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Background: Crossed pulmonary
artery (CPA) is a rare anomalies and it does not cause significant hemodynamic
repercussions, but still has clinic significance. The diagnosis of CPA is more relay on computer
tomography (CT) or cardiac angiography. We aimed to analysis the value of transthoratic echocardiography in the diagnosis
of CPA to see whether it can be diagnosis by echocardiography accurately.
Method: Retrospective analysis the echocardiographic data of CPA in our
single-center from January 2014 to December 2016. The Vivid 7 Dimension (GE) with M4S
transducer, Vivid i Cardiac system (GE) with 7S-Rs transducer and iE33
Ultrasound (Philips) with S8-3 and X5-1 transducer with a frequency of 5 to 7.5
MHz were used.
Result: Totally twenty-nine patients were diagnosed as CPA by echocardiography.
Except tow cases were misdiagnosed as pulmonary artery sling (PAS) at first
time, the other patients got definite diagnosis by echocardiography. Seven
patients had MSCT and three patients underwent surgery for other intracardiac
malformations, which were consistent with the echocardiography. Sixteen
patients with other intracardiac malformations, including eight atrial
septal defect, four ventricular septal defect, one double outlet of right ventricular, one triatriatum, one
patent ductus arteriosus and one bicuspid aortic valve. Thirteen single CPA including one patient was Kawasaki disease with
coronary aneurysm - like dilatation. Sixteen patients coexist with mild
stenosis of the pulmonary branches.
Conclusion: Echocardiography is the preferred method of CPA and can make definite
diagnosis of it, which should be made differential diagnosis with PAS. Sweep
superior-inferior at the high left parasternal view of the bifurcation of the
pulmonary artery is important to diagnose CPA.
Keywords: Echocardiography, Crossed pulmonary artery, Pulmonary artery sling, Pulmonary bifurcation
INTRODUCTION
Crossed pulmonary artery (CPA) is a rare but
cannot be ignored form of malposition of the branch pulmonary arteries [1],
which means both branches of pulmonary artery cross each other on their course
proceeding to the corresponding lung, thus forming a crisscross pattern [2].
According to the degree of its cross, it could be classified into two types,
the typical and the atypical. Single CPA usually had no specific clinical
manifestations. However, CPA often coexists with other intracardiac or
extracardiac anomalies, and also chromosomal abnormalities. Therefore, further
evaluation may be required to manage these patients with CPA. In some cases, a
multidisciplinary consultation should be carried out [3].
In previous reports, CPA was generally
diagnosed by computer tomography or cardiac angiography. No one applies for
echocardiography because of suspecting CPA, but echocardiologists should be
acquainted with CPA to avoid misdiagnosing it as other pulmonary vascular
malformations, such as pulmonary artery sling (PAS). To explore the possibility
of diagnosing CPA by using echocardiography, we retrospectively analyzed our
imaging data of CPA.
METHODS
Study population
The retrospective study was approved by our
institutional research ethics board, and the need for patient consent was
waived. All children diagnosed with CPA by echocardiography between January
2014 and December 2016 was identified from the electronic database of Children’s Hospital of Fudan University.
DATA COLLECTION
Electronic charts of the children with CPA were reviewed. Presentation
of symptoms and echocardiographic parameters of patients were collected. A form
was created to collect the presentation symptoms of the patients, including
murmurs, shortness of breath, or no symptoms. Every patient was examined by
echocardiography during their first admission in our hospital and concomitant
cardiovascular anomalies were recorded. All echocardiographic data were
carefully analyzed.
STUDY DESIGN
The initial seven patients who were suspected as CPA by
echocardiography were transferred to multi-slice spiral computer tomography
(MSCT) exam. We compared the echocardiographic images with the MSCT images
retrospectively to analyze the morphology of the pulmonary branches. The other
twenty-tow cases were diagnosed only by echocardiography.
