Definition, Types and Diagnosis
Definition: In this heart defect the aortic arch is interrupted. Depending on the location of the interruption it is divided into types:
- type A: interruption in the aortic isthmus
- type B (the most frequent): interruption between the subclavian artery and the left carotid artery
- type C: interruption between the left carotid artery and the brachiocephalic trunk.
Typically associated heart defects: VSD (80%), bicuspid aortic valve (40%), subaortic stenosis (30%).
Operation
Access is via a median sternotomy and the heart-lung machine is used. Via cannulation of the brachiocephalic trunck and the ductus arteriosus the heart is arrested by cardioplegia and transtricuspid closure of the ventricular septal defect is performed. While cerebral perfusion continues the head vessels are temporaly occluded, the aortic arch is anastomosed end-to-end and its ventral segment augmented with a patch (homograft or pericardium). In the case of severe left ventricular outflow tract obstruction (LVOTO) or LVOT hypoplasia several surgical methods are possible, depending on the diameter of the ascending aorta and the extent of the LV hypoplasia:
- ascending aorta and left ventricle (LV) normal -> LVOTO resection or Ross-Konno operation.
- ascending aorta hypoplastic/ LV normal -> Yasui operation: the ascending aorta and the pulmonary artery are anastomosed side-to-side as in the Norwood operation and enlarged as far as the aortic arch with a homograft. The blood from the left ventricle then reaches the enlarged ascending aorta via the VSD and right ventricular tunnel through the pulmonary artery (then neoaorta). RV-PA continuity is achieved by means of a homograft.
- ascending aorta and LV hypoplastic: -> Norwood operation.
