Percutaneous Coronary Intervention in a Right Coronary Artery with a Giant Coronary Fistula

Abstract: Congenital coronary fistula is an uncommon coronary artery anomaly. Percutaneous coronary intervention (PCI), in the presence of a coronary artery fistula, may make the procedure more complex. A case of 86-year-old woman with giant coronary artery fistula arising from the right coronary artery (RCA) ostium presented to our facility with non-ST-segment elevation myocardial infarction (NSTEMI). A successful PCI procedure to the mid-RCA lesion was performed. It is necessary to pay special attention to the underlying anatomy, and plan the procedure and equipment in advance, to avoid unnecessary complications. 

Case report

Congenital coronary fistula is an uncommon coronary artery anomaly which is found in approximately 0.1-1.3% of patients undergoing diagnostic coronary angiography.^1,2 About twenty percents of these cases are associated with coronary artery disease.³ Percutaneous coronary intervention (PCI), in the presence of a coronary artery fistula, may make the procedure more complex.

A previously well 86-year-old Chinese woman presented to our institution with typical retrosternal chest pain radiating to both shoulders with a background history of diabetes, hypertension, and dyslipidemia. 

Physical findings on admission were unremarkable, without heart murmur or signs of cardiac failure. An electrocardiogram revealed a normal sinus rhythm with a heart rate of 78/min, and ST depression in leads V2-3 was noted. Echocardiography revealed normal wall motion of the left ventricle, with a left ventricular ejection fraction (LVEF) of 65%. Estimated pulmonary artery systolic pressure was 49 mmHg and no right ventricular dilatation was detected. Cardiac enzymes were elevated; CKMB was 8.5 µg/L (normal range, 1.0-6.0) and troponin I was 1.29 µg/L (normal range, 0.000-0.039). A diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) was made.

After loading of aspirin 300 mg and clopidogrel 300 mg, coronary angiography was performed due to ongoing chest pain. It revealed a giant coronary fistula in the RCA ostium and a severe 90% diameter stenosis in the mid RCA that was considered the culprit lesion (Figure 1). This giant fistula drained into the pulmonary artery. After discussion with the patient and her family, we proceeded to perform PCI to the mid RCA. Due to the advanced age of the patient and absence of symptoms previously, we decided not to treat the coronary artery fistula. A 6 Fr Hockey Stick guiding catheter (Cordis) was used to engage the RCA ostium and provided adequate support for equipment delivery. Despite the presence of the giant coronary artery fistula, a 0.014” Runthrough NS Hypercoat guide wire (Terumo) was able to advance towards the main RCA and cross the lesion. After predilating the lesion with 2.5 x 20 mm Tazuna balloon (Terumo), two (3.0 x 22 mm and 3.25 x 15 mm) Resolute Integrity (Medtronic) stents were implanted in the mid RCA in an overlapping fashion (Figure 2) without any complications. The patient was discharged 3 days post procedure. 

Discussion

Coronary artery fistulas are uncommon congenital or acquired coronary artery abnormalities in which blood is shunted into a cardiac chamber, great vessel or other structures, bypassing the myocardial capillary network. It increases the risk of complications, including heart failure, myocardial ischemia, infective endocarditis, arrhythmias, and rupture. Myocardial ischemia can occur from decreased coronary blood flow distal to the fistula and has been documented in patients with coronary fistulas with no evidence of coronary atherosclerosis.⁴ However, an association between coronary artery fistulas and coronary atherosclerosis has not yet been clarified. The coronary artery fistula itself may eventually lead to premature atherosclerosis, secondary to shear-induced intimal damage caused by the turbulent blood flow.⁵ In our patient, the culprit lesion of the NSTEMI was located in the mid RCA, which was far from the ostium of the fistula (Figure 1). We speculated that the abnormal turbulent flow of the fistula was not associated with coronary atherosclerosis and her ischemic symptoms were due to the severe coronary stenosis, rather than coronary steal by the fistula, as the patient had never previously experienced angina.

We chose not to intervene on the coronary artery fistula, because after PCI the patient was asymptomatic. Most patients with coronary artery fistula are free of symptoms for long periods.⁴ However, if patients are symptomatic, closure of the fistula should be considered. Today, catheter-based closure has become the procedure of choice. It can be performed with a variety of techniques: coils have been used in small fistulas and double-umbrella devices have been used in large fistulas.⁶ Surgery and direct epicardial or endocardial ligations are recommended in cases of extreme tortuous fistula and/or aneurysm formation. Both transcatheter and surgical approaches have shown similar early effectiveness, morbidity, and mortality.⁷

If a coronary artery fistula is situated proximal to the target lesion intended for PCI, it could be difficult to intervene, especially with wiring or delivery of equipment, although in our case, we did not encounter such difficulties. The giant coronary fistula in our patient was located in the ostium to proximal portion of the RCA. A Hockey stick guiding catheter was selected to achieve better support. Furthermore, a soft hydrophilic guide wire was chosen to cross the lesion with the aid of multi-plane fluoroscopy. 

Sometimes it can be difficult to visualize the anatomy of tortuous blood vessels with only one angle during coronary angiography. It is necessary to evaluate arteries, especially in the presence of unusual anatomy, using multiple angles, or coronary computed tomography (CT) to aid the diagnosis and interventional procedures. The use of microcatheter could be considered if there is a difficulty in wiring.

In conclusion, we presented a case of a giant coronary fistula in a patient who had NSTEMI due to a severe mid RCA stenosis. To achieve successful intervention in atherosclerotic coronary artery stenosis close to a fistula, it is important to pay special attention to the underlying anatomy of the coronary artery and its associated fistula, and plan the procedure and equipment in advance to avoid unnecessary complications. 

Disclosure: The authors report no financial relationships or conflicts of interest regarding the content herein. The authors may be contacted via Dr. Takashi Kajiya at t_kajiya@hotmail.com and Dr. Chan Koo-Hui at koo_hui_chan@nuhs.edu.sg.

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