Dr ranjith mp av canal defect

Dr Ranjith MP
Senior Resident
Department of Cardiology
Government Medical college
Kozhikode

 Atrioventricular Septal Defects are characterized by complete absence of
AV septum

 Additional features
 A common atrioventricular ring
 A five leaflet valve that guards the common AV orifice
 An unwedged left ventricular outflow tract
 LV mass characterized by longer distance from apex to aortic valve than
from apex to left AV valve

 Also known as Endocardial cushion defect, AV canal defect, canalis
atrioventricularis communis, persistent atrioventricular ostium

2

 AVSDs account for 4% to 5% of congenital heart disease

 New England Regional Infant Cardiac Program - 0.118/1000 livebirths

 Baltimore–Washington Infant study defined a prevalence of 0.362

 The Alberta Heritage study the prevalence was 0.203 and 0.242 per 1000
live births using invasive or noninvasive methodology for the diagnosis
respectively

 Gender distribution is approximately equal or may show a slight female
preponderance

3

 Rogers, Edwards : Recognised morphology of 10ASD in 1948

 Wakai, Edwards : Term of partial and complete AV canal
defect in 1956

 Bharati & Lev : Term of Intermediate & Transitional in 1980

 Rastelli: Described the of common anterior leaflet in 1966

 Lillehei : 1st repair of AVSD in 1954

 Kirklin, Watkin, Gross: Open repair using oxygenator

4

 Result from Faulty development of the endocardial cushions and of
the atrioventricular septum

 In partial AVSDs, incomplete
fusion of the superior and
inferior endocardial cushions
results in a cleft in the
midportion of the AML ,
often associated with MR

 Complete AVSD associated with lack of fusion between the
superior and inferior cushions
5

 Mitral & tricuspid valves achieve the same septal insertion
level because the mitral annulus is displaced toward the apex

 The distance from mitral annulus
to the left ventricular apex is less
than the distance from the aortic
annulus to the apex
6

 In the normal heart, the aortic valve is wedged between the mitral and
tricuspid annuli. In AVSD the aortic valve is displaced anteriorly and creates
an elongated, so-called gooseneck deformity of the LVOT

7

 Based on the relationships of the anterior bridging leaflets to the crest of
the ventricular septum or RV papillary muscles

 Rastelli type A : the anterior bridging leaflet is tightly tethered to the
crest of the IVS, occurring in 50% to 70%

 Rastelli type B : (3%), the anterior bridging leaflet is not attached to the
IVS; rather, it is attached to an anomalous RV papillary muscle and is
almost always associated with unbalanced AV canal with right
dominance

 Rastelli type C : (30%) a free-floating anterior leaflet is attached to the
anterior papillary muscle.

9

10
Kiyoshi suzuki et al J Am Coll Cardiol 1998;31:217–23

 Partial AVSD
 Most common 20 ASD & LSVC to CS
 Less frequently- PS, TS or atresia, cor triatriatum, CoA, PDA,
membranous VSD, PV anomalies, and HLV

 Complete AVSD
 Type A usually is an isolated defect and is frequent in patients
with Down syndrome.
 Type C – TOF, DORV, TGA and heterotaxy syndromes
 The combination of type C complete AVSD with TOF is observed
Down's syndrome, whereas DORV is a feature of patients with
asplenia

11

12
M. Cristina Digilio et alCardiogenetics 2011; 1:e7

13

14

 Anatomy of AVSD expected to demonstrate one or more of
the following hemodynamic changes
 Shunting across the atrial septal defect
 Shunting through the ventricular septal defect
 Mitral regurgitation
 Tricuspid regurgitation

 Patterns of shunting: obligatory shunting

15

 Greater proportion of SVC blood with a low
oxygen saturation may cross the IAS to the LA
Fetal physiology
 If AV insufficiency were present blood being
ejected from LV to RA

 Increase the PO2 of blood in RA, RV, PA

 Slightly higher PO2 of blood perfusing the lungs
would decrease pulmonary vasoconstriction
and increase pulmonary blood flow

 It is possible that the lesser degree of
constriction of the pulmonary arterioles may
retard the development of a thick medial
muscle layer, so that a more rapid decrease in
16
PVR may occur after birth

Early infancy  Infants with ostium 10 defect usually
present the same hemodynamic
features as those with 20 ASD

 As PVR falls after birth, RV after load
falls & RV stroke volume increases and
exceeds that of the LV. The RV fills
preferentially and thus left-to right
shunting occurs through the ASD

