Truncus Arteriosus Seoul National University Hospital Department of Thoracic & Cardiovascular Surgery

Truncus Arteriosus 1. Definition Congenital cardiac malformation in which one great artery, arising from the base of heart by way of a single semilunar(truncal) valve, gives origin of coronary, systemic, and one or two pulmonary arteries proximal to the origin of the brachiocephalic branches. Beneath the truncal valve, there is a VSD. 2. History Wilson : 1st description in 1798 Buchanan : Clinical & autopsy report in 1864 Collett & Edwards : Classification in 1949 Van Praagh : Alternative classification in 1965 McGoon : 1st repair with homograft in 1967

Truncus Arteriosus  Pathophysiology A single common artery, or truncus, overlying the ventricular septum and a nonrestrictive VSD gives rise to the coronary arteries, pulmonary arteries, and ascending aorta. Complete mixing of systemic and pulmonary venous return at the VSD and truncal valve level results in moderate cyanosis. As the pulmonary vascular resistance decreases after birth, significant left-to-right shunting at the truncal valve level leads to excessive pulmonary blood flow, pulmonary hypertension, and congestive heart failure.

Truncus Arteriosus  Morphogenesis Truncus arteriosus is called also as persistent truncus arteriosus, truncus arteriosus communis, common aorticopulmonary trunk Chromosomal 22q11 deletion is present in a substantial number of patients with conotruncal abnormalities ( about one third with truncus arteriosus) Many of these have additional characteristic features of DiGeorge syndrome, velocardiofacial syndrome, or conotruncal face syndrome As such, their natural history may be complicated by hypocalcemia, palatal abnormalities, learning disability, or other noncardiac problems.

Morphology of Truncus Arteriosus 1. Truncal artery 2. Pulmonary arteries Type I, II : 80~90% III, IV : 5~10% Hemitruncus : 2% Stenosis of origin : 10% 3. Aorta & ductus arteriosus Wide PDA : Arch hypoplasia, IAA or CoA(10~15%) No PDA : majority 4. Coronary arteries 5. Semilunar valve Tricuspid (1/2~2/3), quadricuspid, bicuspid (5%) Myxomatous thickening (1/3) Truncal stenosis (20%) 6. VSD (juxtatruncal) 7. RV (absent conal septum) 8. Left ventricle ; normal 9. Associated anomalies IAA or CoA with PDA : 10~15% RAA : 25~35% Anomalous branch : 10% LSVC : 10% ASD : 10% DiGeorge synd. AV discordance, situs inversus, heterotaxia, DILV, MS, AV-canal, tricuspid stenosis

Classification of Truncus Arteriosus (Collett & Edwards)

Types of Truncus Arteriosus

Pathology of Truncus Arteriosus

Types of Truncus Arteriosus

Truncus Arteriosus VSD Truncal valve

Clinical Features & Diagnosis 1. Symptoms tachypnea, tachycardia, irritability, mild cyanosis 2. Physical examination signs of CHF, overactive heart truncal insufficiency (systolic & diastolic murmur) stenosis of PA (continuous murmur) 3. Chest radiography marked cardiomegaly as well as plethora 4. EKG RAD, biventricular hypertrophy 5. Echocardiography 6. Cardiac catheterization & cineangiography

Truncus Arteriosus  Natural History 1. Incidence rare, unfavorable natural history 1.7% to 2.8% of CHD 2. Survival 50% survival in 1 month 18% survival in 6 months 12% survival in 1 year Others : Eisenmenger syndrome (death in 3rd decade) 3. Modes of death. Congestive heart failure in early life. SBE, cerebral abscess, pulmonary vascular disease. Survival is favorably affected by PS

Operative Techniques 1. Repair with allograft valved conduit 2. Repair truncus I,II with autologous tissue Barbero-Marcial technique 3. Repair of hemitruncus Unifocalization of pulmonary artery 4. Repair of truncus arteriosus with IAA

Operative Indications 1. Diagnosis of truncus is an indication for it’s repair; because about 50% of surgically untreated patients die in the 1 st month of life. 2. Repair should be recommended as early in life as possible rather than deferring to some predetermined age 3. Importantly elevated PVR is a contraindication in old infant (more than 6~12 months old).

Operative Technique (1)

Operative Technique (2)

Truncal Valve Remodeling Technique Diagrams shows truncal valve repair by leaflet excision and annular remodeling, usually there is one leaflet that is grossly prolapsed

Surgical Results of Truncus Arteriosus 1. Survival Early death Time-related survival 2. Modes of death 3. Incremental risk factors for premature death 1) Age at repair 2) Functional class 3) Type 4) Size of VSD 5) Predominance of origin of truncal artery 6) Small size of pulmonary arteries 7) Truncal valve abnormalities 8) Hemitruncus 9) Major associated cardiac anomalies 10) Pulmonary vascular disease 4. Progressing truncal valve incompetence 5. Conduit reoperation