Atrial Septal Defects: Genetics, Hemodynamics, and Clinical Presentation

Genetics of Atrial Septal Defects

Atrial septal defects

• A familial predisposition to ASD is well documented.
• Secundum ASD is the most common congenital cardiac defect associated with
  VACTERL.
• Trisomy 21 is associated with ASD either in isolation or as part of a constellation
  of endocardial cushion defects. Noonan syndrome is associated with ASD and
  pulmonary valve stenosis.
• DiGeorge syndrome (22q11.4 deletion) is associated with primum ASD.

Types of Atrial Septal Defects

Atrial septal defects

Type of atrial septal defect

SVC
FO
TV
IVC
A Patent foramen ovale
B
Secundum defect
C
Primum defect
D Superior sinus venosus defect
E
Coronary sinus defect

Incidence and Natural History of Atrial Septal Defects

Atrial septal defects

• Secundum ASD occurs in 1.6 out of 1000 live births, second in prevalence only to
  ventricular septal defect.
• ASD accounts for 10% to 15% of congenital heart defects in children and 20% to 40% of
  defects discovered in adults.
• A significant number of ASDs close spontaneously within the first few years of life, but
  spontaneous closure after age 3 to 4 is rare.

. Longitudinal data demonstrate that more than half of defects diagnosed in infancy and
measuring 4 to 5 mm close spontaneously while none close spontaneously when the defect
measures larger than 10 mm at diagnosis.
. In contrast to children with ASDs, most patients older than 40 years of age are
symptomatic and have evidence of elevated pulmonary vascular resistance. If these
patients are not treated, their average life expectancy is 40 to 50 years. Seventy-five percent
die by age 50, and 90% die by 60 years of age.

Associated Features of Atrial Septal Defects

Atrial septal defects

• Associated lesions found in the study of infants with ASD dying in the first year of life included:
  Left-to-right shunting lesions
  VSD or patent ductus arteriosus
  Right-sided obstructive lesions
  Pulmonary stenosis
  Left-sided obstructive lesions
  Aortic stenosis, mitral stenosis, or
  coarctation of the aorta
• The most common additional cardiac anomalies associated with ASD include PAPVC, persistent
  left SVC and branch pulmonary artery stenosis.

Hemodynamics and Pathophysiology of Atrial Septal Defects

Atrial septal defects

Left to Right Shunt in ASD

Left to right shunt

• In early infancy, when pulmonary resistance is high, left and right ventricular compliances are
  similar, and net shunting through an ASD is typically slight.
• As the left ventricle matures, it becomes less compliant in diastole than the right, and left atrial
  pressure rises.

ASD
Left-to-right shunt at the atrial level

• With age, the disparity between systemic and pulmonary resistance, and in turn between left and
  right ventricular compliance
  increased left-to-right shunting and advancing right ventricular volume loading
  dilation and hypertrophy of the right ventricle, eventually affecting the function of both ventricles

Pulmonary Vascular Disease in ASD

Atrial septal defects

Pulmonary vascular disease

• Pulmonary hypertension associated with an isolated ASD is rare in childhood, although
  35% to 50% of patients with unrepaired ASD have elevated pulmonary resistance by age 40.
• Pulmonary hypertension can develop at an earlier age in premature infants and in children
  with Trisomy 21.
• Histopathologic evidence of increased preacinar and intra-acinar arterial muscularity in
  infants with ASD and pulmonary vascular disease suggests
  Pulmonary vasculopathy
  is the primary disorder in the uncommon population with early pulmonary vascular disease.

