INTRODUCTION : Left hepatic vein (LHV) draining into coronary
sinus(CS) is a rare vascular anomaly[1] . It has
no hemodynamic or clinical significance, unless it is associated with
other cardiac anomalies requiring surgical correction. Unlike median
sternotomy, access to LHV is difficult in minimally invasive surgery due
to limited exposure and its position with respect to inferior vena cava
(IVC), as seen by the operating surgeon. Main challenges in such cases
are looping IVC and achieving adequate venous drainage during cardio
pulmonary bypass (CPB).
CASE REPORT : A 28 year old female with diagnosis of congenital
heart disease ,ostium secundum atrial septal defect (ASD) with
persistent left superior vena cava (PLSVC) was referred for surgical
correction. She had a massively dilated CS, which is not usually seen in
a case of PLSVC. Magnetic resonance angiography (MRA) was done for
further evaluation, which showed anomalous LHV draining into CS (Figure
1)
We approached through right anterolateral thoracotomy (RALT), with total
peripheral cannulation. After induction with single lumen endotracheal
tube transesophageal echocardiogram (TEE) probe was placed. After
partial heparinization (1- 1.5 mg\kg) right internal
jugular vein was cannulated percutaneously using 16 Fr Edwards cannula.
A 4 - 5 cm sub mammary incision was made and right pleural cavity was
entered through 4th intercostal space. Pericardiotomy
was done 3cm anterior to the phrenic nerve and stay sutures are placed.
Right femoral vessels are exposed. After full heparinization, femoral
artery and vein are cannulated with 19Fr & 21Fr Biomedicus cannulae
respectively by Seldinger technique. Instead of placing femoral venous
cannula tip at the IVC right atrial junction, it was placed in the right
atrium to accommodate venous return from CS. Superior vena cava was
looped. We did not attempt looping IVC or LHV as the space between them
was less and also LHV was behind IVC(as seen by the operating surgeon).
CPB was established with the help of vacuum. After applying aortic cross
clamp (Chittwood clamp) ,cold blood cardioplegia was administered
through root. Just before atriotomy femoral venous cannula was pulled
back to IVC right atrial junction .ASD was closed using autologous
pericardium. During intra cardiac repair venous return from LHV and
PLSVC was managed by keeping a cardiotomy suction in the CS. Femoral
venous cannula was pushed back into right atrium while taking last few
stiches over the atrium. Uneventfully weaned off from the CPB, rest of
the intra operative and post operative period was uneventful.
DISCUSSION : LHV to CS is rare congenital vascular anomaly[1].It is due to persistent connection between
left vitelline vein system and left horn of sinus venosus. Commonly
associated anomalies with this condition are PLSVC, subaortic stenosis ,
anomalous pulmonary venous drainage, atrial and ventricular septal
defects, duplication of superior vena cava or IVC[2,3]. It has no clinical or hemodynamic
significance unless it is associated with other cardiac anomalies
requiring surgical correction. If not detected preoperatively, this
anomaly is found during IVC cannulation or looping[4]. Preoperative diagnosis helps to plan the
proposed surgery properly.
PLSVC can be easily diagnosed by transthoracic echocardiogram, with or
without saline agitation test. However LHV to CS is missed easily due to
limited spatial resolution and limited window with narrow fields of
view. Computed tomography angiography and MRA are more accurate and non
invasive imaging modalities which provide detailed anatomic information,
which helps in planning surgery[5].
During surgery blood flow from LHV can be controlled by a torniquet or
by direct cannulation [3]. Care must be taken to
avoid traction on LHV, as it may cause hemodynamic compromise or
arrhythmias. However access to LHV becomes difficult in minimally
invasive surgeries due to limited exposure and its position with respect
to IVC (lies behind IVC, as seen by the operating surgeon)
Two main challenges in such cases approached through minimal access
approach are 1)looping IVC 2) achieving adequate venous drainage on CPB.
We did not loop IVC as the gap between IVC and LHV was less and access
was also difficult. Venous drainage was assisted by vacuum[6].Adequate venous drainage was achieved by
manipulating the position of femoral venous cannula and by choosing one
size larger cannula. At the initiation of CPB femoral venous cannula was
placed in the right atrium. Just before atriotomy it was pulled back to
its regular position(IVC right atrial junction), again pushed back into
right atrium while taking last few stiches over the right atrium. During
intra cardiac repair venous drainage was achieved by placing cardiotomy
suction in the CS.
Another method to achieve adequate venous drainage is by triple venous
cannulation. Along with right internal jugular and femoral vein ,right
atrial appendage is cannulated. Right atrial cannula is clamped just
before atriotomy and unclamped while taking last few stiches over right
atrium. Other options to achieve adequate venous drainage are, kinetic
assisted drainage or use of new generation or virtually wall- less
cannulas [6,7].
CONCLUSION : LHV draining into CS even though rare, it is
significant when associated with other cardiac anomalies requiring
surgical correction.Pre operative diagnosis helps to plan the surgery
properly. During surgery main challenges are IVC looping and achieving
adequate venous drainage on CPB. This becomes even more challenging in
minimally invasive surgery due to limited exposure and poor access to
LHV and PLSVC. Care must be taken while looping IVC or avoid looping and
use vacuum to assist drainage. Adequate venous drainage can be achieved
by choosing one size larger femoral venous cannula and by manipulating
its position on CPB. Another option is triple venous cannulation, by
additionally cannulating right atrial appendage with a smaller cannula
and clamping it just before atriotomy and unclamping it while taking
last few stiches over right atrium.