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 Table of Contents  
CASE REPORT
Year : 2016  |  Volume : 3  |  Issue : 1  |  Page : 83-86

Interrupted aortic arch by multi-detector computed tomography angiography: A case report with radiological review


Department of Radiology, Padmashree Dr. D. Y. Patil Medical College and Research Institute, Pune, Maharashtra, India

Date of Web Publication22-Dec-2015

Correspondence Address:
Kuldip P Chaudhary
Department of Radiology, Padmashree Dr. D. Y. Patil Medical College and Research Institute, Pune, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2348-3334.172396

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  Abstract 

Interrupted aortic arch (IAA) is a rare congenital vascular malformation, which is defined as lack of luminal continuity, between the ascending and descending thoracic aorta. Many times it is associated with various congenital cardiac anomalies. Early diagnosis is mandatory to assess the patient condition and to plan medical and surgical treatment. Traditionally, chest X-ray, echocardiography, and conventional catheter angiography are the imaging tools being used. Multi-detector computed tomography (MDCT) can accurately diagnose and characterize the various forms of IAA and associated cardiac defects. We report a case of 8-year-old male child detected to have Type A IAA on MDCT with an associated ventricular septal defect and patent ductusarteriosus.

Keywords: Interrupted aortic arch, patent ductusarteriosus, ventricular septal defect


How to cite this article:
Khaladkar SM, Chaudhary KP, Kuber RS, Kamal A. Interrupted aortic arch by multi-detector computed tomography angiography: A case report with radiological review. CHRISMED J Health Res 2016;3:83-6

How to cite this URL:
Khaladkar SM, Chaudhary KP, Kuber RS, Kamal A. Interrupted aortic arch by multi-detector computed tomography angiography: A case report with radiological review. CHRISMED J Health Res [serial online] 2016 [cited 2019 Oct 21];3:83-6. Available from: http://www.cjhr.org/text.asp?2016/3/1/83/172396


  Introduction Top


Interrupted aortic arch (IAA) is defined as a total anatomical and luminal discontinuity between ascending and descending aorta. It was first described by Steidele in 1778.[1] It occurs in one in 10,000 births and at around 1% of coronary heart disease; hence early diagnosis and accurate evaluation is needed before heart surgery. It may occur as a simple or complex anomaly. In simple IAA, only ventricular septal defect (VSD) and patent ductusarteriosus (PDA) are seen. The complex form is associated with truncusarteriosus, transposition of the great arteries, double-outlet right ventricle, aortopulmonary window, and functional single ventricle. Obstruction of the left ventricular outflow tract is also common. DiGeorge syndrome (hypocalcemia and T-cell defects due to thymic hypoplasia) occurs in more than 25% of a complex form of IAA.

Celoria and Patton classification describes three types of IAA: Type A is an interruption distal to left subclavian artery; Type B is an interruption between left common carotid artery and left subclavian artery; and Type C is an interruption distal to innominate artery. Here, descending thoracic aorta reconstitutes from the pulmonary artery through a ductusarteriosus. Each of these three types is subdivided as follows: Subtype 1 - a normal subclavian artery; Subtype 2 - an aberrant subclavian artery; and Subtype 3 - an isolated subclavian artery that arises from ipsilateral pulmonary artery by way of ductusarteriosus. Additional cardiovascular (CVS) anatomic defects are seen in 98% of cases of IAA.[2],[3]


  Case Report Top


We present a case of an 8-year-old male child with complaints of exertional dyspnea and palpitations since birth. He was diagnosed to have VSD and PDA at the age of 2 months on two-dimensional echo. On CVS examination, there was pansystolic murmur present. His blood pressure was normal at the time of discharge (124/72 mmHg). Laboratory investigations were within normal limits. A chest radiograph was suggestive of mild cardiomegaly with pulmonary arterial hypertension [Figure 1]. Two-dimensional echo showed aortic coarctation, muscular VSD, PDA with a left to right shunt, bicuspid aortic valve, tricuspid regurgitation, and dilated right coronary artery (RCA).
Figure 1: Chest X-ray pulmonary arterial view showing mild cardiomegaly with pulmonary arterial hypertension