 MR and LV to RA shunting are not
usually prominent features in infants
with 10 defect

 If MR present, in early infancy cardiac
failure develops within weeks after
birth
17

 Pulmonary blood flow is increased even
later infancy though PVR may still be high, because
shunting occurs from a high-pressure to a low-
pressure chamber

 The increased pulmonary blood flow and PA
pressure interfere with the normal postnatal
maturation of the pulmonary arterioles

 The thick medial muscle layer is maintained
and the fall in PR is delayed

 An interesting association may develop in
some infants of an obligatory left-to-right
shunt through the atrioventricular septal
defect and simultaneous right-to-left shunting
through the ductus arteriosus

 Pulmonary vascular resistance may be 18
increased above systemic arterial resistance

 Partial AVSD
 Patients with 10 ASD are usually asymptomatic during childhood.
 Dyspnea, easy fatigability, recurrent RTI and growth retardation may
be present early in life if associated with major MR or common
atrium
 Patients with 10 ASD usually have earlier and more severe symptoms
than patients with 20 ASD

 Complete AVSD
 Tachypnea and failure to thrive invariably occur early in infancy &
virtually all patients have symptoms by 1 year of age.
 If these symptoms do not develop early on, the clinician should
suspect premature development of pulmonary vascular obstructive
disease

19

 Usually undernourished and have signs of CHF
 Hyperactive precordium with a systolic thrill at the lower
left sternal border is common
 S1 is accentuated. S2 narrowly splits, P2 increases in
intensity.
 A grade 3 to 4/6 holosystolic murmur

20

 ECG
 Superior” QRS axis with the QRS axis between -40 and -1500
 Most of the patients have a prolonged PR interval
 More than 50% have atrial enlargement
 RVH or RBBB is present in all cases (2/3rd have rsR, RSR or Rr in
lead V1, and the rest have a qR or R pattern) & many have LVH
 Chest X-ray
 In 10 ASD findings are same as 20 ASD except for enlargement
of the LA & LV when MR is significant
 In complete AVSD cardiomegaly is always present and involves
all four cardiac chambers. Pulmonary vascular markings are
increased, and the main PA segment is prominent

21

 Primary imaging technique for diagnosing AVSD
 The internal cardiac crux is the most consistent imaging
landmark
 Apical four-chamber imaging plane clearly visualizes the
internal crux
 The 10 ASD is seen as an absence of the lower IAS

22

 Several echocardiac features are shared by all forms of
AVSD:
 Deficiency of a portion of the inlet ventricular septum
 Inferior displacement of the AV valves
 Attachment of a portion of the left AV valve to the septum
 The two separate AV valve orifices are equidistant from the
cardiac apex

23

 The most common left AV valve abnormality, a cleft, is best
visualized from the parasternal and subcostal short-axis
imaging planes.
 Rarely parachute mitral valve and double-orifice mitral valve
also occur

24

 In the transitional form of partial AVSD, there is aneurysmal
replacement of a portion of the inlet ventricular septum

25

 Rarely required for diagnosis

 In older patient it may have a role in assessing the degree of
pulmonary vascular obstructive disease or CAD

 A large Lt to Rt shunt at the atrial level demonstrated by a
significantly higher oxygen saturation sampled from the RA
compared with the blood in the IVC & SVC

 In complete AVSD the PASP is invariably at or near systemic level,
while in partial AVSDs, the PASP is usually <60% of systemic pressure

 LV angiography - gooseneck deformation of the LVOT

36

 Left to-right shunting increases the oxygen saturation in RA

 Sample from high in the SVC usually represents the best

 mixed venous oxygen saturation (normal or 40 to 50%)

 Usually a further increase in oxygen saturation in the RV

 Pulmonary venous oxygen saturation is frequently reduced
to 93–95% in older individuals with very large L to R shunts

 LA & LV O2 saturation is often decreased to as low as 86–88%
37

 The LV angiogram shows features characteristic of AVCD& are best
revealed in the hepatoclavicular orientation

 The LV outflow tract is elongated and appears narrow

 A concavity of the medial border LV that extends along the outflow
region to the aorta due to the abnormal attachment of the AML. If it
attaches to the ventricular septum or right papillary muscle, LVOT
obstruction may be evident

 Detect AV valve regurgitation

38

 The outcome of live-born patients with AVSD depends on
the

 specific morphology of the defect
 The size of the ventricular septal defect
 Degree of ventricular hypoplasia
 Degree of AV valve regurgitation
 Presence or absence of LVOT obstruction
 Presence or absence of coarctation of aorta
 Associated syndromes (cardiac and noncardiac)

