Abstract
Vascular tunnels deriving from one of the aortic sinuses and flowing into the right atrium are known as aorto–right atrial tunnels. These are rare extracardiac vascular structures. Completely intracardiac tunnels are an even more rare congenital malformation. We present 2 cases exhibiting intracardiac and extracardiac aorto–right atrial tunnels. The first patient presented an intracardiac vascular structure originating from the left coronary sinus, running downward, intracavitary through the left atrium, without any communication, ending in the right atrium. The vascular structure was resected, with reconstruction of the coronary sinus and left coronary artery reimplantation. The second patient presented a vascular tunnel originating in the right coronary sinus, going between the atria and ending in the right atrium. The tunnel was resected, the right coronary sinus reconstructed, and right internal mammal artery–right coronary artery coronary artery bypass grafting was performed. We advocate for early surgical closure, even in asymptomatic patients, to avoid further complications.
Key Words: aorta abnormalities, aorto–right atrial tunnel, aorta surgery, coronary vessel anomalies, differential diagnosis, heart abnormalities, heart atria, heart surgery, sinus of Valsalva, computed tomography, superior vena cava superior abnormalities, treatment outcome
Graphical Abstract
Aorto-atrial fistulas are rare and complex clinical entities, exhibiting either acquired or congenital etiologies. Congenital aorto-atrial tunnels, distinguished by their origin proximal to the sinotubular ridge, arise from inherent weaknesses in the aortic wall, giving rise to the formation of a conduit extending into one of the atria. These are rare extracardiac or intracardiac vascular structures that may pass the aorta anteriorly or posteriorly, ending in the right atrium, the right atrial septum, or even the superior vena cava. The imperative need for timely intervention is emphasized by the potential for significant complications, even in asymptomatic patients or those with hemodynamically insignificant shunts. Available treatments include catheter-based intervention, external ligation under controlled hypotension, or surgical closure with the patient under cardiopulmonary bypass.
Take-Home Messages
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Timely surgical repair of aorto–right atrial tunnels is crucial to avoid severe complications, even in asymptomatic cases.
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Multimodal imaging is essential for the proper diagnosis and surgical planning.
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The surgical approach is recommended whenever the origin of coronary arteries is involved.
We present 2 patients admitted to our institution, exhibiting different forms of this rare pathology.
Case Presentations
Patient 1
A 26-year-old man, 181 cm and 70 kg, initially diagnosed with an atrial septal defect (ASD) (ostium secundum) and a patent ductus arteriosus, was referred to our institution for further evaluation. The patient was asymptomatic, with no pathologic signs observed during physical examination. During the investigations, echocardiographic assessment revealed minimal dilation of the right- and left-side heart chambers, as well as a 2-cm fistulous tract originating from the left coronary aortic sinus. This tract traversed the left atrium, ultimately draining into the right atrium (Figure 1). To enhance clarity and precision, we subsequently conducted an angiographic computed tomography (CT) analysis. This demonstrated an intracardiac tunnel (15-20 mm in diameter) originating from the left coronary sinus, running downward, being attached intracavitary to the ceiling of the left atrium without any communication to this cavity, and ending in the right atrium cranially to the ostium secundum ASD, in the interatrial septum (Figures 1A to 1C). The left main coronary artery originated from the proximal part of the fistula and had a normal course. The pathology was addressed surgically. The patient was treated by resecting the tunnel from the aortic sinus and reconstructing the sinus with a Dacron patch (Figure 2). The aortic end of the tunnel was closed by an enforced running suture, and the opening into the right atrium was closed using the same patch as for the ASD closure. The left coronary artery was widely mobilized and reimplanted (Figure 2). Total cardiopulmonary bypass time was 110 minutes, with a cross-clamp time of 87 minutes.
Figure 1.
Imaging Findings
(Top) Echocardiography: minimal dilation of the right- and left-side heart chambers, 2-cm fistulous tract originating from the left coronary aortic sinus. (A to C) The trajectory of the tunnel through the left atrium and into the right atrium (red arrows).
Figure 2.
