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Peer Reviewed

Photoclinic

Truncus Arteriosus With Bicuspid Truncal Valve

Volume 59 - Issue 1 - January 2019

AUTHORS:
Wilson B. Pfeiffer, MS-IV; Alixandria A. Fiore, MS-IV; and Adedeji O. Olusanya, MS-III
Nova Southeastern University, Fort Lauderdale, Florida

Syed A. A. Rizvi, PhD, MS, MBA
Hampton University School of Pharmacy, Hampton, Virginia

Zafar Qureshi, MD, and Rodel Anthony Reyes, MD
UHI CommunityCare Clinic, Miami, Florida

Citation:
Pfeiffer WB, Fiore AA, Olusanya AO, Rizvi SAA, Qureshi Z, Reyes RA. Truncus arteriosus with bicuspid truncal valve. Consultant. 2019;59(1):25-26.

 

A child was born at full term at 38 weeks of gestation via spontaneous vaginal delivery. The mother had received full prenatal care, and the pregnancy had had no complications. The delivery had been uneventful.

Physical examination. At birth, the neonate’s activity was normal, with appropriate grimacing present. However, there was noticeable pallor and respiratory distress. The Apgar score was 7 at 1 minute and 9 at 5 minutes.

Positive-pressure ventilation was administered, giving a fraction of inspired oxygen of 80%. The lung sounds were equal and clear with good air entry bilaterally. At birth, the heart rate was regular, and no murmur was heard on auscultation. The neonate had good perfusion and pulses, and the skin appeared pink and intact.

Due to respiratory distress, the patient was admitted to the neonatal intensive care unit, and the cardiology department was consulted. On day of life 1, a grade 2/6 systolic ejection murmur was heard on the left sternal border.

Diagnostic tests. The patient was taken for chest radiographs, the results of which showed cardiomegaly (Figure 1).

fig 1

Subsequent echocardiography results on day of life 2 showed truncus arteriosus with a right arch, with associated truncal and apical muscular ventricular septal defect (VSD) (Figure 2). Additionally, the truncal valve was noted to be bicuspid. Computed tomography angiography of the chest showed significant narrowing of the right pulmonary artery and moderate narrowing of the branch pulmonary artery.

fig 2

Initial treatment. On day of life 7, the patient underwent a cardiac surgical procedure to repair truncus arteriosus using a 9-mm homograft valve and an extracellular matrix patch. Postoperatively, the patient continued to have mild branch pulmonary artery narrowing, worsening of the right pulmonary artery stenosis, and simultaneous ventricular dysfunction. After stabilization in the neonatal intensive care unit, the patient was discharged home with planned interventional treatment to continue at 4 months of age.

Follow-up treatment. At 4 months of age, the patient was scheduled for angioplasty of the right pulmonary artery. Preoperative imaging findings showed spontaneous closure of the muscular VSD with no other changes noted compared with previous imaging findings. 

Angioplasty of the right pulmonary artery was performed, during which a 10-mm diameter balloon catheter was inserted and inflated to 12 atmospheres. The patient showed dramatic improvement immediately after the procedure; however, restenosis of the right pulmonary artery quickly ensued at a location near the homograft valve.

On follow-up visits at 12 and 15 months of age, the patient was noted to have a reduced growth rate, and therefore it was decided to postpone further intervention until approximately 2 years of age to allow time for appropriate growth. 

At 2 years of age, angioplasty of both the pulmonary valve and pulmonary artery were performed, which led to mild improvement—the right ventricle to pulmonary artery systolic pressure difference decreased from 35 mm Hg to 30 mm Hg. Subsequent diagnostic cardiac catheterization was performed, which found proximal left and right pulmonary artery narrowing with some obstruction to flow at the origin of the homograft. It was determined that surgical reintervention should be planned for approximately 3 years of age.

At 3 years of age, the patient underwent surgical reintervention, during which the 9-mm right ventricle to pulmonary artery conduit was replaced using a larger 21-mm homograft. After stabilization in the hospital, the patient was discharged on postoperative day 5.

Outcome of the case. Follow-up visits at 1 month, 3 months, and 6 months showed a full recovery, with excellent functional ability of the right ventricle to pulmonary artery conduit. Echocardiography results showed near-full resolution of the right ventricular dilation, and the patient’s respiratory status was without problems.

At this time, regular follow-up visits were discussed, and the patient was released with clearance for full participation in recreational activities, including physical education. The patient is doing well and is being monitored semiannually.

