embroyology natural history and management of atrial septal defect

2. Epidemiology of Congenital Heart Disease in India. R Bhardwaj et al. Cong
heart dis 2014

3. CONTENT
 Embryology
 Classification/Types
 Natural History
 Timing ,Indications For Intervention

18.  Ostium Secundum (85%)
 Ostium Primum (6%)
 Sinus Venosus (8%)
 Common atrium (1pt)
CRAIG & SELZER 1968 (Circulation)

19. CLASSIFICATION
 Ostium secundum defects (75%- 85% of ASDs)
are located in the region of the fossa ovalis.
 Ostium primum defects (10 - 15%) occur in the
lower portion of the atrial septum.
 Sinus venosus defects (5 - 10%) are located near
the orifice of the superior vena cava.
 Sinus venosus defects of IVC type (1%).
 Coronary sinus (1%) septal defect (in which a
defect between the coronary sinus and the left
atrium allows a left-to-right shunt to occur through
an “unroofed” coronary sinus).

21. Ostium secundum defect
 Excessive cell death and resorption of the septum
primum or
 Inadequate development of the septum
secundum.
Ostium primum defect
 Failure of EC to fuse completely

24. OSTIUM PRIMUM DEFECT CAUSED BY INCOMPLETE
FUSION OF ATRIOVENTRICULAR ENDOCARDIAL CUSHIONS

25. Sinus venosus defects occur outside the margins of the fossa ovalis, in relation to
the venous connections of the right atrium. They are located posterior and
superior to the fossa ovalis . Most often, the defect is rimmed by atrial septal
tissue only anteroinferiorly. Its posterior aspect is the right atrial free wall, and its
superior border is often absent because of an overriding superior vena cava.
Infrequently, the defect may be directly posterior to the fossa ovalis or may be
posteroinferior such that the inferior vena cava may join both atria

26. The left horn of sinus venosus forms the CS. The CS defect (unroofed
CS) results from failure of the wall between the left atrium and CS to
develop. There may be complete or partial unroofing of the CS
resulting in direct communication with the left atrium. Almost always
this anomaly is associated with left SVC.
Defect is at the site of CS ostium,anterior
and inferior to the fossa ovalis

27. BASED ON SIZE
 SMALL: > 3mm - < 6 mm
 MODERATE: ≥ 6 - < 12mm
 LARGE: ≥ 12mm
McMohan et al 2002
 SMALL: 4 - 5MM
 MEDIUM: 6 – 8MM
 LARGE: > 8MM
Anita Saxena 2005

29.  ASD constitutes 8-10% of congenital heart
defects in children.
 Incidence = 56 per 100,000 live births
 Recent estimates are much higher (100 per
100,000 live births), likely due to increased
recognition in the era of common use of
echocardiography
 female:male ratio for secundum ASD = 2:1
 For sinus venosus ASD= 1:1

30. GENETICS
 The genetic basis of ASD is not
completely understood.
 In the majority of cases this is a sporadic
lesion,yet some homeobox gene defects
have been found to explain some of the
well known familial cases of ASDs, such
as NKX2-chromosome-5, which has an
autosomal dominant inheritence and AV
conduction defect.

31. GENETICS
 Other genetic syndromes with skeletal
abnormalities HOLT-ORAM
Syndrome,which is acused by mutations
in the transcription factor TBX5,
essential in development of both the
heart and upper limbs.
 ASD can be part of many other
syndromes like DOWN syndrome and
Nooonan syndrome

33. A. SPONTANEOUS CLOSURE
 Spontaneous closure has been reported to occur
in anywhere between 14–66% of ASDs.
 Predictors of Closure
1. Smaller size
2. Earlier age at diagnosis (< 2yrs)

34. Cockerham et al 1983
(age)
 87 children
 Underwent cath < 4 yrs of age for a
significant secundum ASD
 Spontaneous closure occurred in 22 % of
those who underwent cath in age <1 yr
 Those who were 2-4 yrs at time of cath rate
of spontaneous closure decreased to 3%
 The group advocated to wait till 4 years of
age for elective closure.

