Truncus arteriosus is a rare congenital heart defect where a single arterial trunk arises from the heart to supply the pulmonary and systemic circulations. It occurs when the embryonic truncus arteriosus fails to divide into the aorta and pulmonary artery. Left untreated, it causes cyanosis and heart failure in newborns. Surgical repair is now possible to connect the pulmonary artery to the right ventricle, improving survival rates to over 80% at one year of age compared to just 15% for uncorrected patients.

1. TRUNCUS ARTERIOSUS cyanotic

2. DEFINITION
A single trunk arising from the heart
Supplying the coronary, pulmonary, and systemic circulations
No remnants of an atretic aorta or pulmonary artery, attached to
both ventricles
Overriding the ventricular septum due to failure of the Truncus
arteriosus to divide during in the embryonic period

3. HISTORY
 Wilson : 1st description in 1798
 Buchannan : Clinical & autopsy report in 1864
 Collett & Edwards : Classification in 1949
 Van Praagh : Alternative classification in 1965
 McGoon : 1st repair with homograft in 1967

4. QUICK ANATOMY
Single artery arising from the two ventricles which gives rise to both the aortic and
pulmonary vessels
Abnormal truncal valve
Right sided aortic arch in about 30% of cases (not shown)
Large ventricular septal defect
Pulmonary hypertension
Complete mixing occurring at level of the great vessel
Right-to-left shunting of blood

5. BLAMED
 Baltimore-Washington Infant Study: maternal cigarette smoke(odds ratio [OR]: 1.9,
95% CI 1.04-3.45)
 Texas Birth Defects Registry (1999 to 2004): advancing maternal age
 22q11.2 deletions: Deletions in three genes in this locus (TBX1, CRKL, and ERK2)
cause neural crest cell and anterior heart anomalies seen in patients with DiGeorge
syndrome
Retinoic acid
Bismuth

6. EMBRYOLOGY
Defect in the development of the truncoconal[more conal than Truncus] septum result
in Conotruncal abnormalities including Truncus arteriosus
Neural crest hypothesis
Bulbar septum is deficient just below the singular truncal=semilunar valve

7. INCIDENCE
 40% trunk connects predominantly with the right ventricle
 40% overriding is symmetrical
 20% trunk connects mainly with the left ventricle
Prevalence:0.3:10,000 births
12 times higher in women with pregestational diabetes mellitus
Sibling recurrence is 1/100
6 to 10 per 100,000 live births
 0.7 percent of all CHD
 4 % of all critical CHD.

8. SEMILUNAR CUSPS
2-6
 Tricuspid:69%
 Quadricuspid:22%
 Bicuspid valve:9%

9. VSD
Large
Maligned
 Conoventricular
 Occasionally muscular

10. HOW THE PULMONARY ARTERY IS CONNECTED TO
THE TRUNCUS?
Type 1: a single pulmonary vessel originates from the arterial trunk and bifurcates
in left and right pulmonary arteries.
Type 2: the pulmonary arteries originate from the back of the Truncus
Type 3: the pulmonary arteries originate on each side of the Truncus
Type 4: absent pulmonary arteries; collaterals originate from the systemic
circulation, most frequently from the descending aorta
Collet RW, Edwards JE. Persistent truncus arteriosus: a classification according to anatomic types.
Surg Clin North Am 1949;29:501-10

11. VSD OR NO VSD[SOCIETY OF THORACIC
SURGEONS (STS) ]
TYPE A[VSD+] TYPE B[VSD-]
 A1: As CE type 1, in which a main pulmonary artery is present, and
arises from the left side of the truncal root.
 A2: h CE types II and III, as the two CE types do not differ
embryologically and the surgical approach is the same. Type A2
consists of right and left branch pulmonary arteries with separate
origins (regardless of the distance separating the two pulmonary
arteries) from the truncal root.
 A3: Unilateral pulmonary atresia with collateral supply to the
affected lung.
 A4:Interrupted aortic arch
Van Praagh R, Van Praagh S. The anatomy of common aorticopulmonary trunk (truncus arteriosus communis) and its
embryologic implications: a study of 57 necropsy cases. Am J Cariol 1965;16:406-26

12. Major classification systems for truncus arteriosus reproduced from [25] with permission from
Elsevier.
Sojak V et al. MMCTS 2012;2012:mms011
© The Author 2012. Published by Oxford University Press on behalf of the European Association
for Cardio-thoracic Surgery. All rights reserved

13. TYPE I TRUNCUS WITH RT AORTIC ARCH

14. TYPE I TRUNCUS WITH RIGHT AORTIC ARCH

15. HEMODYNAMIC
Hemodynamic is not affected during intrauterine life
 Cardiac failure occurs after birth because of the fall in blood pressure in the
pulmonary circulation leads to medical emergency
 Pulmonary vascular obstructive disease may develop in surgically uncorrected
patients with large pulmonary blood flow, with changes noted as early as six months
of age
Coronary under perfusion due to AR and pulmonary run off

16. NATURAL HISTORY
a mean age of death at five weeks
 survival of only 15 percent at one year of age
 beyond the first year of life develop severe pulmonary vascular obstructive disease

17. SYMPTOMS
Bluish skin (cyanosis)
Delayed growth or growth failure
Fatigue
Lethargy
Poor feeding
Rapid breathing (tachypnea)
Shortness of breath (dyspnoea)
Widening of the finger tips (clubbing)

18. SIGNS
Cyanosis presents at birth
Heart failure may occur within weeks
Systolic ejection murmur is heard at the left sternal border
Widened pulse pressure
Bounding arterial pulses
Loud second heart sound
Biventricular hypertrophy
Cardiomegaly
Increased pulmonary vascularity
Hypocalcemia (if associated with DiGeorge syndrome)

19. ASSOCIATED
Up to 50% of the cases, including unilateral renal agenesis or hypoplasia, absent
gallbladder, pulmonary hypoplasia and cleft palate
DiGeorge, velocardiofacial (DFG/VCFS) and conotruncal anomaly face syndromes
(CTAFS) are associated with conotruncal anomalies
Aortic arch anomalies :Right aortic arch – 21 to 36%,Interrupted aortic arch – 11
to 19 percent,Hypoplastic aortic arch (with or without coarctation of the aorta) – 3
percent
Secundum ASD:9 to 20%, mild tricuspid stenosis:6%, aberrant subclavian arteries: 4
to 10%, persistent LSVC :4 to 9% and PDA :50%

20. DIFFERENTIAL DIAGNOSIS
Pulmonary atresia/intact IVS
Tetralogy of Fallot
large ventricular septal defect (VSD)
 pulmonary atresia with VSD
Univentricular heart

21. TREATMENT
Initial medical management Surgery
Treat heart failure due to large left to right shunt Connect pulmonary artery[right ventricle to
pulmonary artery (RV-PA) conduits ] to right
ventricle
Primary surgical repair during the neonatal period
(less than 30 days of age) has led to an improved
survival rate at one year of age of greater than
80 percent compared with the 15 percent rate
observed in uncorrected patients

22. THANKS
 http://en.wikipedia.org/wiki/Persistent_
truncus_arteriosus
 http://www.cincinnatichildrens.org/pati
ents/child/encyclopedia/defects/graphic
summaries/truncusswf/
 http://www.youtube.com/watch?featur
e=player_embedded&v=RBYCU_DH4q
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