Discussion and Conclusion
Congenital IVC malformation reflects the complicated multi-segmental development of the IVC during embryogenesis [2]. It is classified by Huntington and McLure with up to 14 theoretical variations [3]. The most common anomalies of the IVC include the circumaortic left renal vein (1.5%-8.7%), the retroaortic left renal vein (2.1%), the double IVC (0.2%-3%), azygos, the hemi-azygos continuation of IVC (0.6%), and the isolated left-sided IVC (0.2%-0.5%) [4]. The Double IVC, the azygos and hemiazygos continuation, the intrahepatic IVC interruption, and the transhepatic venous shunt were rare. Here we reported the patient with the intrahepatic shunt on the right and hemi-azygos system on the left for the venous return from extremities. The patient had the retroaortic anastomotic vein connecting 2 venous collateral pathways towards the heart. Most patients with IVC malformation are asymptomatic. The prevalence of thromboembolic disease in patients with a duplicated IVC is unknown, yet there are case reports of pulmonary embolism in those patients [4].
Cardiologist may use a superior vena cava (SVC) approach for transseptal puncture through the right internal jugular vein in LA ablation, but that is not a conventional choice. It is impossible to puncture the atrial septal by IVC approach in patients with IVC anomaly. The Cox Maze III procedure has been considered the “gold standard” to eliminate AF,but it is not well accepted by patients because of its invasiveness. Wolf and colleagues introduced using the thoracoscopic technique to perform Cox Maze procedure [5]. However, the procedures are technically challenging. It was further modified, such as Mei who reported a complete thoracoscopic ablation of the LA via the left chest to treat lone atrial fibrillation [6]. The ablation circuit was shown in figure 4. We used Mei’s method on the beating heart through 3 ports in the left chest wall. Pulmonary vein isolation and ablation of the left atrium were achieved by bipolar radiofrequency ablation. Ganglionic plexus ablation was completed using the ablation pen. The left atrial appendage was excluded. By using this modified procedure, we shortened the operation time, simplified workload of anesthetists, and reduced injury for patients by avoiding thoracotomy, minimizing changes of patient’s position during the surgery, and simplifying the trachea cannula management by the anesthetists. In conclusion, we have shown that the modified Cox Maze III procedure under VATS has technical advantage and feasible especially to AF patients with IVC anomalies.
The sinus rhythm was restored in the patient after surgery. She has been well followed up for 2 years since the operation with no recurrence of AF. The results indicate that the modified Cox Maze III procedure is efficient, safe, convenient and reproducible for treatment of paroxysmal or persistent atrial fibrillation. More cases and further follow-up data should be collected to substantiate our findings.