Left Atrial Aneurysm—Approach by IVC Transection

An isolated left atrial (LA) aneurysm is a rare congenital abnormality. It can involve the left atrium or very rarely, the entire left atrium (1). The main concerns about the LA aneurysm are the possible complications such as atrial arrhythmias, thromboembolic events, and CHF symptoms caused by pressure effect malfunction of cardiac structures, mainly the mitral valve (2).

This video presents a large LA aneurysm in a fourteen-year-old boy with a history of previous mitral valve repair. He presented with breathlessness when he was two years old, and an echocardiogram showed dilated LA and severe MR due to annular dilation. The mitral valve was fixed with a 26 mm annuloplasty ring at that point. Since then, the patient had no symptoms until one year prior to this procedure, when he was referred with dyspnea on exertion. 

Echocardiography confirmed a large left atrial aneurysm and only trivial MR. The ECG revealed a rhythm of atrial fibrillation. The CT angiography revealed a massive left atrial aneurysm involving the LA appendage and the entire LA body, extending to the diaphragmatic surface of the heart behind the IVC. There was no thrombus inside. The reoperation was undertaken to prevent the occurrence of complications associated with the aneurysm, alleviate the associated symptoms, and restore sinus rhythm.

The Surgery

The large size of the aneurysm and its extensive spread throughout the posterior cardiac border led to the assumption that a conventional approach from outside the heart would be impossible and would result in significant aneurysmal tissue remaining. Therefore, the authors decided to approach this case by excluding the aneurysm from inside the LA. However, the narrow space above the right pulmonary veins was not sufficient to provide adequate access to the aneurysm from within the LA through a usual left atriotomy incision. 

To obtain sufficient exposure to the left atrial structures, the team first transected the IVC, lifted the right atrium and the atrial septum anteriorly, and entered the aneurysm underneath the transected IVC. This approach allowed exclusion of all the aneurysmal tissue from inside the LA while preserving the vital structures, the mitral valve, and the left and right pulmonary veins. Aneurysm exclusion was performed by two layers of sutures, a horizontal mattress, and a continuous locking suture. The first suture line was used to restore the architecture as a road map, and the second deep full-thick suture line was constructed to achieve hemostasis. This double layer suturing was also expected to stop the electrical connection between the normal left atrial tissue and the aneurysmal tissue, which was the most likely source of arrhythmias. Finally, the remaining left atrium was then closed, followed by the IVC being reconnected.

The patient experienced a complete recovery without incident. The sinus rhythm was immediately reestablished, and it has remained stable in sinus rhythm for the past two years.

Conclusion

After the operation, surgeons concluded that approaching the LA aneurysm by IVC transection had a substantial role in providing a good view and access to the left atrial structures during this redo operation. This approach may be suggested when the exposure of the mitral valve or other LA structures is very limited and does not allow for a comfortable and precise procedure. The exclusion policy may also make the operation easier since there is less chance of suture line hemorrhage in these extensive cases. The two-layer, full thickness suturing technique employed in this case was effective in stopping atrial fibrillation, which is normally achieved through the cut-and-sew technique used in Maze operations.

References

1. Shams KA. When the left atrium becomes a monster: a case report. European Heart Journal-Case Reports. 2020 Jun 17.
2. Mandegar MH, Moradi B, Roshanali F, Ojaghi Z. Giant left atrial aneurysm. Journal of Cardiology Cases. 2014 Oct 1;10(4):144-6.

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