Ventricular Septal Defects - A short Review....

1. Ventricular Septal Defects – A
Review

2. Ventricular Septal Defect
• Henri Roger was the first man to
describe a ventricular septal defect,
in 1879 he wrote:
“A developmental defect of the heart occurs
from which cyanosis does not ensue in spite
of the fact that a communication exists
between the cavities of the two ventricles
and in spite of the fact that the admixture of
venous blood and arterial blood occurs. This
congenital defect, which is even compatible
with long life, is a simple one. It comprises a
defect in the interventricular septum”

3. .
• Roger in 1879 - first described
• Eisenmenger – 1897 - autopsy finding
• Pathophysiology by Abbott (1936) & Selzer (1949)
• 1952 – Muller and Danman- pulmonary artery band
• 1954 – Lillehei and associates – First vsd repair
• 1961 – Kirklin - Repair of VSD in infants
• 1987 – Device closure by Lock et al with Rashkind double umbrella
HISTORICAL ASPECT

4. .
• VSD occurs during the first 8 weeks of fetal life
• 3 components – Interventricular muscular partition
• - Endocardial cushions
• - Bulbar ridges that separate great vessels
EMBRYOLOGY

5. Four cushions (AVC) have
developed at the A/V junction; the
superior and inferior cushions will
meet to divide the AV orifice (AVO)
into the tricuspid and mitral valves.
The inferior septal crest (VS)
will aim to meet the divided valve
where the cushions fuse.

6. Formation of IV septum
 IV septum moves upwards
from the floor of the
bulboventricular cavity,
division into right and left
halves. It meets fused AV
cushions and partially fuse
with them.
 Two ridges right and left arise
in conical upper part of
bulboventricular cavity which
fuse with each other to form
bulbar septum.
 Gap persists between the two-
filled by proliferation of tissue
from the AV cushions.

7. Membranous IV septum
• Ant part separates
right and left
ventricles.
• Post part separates
right atrium and left
ventricle.
• This is because the
interatrial and
interventricular
septum don’t meet
in the midline.

8. Classification by Soto et. al

9. Ventricular Septum
• The membranous septum is small and is located at the base of the
heart between the inlet and outlet components of the muscular
septum and below the right and noncoronary cusps of the aortic
valve.
• The septal leaflet of the tricuspid valve divides the membranous
septum into 2 components, the pars atrioventricularis and the pars
interventricularis.
• Tricuspid, aortic, and mitral continuity is via this central fibrous
body.
• True defects of the membranous septum are surrounded by fibrous
tissue without extension into adjacent muscular septum.
• Defects that involve the membranous septum and extend into 1 of
the 3 muscular components are called perimembranous,
paramembranous, or infracristal.

10. • The muscular septum is a nonplanar structure that can be divided
into inlet, trabecular, and infundibular components.
• The inlet portion is inferioposterior to the membranous septum.
• It begins at the level of the atrioventricular valves and ends at their
chordal attachments apically.
• An inlet VSD has no muscular rim between the defect and the
atrioventricular valve annulus.
• Defects in the inlet muscular septum are called inlet VSDs.
• Another classification scheme divides the inlet septum into the
atrioventricular septum and the inlet septum.
• Defects in the inlet septum can include abnormalities of the
tricuspid and mitral valves that are called common atrioventricular
canal defect.

11. • The trabecular septum is the largest part of the
interventricular septum.
• It extends from the membranous septum to the apex and
superiorly to the infundibular septum.
• A defect in the trabecular septum is called muscular VSD if the
defect is completely rimmed by muscle.
• The location of defects in the trabecular septum can be
classified as anterior, midmuscular, apical, and posterior, as
proposed by Kirklin et al.

12. • The infundibular septum separates the right and left
ventricular outflow tracts.
• On the right side, it is bordered by the line from the
membranous septum to the papillary muscle of the conus
inferiorly and the semilunar valves superiorly.
• The right side of the infundibular septum is more extensive.
• Defects in the infundibulum are called infundibular, outlet,
supracristal, conal, conoventricular, subpulmonary, or doubly
committed subarterial defects.
• A deficient infundibular septum may be present with
corresponding degrees of malalignment.

13. • Many defects involve 1 component of the ventricular septum.
• Perimembranous defects extend into the adjacent muscular septum
and have been called perimembranous inlet, perimembranous
muscular, and perimembranous outlet on the basis of the
extension.
• Abnormalities of the tricuspid valve adjacent to these defects can
be in the form of an aneurysm partially or completely occluding the
defect.
• The tricuspid valve can have perforations, clefts, or commissural
abnormalities.
• There can be straddling of the mitral valve in the presence of
infundibular defects.
• Inlet defects can involve malalignment of the atrial and ventricular
septa.

