Interrupted Aortic Arch Seoul National University Hospital Department of Thoracic & Cardiovascular Surgery

Interrupted Aortic Arch 1. Definition A complete luminal & anatomic discontinuity between the two segments of the aortic arch 2. History Steidely : 1st description in 1778 Celoria and Patton : A, B, C type in 1959 Samson : 1st successful operation in Classification Type A (40%), Type B (55%), Type C ( 5%)

Pathophysiology of IAA Luminal interruption between the ascending and descending aorta is found, and distal blood flow is dependent on a patent ductus arteriosus. Spontaneous ductal closure results in systemic hypoperfusion, metabolic acidosis, and end- organ failure Associated cardiac anomalies are common, particularly a nonrestrictive VSD, and IAA comprises less than 1% of all CHD

Embryonic Origin of Aortic Arch 1. Ascending aorta : Embryonic conotruncus 2. Proximal arch : Embryonic aortic sac 3. Distal arch : 4th embryonic aortic arch 4. Isthmus : Junction of 6th embryonic arch with left dorsal aorta & 4th embryonic aortic arch

3 Components of Aortic Arch

Morphology of IAA 1. Aortic arch * Anomalies of brachiocephalic vessels are frequent. * Rare interruption in right aortic arch 2. Left ventricular outflow anomalies * Bicuspid in 30-50% * Aortic and subaortic stenosis * Aortic ring is frequently small 3. Coexisting cardiac anomalies * PDA is almost always * Large VSD is nearly always * Truncus arteriosus, aortopulmonary window 4. Associated syndrome * DiGeorge’s syndrome (absence of thymic tissue) - hypocalcemia & immunologic problem (Type B)

Types of IAA

IAA

Clinical Features in IAA 1. Clinical features * Critically ill neonate in severe CHF * Cardiac murmurs are not specific. * Closing PDA ; anuria & metabolic acidosis 2. Natural History * 1~4% of CHD in autopsy ( 1.3% of CHD in infancy ) * Median age of death : 4~10 days * 90% death in the 1 st. year even though PDA * Pulmonary vascular disease after one year

DiGeorge’s Syndrome 1. Complete type * dysmorphic facial feature : hypertelorism, carp-shaped mouth, micrognathia, notched ear pinnae * hypocalcemia * Low T lymphocyte CD4 * IAA 2. Partial type * Facial feature with hypocalcemia and IAA in the absence of any deficit of CD4 T lymphocyte

Berry Syndrome 1 Interrupted aortic arch 2 Distal aortopulmonary septal defect 3 RPA from ascending aorta 4 Intact ventricular septum

Operation of IAA 1. Indication * Urgent operation is advisable, preferably by a one-stage. 2. Technique * Direct anastomosis (open or non-open technique) * Interposition of graft * One stage repair Median sternotomy and circulatory arrest, IAA and associated anomaly repair

IAA Type B Operative Procedure

Early Operative Results of IAA Mortality & morbidity 1) Early death A cute or subacute heart failure without or with multisystem failure. One stage repair : under 10% IAA repair & second repair : 12-47% mortality 2) Late Survival : good Aortic anastomotic narrowing Development of subaortic stenosis (44-85%)

Operative Results of IAA 1. Survival Early death Time-related survival 2. Modes of death 3. Incremental risk factors for premature death 1) Coexisting cardiac anomalies 2) Location of interruption 3) Preoperative condition 4) Earlier date of operation 4. Left ventricular outflow obstruction 5. Persistent or redeveloped aortic arch obstruction