Dual Sources of Coronary Steal Presenting as Acute Coronary Syndrome

This article has supporting videos to Figures 1-4:

Video 1 (Figure 1)

Video 2 (Figure 2)

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Video 4 (Figure 4)

Abstract

Left internal mammary arterial bypass grafts (LIMA) have been used with well documented, reliable long-term patency rates. LIMA to pulmonary artery fistulas are a rare phenomenon, with few reported cases, and can lead to coronary steal.¹ Percutaneous treatment options have been reported, and include intravascular coiling and covered stent angioplasty. Herein, we present a case of coronary steal from a previously coiled yet recanalized LIMA to pulmonary artery fistula, in combination with severe left subclavian artery stenosis, presenting as acute coronary syndrome.

Case Presentation

A 74-year-old male with a history of coronary artery disease, prior coronary artery bypass graft surgery with bioprosthetic aortic valve replacement in 2006, and prior coiling of a LIMA to pulmonary artery fistula in 2013 was admitted to the hospital with recurrent symptoms of typical chest pain consistent with unstable angina. He responded well to initial medical therapy; however, he was noted to have chest pain on hospital day number 2 with a peak cardiac troponin of 0.05 ng/ml.

A coronary angiogram was performed that demonstrated a left dominant circulation with a patent, minimally diseased vein graft to a large first obtuse marginal artery, mild left main artery disease, mild left posterior descending artery disease, and a small-caliber, mildly diseased right coronary artery. There was 80% ostial stenosis of the left subclavian artery with a 40 mmHg gradient (Figure 1). The LIMA to left anterior descending (LAD) coronary artery graft was patent with non-obstructive disease; however, a large LIMA sub branch that was previously coiled in 2013 was noted to have brisk flow extending into the left pulmonary artery (Figure 2). Based on the patient’s clinical symptoms, suggestive of coronary steal originating from a combination of left subclavian artery stenosis, and LIMA to pulmonary artery fistula, the decision was made to treat both issues.

A 6 French (Fr) internal mammary artery (IMA) guide was used to engage the LIMA. A 300 cm Prowater wire (Asahi Intecc) was advanced into the LIMA sub branch (pulmonary artery fistula) and a Renegade microcatheter (Boston Scientific) advanced over the wire into the vessel. A 3 mm x 6 mm Interlock Coil (Boston Scientific) was deployed in the proximal portion of the sub branch with interval decrease in flow. The final angiogram noted significantly reduced flow in the LIMA sub branch with preserved flow in the LIMA to LAD graft (Figure 3).

Next, attention was turned to the left subclavian artery stenosis. The 6 Fr, 11 cm femoral sheath was exchanged for a 7 mm x 90 cm Pinnacle Destination sheath (Terumo). A Magic Torque wire (Boston Scientific) was advanced into the left axillary artery and a 7 mm x 20 mm balloon used to pre-dilate the ostium of the left subclavian artery. An Express 9 mm x 25 mm balloon-expandable bare-metal stent (Boston Scientific) was then deployed at nominal pressures at the left subclavian ostium and post-dilated with a 9 mm balloon. There was a good angiographic result with brisk flow in the left subclavian artery and LIMA-to-LAD graft (Figure 4). The patient’s post procedure course was uncomplicated and he was discharged home the following day. At one-month follow-up, the patient reported complete resolution of chest pain symptoms.

Discussion

Coronary steal resulting from a LIMA to pulmonary artery fistula after coronary artery bypass graft surgery is a rare finding, with fewer than 30 cases reported in the literature.¹ Risk factors for development of fistula formation include incomplete ligation of LIMA side branches, surgical injury to the pleura and lung parenchyma, infection, and inflammation causing neovascularization.^1,2 The most common presenting symptom is recurrent angina; however, dyspnea and congestive heart failure have also been reported.³ Multiple percutaneous treatment options exist, including intravascular coils (additional information on the intravascular coil used in our case can be found in Figure 5), covered stents, vascular plugs, and surgical ligation.⁴ The utilization of physiological testing for the significance of side branch flow using coronary flow reserve has also been reported.⁵ The majority of the literature supports intervening at the onset of symptoms, with confirmation of adequate treatment by subjective questioning and symptom relief.

Conclusion

Herein, we present a case of unstable angina and two sources of coronary steal originating from severe left subclavian artery stenosis and a recanalized LIMA to pulmonary artery fistula, both successfully treated percutaneously with complete resolution of symptoms. 

Disclosure: The authors report no conflicts of interest regarding the content herein.

The authors can be contacted via Vincent Varghese, DO, Director, Interventional Cardiology Fellowship Program, at varghesev@deborah.org.

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