35. Radzik et al 1993 (size)
 2-D echo based
 ASD < 5 mm including PFO = 87 %
SPONATNOUS CLOSURE
 > 8 mm- NO SPONTANEOUS
CLOSURE

36. HANSLIK et al 2006, AUSTRIA
 Retrospective analysis of 200 isolated ASD in children (diagnosis
Age: 5M; < 1M – 13.9 Y)
 Median age at follow – up: 4.5 Y (6.8m – 16.2Y)
 Spontaneous closure: 34%
 Decrease in size to < 3mm: 28%
 Initial ASD size at diagnosis was the main predictor of spontaneous
closure
SIZE AT
DIAGNOSI
S (mm)
NUMBER CLOSURE REGRESSIO
N
INTERVENT
ION
4 – 5 40% 56% 30% NONE
6 – 7 28%
8 – 10 21%
> 10 11% 0 0 77 %

38. GROWTH OF ISOLATED OSTIUM
SECUNDUM DEFECTS
McMohan et al. Heart 2002;87:256–259
 104 pts with isolated secundum ASD at Texas Children Hospital,
Houston between 1991 - 1998
 Reviewed retrospectively all patients presenting to the Texas
Children’s Hospital with isolated secundum ASD and assessed
the change in maximal defect diameter as measured by sequential
echocardiographic studies.
 The rate of change in size (mm/year) of ASD, age at diagnosis,
and interval of follow up were recorded.
 The mean age at diagnosis of the ASD was 4.5 years (range 0.1–
71 years).
 The mean interval between echocardiograms was 3.1 years
(range 0.7–8.1 years).

39. OVERALL GROUP
 29% had large ASD, 38% had moderate sized ASD, and 33%
had small sized ASD.
 66% had increase in the size of ASD at a rate of 0.8mm/year
(0.2 – 6.4mm/year) with 30% having > 50% increase in ASD
size.
 ASD size decreased in 15 patients (14%)
 Unchanged in 21 (20%).
 The rate of growth was independent of age at diagnosis,
ranging from 0.72 mm/year for the 2–4 year age group to
1.29 mm/year for the 4–6 year age group, which was not
significant (p = 0.9).
 The mean duration of follow up was 4.2 years (range 1.8–7.7
years) for defects that increased > 20 mm, indicating a
tendency for continued ASD growth with time.
 Strong correlation between the initial size and the final size
of defects with a r2 = 0.61.

40. SMALL SIZED ASD
 34 (33% of total defects)
 Three (10%) defects closed spontaneously.
 Seventeen (50%) defects increased in size.
 Seven (20%) of these defects increased from the
small to the moderate group and three (9%) defects
increased from the small to the large group.
 In ASDs that increased from the small to the large
group, the diameters increased from 3 mm to 22 mm,
3 mm to 17 mm, and 3 mm to 15 mm.
 The mean rate of increase in ASD size was 0.63 (1.6)
mm/year for defects in this group (fig 2).
 The mean follow up was 3.2 years (range 0.9–7.1
years).

42. MODERATE SIZED ASD
 40 defects (38%) were moderate sized.
 Three (7.5%) defects decreased to < 6 mm
 Eight (20%) defects increased to > 12mm

43. LARGE ASD
 30 defects were large (29%) and on follow up 45 defects qualified as large
(43%).
 All patients with large defects remained in the same group.
 The mean increase in size was 1.44 (1.9) mm/year.
 Mean follow up was 2.9 years (range 0.7–8.1 years).

45. Nawal Azhari. Cardiol Young 2004; 14: 148–155
 Retrospective analysis of 121 cases isolated
secundum ASDs between 1990 – 2003
 18.2% - 3 to 5 mm,
 22.3% - 5 to 8 mm, and
 59.5% - > 8 mm
 Mean age at diagnosis was 23.0 ± 24.3 M (1 day
to 11 years).
 25.6% had spontaneous closure

47. ANITA SAXENA Indian Heart J 2005
 52 consecutive patients diagnosed with ASD in first year of
life
 F/U: 0.7 – 7.0 years
SMALL 4 -5
MODERATE 6 – 8
LARGE ≥ 8
SPONTANEOUS CLOSURE 26%
DECREASED SIZE 20%
SAME 25%
ENLARGED 29%
SMALL (4-5 mm): Likely to close
LARGE ≥ 8 mm: Likely to remain same or enlarge

48. Summary
 Defects larger than 8-10 mm are less likely
to close spontaneously and most likely will
require surgical or transcatheter closure
,regardless of the age at diagnosis.
 ASDs diagnosed after the first 4 yrs of life
are less likely to spontaneously close and
they can present later in life with several
complications.