Discussion. Truncus arteriosus is a very rare congenital heart defect, with a reported prevalence of 0.03 to 0.05 in 1000 live births.1,2 The defect consists of a single arterial trunk arising from the normally formed right and left ventricles by means of a single valve, also known as a truncal valve. This is contrasted with the normal cardiac anatomy, which features 2 separate arterial trunks arising from 2 separate semilunar valves, specifically the aortic valve and pulmonary valve. The mixing of oxygenated and deoxygenated blood leads to multiple suboptimal physiologic effects, including deficient oxygenation of the systemic tissues and overflow of the pulmonary circulation.3

The truncal valve can consist of anywhere from 1 to 6 leaflets, with the most common variant being 3 leaflets, followed by 4 leaflets. Less than 5% of truncus arteriosus cases have 2 leaflets, and the variants of 1, 5, and 6 leaflets are almost never seen.3 Due to the absence of the infundibular septum, a “truncal” VSD is often seen between the left and right ventricles. Occasionally, an additional “muscular” VSD can also be seen, which typically closes spontaneously.4

With recent improvements in pediatric cardiothoracic surgery, correction of truncus arteriosus at an early age is now the preferred plan of treatment. Surgical correction is done by closing off the VSD, eliminating a patent ductus arteriosus, and then placing a homograft either in the pulmonary or aortic valve outflow tracks with the purpose of creating continuity between the right ventricle and pulmonary artery.5,6 The homograft is most commonly derived from a bovine conduit, with the size being determined via the calculated cardiac valve Z-score, which uses the valve diameter compared with the normal value.

As the patient grows and develops, close observation and follow-up are necessary to allow for monitoring of growth rates and oxygenation status.7 As the patient develops, the conduit eventually will be outgrown, requiring additional cardiac surgical procedures to replace the existing conduit with a new, larger conduit. Echocardiography should continue to be used to monitor the status of the cardiac anatomy, with cardiac catheterization being employed when diagnostically necessary.8

While truncus arteriosus is a rare cardiac anomaly, truncus arteriosus with a bicuspid valve and muscular VSD, as seen in our patient’s case, is exponentially rarer. This case illustrates the importance of collaborative care in the treatment plan of truncus arteriosus. Unlike other cardiac anomalies, truncus arteriosus requires a series of interventional procedures during the first 5 years of life, which necessitates close collaboration between all clinicians involved with the patient. 

In our patient’s case, it was of extreme importance to have full collaboration between the pediatrician, pediatric surgeon, and pediatric cardiologist in order to provide the necessary care and successful outcome.

 

References:

  1. de Siena P, Ghorbel M, Chen Q, Yim D, Caputo M. Common arterial trunk: review of surgical strategies and future research. Expert Rev Cardiovasc Ther. 2011;9(12):1527-1538.
  2. O’Byrne ML, Mercer-Rosa L, Zhao H, et al. Morbidity in children and adolescents following surgical correction of truncus arteriosus communis. Am Heart J. 2013;166(3):512-518.
  3. Corno AF. Truncus arteriosus. In: Corno AF. Congenital Heart Defects: Decision Making for Surgery. Vol 2. Heidelberg, Germany: Steinkopff; 2012:chap 2.5.
  4. Spicer DE, Hsu HH, Co-Vu J, Anderson RH, Fricker FJ. Ventricular septal defect. Orphanet J Rare Dis. 2014;9:144.
  5. Fan C, Yang Y, Xiong L, et al. Reconstruction of the pulmonary posterior wall using in situ autologous tissue for the treatment of pulmonary atresia with ventricular septal defect. J Cardiothorac Surg. 2017;12(1):12.
  6. Chen Q, Gao H, Hua Z, et al. Outcomes of surgical repair for persistent truncus arteriosus from neonates to adults: a single center’s experience. PLoS One. 2016;11(1):e0146800.
  7. Feltes TF, Bacha E, Beekman RH III, et al; American Heart Association Congenital Cardiac Defects Committee of the Council on Cardiovascular Disease in the Young, Council on Clinical Cardiology, and Council on Cardiovascular Radiology and Intervention. Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association. Circulation. 2011;123(22):2607-2652.
  8. Di Donato RM, Fyfe DA, Puga FJ, et al. Fifteen-year experience with surgical repair of truncus arteriosus. J Thorac Cardiovasc Surg. 1985;89(3):414-422.