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.