1. Truncus Arteriosus CICU lecture January 7, 2011 Chrissy Sarlone

2. Features A single vessel arises from the heart Origin to the coronary arteries, pulmonary arteries, and aorta Truncus overrides VSD 1-2.5% of all congenital heart disease

3. Features Truncal valve is usually a single valve with 2 to 4 cusps PDA absent in 50% of patients Size of PDA and aorta vary inversely

4. Embryology Failure of normal septation and the division of the embryonic truncus into the aorta and pulmonary artery VSD forms from an absent or minimal conal septum

5. Classification 48-68%29-48%6-10%

6. Risk Factors Genetics: Recurrence rates vary from 1.2% to 13.6% with complex disease(Allen et al, 2000 ) IDM (12-13 fold increase in Baltimore Washington Infant Study) – Ferencz, Teratology, 1990 Fetal exposure to retinoic acid

7. Associated Defects Truncal Valve Insufficiency/Stenosis-detected by 24 weeks gestation Right sided aortic arch- 30% Interrupted aortic arch- 11-20% – Type B Coronary Artery Anomalies

8. 22q11 Microdeletion Syndrome 1/3 of infants Higher risk if associated aortic arch anomaly Important to assess for hypocalcemia and immunodeficiency as these complicate the course

9. Physiology With the large VSD, the combined cardiac output travels through the truncal valve PBF depends upon the balance between PVR and SVR

10. Physiology After birth, high PVR leads to almost equal distribution of Qp:Qs As the PVR falls, Qp:Qs increases at the expense of systemic oxygen delivery and CHF ensue

11. Delivery Room Management Usually no intervention needed in the DR Several Factors to Consider: – Truncal valve insufficiency – Pulmonary artery hypoplasia If moderate or greater truncal valve insufficiency, the infant will be gray at birth because of low Mvsat and decreased systemic oxygen delivery

12. “The Unknown” Presentation If not prenatally diagnosed and no truncal valve insufficiency or PA hypoplasia, there may be mild cyanosis due to complete mixing Once PVR falls, sats will range 90% and higher, no visible cyanosis (increase Qp:Qs ratio) Over several weeks, the infant will become symptomatic with signs of CHF due to increased PBF and as a result decreased systemic oxygen delivery – Tachypnea, retractions – Poor feeding and growth – Excessive sweating

13. Clinical Presentation 22q Microdeletion Syndrome (DiGeorge) – Hypertelorism, micrognathia, low set and posteriorly rotated ears, bulbous nose Physical Exam – Bounding pulses – Increased pulse pressure – Normal first heart sound, followed by single S2 – Systolic ejection click from single semilunar valve

14. Clinical Presentation Truncal valve insufficiency – Diastolic high-pitched murmur along left sternal border Heart Failure – Tachypnea, rales, retractions – Hepatomegaly PA Hypoplasia – Normal peripheral pulses and near normal pulse pressures – Cyanosis

15. Studies EKG – Normal QRS or minimal right axis deviation – Increased Pulmonary Blood Flow: Combined biventricular hypertrophy, left atrial enlargement – Decreased PBF: right ventricular hypertrophy only X-ray – Cardiomegaly – Increased pulmonary vascularity or no pulmonary vascularity on side without PA – Right aortic arch

16. X-ray Normal Chest X-rayTruncus Arteriousus

17. Studies Echo – Required for diagnosis confirmation and anatomic assessment of truncal valve, aortic arch orientation/interruption, VSD, coronary arteries and pulmonary arteries Cardiac catheterization/Angiography – Undiagnosed older patients to assess pulmonary vascular disease – Coronary artery and pulmonary artery mapping

18. Management Early surgical repair is key to prevent pulmonary vascular disease – Can develop by 4-6 months of age – Repair after PVR has fallen Treat CHF: diuretics, afterload reduction, fluid restriction – Vent strategies: sats 85-90%, PCO2 of 40 mmHg Prostaglandin infusion: If the ductus is present, consider prostaglandins if there is restriction to pulmonary blood flow

19. Surgical Repair Goals Detach pulmonary arteries from truncus and if separated (Type II or III) create anastomosis Patch Closure of the aorta

