Large, tortuous, and complex coronary artery fistulas (CAFs) present significant challenges for both interventionists and surgeons (1–3). In a 4-month-old boy with an isolated, aneurysmal, and large CAF originating from the right coronary artery (RCA) and draining into the left ventricle (LV) (Supplementary Video S1), conventional surgery posed high risks, and a percutaneous intervention was difficult. This report details a minimally invasive percoronary device occlusion technique that offers a safe and effective solution for CAFs, regardless of their origin or drainage site.

A 4-month-old male infant (weight 6 kg, height 67 cm) presented with heart failure and was diagnosed with an isolated CAF via transthoracic echocardiography and computed tomography angiography. The RCA was tortuous, aneurysmal, drained into the LV, and was without evident side branches. The drainage opening measured 8.9 mm and was located posterior to the heart, below the mitral valve annulus. A continuous murmur was auscultated at the left third to fourth intercostal space. Transthoracic echocardiography revealed a mean pressure gradient of 9 mmHg and LV dilation.

Due to the high morbidity of conventional open-heart surgery at this age and the challenges of percutaneous closure requiring a large arterial sheath, a percoronary approach was chosen.

The procedure was performed under general anesthesia with transesophageal echocardiographic (TEE) guidance (Figure 1). The patient was placed in a supine position, and a 3 cm lower mini-sternotomy incision was made. The pericardium was incised and suspended, and purse-string sutures were placed on the straight section of the RCA. The RCA was punctured and a flexible guidewire (16 cm; Lifetech, Shenzhen, China) was advanced through the RCA into the LV. An 8-Fr short delivery sheath was introduced into the LV over the guidewire (Figure 2). A 10 mm muscular ventricular septal occluder (retention disk diameter: 14 mm; Starway Medical Technology, Beijing) was deployed to occlude the CAF outlet. The delivery system used is shown here (Figure 3). A 15-min occlusion endurance test confirmed no ischemia, as indicated by continuous electrocardiogram monitoring. After confirming stability with a push-and-pull test, the occluder was released (Supplementary Video S2).

The patient stayed in the intensive care unit (ICU) overnight without ST-T segment abnormalities. Heparin was administered for 24 h postoperatively. The patient was discharged on postoperative day 7 and was prescribed aspirin (4 mg/kg/day).

At the 3-month follow-up, computed tomography angiography, and echocardiography showed decreased LV size, excellent device positioning, and complete CAF occlusion without thrombus formation (Figure 4). The RCA had no branches; therefore, we discontinued the aspirin after a departmental meeting. By 6 months, optimal remodeling was achieved, as evidenced by imaging studies (Supplementary Video S3). Troponin I levels and electrocardiograms remained normal during 10 years of follow-up, with no ST-T segment abnormalities observed. A short video demonstrates how the procedure is carried out (Supplementary Video S4).

Surgical intervention in this infant would have caused significant trauma, as it would have included sternotomy, cardiopulmonary bypass, and prolonged ICU stay, all of which are well-documented risks (2). In addition, the transcatheter approach was constrained by the challenges of arterial access and the inability to establish an arteriovenous circuit, as the fistula terminated in the LV. Creating such a circuit would have required advanced materials and large-profile devices, increasing the risk of electrical disturbances. The extensive use of fluoroscopy and contrast in such cases poses further risks, especially in infants.

Recent advances, including using microcoils and microcatheters, have shown promise even in small children (3). Combining these with our approach could provide a viable salvage strategy for failed transcatheter interventions or cases where surgery is the only alternative. Retrospective studies spanning three decades highlight that surgical closure is not commonly utilized, underscoring the need for less invasive options (3).

Treatment options for CAF include repair with cardiopulmonary bypass, ligation without cardiopulmonary bypass, and transcatheter closure using coiling, device occlusion, or covered stents. The choice depends on factors such as patient age, body weight, fistula size and tortuosity, termination site, coronary anatomy, and the number of fistulas (4, 5). Traditional surgery in small children is associated with significant morbidity, trauma, and complications (6).

In this case, the tortuous RCA draining into the LV, the large fistula opening, and the patient's low body weight made the transcatheter approach impractical. Open-heart surgery posed high morbidity risks, and percutaneous device closure was challenging due to the need for large arterial sheaths.

Previously, we reported CAF occlusion using right or left parasternal intercostal incisions, tailored to the fistula's origin, course, and termination (7, 8). This demonstrates the flexibility of our approach to ensure consistent outcomes while accommodating diverse patient anatomies. Our methods, which include peratrial, perventricular, and percoronary techniques, enable the occlusion of a wide range of CAFs, regardless of their origin, termination, or the patient's age and body weight.

CAF cases with specific characteristics, such as drainage into the right ventricle or other cavities and/or superficially dilated coronary segments (e.g., RCA or left anterior descending artery), may also benefit from this technique. Managing rare and complex CAFs requires expertise, but our approach simplifies the process without sacrificing efficacy.

In conclusion, the percoronary device occlusion of CAF offers the following benefits: no fluoroscopy or contrast agent use, no cardiopulmonary bypass, no age or weight limitations, and minimal technical requirements. This technique provides a safe, effective, and less invasive alternative therapy for selected patients.