Echocardiographic Imaging
Two-dimensional and Doppler echocardiography were performed with GE
Vivid 7 Dimension (GE-Vingmed Ultrasound AS, Horten, Norway) with M4S transducer,
GE Vivid i Cardiac system (GE Medical system Israel) with 7S-Rs transducer and
iE33 imaging system (Philips Healthcare, Bothell, Eberett Highway, Washington,
USA) with S8-3 and X5-1 transducer with a frequency of 5 to 7.5 MHz. The left lateral decubitus and
supine position was taken and, if necessary, 10% chloral hydrate was
administered at a dose of 0.1 mg/kg for sedation. Echocardiographic images were
obtained in the parasternal, apical and sub-xiphoid views together with color
Doppler echocardiography.
The high left parasternal view and the supra-sternal fossa view were
emphasized to observe the pulmonary bifurcation. The left parasternal long-axis
view was adopted to display the abnormal branch arising from the ascending
aorta. The supra-sternal fossia view to display the anatomical structure of the
aortic arch as much as possible to illustrate the position, development, and
other abnormalities of the aortic arch. To clarify the origin, the flow of the
pulmonary branch was shown by color Doppler. The velocity of the pulmonary branches
was measured by pulse-wave or continuous-wave Doppler to see if narrow or not.
MSCT imaging
MSCT was performed in the initial seven patients. Three-dimensional
reconstruction was done to show more details about the spatial structure of the
pulmonary branches. The relationship of the pulmonary vessels and trachea was
also demonstrated. Other co-exited anomalies were diagnosed simultaneously.
STATISTICAL ANALYSIS
Data were presented as frequencies (percentages), medians (ranges) or
means ± standard deviations. Differences between groups were tested with the χ2
test. P value < 0.05 is
considered as significant difference. Data analysis was carried out using SPSS
version 16.0.
RESULTS
Clinical characteristics of CPA
Between January 2014 and December 2016, 29 patients (17 males and 12
females; age range: 4 days to 10 years at the time of initial diagnosis; median
age: 5 months old) who were diagnosed as CPA by echocardiography enrolled in
our study.
The complains of patients with CPA include heart murmurs (72.4%, n=21),
mostly was a mild murmur at the left sternum border, health examination (17.2%,
n=5), shortness of breath or other respiratory symptoms (6.9%,n=2) , and other
diseases needed echocardiographic examination, such as Kawasaki
disease(3.5%,n=1).
Sixteen
patients coexisted with other congenital intracardiac malformations, including
atrial septal defect (27.5%,n=8), perimembrane ventricular septal defect
(13.8%,n=4), double outlet of right
ventricular (3.5%,n=1), triatriatum (3.5%,n=1), patent ductus arteriosus
(3.5%,n=1) and bicuspid aortic valve (3.5%,n=1). The other thirteen cases were
the single CPA with one patient was coronary aneurysm related to Kawasaki
disease. (Table 1).
Types of CPA and their echocardiographic
characteristics
The direct sign of CPA was displayed at the
high left parasternal short-axis view and the suprasternal fossa view, while
the typical bifurcation disappeared in the routine left parasternal view. For
the typical form, moving the probe up 1 or 2 intercostals in the high
parasternal view and sweeping from superior to inferior to show the left
pulmonary artery was located in the right to the pulmonary artery and above the
right pulmonary artery, and the right pulmonary artery was located in the left
to the pulmonary artery and below the left pulmonary artery (Figure 1). For atypical form, in the high left
parasternal view, the main pulmonary artery continues to the right or left
pulmonary directly (Figure 2), then
the left pulmonary artery was located just above the right pulmonary artery or
the right pulmonary artery was located below the left pulmonary artery. There
were no other indirect echocardiographic signs of the single CPA.
The initial diagnose rate was 89.7% (26/29).
Two cases were diagnosed as PAS initially, and corrected as CPA by repeat echocardiography. One case showed unclear origin of the left
pulmonary artery by bedside echocardiography, then confirmed as CPA by
follow-up echocardiography.
Two cases with the typical form while
twenty-seven cases with the atypical form of CPA, among which twenty-six cases
with left pulmonary artery cross and the another one case with right pulmonary artery cross.