20. Surgical Repair Goals Closure of the VSD via right ventriculotomy (via patch baffle) with LVOT blood flow directed to truncal valve Creation of RV to PA continuity via homograft conduit usually, rarely direct connection of MPA to Anterior RV Leave PFO for “pop-off” elevated RV end- diastolic pressures

21. Other Surgical Factors Truncal Valve Insufficiency – Manage conservatively if mild to moderate – Suture prolapsing leaflet to other leaflets making tricuspid or bicuspid valve – May need to replace valve if severe TV insufficiency with homograft valve, mechanical valve in older children Interrupted Aortic Arch – Repaired at the same time – May require homograft to connect ascending aorta and aortic arch

22. Post-Op Complications Decreased LV output (Qs) due to RV systolic (RV infundibulotomy), RV diastolic dysfunction, and increased PVR – Decreased RV filling – Decreased RV output – Decreased preload to the LV – PFO extremely beneficial (Shunting Right to Left) Better to be “blue” than “gray”

23. Post-Op Complications Pulmonary Hypertension – Can be present post-op despite no disease pre-op – High Qp:Qs pre-op with excessive flow Postop hemorrhage – Tamponade AV block – Conduction injury from VSD repair – May require cardiac pacing

24. Long-Term Outcomes Likely to need replacement of RV to PA conduit as child grows Potential replacement of truncal valve Progressive Left Ventricular Dysfunction if there is moderate to severe truncal valve insufficiency

25. Morbidity and Mortality Nichols 1995

26. Morbidity & Mortality Decreased with earlier repair over the years 90% survival at CCHMC Eur J Cardiothorac Surg 2010 – 83 patients in Prague – Post-op mortality of 46% between 1981-1997 and 4% between 1997-2008, – 54% with Type I, 12% with severe truncal valve insufficiency, 17% with IAA – 75% patients required conduit replacements within 5 years, 13% with balloon dilation or stent placement in conduit

27. Truncal Valve Replacement Ann Thorac Surg, 2010: Utah – 1995 to 2008, 27% of patients with truncus arteriosus underwent truncal valve repair/replacement initially – Repeated repair or replacement indicated when severe regurgitation with symptoms, LV dilatation – 30% underwent second truncal valve operation (mean age 47 +/- 33 months) for severe regurgitation – 70% required no intervention after 5 years, 50% after 7 years

28. Truncal Valve Replacement Nichols 1995

29. Take Home Points 1-2% of all congenital heart disease Associated defects: Truncal valve stenosis/insufficiency, right sided arch, IAA 22q11 microdeletion syndrome May not be cyanotic at birth As PVR falls, Qp:Qs increases and systemic oxygen delivery decreases

30. Take Home Points Early repair key to prevent pulmonary vascular disease, impaired systemic oxygen delivery and decrease mortality High risk of replacement of RV to PA conduit and potentially the truncal valve as the child grows

31. References Allen, H. D., Adams, F. H., & Moss, A. J. (2000). Moss and adams' heart disease in infants, children, and adolescents : Including the fetus and young adult (6th ed.). Philadelphia, PA: Lippincott Williams and Wilkins. Artman, M., Mahony, L., & Teitel, D. F. (2002). Neonatal cardiology. New York: McGraw-Hill, Medical Pub. Division. Henaine, R., Azarnoush, K., Belli, E., Capderou, A., Roussin, R., Planche, C., et al. (2008). Fate of the truncal valve in truncus arteriosus. The Annals of Thoracic Surgery, 85(1), 172-178. Kaza, A. K., Burch, P. T., Pinto, N., Minich, L. L., Tani, L. Y., & Hawkins, J. A. (2010). Durability of truncal valve repair. The Annals of Thoracic Surgery, 90(4), 1307-12; discussion 1312. Nichols, D. G. (1995). Critical heart disease in infants and children. St. Louis: Mosby. Stark, J., De Leval, M., & Tsang, V. T. (2006). Surgery for congenital heart defects (3rd ed.). Chichester ; Hoboken, NJ: J. Wiley & Sons. Tlaskal, T., Chaloupecky, V., Hucin, B., Gebauer, R., Krupickova, S., Reich, O., et al. (2010). Long-term results after correction of persistent truncus arteriosus in 83 patients. European Journal of Cardio-Thoracic Surgery : Official Journal of the European Association for Cardio- Thoracic Surgery, 37(6), 1278-1284.