14. Location of various types of ventricular septal defect as
viewed from the right ventricular aspect of the septum

15. The Ventricular Septum and related Defects
1. Membranous
2. Outflow
3. Trabecular
septum
4. Inflow
5. Subarterial /
Supracristal

16. Nomenclature / Classification
KIRKLIN Classification
• TYPE I-
Conal,Supracristal,
Infundibular,Subarterial
• TYPE II – Perimembranous
• TYPE III – Inlet / AV canal
type
• Type IV – Muscular

17. Classification
Anderson et al
• Perimembranous
• Muscular
• Doubly committed Juxta
arterial defects
• Juxtatricuspid
Van Praagh et al
• AV canal type
• Muscular VSDs
• Conoventricular (Proximal
Conal)
• Distal Conal(Outlet septum)

18. Lesion Size
• Restrictive VSD
– < 0.5 cm2 (Smaller than Ao valve orifice area)
– Small L to R shunt
– Normal RV output
– 75% spontaneously close < 2yrs
• Non-restrictive VSD
– > 1.0 cm2 (Equal to or greater than to Ao valve orifice area)
– Equal RV and LV pressures
– Large hemodynamically significant L to R shunt
– Rarely close spontaneously

19. Based on size
1) Large : > 2/3rd of aortic annular size,
or > 1cm2/m2 of BSA
Peak RV sys = LV sys pressure(Difference < 20 mm of Hg)
PA/Ao Systolic Pressure > 0.66
Qp/Qs > 2.2
2) Moderate : 1/3rd to 2/3rd the size of aortic annulus,
or >0.5-1 cm2/m2 of BSA
RV pressure to ½ of LV (Difference > 20 mm of Hg)
PA/Ao Systolic pressure < 0.66
Qp/Os>2.0
3) Small : One third of aortic annular size, or < 0.5 cm2/m2 of BSA
insufficient size to raise RV pressure,
PA/Ao systolic pressure <0.3
& Qp/Qs < 1.75

21. Physiology
• The primary anatomic variable that determines the physiologic state of the
patient is defect size.
• In small or medium-sized VSD, the size of the defect limits the left-to-right
shunt; however, in large defects (those approximately the size of the aortic
orifice), there is essentially no resistance to flow across the VSD, and the
relative resistances of the systemic and pulmonary circulations regulate flow
across the defect.
• Pulmonary vascular resistance determines the magnitude of the left-to-right
shunt in infancy.
• Following birth, the small muscular pulmonary arteries normally change from
the fetal state, with a small lumen and a thick medial muscle layer, to thin-
walled structures with increased lumen size.
• The normal rate of decline in pulmonary vascular resistance that accompanies
these changes is such that the right ventricular pressure is near adult levels
within 7 to 10 days.
• In the presence of large VSDs, the rate of this process is delayed, and the
increased pulmonary resistance prevents massive shunting of blood through
the lungs.
• Elevation of left atrial pressure (pulmonary venous pressure) plays an
important role in maintaining this phase of pulmonary vascular constriction.

23. Spontaneous closure
• The incidence varies considerably.
• It is reported as 50-75% for restrictive perimembranous and
muscular defects observed from birth.
• Moderately restrictive and non-restrictive defects also close
spontaneously but incidence is low, around 5-10%.
• Most defects destined to close do so within first year of life,
with approx 60% closing by 3 yrs and 90% by 8 yrs of age.
• Multiple defects have a strong tendency to close
spontaneously.

24. Mechanism of spontaneous closure
• Adherence of the septal tricuspid leaflet tissue to the margin
• Prolapse of the aortic cusp
• Intrusion of sinus of valsalva aneurysm
• Growth of the septum

25. Clinical Features
• VSDs can be detected by auscultation.
• The murmurs are typically described as holosystolic or pansystolic.
• The grade of murmur depends on the velocity of flow; the location
of murmur is dependent on the location of the defect.
• Smaller defects are loudest and may have a thrill.
• Muscular defects can be heard along the lower left sternal border
and may vary in intensity as the defect size changes with muscular
contraction throughout systole.
• Infundibular defects shunt close to the pulmonary valve and can be
heard best at the left upper sternal border.
• Perimembranous defects may have an associated systolic click of a
tricuspid valve aneurysm.

26. • In the setting of low pulmonary vascular resistance, larger defects
have murmurs of constant quality that vary little throughout the
cardiac cycle and less commonly have an associated thrill.
• These defects will have a corresponding increase in mitral flow,
resulting in a diastolic rumble at the apex.
• There may be evidence of left ventricular volume overload on
palpation of the precordium with a laterally displaced impulse.
• Elevated pulmonary pressure causes an increase in the pulmonary
component of the second heart sound.
• Large defects with no shunt and defects with Eisenmenger
physiology and right-to-left shunt often do not have a VSD murmur.
• Patients with Eisenmenger syndrome often are cyanotic with
clubbing.
• They have a right ventricular heave on palpation of the precordium
and a loud pulmonary component of the second heart sound.
• A VSD murmur may not be present.