Totally, sixteen cases of CPA were
complicated by the stenosis of the pulmonary branches, including twelve cases
with left pulmonary artery stenosis (mean velocity 2.44 ± 0.38(m/s), ranged
from 2.08m/s to 3.34m/s), one case with right pulmonary artery stenosis
(velocity 3.57m/s), and three cases with mild stenosis at both branches (mean
velocity 2.77 ± 0.67(m/s) and 2.37 ± 0.33(m/s), ranged from 2.33m/s to 3.54m/s
and 2.05m/s to 2.7m/s, respectively). (Table
2).
CPA in MSCT and intraoperative diagnosis
compared to echocardiography
MSCT was performed in the initial seven
cases. Among these patients, one patient with unclear origin of the left
pulmonary artery and two patients diagnosed as PAS at first time, which were
diagnose as CPA by the follow-up echocardiography. Left pulmonary artery at the
right of the pulmonary artery appeared in the imaging firstly in a set of
sequential scanning imaging, and then came with the right
pulmonary artery, which located in its normal
place or at the left of the pulmonary artery (Figure 3). That was in accordance with the echocardiaographic
imaging. Three-dimensional reconstruction imaging could show it more clear.
None of the patients had the vascular ring. Only one patient with right aortic
arch and aberrant left subclavian artery was diagnosed by MSCT. There was no
statistical difference between the initial echocardiographic diagnosis and MSCT
(p=0.096).
Three patients with congenital heart diseases
received surgery. One case with large ventricular septal defect and two cases
with atrial septal defect underwent surgery for repairing the defects and
without correcting pulmonary artery branches. All these patients were left
pulmonary artery crossed and were confirmed during operation, which show the
left pulmonary artery lies above the right pulmonary artery and make a cross
with right pulmonary artery (Figure 4).
The crossed pulmonary was not corrected during surgery.
The remaining cases were recommended for
long-term follow-up by echocardiography. Up to now, no patients with branch
pulmonary artery stenosis got worse.
DISCUSSION
In 1966, Jue et al first reported CPA [4],
the classic form also called typical CPA was the pulmonary branches cross each
other, the ostium of the left pulmonary artery originated superior to the right
pulmonary artery and to its right, and the right pulmonary artery originated
inferior to the left pulmonary artery and to its left. Thus, the two branches
crisscross one another along their courses to their related lungs. In 1970,
Becker et al reported the less form also called atypical CPA [5], that is left
pulmonary artery openings directly above the right pulmonary artery walking
into the left lung without crossing, and this type was more common, while the
right pulmonary artery openings directly below the LPA is rare. Its
pathogenesis is still unclear. It may be associated with embryonic pulmonary
total counterclockwise rotation or due to faulty differential growth during the
partitioning of the truncus arteriosus into the aorta and pulmonary trunk, so
CPA is easily associated with intracardiac abnormalies especially the
conotruncal and aortic arch defects [6], extracardiac malformations [7] and are
associated with chromosome 22q11.2 microdeletion [8,9].
Single CPA was asymptomatic. According to our
result, if the branch of the pulmonary artery curvature due to narrow or flow
faster, a systolic murmurs could be heard at the second intercostal of left
sternal border, but always mild. Most patients were diagnosed by accident when
they received echocardiograhic examination for other reasons, such as suspected
vascular rings, heart murmurs and health examination.
Some centers suggested that diagnosis of
malposition of the branch pulmonary arteries could be challenging if based
solely on echocardiography [3], but we don’t think so. MSCT could help us to
comprehend the spatial structure of the CPA more directly, but it is
radioactive. For the safety of our children, MSCT required indications. In the
beginning of our research, we had less experience of this malformation. We
suggested MSCT and all of them were confirmed as CPA. The subsequent patients
didn’t do MSCT unless with double of the other vessels abnormality. The left
pulmonary artery appeared at first in a set of the imaging which located at the
right of the pulmonary artery. Then, came with the right pulmonary artery. This
was in accordance with the echocardiographic imaging. When we swept from
superior to inferior at the high left parasternal, we found the left pulmonary
artery at first and then the right pulmonary artery. We thought
echocardiography could instead of MSCT in diagnosis of the CPA without other
vascular malformation by comparing the imaging of them according to our result.
