Comment
We present an unusual situation in which a patient requiring lung transplantation had congenital absence of the IVC. In this case the Protek Duo cannula not only allowed for intraoperative support but also post-operative oxygenation.
Aberrant IVC anatomy may lead to significant morbidity and mortality secondary to vascular injuries during cannulation. Wolfhard et al. described a case in which absence of the IVC was discovered during routine coronary bypass grafting. Inspection of the right atrium revealed hepatic vein connection without an IVC. For cardiopulmonary bypass, the SVC and right atrium were cannulated separately and then Y-connected. Post operative imaging revealed bilateral IVC with azygous continuation. 3 The prevalence of IVC duplication is 0.2%-3%. Typically, the IVC ends at the left renal vein, which then crosses anterior to the aorta and joins the right IVC.4
Ng et al. presented a vascular injury in a patient with a double IVC due to ECMO cannula placement. In this case, the left femoral vein was accessed using ultrasound guidance and on routine abdominal x-ray, there was abnormal cannula positioning. A subsequent CT scan revealed a double IVC with venous perforation at the junction of the left IVC and left renal vein. The venous injury was repaired surgically and the cannula position was moved to the right femoral vein which had a normal course. Adequate oxygenation and flow was achieved. 5
This double lumen cannulation technique as a method of cardiopulmonary bypass has previously been used in the setting of lung transplantation and has demonstrated several advantages. (1) It can be left in place postoperatively for ongoing RV support, (2) avoids complete diversion of pulmonary blood flow therefore reducing allograft ischemia, (3) may reduce the need for arterial access, (4) and allows for bedside decannulation. Caution should be taken in the setting pulmonic valve insufficiency due to possible RV distention. 6
In summary, in a patient with an anatomic variant or absence of the IVC undergoing lung transplantation, satisfactory cardiopulmonary support can be achieved. With the Protek Duo connected to a modified CPB system in an Oxy-RVAD configuration, RV support and adequate oxygenation can be maintained both intra operatively and post operatively. This technique is a relatively simple solution to an otherwise challenging situation.