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.