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Hemitruncus with ventricular septal defect in a 6-year-old child.
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PMID:  24688246     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
We report a 6-year-old girl with anomalous origin of the right pulmonary artery from the aorta associated with a large ventricular septal defect. The challenges in the assessment of operability and issues in the surgical management are discussed.
Authors:
Sachin Talwar; Ajay Meena; Sivasubramanian Ramakrishnan; Shiv Kumar Choudhary; Balram Airan
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Annals of pediatric cardiology     Volume:  6     ISSN:  0974-2069     ISO Abbreviation:  Ann Pediatr Cardiol     Publication Date:  2013 Jul 
Date Detail:
Created Date:  2014-04-01     Completed Date:  2014-04-01     Revised Date:  2014-04-03    
Medline Journal Info:
Nlm Unique ID:  101495459     Medline TA:  Ann Pediatr Cardiol     Country:  India    
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Languages:  eng     Pagination:  194-6     Citation Subset:  -    
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Journal Information
Journal ID (nlm-ta): Ann Pediatr Cardiol
Journal ID (iso-abbrev): Ann Pediatr Cardiol
Journal ID (publisher-id): APC
ISSN: 0974-2069
ISSN: 0974-5149
Publisher: Medknow Publications & Media Pvt Ltd, India
Article Information
Copyright: © Annals of Pediatric Cardiology
open-access:
Print publication date: Season: Jul-Dec Year: 2013
Volume: 6 Issue: 2
First Page: 194 Last Page: 196
PubMed Id: 24688246
ID: 3957458
Publisher Id: APC-6-194
DOI: 10.4103/0974-2069.115286

Hemitruncus with ventricular septal defect in a 6-year-old child
Sachin Talwaraff1
Ajay Meenaaff1
Sivasubramanian Ramakrishnanaff1
Shiv Kumar Choudharyaff1
Balram Airanaff1
Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi, India
Correspondence: Address for correspondence: Dr. Sachin Talwar, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi - 110 029, India. E-mail: sachintalwar@hotmail.com

INTRODUCTION

Hemitruncus is defined as anomalous origin of one branch of the pulmonary artery from aorta with the other branch arising normally from the right ventricular outflow tract. The patient with this anomaly presents with congestive cardiac failure and early onset of pulmonary hypertension usually in the first year of life. Survival in unoperated patients is exceptional beyond the first year of life. Associated cardiac anomalies may worsen the prognosis even further. We report a six year old patient with anomalous origin of the right pulmonary artery (RPA) from the aorta associated with a large ventricular septal defect and pulmonary hypertension, who underwent successful surgical correction. A brief review of the literature and the challenges in the management of the case are discussed.


CASE REPORT

A 6-year-old girl had presented with history of recurrent episodes of lower respiratory tract infection since 3 months of age and easy fatigability of 4 years duration. The frequency of chest infections had decreased during the last 2 years. There was no history of cyanosis. On examination the child was fairly built and nourished. Her pulse rate was 102/min, and blood pressure was 110/64 mm Hg. The apex beat was in the 6th intercostal space lateral to mid clavicular line. On auscultation thesecond heart sound was loud and single. A soft systolic murmur of grade 2/6 was heard in left 2nd/3rd intercostal space.