39

 Patients with the complete form of AVSD and large VSD not
undergoing repair die in infancy with CHF & PAH

 Those who survive without surgery into childhood usually develop
pulmonary vascular obstruction and eventually die with
Eisenmenger’s syndrome

 Berger and his colleagues found that only 54% of patients born
with a complete form of AVSD were alive at 6 months of age, 35%
at 12 months, 15% at 24 months, and 4% at 5 years of age

 This data would support surgical intervention in the first 3–6
months of age

40
Berger TJ,et al Ann Thorac Surg 1979; 27: 104–11.

 Infants with 10 ASD presenting in infancy have a poor outcome,
mainly because of the associated risk factors that bring these
infants to early attention

 Those with the partial form of AVSD and minimal left AV valve
regurgitation seem to fare the best without surgery, although
there is still likely considerable morbidity and mortality

 According to Somerville, 50% die before 20 years of age and only
25% survive beyond 40 years of age

 Atrial fibrillation in these patients was an important cause of late
morbidity and mortality

41

 The complete form of AVSD is the most frequent type of CHD
associated with trisomy 21

 70% of children with complete AVCD display this aneuploidy

 Children with Down syndrome show a simple form of AVCD
which is usually complete & rarely associated with additional
cardiac anomalies (with the only notable exception of TOF)

42

 Left-sided obstructive lesions are significantly rare in
children with AVCD and Down syndrome compared to
patients with AVCD without Down syndrome

 Accordingly, some types of situs abnormalities such as l-loop
of the ventricles, atresia of the AV valves and TGA are
virtually absent in subjects with Down syndrome

 Surgical correction of AVCD in individuals with Down
syndrome results in lower mortality and morbidity rates,
compared to the children without trisomy (12.6% Vs 17.8%)

43

 Patients are at increased risk for the development of pulmonary
vascular obstructive disease

 These patients have a greater degree of elevation of pulmonary
vascular resistance in the first year of life and more rapid
progression to fixed pulmonary vascular obstruction than patients
without Down syndrome

 Chronic upper airway obstruction with macroglossia and an
inherently small hypopharynx, hypotonia, the predisposition to
chronic infection, an abnormal capillary bed morphology, and the
suggestion of pulmonary hypoplasia can all adversely affect the
pulmonary vascular bed

 surgical correction should be carried out by 6 months
44

 Incidence
 1% in unoperated cases
 Higher incidence in operated cases
 10% may require reoperation to relieve LVOT obstruction
 more common in partial than in complete AVSD
 Etiology
 Attachments of SBL to ventricular septum
 Extension of the anterolateral papillary muscle into LVOT
 Discrete fibrous subaortic stenosis
 Tissue from an aneurysm of the membranous septum
bowing into the LVOT
 Septal hypertrophy

45

Systolic (left) and diastolic (right) echocardiographics demonstrating
LVOT obstruction in a 17-year-old who had repair of a partial AVSD at
age 15 months
46

 PA banding is now performed infrequently in infants with
AVSD because the surgical risks of intracardiac repair are not
significantly greater than the palliative procedure

 Perioperative mortality is about 5%

 It is reserved for those few patients in whom intracardiac
repair is likely to be associated with a high risk like
 Single papillary muscle
 Severe left ventricular outflow obstruction
 Unbalanced commitment of the AV valve to the ventricles

47

 Objectives - closure of the interatrial communication and restoration
and preservation of left AV valve competence

 These objectives can be accomplished by careful approximation of the
edges of the valve cleft with interrupted nonabsorbable sutures

 The repair is completed by closure of the interatrial communication
(usually with an autologous pericardial patch), avoiding injury to the
conduction tissue

 This repair results in a two-leaflet valve

 Alternatively, if the left AV valve is to be considered a trileaflet valve,
with the cleft viewed as a commissure, surgical repair demands that
this commissure be left unsutured and that various annuloplastic
sutures be placed to promote coaptation of the three leaflets
48

A: Surgical exposure

B: Closure of the mitral
valve cleft

C: Prosthetic patch
closure of an 10 defect

D: Repair completed

49

 Surgical repair of complete forms of AVSD is indicated earlier
in life than for the partial forms of AVSD

 Repair should be done electively before 6 months of age &
earlier repair should be considered for infants with failure to
thrive

 For the symptomatic infant, surgical options include
palliative pulmonary artery banding and complete repair of
the anomaly