Clinical Presentation of Atrial Septal Defects

Atrial septal defects

Clinical presentation

• A great majority of ASDs are asymptomatic, and palpitations, atrial fibrillation, and
  congestive failure are late sequelae, uncommon in patients younger than 40 years of age.
• Additional clinical associations with PFO include stroke, migraine headache, high altitude
  pulmonary edema, and diver's decompression disease.
• Recurrent respiratory infection in the presence of a large ASD is not uncommon.
  Cyanosis can develop in the setting
  advanced irreversible pulmonary hypertension

Diagnostics and Examination for Atrial Septal Defects

Atrial septal defects

Transthoracic Echocardiography for ASD

Transthoracic echocardiography

• Is the most accurate modality of ASD diagnosis
  Small defects remain difficult to image by echo

Cardiac Magnetic Resonance Imaging for ASD

• Cardiac magnetic resonance imaging (MRI)
  Is useful in imaging partial anomalous pulmonary venous structures that may lie adjacent to the
  airways and lung.
  Right SVC
  Right upper
  pulmonary vein

Management of Atrial Septal Defect and Patent Foramen Ovale

Atrial septal defects

Indications for Atrial Septal Defect Closure

Indications for Atrial Septal Defect Closure

• Elective closure of ASD is generally recommended when the ratio of pulmonary to systemic
  blood flow (Qp : Qs) is 1.5:1 or greater.
• ASD closure should be performed at age 2 to 5 years, and before school.
• Long-term follow-up data after surgical ASD closure show survival equal to the normal
  population when repair is performed early in life, with an age-related diminution in survival
  when closure is delayed.

Contraindications for Atrial Septal Defect Closure

Contraindications for Atrial Septal Defect Closure

• Advanced pulmonary hypertension is a contraindication to ASD closure.
• Irreversible pulmonary hypertension is characterized by a PVR 8 to 12 Wood unit X m2,
  with Qp : Qs less than 1.2:1, despite aggressive vasodilator challenge.

Catheter-Based Treatment for Atrial Septal Defects

Atrial septal defects

Catheter-based treatment

• King and Mills reported the first catheter-delivered ASD closure in 1976, using a double
  umbrella device and a 23 Fr delivery catheter.
• In 1983, Rashkind introduced a self-expanding patch device that attached to the septum with
  small barbed hooks.
• Over the subsequent years, numerous devices have been designed and investigated for the
  treatment of secundum ASDs.
• The two devices currently approved by the Food and Drug Administration (FDA) in the
  United States are the Amplatzer septal occlude (St. Jude Medical, St. Paul, MN) and the
  Helex septal occluder (Gore & Associates, Flagstaff, AZ).

Complications and Prohibitions of Catheter-Based Treatment

Atrial septal defects

Catheter-based treatment

• Current published studies comparing the two approaches with anatomically similar defects show a device
  success rate of 80% to 95.7% and a surgical closure success rate of 95% to 100%.
• Major procedural complications of device closure include device embolization; cardiac tamponade;
  stroke or TIA; retroperitoneal hematoma; thrombosis; device erosion; obstruction of the IVC, coronary
  sinus, or pulmonary vein; and tricuspid or mitral insufficiency.

Anatomic determinants that prohibit device closure

1. Defects exceeding 38 mm size require surgical closure
2. Defects without sufficient septal rim to engage the device
3. Sinus venosus defects for which device closure would threaten obstruction of pulmonary veins,
   IVC, or SVC
4. Defects unsuitable for device closure that have failed attempted device closure.

Outcome Comparison: Device vs. Surgical Treatment

Atrial septal defects

A recent 20-year outcome comparison of device versus surgical treatment of
comparable ASDs shows no significant differences in:

• Survival
• Functional capacity
• Arrhythmia
• Late embolic stroke
  between methods of closure, supporting a transcatheter approach for defects amenable
  to device closure.

