Adults with congenital heart defects and congestive heart failure are a challenging population because of its complex anatomy, prior surgical palliation, and hemodynamic status. Advances in palliation of congenital heart disease have resulted in improved survival to adulthood. Many of these patients ultimately develop end-stage heart failure requiring heart transplant or LVAD implantation.
The CCTGA is characterized by atrio-ventricular and ventriculo-arterial discordance in which morphologic right ventricle functions as the systemic ventricle (SV), whereas the morphologic left ventricle functions as the pulmonary ventricle (PV). In this anomaly, the systemic atrio-ventricular valve (SAVV) is a morphologic tricuspid valve, whereas the pulmonary atrio-ventricular valve (PAVV) is a mitral valve [1, 2]. The great arteries are transposed, with the aorta rising from the RV and the PA rising from the LV. The aorta is located anterior to and left of the PA; thus, the prefix of ‘L’ is used . Despite adequate repair, patients with systemic RVs have an increased risk for developing heart failure accompanied by a high mortality rate .
At the time of referral for surgical repair, the majority of these patients have significant SV dysfunction with advanced symptoms. Although excellent early surgical results can be achieved, residual impairment of the SV is common and may eventually necessitate cardiac transplantation [5, 6]. Systemic ventricular failure is a known complication after a Senning or Mustard procedure because the morphologic RV must function as the systemic ventricle .
Development in the field of mechanical circulatory assist devices in recent decades offer an additional option for patients of end stage heart disease with various aetiologies including congenital heart disease . If rapid deterioration of cardiac function ensues before a donor heart becomes available, the use of an LVAD may be the only option for these patients. Implantation of an LVAD in a patient with TGA after surgical repair was first described by Wiklund et al., who achieved a successful outcome using a HeartMate device . Several cases of VAD implantation using different generations of device are reported in the literature [10, 11].
Normally, the outflow graft of the VADs, especially with new axial flow devices, ejects from the device and navigates by the right side of the heart to terminate into the ascending aorta. Both in TGA and CCTGA, the aorta is located anterior to and left of the PA with various degrees of malrotation. Hence, the outflow graft has to traverse across the PA from right to left to reach the ascending aorta. This brings the graft under the sternum in close proximity. Reoperation is needed these cases for VAD explant, VAD up-gradation, pulmonary VAD implantation or eventual heart transplant. Re-entry through the median sternotomy is unavoidable under such circumstances. The outflow graft lying under the sternum yields a great risk of cutting through the graft which may leads to catastrophic haemorrhage and exsanguinations.
Different techniques of reinforcing and positioning the outflow graft to make them less vulnerable at re-do sternotomy like tunnelling the graft in PTFE patch or through the right pleural cavity were reported . However, these techniques protect the graft in presence of normal heart anatomy. In case of TGA due to anomalous relation of great arteries, the outflow graft crosses midline over PA and comes in contact with sternum. The injury at the time of re-do sternotomy can be avoided by approximating the pericardium over the graft, but there remains possibility of graft obstruction due to pericardial tension. The thymic fat over the pericardium can be mobilised and approximated over the graft. Use of Gore-Tex, PTFE or Teflon sheet as a pericardial substitute in cases of major cardiovascular operation to avoid injury during re-do sternotomy is well reported . Its use in LVAD surgery is not yet published, although can be used in cases with graft coming in contact with sternum. Another way to protect the outflow graft is to tunnel it under superior vena cava before anastomosing over ascending aorta . If none of the techniques of graft protection were utilized at the time of LAVD implantation, femoro-femoral cardiopulmonary bypass and a careful dissection through right second or third intercostal space before re-do sternotomy is essential.