Chest roentgenogram [Figure 1] showed cardiomegaly with a cardiothoracic ratio of 0.70 and left ventricular type of apex with dilatation of pulmonary trunk and proximal pulmonary arteries. Transthoracic echocardiography showed an enlarged left ventricle, a large malaligned sub aortic ventricular septal defect (VSD) with bidirectional shunt. There was evidence of severe pulmonary arterial hypertension. The pulmonary artery confluence was not clear. Cardiac catheterization revealed a systemic saturation of 93% and systemic pulmonary artery pressures. The left pulmonary artery (LPA) pressure and saturation was 106/46 and 83% respectively. The aortic pressures and saturation was 120/69 and 93% respectively. The superior vena cava saturation was 65%. Calculation of flows and resistances in this situation using Fick's principle has many fallacies. The relative contribution of the right lung in real oxygenation is likely to be small as the saturation at entry is 93%. The whole right sided cardiac output, in the absence of significant right-to-left shunt traverses the left lung. Based on these assumptions, the calculated PVRI for left lung was 8.9 Wood Units. Calculation of right sided PVRI may be impossible with conventional principles. The angiogram showed a large sub aortic VSD with aortic override of < 50%, and the RPA arising anomalously from the ascending aorta. The LPA was seen to be a continuation of the main pulmonary artery that was arising normally from the right ventricle. In this case, aortic saturation of 93%, wide pulse pressure and low left lung PVRI supported the clinical assessment of operability. CT angiogram [Figure 2] showed the RPA (1.08 × 1 cm) was arising from aorta approximately 2 cm from aortic valve leaflet without ostial narrowing, and main pulmonary artery (1.6 × 1.5 cm) was continuous with the left pulmonary artery (1.1 × 1 cm). An echocardiogram was repeated that showed continuous flow signals into the RPA without ostial narrowing. There was no pulmonary regurgitation.

Single stage repair was planned. Through a standard median sternotomy approach, aorta, LPA, and RPA were dissected and mobilized. On cardiopulmonary bypass (CPB), the RPA was divided from the ascending aorta and its aortic end was sutured primarily. An arteriotomy was made in the MPA at the lateral aspect just opposite to MPA-LPA junction and RPA was anastomosed to MPA with a continuous 6-0 prolypropylene suture. The VSD was then closed through the right atrium using a patch; the surgically created 4mm atrial septal defect was left open. The saturation at the time of weaning from CPB was 88% on FiO2 of 100%. The measured pulmonary artery pressure was equal to the systemic arterial pressure. Transesophageal echocardiography revealed right-to-left shunting through the atrial septal defect. In the intensive care unit, elective nitric oxide was started in the usual doses in view of severe pulmonary arterial hypertension. Over the next 5 days the systemic oxygen saturations improved, the catecholamine support and nitric oxide were gradually withdrawn and she was removed from mechanical ventilator support on the 5th post-operative day. Oral medications consisted of a diuretics and sildenafil 10 mg thrice a day and she was discharged on day 9. Post operative chest X-ray [Figure 1b] showed normal lung vascularity on both the sides and a lung perfusion scan [Figure 3] three weeks following surgery showed normal perfusion of both the lungs. At follow-up transthoracic echocardiogram, the estimated right ventricular systolic pressure was 60 mm Hg.


DISCUSSION

The anomalous origin of one pulmonary artery from aorta was first described by Fraentzel in 1868.[1] Anomalous origin of RPA from aorta results from a delay in or abnormal migration of the sixth right aortic arch to the left side. This entity is 4-8 times most common than LPA from aorta. In patients with anomalous origin of one pulmonary artery from the aorta, the affected lung is perfused at systemic pressure and the remaining lung is exposed to the entire output of the right ventricle. As the pulmonary resistance decreases in the neonatal period, the blood pressure and flow increases in the anomalous pulmonary artery causing pulmonary over-circulation and pulmonary hypertension. Pulmonary circulation of both lungs are exposed to pressure and volume overload in hemitruncus. Serious pulmonary vascular disease may develop as early as the third month of life due to several mechanisms including high pulmonary blood flow, circulating vasoconstrictor substances, neurogenic crossover from unprotected lung and left ventricular failure. The prevalence of hemitruncus beyond infancy is not known as majority of the series have patients who are below one year of age and only sporadic cases are encountered in larger series.[1, 2, 3] However, in our 17-year experience that was published recently,[4] eight out of 17 patients were seen beyond 1 year of age. Five of these had associated Tetralogy of Fallot and one 25 year old patient has severe narrowing at the origin of the right pulmonary artery. Hemitruncus in adults is very rare and to the best of our knowledge only ten cases have been reported so far[5] as the mortality is very high in the first year of life. As already discussed, early repair is mandatory to prevent development of irreversible pulmonary vascular disease.[2, 3, 6]

Many techniques have been proposed for the repair of hemitruncus including end to end anastomosis with a synthetic graft, interposition of a homograft patch, aortic flap or interposition of autologous pericardial patch for increasing the length of the anomalous PA.[7] However, wherever possible a direst tissue-to tissue anastomosis, as done in the present case, avoids problems of conduit obstruction requiring re-intervention.