As a convenient, economical and safe imaging
technique, echocardiography was the primary method used to make definite
diagnosis of CPA in our series. Usually, left parasternal view hardly showed
the bifurcation of the pulmonary artery. We must made superointerior sweeps
from the high left parasternal view and added color Doppler to confirm this
abnormality. By observing this view, always found the left pulmonary artery
lying superior and to the right of the main pulmonary artery and extending to
the left and the right pulmonary artery was lying inferior from the left
extending to the right, which is the typical type. If we found that the left
pulmonary artery was lying superior on the right pulmonary artery to the left,
which is the atypical type. If we failed to obtain the image of the bifurcation
of the pulmonary arteries on echocardiography, it may be a clue of malposition
of pulmonary arteries branches. We must sweep at the high left parasternal view
from superior to inferior more carefully to find the branches.
Single CPA usually does not affect
hemodynamics, so it does not require special intervention. Unless CPA cause
stenosis of the branches, it might need treatment according to the degree of
stenosis. But the diagnosis of CPA had some other meanings. Abnormalities of
pulmonary artery branches include PAS, anomalous origin of one pulmonary artery
(AOPA) [10] and CPA. In the echocardiographic diagnosis, if the bifurcation of
the pulmonary artery disappeared, we should look for the branches to resolve the
question of where were the branches. At the supra-sternal fossia view, we
demonstrated the ascending aorta and the aorta arch clearly to see if any of
the branches arise from it to exclude AOPA [11]. But AOPA always accompanied
with severe pulmonary hypertention, the echocardiography showed dilated right
atrium and right ventricular and high pressure gradient of tricuspid valve
regurgitation, while CPA is not. On the other hand, CPA was more common to
confused with PAS. In our study, two patients were diagnose as PAS at first,
which were corrected by the following echocardiagraphy and also confirmed by
MSCT as left pulmonary artery crossed. PAS is the left pulmonary artery
originated in the right pulmonary artery and bypass the trachea formatting of
vascular rings result in airway narrowing [12], which should receive MSCT to
access the compression degree and development degree of trachea and it required
surgical intervention. Because the left pulmonary artery of CPA was originated
at the right of main pulmonary artery, the initial region might be overlap with
the initial region of right pulmonary artery and then extended to the left into
the left lung, especially for the atypical type. The image may be similar to
the left pulmonary artery originated from right pulmonary artery. But CPA
itself usually does not form vascular rings, resulting in airway narrowing [3].
In the echocardiography of the identification point was to clearly show the
ostium of the left pulmonary artery. The important views of this include the
high left parasternal view and supra-sternal fossa view of the pulmonary
branches. Color Doppler echocardiography enabled confirmation of blood
direction of pulmonary artery branches, as well as assessment of the stenosis
of them.
Since 1966, the number of reported CPA in the
world no more than 60 cases, which always were reported sporadically [13,14].
Echocardiography is the preferred method to diagnose CPA as a non-invasive
examination [15,16]. Since January of 2014, we paid more attention of CPA, and
diagnosed 29 cases in three years. We estimated the morbidity of CPA might be
more than reported. Missed diagnosis often because of: firstly,
echocardiography physician does not pay attention to branch pulmonary arteries
of normal children; secondly, notice of other intracardiac malformations,
easily overlooked the bifurcation; thirdly, because it does not cause
meaningful hemodynamic effects, even if found the CPA not diagnosed. However,
the diagnosis of CPA has a certain clinical significance, if echocardiography
diagnosed as CPA, children may not need further image examination, such as
MSCT, which had radioactivity, unless echocardiography showed unclear of the
bifurcation or had other anomalies of the aorta arch, but instead to have
comprehensive clinical evaluation and molecular examination according to clinic
manifestation. So we should carefully studied morphology of pulmonary artery
ostia and branches by echocardiography.
LIMITATIONS
The study samples are small and may have been
influenced by the limited cognition of the CPA for every echocardiologist and
clinicians in our center. All the patients diagnosed as CPA did not undergo
further clinical examination to access the extracadiac and chromosomal
abnormality.