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Multi-detector computed tomography (MDCT) angiography examinations were performed with a 128-slice MDCT (Philips Healthcare). It revealed total luminal discontinuity in aortic arch distal to the origin of left subclavian artery suggestive of Type A interruption [Figure 2]. The ascending aorta and aortic arch were small in caliber while descending aorta showed mild dilatation distal to interruption [Figure 3]. There was left ventricular hypertrophy (wall thickness 8 mm), muscular VSD (5 mm), and PDA (7 mm length × 5 mm width) [Figure 4] and [Figure 5]a. Left subclavian artery was dilated and tortuous near its origin communicating with PDA (2.5 mm defect) [Figure 4]. Collaterals were noted along posterior chest wall on either side. RCA near its origin extending over a length of 6 mm showed mild dilatation (6 mm caliber) [Figure 5]b. The rest of coronary arteries appeared normal. Findings were in favor of Type A IAA.
Figure 2: (a) Sagittal two-dimensional multiplanar reconstruction and (b) volume rendering showing interruption of aorta distal to origin of left subclavian artery (long arrow)

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Figure 3: (a) Axial contrast enhanced computed tomography, (b) coronal two-dimensional multiplanar reconstruction, (c) volume rendering showing small caliber of ascending aorta (short white arrow), patent ductusarteriosus (long white arrow) and mild dilatation of descending aorta (dotted white arrow)

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Figure 4: (a) Sagittal two-dimensional multiplanar reconstruction, (b and c) volume rendering images showing patent ductusarteriosus (short arrow) between main pulmonary artery and descending aorta and communication of left subclavian artery (long arrow) with patent ductusarteriosus

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Figure 5: (a) Axial contrast enhanced computed tomography showing ventricular septal defect (asterix) in muscular portion and (b) dilated right coronary artery (short arrow) in its proximal portion

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  Discussion Top


In the embryo, six pairs of aortic arches connect the two primitive ventral and dorsal aortas. Type A results from abnormal regression of the left fourth aortic arch after the ascension of the left subclavian artery to its expected position. Type B occurs when the left fourth aortic arch regresses before the normal ascension of the left subclavian artery to its expected position. Type C occurs when the ventral portion of the left third aortic arch and left fourth aortic arch in-volute and there is a persistent ductuscaroticus, a structure which normally regresses.[4]

Type B IAA is associated with DiGeorge syndrome. The syndrome is characterized by maldevelopment of 3rd and 4th pharyngeal pouch seen in hypoparathyroidism and cellular immune deficiency. IAA should be differentiated from: (a) Atresia of aortic arch - in which continuity between the segments is achieved by a fibrous band, (b) coarctation of aorta - in which there is narrowing of aorta but luminal and anatomical continuity is maintained.

PDA is associated with IAA in 97% of patient with IAA.[4] PDA is required to provide blood flow beyond the site of interruption to descending thoracic aorta. VSD is associated in 90% of cases in IAA.[5],[6] Conditions which decreases blood flow to aortic arch are associated with IAA. They are subaortic stenosis, bicuspid aortic valve, truncusarteriosus, and aortopulmonary window.[4],[5],[7]

Rarely IAA occurs as an isolated finding without associated cardiac defect. In these cases, extrinsic compression or mechanical force is the cause. 15% cases of IAA are associated with a chromosomal 22q11.2 deletion, particularly in the presence of right descending thoracic aorta. This chromosomal abnormality is seen in up to 75% of patients, with Type B IAA. It is relatively rare in Type A IAA, which suggests either another genetic or mechanical cause. IAA affects up to 42% of individuals with DiGeorge syndrome. This chromosomal deletion is observed in both DiGeorge and velocardiofacial syndromes and a variety of conotruncal cardiac anomalies.[4],[7]