 In the modern era complete repair appears to be the
procedure of choice

50

 Closure of interatrial and interventricular communications,
construction of two separate and competent AV valves from
available leaflet tissue, and repair of associated defects

 Techniques are based on the use of a single patch or double patch
(separate atrial and ventricular patches) to close the ASD and VSD
and then reconstruction of the left AV valve as a bileaflet valve

 Some surgeons consider the cleft of the left AV valve, a true
commissures and envision this valve as a trileaflet valve. This is
the basis for Carpentier technique for repair of complete AVSD

 The two-patch technique has become the method of choice

51

Carpentier technique for repair of complete AVSD with the double-patch technique.
Concept of a trileaflet left atrioventricular valve 52

 The risk of hospital death for repair is 3%

 Determinants of hospital mortality include CHF , cyanosis,
failure to thrive, age at operation of <4 years, and moderate
to severe MR

 20- and 40-yr survivals after repair is 87% and 76%
respectively

 Closure of the mitral cleft and age <20 years at time of
operation is associated with better survival
53

 Partial AVSD:
 Regurgitation or stenosis of the left AV valve
 Subaortic stenosis
 Residual recurrent ASD

 Reoperation for MR occurs in 10% to 15% of survivors of primary repair
of partial AVSD

 Risk factors for reoperation include significant residual MR as assessed
intraoperatively at the time of initial repair, the presence of a severely
dysplastic mitral valve, and failure to close the cleft in the AML

 Repeat repair is possible if valve dysplasia is not severe or when the
mechanism of regurgitation is through an unsutured cleft

 Replacement of the mitral valve may be required in the presence of a
severely dysplastic valve
54

Complete AVSD
 Needed in 17% of patients during the first 20 years after surgical repair

 Lesions requiring reoperation include - left and right AV valve
regurgitation, left AV valve stenosis (native and prosthetic), and
residual/recurrent ASDs or VSDs

 Residual left AV valve regurgitation may result from inadequate surgical
reconstruction

 Right AV valve regurgitation requiring reoperation is rare . It is more
apparent with the presence of PAH or in association with TOF with RV
dysfunction owing to persistent RVOT obstruction or PR

 Residual shunts are rare causes for late reoperation
55

 Parachute Deformity of the Mitral Valve
 Closure of the mitral cleft at the time of repair may result in an
obstructed mitral orifice
 If the patient has significant AV valve regurgitation, valve
replacement may be the only suitable option

 Double-Orifice Mitral Valve
 The surgeon must resist the temptation of joining the two
orifices by incising the intervening leaflet tissue. The combined
opening of both orifices is satisfactory for adequate mitral valve
function

56

 Right or Left Ventricular Hypoplasia
 The only option for definitive surgical treatment is the modified
Fontan's procedure preceded by adequate pulmonary artery
banding in infancy

 Subaortic Stenosis
 If discovered at the time of initial preoperative evaluation,
subaortic stenosis tends to be of the fibromuscular membrane
type and should be treated by appropriate resection during
surgical repair

57

 Common atrium is characterized by near absence of the atrial
septum

 In the presence of two ventricles, it always is associated with an
AVSD

 Most patients with common atrium present in infancy with
symptoms of excess pulmonary blood flow

 These patients are symptomatic earlier in life than patients with
only a 10 ASD

 The precordium is hyperactive with a prominent RV impulse.
S2 is widely split and fixed
58

 P2 intensity proportionate to the severity of pulmonary
hypertension

 An ESM present over the upper left sternal border. A distinct
holosystolic murmur of MR may be heard at the apex. A
middiastolic murmur commonly is detected over the lower
left sternal border resulting from an increase in right atrial to
right ventricular blood flow

 The radiographic and electrocardiographic characteristics of
patients with common atrium are indistinguishable from
those with other forms of AVSD

59

 Echocardiography
 Subcostal four-chamber view is most suitable for accurate diagnosis
 A muscle bundle or band coursing through the atrium should not
be interpreted as an atrial septum

 Cardiac Catheterization and Angiography
 The hemodynamic diagnosis of common atrium depends on the
demonstration of complete mixing of systemic and pulmonary
venous blood
 The oxygen saturations of pulmonary and systemic arterial blood
are nearly identical
 Pulmonary blood flow exceeds systemic flow, except in patients
with PAH
 Right ventricular pressure is increased more often than in 20 ASD or
partial AVSD 60

 If definitive repair is delayed, significant pulmonary
vascular obstructive disease may develop more easily
than in patients with secundum ASD or partial AVSD