50. COMPLICATIONS
 Symptoms of exercise intolerance and
fatigue/CCF
 Atrial arrhythmias
 Pulmonary hypertension
 Systemic embolization
 Reduced life expectancy

51. Symptoms of exercise
intolerance and fatigue/CCF
 uncommon presentation in childhood
 But these symptoms are common in
older patients.
 Craig and Selzer 1960 circulation 128
patients of ASD >18-68 yrs age
Age % patients with exertional
dyspnea
20-40 yrs 14 %
40-60 yrs 24%
>60 yrs 75%

52. Atrial arrythmias
 Right atrial dilatation secondary to chronic
stretching and volume overload predisposes
older patients to atrial arrhythmias such as AF
and less commonly Afl, this can exacerbate
signs and symptoms of CCF.
 They are one of the most common presenting
symptoms in the 4th to 5th decade of life.
 Incidence has been reported to be >50% in
patients older than 60 yrs (Berger F et al 1999)
 In series by Craig and Selzer 1960 circulation ,
80% of ASD patients above 40 yrs age had
chronic atrial tachyarrhythmias

53. JAMES GAULT, Circulation, Volume XXXVII, February 1968
 62 pts > 40 years (46.5 years)
CLINICAL FEATURES
 94% were symptomatic at initial presentation
1. Dyspnea – 90%
2. Fatigue – 48%
3. Palpitations – 43%
4. Edema – 28%
5. Angina – 8%
 NYHA II - 45% NYHA III – 43.5%
 82% in NYHA II/III had PAH with > 50% having severe PAH
 Severe PAH with balanced or reversed shunt: 13%

54. Pulmonary hypertension
 Most serious complication
 Not common in young age
 According to craig and selzer 14 -18 %
between 20-40 yrs age develop PAH
 It is still debatable that whether this is caused
by the presence of large shunts or due to other
predisposing conditions such as
thromboembolic phenomenon.
 Eissenmenger is infrequent and usually occurs
late in life
 In a series BY konstantinides et al, mean age
was 56 yrs

55. PULMONARY HYPERTENSION IN ASD

57. HEART 1999
Heart 1999;82:30-33Heart 1999;82:30-33Heart 1999;82:30-33

59. SEVERE PAH IN INFANCY
Sora Goetschmann et al. Am J Cardiol 2008; 102:340 –342
 Retrospective analysis of 355 patients with isolated ASD
undergoing closure through surgery or device over a 10 year
period between 1996 and 2006.
 2.2% of the total study population had severe PAH (> 50 % of
systemic pressure)

61. MORTALITY
 Secondary to pulmonary artery
thrombosis, congestive heart failure,
paradoxical embolism and recurrent
respiratory tract infections.
 It is now difficult these days to estimate
age of survival in patients with
unrepaired ASDs in the modern era of
surgical and catheter interventions.

62. Campbell et al 1970

63. Analysis by Maurice Campbell,
1970 british heart journal

65. Management issues
 Management questions arise once an ASD
is found.
 Whether to close it?? Or just observe?
 What is the appropriate timing??
 What are the options for closure??

66. ACC AHA Recommendations for Interventional
and Surgical Therapy- CLASS 1
 1. Closure of an ASD either percutaneously
or surgically is indicated for right atrial and
RV enlargement with or without symptoms.
(Level of Evidence: B)
 2. A sinus venosus, coronary sinus, or
primum ASD should be repaired surgically
rather than by percutaneous closure.
(Level of Evidence: B)
 3. Surgeons with training and expertise in
CHD should perform operations for various
ASD closures. (Level of Evidence: C)

67. Class 2A recommendations
 1. Surgical closure of secundum ASD is
reasonable when concomitant surgical
repair/replacement of a tricuspid valve is
considered or when the anatomy of the
defect precludes the use of a percutaneous
device. (Level of Evidence: C)
 2. Closure of an ASD, either percutaneously
or surgically, is reasonable in the presence
of:
 a. Paradoxical embolism. (Level of Evidence: C)
 b. Documented orthodeoxia-platypnea. (Level of
Evidence: B)