MDCT has advantages of a short scanning time, high spatial resolution, adequate temporal resolution, and ability to use electrocardiography gating. This allows retrospective reconstruction at any phase of cardiac cycle which is suitable for the evaluation of fine anatomic structures.[8] Detailed anatomy of vascular structures, their spatial relationship to adjacent organs combined with availability of postprocessing options such as maximum-intensity projection, multiplanar reconstruction and volume rendering; it has significant advantage in comparison to other imaging modalities in evaluation of aortic arch anomalies. Three-dimensional reconstruction images are three-dimensional and clearly delineate the spatial position of large vessels. MDCT has become a principle diagnostic method for evaluation of thoracic aortic abnormality. It is a noninvasive technique which shows detailed status of tracheal and esophageal compression apart from the evaluation of vascular anomalies. Disadvantages of this technique are the use of iodinated contrast material and increase in patient radiation exposure.

Magnetic resonance angiography is an alternative noninvasive method without the need of contrast medium or radiation exposure. However, this technique is time-consuming, needs prolonged sedation in pediatric patients and does not provide sufficient information regarding esophagus and trachea.

IAA patients often undergo cardiac surgery during 1st year of life; the abnormality is rarely identified later in adult life when significant collateral circulation develops. The overall survival rate at 16 years is around 59–70%.[9]

Administration of prostaglandin E1 therapy in the neonatal period to keep the ductusarteriosus open has improved survival. The goal of treatment is to reestablish the continuity of the aorta, but the surgical approach (i.e., one- or two-stage surgery) is controversial, with reconstruction through an end-to-end anastomosis, creation of a left subclavian flap, carotid turndown, and placement of an interposition graft. Mortality ranges from 15% to 20%.[3],[10]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Steidele RJ. Sammlung verchiedener in der chirurg. Prakt Lehschule Gemachten Beobb (Viena) 1778;2:114.  Back to cited text no. 1
    
2.
Goo HW, Park IS, Ko JK, Kim YH, Seo DM, Yun TJ, et al. CT of congenital heart disease: Normal anatomy and typical pathologic conditions. Radiographics 2003;23:S147-65.  Back to cited text no. 2
    
3.
Dillman JR, Yarram SG, D'Amico AR, Hernandez RJ. Interrupted aortic arch: Spectrum of MRI findings. AJR Am J Roentgenol 2008;190:1467-74.  Back to cited text no. 3
    
4.
Reardon MJ, Hallman GL, Cooley DA. Interrupted aortic arch: Brief review and summary of an eighteen-year experience. Tex Heart Inst J 1984;11:250-9.  Back to cited text no. 4
    
5.
Ho SY, Wilcox BR, Anderson RH, Lincoln JC. Interrupted aortic arch – Anatomical features of surgical significance. Thorac Cardiovasc Surg 1983;31:199-205.  Back to cited text no. 5
    
6.
Everts-Suarez EA, Carson CP. The triad of congenital absence of aortic arch (isthmus aortae), patent ductus arteriosus and interventricular septal defect; a trilogy. Ann Surg 1959;150:153-9.  Back to cited text no. 6
    
7.
Conley ME, Beckwith JB, Mancer JF, Tenckhoff L. The spectrum of the DiGeorge syndrome. J Pediatr 1979;94:883-90.  Back to cited text no. 7
    
8.
Pannu HK, Flohr TG, Corl FM, Fishman EK. Current concepts in multi-detector row CT evaluation of the coronary arteries: Principles, techniques, and anatomy. Radiographics 2003;23:S111-25.  Back to cited text no. 8
    
9.
Brown JW, Ruzmetov M, Okada Y, Vijay P, Rodefeld MD, Turrentine MW. Outcomes in patients with interrupted aortic arch and associated anomalies: A 20-year experience. Eur J Cardiothorac Surg 2006;29:666-73.  Back to cited text no. 9
    
10.
Sandhu SK, Pettitt TW. Interrupted Aortic Arch. Curr Treat Options Cardiovasc Med 2002;4:337-340.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

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