of patients. In a study reporting long-term results of 27 percutaneously treated patients, small residual leak was seen18%.⁶ Although a residual leak was also observed in our patient after percutaneous closure, the main mechanism causing this leak was de novo formation of collaterals, instead of technical failure.

Coronary fistula draining to the superior vena cava is extremely rare and we present the first patient in the literature wherein variant angina accompanied a giant right coronary to superior vena cava fistula. We applied both medical and interventional treatment for success. Although surgery is frequently used to treat these types of fistulas,^7,8 coil embolization can be an effective and comfortable procedure in experienced hands.

References

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3. Prinzmetal M, Kennamer R, Merliss R, et al. Angina pectoris. I. A variant form of angina pectoris; preliminary report. Am J Med 1959;27:375–388.

4. Yamagishi M, Miyatake K, Tamai J, et al. Intravascular ultrasound detection of atherosclerosis at the site of focal vasospasm in angiographically normal or minimally narrowed coronary segments. J Am Coll Cardiol 1994;23:352–357.

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6. Armsby LR, Keane JF, Sherwood MC, et al. Management of coronary artery fistulae. Patient selection and results of transcatheter closure. J Am Coll Cardiol 2002;39:1026–1032.

7. Lapenna E, Torracca L, De Bonis M, Alfieri O. A giant right coronary artery-to-superior vena cava fistula. Eur J Cardiothorac Surg 2007;31:546.

8. Pagni S, Austin EH, Abraham JS. Right coronary artery to superior vena cava fistula presenting with 'steal' phenomenon. Interact Cardiovasc Thorac Surg 2004;3:573–574.

From the ªCardiology, bRadiology, and cPediatric Cardiology Departments, Dr. Siyami Ersek Cardiovascular and Thoracic Surgery Training and Research Hospital, Department of Cardiology, Istanbul, Turkey. The authors report no conflicts of interest regarding the content herein. Manuscript submitted April 27, 2010, provisional acceptance given May 18, 2010, final version accepted June 2, 2010. Address for correspondence: Dr. Erkan İlhan, Meclis Mahallesi Teraziler Caddesi Sarıbelde Sitesi U7A blok daire: 3 34785 Sancaktepe Istanbul, Türkiye. E-mail: erkan.ilhan@yahoo.com.tr