68. Class 2B recommendations
Closure of an ASD, either percutaneously
or surgically, may be considered in the
presence of
 net left-to-right shunting, Qp/Qs>1.5
 pulmonary artery pressure less than two
thirds systemic levels,
 PVR less than two thirds systemic vascular
resistance,
 or when responsive to either pulmonary
vasodilator therapy or test occlusion of the
defect. (Level of Evidence: C)

69. Class 3 recommendation
 Patients with severe irreversible PAH
and no evidence of a left-to-right shunt
should not undergo ASD closure. (Level
of Evidence: B)

70. IDEAL AGE FOR
CLOSURE
 In asymptomatic child: 2-4 years (Class I).
 For sinus venosus defect surgery may be delayed
to 4-5 years (Class IIa).
 Symptomatic ASD in infancy (congestive heart
failure, severe pulmonary artery hypertension):
seen in about 8%-10% of cases. Rule out
associated lesions (e.g., total anomalous
pulmonary venous drainage, left ventricular inflow
obstruction, aorto-pulmonary window). Early
closure is recommended (Class I).
 If presenting beyond ideal age: Elective closure
irrespective of age as long as there is right heart
volume overload and pulmonary vascular
resistance is in operable range (Class I).

71. What to do for small defects???
 Closure of small defects without any right sided
cardiac enlargement is controversial.
 While these patients may remain asymptomatic well
into their fourth and fifth decades of life, there is
concern about increase of the left to right shunt at
an older age due to reduced LV compliance as a
result of CAD, systemic HTN, or valvular heart
disease.
 Routine follow up of these patients during adulthood
is recommended.
 And should include assessment for atrial
arrhythmias, paradoxical embolic events and an
echocardiogram every 2-3 yearly.

73. Murphy et al NEJM 1990
 123 pts who underwent surgical closure of ASD
at MAYO clinic between 1956 – 1960.
 F/U: 27 – 32Y
 Operative mortality: 3.3%
 Survival
5y: 97% 10y: 90%
15y: 88% 20y: 83%
25y:81% 30y: 74%

78. MARTIN G. ST. JOHN SUTTON, Circulation 64, No. 2, 1981.
 Between 1955 and 1977, 66 patients aged > 60
years.
 Operative mortality: 6%
 Forty-seven patients were followed up for 2-20
years (mean 6.6 years), and of these, 41 (87%)
improved by at least one functional class.
 Symptomatic benefit occurred in all groups,
regardless of preoperative PAP, pulmonary
vascular resistance or functional class.

79. Michael Humenberger, EHJ 2010
 To assess the impact of age on benefit of
closure of ASD

84. STAVROS KONSTANTINIDES, NEJM 1995
 Retrospective analysis of surgical vs medical
therapy in 179 patients > 40 years of age
with ASD
 F/U: 8.9 ± 5.2 years (range, 1 to 26)

91. In conclusion,this study, demonstrated that the early
successful closure rate and primary and secondary
efficacy success rates were not statistically different in
patients with ASD who underwent transcatheter device
closure using the ASO and those patients who underwent
surgical repair.
However, the complication rate was lower and the length
of hospital stay was shorter for device closure compared
with surgical closure.
Therefore, transcatheter device closure using an ASO
seems to be a safe and effective alternative treatment for
secundum ASD.

92. TAKE –HOME
MESSAGES
 ASD is a common congenital disorder
 Ostium secundum is the most common ASD
 Patient selection is the most important step
in management
 ACC AHA recommendations should be
followed to decide the management strategy
 Any kind of closure is safe and effective and
associated with improved life expectancy

93. CXR
Enlarged
pulmonary
arteries and
increased
vascular
markings
Enlarged
right atrium
along with
dilatation of
right ventricle

94. ECG
Enlarged ‘p’
wave
indicating
Right atrial
hypertrophy
rSR’ seen and tall R wave
Indicating RBBB and RVH
Also note that the aVF is
predominantly upwards
as compared to Lead I
indicating Right Axis
Deviation
LAD with rSR’ in V1 is suggestive of
Ostium primum defect

95. CROCHETAGE SIGN