Amplatzer Septal Occluder Advantages

Atrial septal defects

Amplatzer® Septal Occluder
Advantages

• No CPB
• No skin incision
• Less/absent postop pain
• No ICU stay
• Shorter hospitalization
  30 Aur 0
  ESTO Services
  9.47:17 am
  TE-45H
  502
  70 Ha
  ROmm
  TEE
  General /'
  Lans Tomp=37 4ª=
  63 $1/+1/1/ 4
  Gin= 1603 == 2
  Store in progress
  EX
  FR= 58bom

-
@ Images Paediatr Cardiol

Surgical Treatment for Atrial Septal Defects

Atrial septal defects

Advantages of Surgical Closure

Surgical treatment
Advantages of surgical closure

• Direct vision of atrial septum: closure
  of any additional defects
• Complete interatrial re-septation (PFO
  plus Rete Chiari)
• Management of associated cardiac
  lesion (PAPVC)
• No foreign material
• Very low morbidity and mortality
• Good long-term results

Disadvantages of Surgical Closure

Disadvantages of surgical closure

• Needs for ICU (?)
• Surgical incision (need for analgesic
  medications)
• Potential complications linked to the CPBP
• Post operative complications (blood trasfusions,
  pericardial effusion etc.)

Surgical Technique for Atrial Septal Defects

Atrial septal defects

Surgical treatment

A portion of the
anterior
pericardium is
preserved for use
as a patch

RAA
Limbus
SVC
Aorta
AVN
RUPV
TV
RLPV
IVC
EV
CS
Atrial septal defect and patent foramen ovale

Suture Placement in ASD Surgery

Atrial septal defects

Surgical treatment
Atrial septal defect and patent foramen ovale

Care is exercised to
place sutures into
surrounding tissue
But
without interfering
with the adjacent
structures

RAA
Limbus
SVC
Aorta
AVN
RUPV
TV
RLPV
IVC
EV
CS

Autologous Pericardial Patch for ASD

Atrial septal defects

Surgical treatment
Atrial septal defect and patent foramen ovale

Orifices of
pulmonary
veins

Autologous
pericardial patch

Left atrium seen
through large 2° ASD
(septum primum absent)

Sinus Venosus Atrial Septal Defect with Partial Anomalous Pulmonary Venous Return

Atrial septal defects

Surgical treatment
Sinus Venosus Atrial Septal Defect
with Partial Anomalous Pulmonary Venous Return

A pericardial
baffle is
constructed to
direct right upper
pulmonary vein
flow to the left
atrium, through a
created or enlarged
secundum defect.

SVC
RUPV
IVO
A
B
D
C

The Warden Procedure for Sinus Venosus ASD

Atrial septal defects

Surgical treatment
Sinus Venosus Atrial Septal Defect
with Partial Anomalous Pulmonary Venous Return

The Warden
procedure

A
1
D
C
B

Mini-Invasive Surgical Treatment for ASD

Atrial septal defects

Surgical treatment
Mini invasive surgical treatment
Gender differenciated
approach
Males
Females

Mini-Sternotomy for ASD

Atrial septal defects

Surgical treatment

MINI-
STERNATOMY
Periphera
CPB

AZIENDA-OSPETTNĚ
AZ.OSP.PD
3 cm skin incision
A
3
In pts >20
Kg BW

Mini-Thoracotomy for ASD

Atrial septal defects

Surgical treatment

MINI- THORACOTOMY

• 2.5-3.5 cm skin incision
• Fourth intercostal space
  MED
  5
  RACTOR
  3 1101051 4
  1/2mm1
  CARD
  AN CARDIOVATIONS
  S JASS
  SOFT Y
  7

Surgical Treatment Results: Multifenestrated ASD II

Atrial septal defects

Surgical treatment
RESULTS 1

24 year-old, F,
Multifenestrated ASD II direct closure

Surgical Treatment Results: Large ASD II

Atrial septal defects

Surgical treatment
RESULTS 2

49 year-old, F, large ASD II patch closure
92
93
94
95
96
97
98
99
100
( cm )

Ventricular Septal Defects Background

VENTRICULAR SEPTAL DEFECTS
Ventricular septal defects

Background

• A ventricular septal defect (VSD) is a hole between the left and right ventricles.
• A VSD may occur as an isolated anomaly or with a wide variety of intracardiac
  anomalies, such as tetralogy of Fallot or transposition of the great arteries.
• Banding of the pulmonary artery as a palliative maneuver was first described in
  1952.
  Decreased left-to-right shunting
  Prevented the development of pulmonary vascular obstructive disease