Intraoperative View
(A) Intraoperative view of the tunnel in the left atrium (white circles) and atrial septum defect (red arrows). (B) The opening of the tunnel (stars) just cranial of the atrial septum defect. (C) Dacron patch used to close the coronary sinus defect (x), and left coronary reimplanted in the patch (black dots).
Patient 2
A 27-year-old woman, 170 cm and 55 kg, initially diagnosed with a right coronary sinus aneurysm and an interatrial aneurysmal vascular structure, was referred to our clinic for further investigations and surgical treatment. The patient presented with mild dyspnea, without pathologic signs during physical examination. Transthoracic echocardiography revealed normal left ventricular function without ventricular chamber dilation, and a structure attached to the interatrial septum. The right coronary sinus was significantly dilated, and a conduit originating from it was observed. CT angiography further revealed a 36-mm-long vascular tunnel originating in the aneurysmal right coronary sinus (15 mm in diameter), running between the atria, ending in an aneurysmal structure (30 mm diameter) with minimal compression, and a fistulous opening in the right atrium near the superior vena cava (Figure 3). The right coronary artery originated from the inferior portion of the right coronary sinus. The pathology was addressed surgically. The aneurysmal right coronary sinus had in its anterolateral portion the origin of the tunnel. The right coronary artery had its origin in the proximal part of the aorto–right atrial tunnel, approximately 2 cm away from the aortic wall. Thus, when the aorto-atrial tunnel was resected and the right coronary sinus reconstructed with a Dacron patch, the reimplantation of the right coronary artery to the neosinus was not possible. Accordingly, an end-to-end anastomosis with right internal mammary artery had to be performed. Total cardiopulmonary bypass time was 194 minutes, with a cross-clamp time of 158 minutes.
Figure 3.
Computed Tomography Angiography Visualization
(A) Axial section; (B) sagittal section; (C) 3-dimensional reconstruction: The vascular tunnel originates in the aneurysmal right coronary sinus, running between the atria.
Both patients were discharged without major cardiovascular events after 7 days of hospitalization. At a mean follow-up time of 7 years, both patients had recovered well, undergoing regular cardiologic check-ups without major cardiovascular events and with normal echocardiographic parameters.
Discussion
Most aorto–right atrial tunnels are extracardiac. However, the first case presented here deviates from this pattern, presenting a trajectory that is partially intracardiac, ending in the interatrial septum. An important differential diagnosis of these tunnels is with sinus of Valsalva aneurysm. This anomaly has its origin inferior to the sinotubular ridge and may have intracardiac rupture, whereas aorto–right atrial vascular tunnels have their end in the atrium. The second case depicts a vascular tunnel with its origin in an aneurysmal right coronary sinus. Given the high risk of complications associated with aorto-atrial fistulas, prompt therapeutic intervention becomes imperative. The clinical manifestation of such patients ranges from asymptomatic to severe heart failure. Even in asymptomatic patients or those with a hemodynamically insignificant shunt, there is a potential risk of tunnel calcification, rupture, aortic regurgitation, biventricular volume overload, or aneurysmal expansion. Furthermore, complications may include pulmonary vascular disease, infective endocarditis, and a higher mortality rate during surgery if the lesion remains uncorrected as the patient ages.
The imaging protocol should encompass cross-sectional coronary CT angiography, transthoracic echocardiography, cardiac catheterization, and aortography. The presence of an ASD with a left-to-right shunt and a right coronary sinus aneurysm represents a sign pointing toward these types of vascular structures. Surgical or transcatheter closure of the aorta-atrial tunnel has been recommended as the main therapeutic option. Whenever the origin of the coronary artery is involved, surgical treatment should be chosen. According to the type of ASD, transcatheter closure may be contraindicated (eg, in the case of large multiple ASDs), making surgical treatment the primary recommendation in such cases. The diameter of the vascular tunnel and the size of the opening are pivotal factors in the choice of therapy. As in the first case, some patients may require aortic root reconstruction owing to the increased diameter at the aortic opening.
Conclusions
We emphasize the pivotal role of early surgical closure of such defects as a crucial measure to prevent the progression to serious complications. We advocate the surgical closure of the tunnel and reimplantation of the native coronary artery into the aortic sinus whenever the coronary artery arises from the tunnel.
Funding Support and Author Disclosures
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.