aortic arch development with anamolies with pulmonary HTN

1. Development of aortic arch
Dr Vinayak M Nadiger

2. • First arch arteries to appear in the embryo are Rt
& Lt primitive aorta
• Each primitive aorta consists of
1.a portion lying ventral to the foregut ( ventral
aorta)
2.an arched portion lying in the first pharyngeal
arch
3. and a dorsal portion lying dorsal to the gut
(dorsal aorta)

3. ventral aorta develops ventral to foregut .
• dorsal aorta is formed dorsal to the foregut
• After fusion of two endocardial heart tubes ,
two ventral aorta partially fuse to form
aortic sac
• unfused part remain as right & left horns of
the sac ( some define aortic sac as the most
distal part of the truncus arteriosus)

4. diagram showing 6 paired branchial arches and an intersegmental artery .The
branchial arches connectpaired ventral aortae and dorsal. IA indicates
intersegmental artery

6. Fate of arch arteries
• The majority part of the first &second arch
artery disappear
• In adult life – the first arch artery is
represented by maxillary artery
• The second arch artery – persist for some part
of fetal life as the stapedial artery
• The fifth arch artery also disappears
• Only 3rd ,4th & 6th arch artery remains

7. FATE OF AORTIC ARCHES
1. First aortic arch – disappears (except a small portion
which formspart of maxillary artery).
2. Second arch artery – disappears (except the stapedial
artery which also disappears after birth).
3. Third aortic arch forms :a. Common carotid artery from
itsproximal part.b. Internal carotid artery from its distal
part.
4. Fourth aortic arch :• a. On the right side forms proximal
part of right subclavian artery.• b. On the left side forms
part of arch of aorta
5. Firth aortic arch ‐ disappears.
6. Sixth aortic arch: a. Proximal part forms pulmonary
artery
b. Distal part –i) Disappears on right side. ii) Forms ductus
arteriosus

8. • Ascending aorta is formed by aortic sac.
• The Rt horn of the aortic sac forms the brachiocephalic
artery
A)Part of arch of aorta between brachiocephalic
and left common carotid arteries is formed by left horn of
aortic sac.
B). Part of arch of aorta between left common
carotid and left subclavian arteries is formed by left 4th
aortic arch.
c). Remaining part is formed by left dorsal aorta
up to the level of the future lower border of4th thoracic
vertebra.
• Descending aorta-by The left dorsal aorta below the
attachment of 4th arch artery and by fused median
vessels

9. Formation of normal left AA

10. Left AA with Abarrent right SCA

11. Left AA with aberrant rt sub clavian

14. Right AA

15. Rt AA with Abarrent left SCA
Kommerell diverticulum

16. Right sided AA with aberrant lt sub
clavian a

18. Rt AA WITH ISOLATION OF THE LEFT
SCA

19. Double aortic arch

20. Pulmonary HTN

21. Plain X-Ray

22. By the time the diagnosis of
pulmonary arterial hypertension is
made, 90% of patients have an
abnormal chest radiograph .
-low sensitivity and specificity.
Plain film

23. -elevated cardiac apex due
to right ventricular
hypertrophy.
-enlarged right atrium.
-prominent pulmonary
outflow tract.
-enlarged pulmonary
arteries.
-pruning of peripheral
pulmonary vessels.
(+ve) Findings :

27. The X-ray shows gross enlargement of the cardiac shadow. The right border
extends far to the right indicating gross right atrial enlargement

28. Lateral chest radiograph shows filling of the retrosternal airspace
(arrow), a result of right ventricular dilatation.

29. Chest radiograph reveals enlargement of the pulmonary
vasculature and the central pulmonary arteries (arrows).

30. Secondry hypertension By atrial septal defect

31. Lateral CXR of the same patient, showing
enlarged pulmonary artery.

32. Cardiomegaly and prominent bilateral pulmonary arteries in the
hilar areas can be seen in the posteroanterior chest radiograph

33. Computed Tomography

34. 1- CT is good , noninvasive , used to
confirm presence of pulmonary
hypertension.
2- It is useful in delineating the anatomic
detail of the pulmonary vasculature.
3-CTPA is the best method for
demonstrating emboli.
4- Contrast-enhanced images may show
intraluminal abnormalities in the arteries
and veins and can detect emboli if it’s
large.
Advantages of CT

35. PH signs on CT
Extr-acardiac
Cardiacparenchymal

36. Enlarged pulmonary trunk >29 mm diameter is
often used as a general predictive cut-off
Enlarged pulmonary arteries
Mural calcification in central pulmonary arteries
Evidence of previous pulmonary emboli
Extra-cardiac vascular signs:

37. T angiogram shows dilatation (29 mm or more) of
the main pulmonary artery.

38. Axial contrast-enhanced CT scan ,shows central pulmonary artery
dilatation with aneurysmal enlargement of the left lower lobe
pulmonary artery .