CONCLUSION
CPA may be not a so rare pulmonary malposition anomaly as we thought before. Although it had no meaningful hemodynamics, its clinical significance lies in differential diagnosis of vascular rings and reminding clinician to do other assessments. The diagnosis of the CPA is also significant. For the consideration of children of avoiding radioactive contact, MSCT is not recommended for CPA. Echocardiography can diagnose CPA accurately as an economic, convenient, safe, non-radioactive, image modality.
- Zimmerman FJ, Berdusis K,
Wright KL, Alboliras ET (1997) Echocardiographic diagnosis of anomalous
origins of the pulmonary arteries from the pulmonary trunk (crossed
pulmonary arteries). Am Heart J 133: 257-260
- Chaturvedi R, Mikailian H,
Freedom RM (2005) Crossed pulmonary arteries in tetralogy of Fallot.
Cardiol Young 15: 537.
- Cuturilo G, Drakulic D,
Krstic A, Gradinac M, Ilisic T, et al. (2013) The role of modern imaging
techniques in the diagnosis of malposition of the branch pulmonary
arteries and possible association with microdeletion 22q11.2. Cardiol
Young 23: 181-188.
- Jue KL, Lockman IA, Edwards
JE (1996) Anomalous origins of pulmonary arteries form pulmonary
trunk(crossed pulmonary arteries). Am Heart J 71: 807-812
- Becker AE,Becker MJ, Edwards
JE (1970) Malposition of pulmonary arteries (crossed pulmonary arteries)
in persistent truncus arteriosus. Am J Roentgenol Radium Ther Nucl Med
110: 509-514.
- Altun G, Babaoğlu K, Oğuz D,
Dönmez M (2013) Crossed pulmonary arteries associated with persistent
truncus arteriosus and right aortic arch on the three-dimensional computed
tomographic imaging. Anadolu Kardiyol Derg 13: E29.
- Babaoglu K, Binnetoglu FK,
Altun G, Dönmez M, Anik Y (2010) Echocardiographic and three-dimensional
computed tomographic diagnosis of crossed pulmonary arteries: report of
three cases. Pediatr Cardiol 31: 720-722.
- Babaoğlu K, Altun G,
Binnetoğlu K, Dönmez M, Kayabey Ö, et al. (2013) Crossed pulmonary
arteries: a report on 20 cases with an emphasis on the clinical features
and the genetic and cardiac abnormalities. Pediatr Cardiol 34: 1785-1790.
- Siwik ES, Everman D, Morrison
S (2002) Images in cardiology: Crossed pulmonary arteries, ventricular
septal defect, and chromosome 22q11 deletion. Heart 88: 88.
- Garg P, Talwar S, Kothari SS,
et al. (2012) The anomalous origin of the branch pulmonary artery from the
ascending aorta [J]. Interact Cardiovasc Thorac Surg 15: 86-92.
- Hadeed K, Ohanessian G, Acar
P (2010) Anomalous origin of the pulmonary artery from the ascending aorta
in a neonate, assessed by two-dimensional echocardiography[J]. Arch
Cardiovasc Dis 103: 493-495
- Uçar S, Zorlu P, Metin O,
Orün UA (2010) Pulmonary artery sling as a cause of recurrent wheezing in
children. Tuberk Toraks 58: 311-315.
- Chen J, Feng Y (2013) A rare
case of crossed pulmonary arteries in an infant - case report. J
Cardiothorac Surg 8: 79
- Chen BB, Hsieh HJ, Chiu IS,
Chen SJ, Wu MH (2008) Crossed pulmonary arteries: report of two cases with
emphasis on three-dimensional helical computed tomographic imaging. J
Formos Med Assoc 107: 265-269.
- Babaoglu K, Binnetoglu FK,
Altun G, Dönmez M, Anik Y (2010) Echocardiographic and three-dimensional
computed tomographic diagnosis of crossed pulmonary arteries: report of
three cases. Pediatr Cardiol 31: 720-722.
- Koca B, Oztunç F, Yalçın Y
(2011) Crossed pulmonary arteries in conjunction with tetralogy of
Fallot.Turk Kardiyol Dern Ars 39: 499-500.
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