 Treatment
 Medical therapy -Digoxin and diuretic therapy are traditional
forms of therapy
 Surgical repair, which should be performed early in life
because the patient usually has symptoms and is at risk for
developing pulmonary vascular obstructive disease

61

 One ventricle and its corresponding AV valve are hypoplastic
while the other ventricle receives the larger portion of the
common AV valve
 The most common arrangement is a dominant right ventricle
with a hypoplastic left ventricle
 The left-sided component of the common AV valve may be
stenotic after two-ventricle repair has been performed

62

1. Down syndrome most commonly associated with Type A

2. Most common form complete AVCD is Type B.

3. Free interventricular communication exists in type A

4. In type A anterior bridging leaflet has been described as free
floating

1. Sinus rhythm is present in most patients with a 1⁰ ASD

2. P-wave changes indicating right atrial, left atrial, or biatrial
enlargement are seen in 54% of patients.

3. The mean QRS axis ranges from +30⁰ to +120⁰

4. ventricular volume overload results in the rsR or RSR pattern in
the right precordial leads in 84%.

1. Single papillary muscle

2. Severe left ventricular outflow obstruction

3. Unbalanced commitment of the AV valve to the ventricles

4. Associated TOF

1. The only option for definitive surgical treatment in Right or Left
Ventricular Hypoplasia is the modified Fontan's procedure preceded
by adequate pulmonary artery banding in infancy

2. In double-orifice Mitral Valve, better results by joining two orifices
by incising the intervening leaflet tissue

3. Closure of the mitral cleft at the time of repair may result in an
obstructed mitral orifice in Parachute Deformity of the Mitral Valve

4. If discovered at the time of initial preoperative evaluation, subaortic
stenosis tends to be of the fibromuscular membrane type & should
be treated by appropriate resection during surgical repair

68

1. Oxygen saturation step up from RA to RV

2. Mixed venous sample best represented by low SVC sample

3. Oxygen saturation 93 to 95 in pulmonary vein

4. Left atrial and left ventricular oxygen saturation is often
decreased to as low as 86–88%

69

1. Noonan syndrome

2. Down syndrome

3. CHARGE syndrome

4. Ellis-van creveld syndrome

1. 20- and 40-yr survivals after repair is 87% and 76% respectively

2. Closure of the mitral cleft and age <20 years at time of operation
is associated with better survival

3. Right AV valve regurgitation requiring reoperation is rare

4. The risk of hospital death for repair is 12- 16%

1. Gender distribution is approximately equal or may show a
slight female preponderance

2. A five leaflet valve that guards the common AV orifice

3. An wedged left ventricular outflow tract

4. LV mass characterized by longer distance from apex to aortic
valve than from apex to left AV valve

1. Inferior displacement of the AV valves

2. The two separate AV valve orifices are not equidistant from
the cardiac apex

3. The internal cardiac crux is the most consistent imaging
landmark

4. Deficiency of a portion of the inlet ventricular septum

73

1. Reoperation for MR occurs in 10% to 15% of survivors of
primary repair of partial AVSD

2. Replacement of the mitral valve may be required in the
presence of a severely dysplastic valve

3. Residual shunts are common causes for late reoperation

4. The risk of hospital death for repair is 3%

74

1. The only option for definitive surgical treatment in Right or Left
Ventricular Hypoplasia is the modified Fontan's procedure preceded
by adequate pulmonary artery banding in infancy

2. In double-orifice Mitral Valve better results by joining two orifices by
incising the intervening leaflet tissue

3. Closure of the mitral cleft at the time of repair may result in an
obstructed mitral orifice in Parachute Deformity of the Mitral Valve

4. If discovered at the time of initial preoperative evaluation, subaortic
stenosis tends to be of the fibromuscular membrane type & should
be treated by appropriate resection during surgical repair

79

1. Oxygen saturation step up from RA to RV

2. Mixed venous sample best represented by low SVC sample

3. Oxygen saturation 93 to 95 in pulmonary vein

4. Left atrial and left ventricular oxygen saturation is often
decreased to as low as 86–88%

80

1. Inferior displacement of the AV valves

2. The two separate AV valve orifices are not equidistant from
the cardiac apex

3. The internal cardiac crux is the most consistent imaging
landmark

4. Deficiency of a portion of the inlet ventricular septum

84

1. Reoperation for MR occurs in 10% to 15% of survivors of
primary repair of partial AVSD

2. Replacement of the mitral valve may be required in the
presence of a severely dysplastic valve

3. Residual shunts are common causes for late reoperation

4. The risk of hospital death for repair is 3%

85

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