An anomalous origin of the right pulmonary artery (RPA) from the ascending aorta (AORPA) is a rare cardiac malformation.[1] Partial or complete occlusion of the RPA may be seen following re-implantation of the RPA on the main pulmonary artery (MPA). An occluded RPA can be recanalized either surgically or by transcatheter methods.

A five-month-old female infant diagnosed with AORPA was admitted to our hospital. She had a history of RPA re-implantation on the MPA at 11 days old. One month after the first operation, embolectomy was performed for proximal RPA thrombosis. Transthoracic echocardiography on admission revealed a disconnected RPA (Figure 1), which was confirmed with computed tomography angiography (CTA) (Figure 2).

Figure 1. Transthoracic echocardiography showing disconnected right pulmonary artery.
MPA: Main pulmonary artery; LPA: Left pulmonary artery.

Figure 2. Computed tomography angiogram demonstrating right pulmonary artery disconnection.
MPA: Main pulmonary artery; LPA: Left pulmonary artery.

On catheter angiography, contrast injection through the right ventricular outflow tract and MPA showed no flow to the distal RPA branches (Video 1-Part 1). Then, additional contrast material injection to the obstructed part showed a tiny passage to the RPA (Video 1-Part 2). A 0.014-inch extra-support coronary guidewire was passed through the obstructed segment. A 2Fr microcatheter passed over the guidewire (Video 1-Part 3). Predilation of the target lesions with 2x15 mm, 4x15 mm coronary angioplasty balloons was followed by a 6x20 mm Numed TyShak II® balloon (NuMED Canada Inc., Cornwall, Ontario, Canada) (Video 1-Part 4). Proximal RPA stenosis, measuring 2.7 mm, persisted after ballooning (Video 1-Part 5). A 5Fr guiding catheter was advanced over the extrasupport coronary guidewire up to the distal RPA. A 4.5x12 mm bare-metal coronary stent was successfully deployed into the proximal RPA (Video 1-Part 6). The post-deployment angiogram showed optimal stent implantation with revascularization of RPA (Video 1-Part 7). The procedure was completed without any complications. The CTA and transthoracic echocardiography three months after the catheter intervention showed a patent RPA stent (Figure 3, Video 2). This case demonstrates that transcatheter recanalization may be possible in postoperative pulmonary artery obstructions, even in patients with minimal flow to distal branches.

Figure 3. Computed tomography angiogram demonstrating right pulmonary artery connection and patent stent lumen.
MPA: Main pulmonary artery; LPA: Left pulmonary artery; RPA: Right pulmonary artery.

Video 1.
Part 1: Catheter angiogram showing that the main pulmonary artery and left pulmonary artery are filled with contrast material whereas the right pulmonary artery is not opacified. The stump of RPA is noticeable.
Part 2: Contrast material administration through hand injection showing a tiny passage to the proximal RPA.
Part 3: The angiogram showing that the 0.014-inch extrasupport coronary guidewire passes through the obstructed segment, and catheter position is confirmed by contrast injection through a 2Fr microcatheter.
Part 4: Predilation of the target lesions with consecutive angioplasty balloons.
Part 5: Angiogram showing persisting proximal RPA stenosis after predilations.
Part 6: Angiogram showing bare metal coronary stent implanted into the proximal RPA.
Part 7: Post-deployment angiogram showing optimal stent implantation with revascularization of RPA.

Video 2. Contrast material administration through hand injection showing a tiny passage to the proximal right pulmonary artery.

Patient Consent for Publication: A written informed consent was obtained from parents of the patient.

Data Sharing Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Author Contributions: Wrote the paper: B.Y.; Design: S.U.A.; Literature review: S.G.; Data collection: M.M.A.; Control and supervision: A.G.

Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding: The authors received no financial support for the research and/or authorship of this article.

References

1) Keane JF, Maltz D, Bernhard WF, Corwin RD, Nadas AS. Anomalous origin of one pulmonary artery from the ascending aorta. Diagnostic, physiological and surgical considerations. Circulation 1974;50:588-94.