39. -Right ventricular hypertrophy: defined as wall
thickness of more than 4 mm.
-Straightening or bowing (towards the left
ventricle) of the interventricular septum
- Right ventricular dilatation
- Decreased right ventricular ejection fraction
- Dilatation of the inferior vena cava and hepatic
veins
- Pericardial effusion
Cardiac signs :

40. right ventricular myocardium (white arrow) is more than 4
mm thick. Straightening of the interventricular septum (black
arrow) also is seen.

41. right ventricular dilatation, which is defined as a diameter ratio (the ratio of
the right ventricular diameter [black arrow] to the left ventricular diameter
[white arrow]) greater than 1:1 at the midventricular level.

42. reflux of contrast material into the inferior vena cava,
which is dilated, and hepatic veins

43. Centrilobular ground-glass nodules (Cholesterol
granuloma).
Neovascularity: tiny serpiginous intrapulmonary
vessels that often emerge from centrilobular
arterioles.
Parenchymal signs:

44. Axial contrast-enhanced CT scan shows corkscrewlike
peripheral pulmonary arteries (arrows), findings indicative
of plexogenic arteriopathy.

45. Axial contrast-enhanced CT scan shows an eccentric wall-
adherent thrombus (arrow) in the right interlobar pulmonary
artery .

46. Axial contrast-enhanced CT scan shows:
-right atrial and ventricular enlargement with inverted interventricular
septum
- right ventricular hypertrophy,
- -eccentric chronic thrombus causing a crescent-shaped intraluminal filling
defect (arrow) in the left lower lobe pulmonary artery.

47. Axial contrast-enhanced CT scan shows a thrombotic
mass (straight arrows) in the right main pulmonary
artery.

48. Echocardiography

49. - It’s performed to estimate the pulmonary artery
systolic pressure and to assess right ventricular
size, thickness, and function.
- evaluate right atrial size, left ventricular systolic
and diastolic function, and valve function.
- detecting pericardial effusions and intracardiac
shunts.
- uses Doppler ultrasound to estimate the
pulmonary artery systolic pressure.
Advantages

50. 1. Right ventricular enlargement
(RVE).
2. Right ventricular hypertrophy
(RVH).
3. Right atrial enlargement
(RAE).
4. Functional tricuspid
regurgitation (TR) with a high
velocity regurgitant jet by
Doppler (TR jet).
5. The interventricular septum is
shifted toward the left
ventricular cavity.
Main findings

51. The short axis view from a 2-D echocardiogram shows
significant right ventricular pressure and volume
overload as a result of pulmonary hypertension.

52. The short axis view from a 2-D echocardiogram shows
significant right ventricular pressure and volume overload as a
result of pulmonary hypertension.

53. Angiography

54. Right heart catheterization may be
required.
-Pulmonary angiography is the most
accurate modality for evaluating the
anatomy and pathophysiology of
pulmonary hypertension
-The disadvantage :
it is an invasive procedure as one cannulates
the right side of the heart and thea
pulmonary artery.

55. Selective right pulmonary arteriogram demonstrates large central
pulmonary arteries and attenuation of the peripheral vessels.

56. Pulmonary hypertension. Selective left pulmonary arteriogram
reveals large central pulmonary arteries and attenuation of the
peripheral vessels

57. Angiograms showing a healthy pulmonary artery (left) and a
pulmonary artery with numerous blockages (right).

58. Magnetic resonance
Imaging

59. Cardiac MRI showing dilated right ventricle
(Axial View )

60. Cardiac MRI showing dilated right
ventricle (Sagittal view).

61. Magnetic Resonance Angiography
from a patient with PH

62. Magnetic Resonance Angiography in patient with Chronic
Thromboembolic Pulmonary Hypertension.