Our patient was a 6 year old child with severe PAH and operability in such settings remains the major preoperative issue. Fallacies of PVRI estimation in this condition are well known. Often the PVRI estimated is prohibitively high precluding surgery. Ideally, the differential blood flow may be estimated with cardiac MRI and the PVRI should be individually calculated for both the lungs. In the present case, clinical signs of operability, cardiomegaly on X-ray, good pulmonary venous return with volume overloaded left atrium and left ventricle suggested operability. On echocardiography, apart from the volume overloaded left ventricle, continuous flows in RPA and PR velocities on Doppler (not found in our patient) give a clue about operability. Presence of continuous flow on pulse Doppler, as was seen this case, suggests a low PVRI in the right lung. Some may consider cardiac catheterization to be of not much value. On cardiac catheterization, there was a good step up and the PVRI was within the operable range. However, the catheterization values of PVRI may be fallacious. When the calculated PVRI in one lung is higher than the other one the expected PVRI following connection in series can be estimated by the formula 1/R = 1/R1 + 1/R2.[8] Hence, even when one of the PVRI is within operable limits, the patient may be considered for corrective surgery. The cut-offs for operability based on expected combined resistances are not known.

Hemitruncus is rare beyond infancy. Cardiac catheterization for assessment of reversibility is often fallacious. Careful pre-operative planning and post operative care of pulmonary hypertension are necessary for successful outcome.


Notes

Source of Support: Nil

Conflict of Interest: None declared

REFERENCES
1. Penkoske PA,Castañeda AR,Fyler DC,Van Praagh R. Origin of pulmonary artery branch from ascending aorta. Primary surgical repair in infancyJ Thorac Cardiovasc SurgYear: 198385537456834873
2. Nathan M,Rimmer D,Piercey G,J Del Nido P,Mayer J,Bacha E. Early repair of hemitruncus: Excellent early and late outcomesJ Thorac Cardiovasc SurgYear: 200713313293517467452
3. Prifti E,Bonacchi M,Murzi B,Crucean A,Leacche M,Bernabei M,et al. Anomalous origin of the right pulmonary artery from the ascending aortaJ Card SurgYear: 2004191031215016045
4. Garg P,Talwar S,Kothari SS,Saxena A,Juneja R,Choudhary SK,et al. The anomalous origin of branch pulmonary artery from the aortaInteract Cardiovasc Thorac SurgYear: 201215869222467006
5. Talwar S,Kothari SS,Sharma S,Chauhan S,Gulati GS,Choudhary SK,et al. Successful surgical correction of anomalous origin of right pulmonary artery from aorta in an adultJ Card SurgYear: 201126201421395684
6. Kutsche LM,Van Mierop LH. Anomalous origin of a pulmonary artery from the ascending aorta: Associated anomalies and pathogenesisAm J CardiolYear: 19886185063354450
7. Mee RB. Surgical repair of hemitruncus: Principles and techniquesJ Card SurgYear: 198724756
8. Preston RR,Wilson TECardiovascular regulationLippincott's illustrated reviews: PhysiologyYear: 2012PhiladelphiaLippincott Williams and Wilkins23250

Figures

[Figure ID: F1]
Figure 1 

Chest X-Ray (a) Pre-operative showing cardiomegaly and marked pulmonary plethora. (b) Post-operative showing equal lung vascularity



[Figure ID: F2]
Figure 2 

Pre-operative CT angiogram (a) Axial image showing RPA from the aorta and LPA from the main pulmonary artery (b) Image in the vertical plane showing the origin of RPA from the posterior aspect of aorta



[Figure ID: F3]
Figure 3 

Post-operative lung scan showing normal perfusion of both lungs



Article Categories:
  • Case Report

Keywords: Congenital heart disease, hemitruncus, pulmonary arterial hypertension.

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