27. Electrocardiography
Moderately Restrictive VSD

28. Non-Restrictive VSD

29. Eisenmenger Syndrome

30. Chest X-rays
Restrictive Perimembranous VSD

32. VSD with Eisenmenger

33. Echocardiography
• Two-dimensional echocardiography, coupled with Doppler
echocardiography and color flow mapping, can be used to
determine the size and location of virtually all VSDs.
• Also, Doppler echocardiography can provide physiologic
information regarding right ventricular and pulmonary artery
systolic pressures and the interventricular pressure difference.
• VSD sizes can be measured in absolute terms from the two-
dimensional image.
• Doppler and color flow echocardiography have been used to
demonstrate the shunting patterns in VSD.

39. Cardiac Catheterization
• It is performed to
– document the number of defects
– evaluate the magnitude of shunting
– estimate pulmonary vascular resistance
– estimate the workload of the two ventricles
– document or exclude the presence or absence of associated defects
– provide the surgeon or interventional cardiologist with a clear
anatomic picture of the location of the defect (or defects) in those
patients needing intervention.

40. Clinical Course and Prognosis
• In general, long-term survival is good.
• Patients with small defects have an excellent prognosis, albeit with
a small risk of endocarditis, aortic valve insufficiency, and late
cardiac arrhythmia.
• A large number of these defects close spontaneously, this number
approaches 75% to 80%, with most closing in the first 2 years of life.
• Endocarditis is a lifelong risk in unoperated patients
(18.7 per 10 000 patient-years) and those with residual defects.
• Proper prophylaxis and periodic follow-up are indicated.

41. • Patients with moderate-sized defects may develop large left-
to-right shunts in infancy, and their main risk is heart failure
between 1 and 6 months of age.
• Usually, this group can be managed medically without surgical
intervention during infancy.
• If catheterization demonstrates that the right ventricular
pressure is normal or only mildly elevated, most of these
patients will have decreasing shunts over the first year of life
and never require operative intervention.
• Approximately 15% to 20% of these patients continue to have
large left-to-right shunts following infancy. If the clinical signs
indicate that the shunt remains large, operation is
recommended.

42. • Patients with large defects are the most difficult to manage
because of the dangers of mortality in the first year of life
owing to heart failure and associated pulmonary infections as
well as the problem of development of elevated pulmonary
vascular resistance.
• Patients who respond poorly to medical therapy and who
continue to show signs of a large left-to-right shunt with
growth failure and pulmonary infection should undergo
surgery within the first year of life.

43. • The development of pulmonary vascular disease is
uncommon in patients who undergo surgery before 2 years of
age but may occur in as many as a quarter of patients with
large defects who undergo surgery after 2 years of age.
• In addition, there was a progressively higher frequency of
increased postoperative pulmonary resistance in the older
patients.
• These data indicate that the pulmonary vascular obstructive
changes can occur as early as 2 years of age.
• Generally, infants with VSD and increased pulmonary artery
pressure should undergo repair between 3 and 12 months of
age.

44. Management
• The management of VSDs varies depending upon several
factors including -
– The size of the defect
– The likelihood of spontaneous closure or decrease in size over time
– The involvement of one or more cardiac valves
– The anticipated difficulty and effectiveness of surgical closure

45. Small VSD
• Infants who continue to have a murmur, but are otherwise
asymptomatic and growing well should be seen again by the
pediatric cardiologist at approximately 12 months of age.
• They are expected to remain asymptomatic and to experience
possible disappearance of the murmur over time.
• If at the 12-month visit, the murmur is gone, repeat
echocardiogram is not necessary, unless clinical concerns arise (ie,
endocarditis).
• However, some physicians opt to obtain an echocardiogram to
verify closure.
• If there is no evidence of a defect on examination or
echocardiography, no additional follow-up is necessary.
• Children in whom closure is associated with aneurysmal tissue
should be followed every two to three years to monitor the possible
development of obstruction to right ventricular outflow.

46. Moderate to large VSD
• Infants with moderate to large VSDs usually become symptomatic
within the first months of life as pulmonary vascular resistance
(PVR) declines.
• The frequency of cardiology follow-up in these infants depends
upon the progression of symptoms and the response to medical
therapy.
• The primary care provider should monitor the infant for
manifestations of heart failure (eg, poor weight gain, tachypnea,
tachycardia) and for changes in physical examination that should
prompt an earlier appointment with the cardiologist.
• These include a hyperdynamic precordium, displacement of the
cardiac apex outside the midclavicular line, increased intensity of
the second component of the second heart sound, or the onset of a
diastolic murmur.

47. • Medical therapy, should be instituted in infants with obvious cardiac
failure.
• The goals of therapy include:
– relief of symptoms,
– normalization of growth,
– minimization of frequency and severity of respiratory infections
• The symptoms of children with heart failure from left-to-right
shunts can improve with medical therapy, postponing and possibly
avoiding the need for surgical correction.
• However, despite maximum medical management, 50 percent of
patients with moderate to large VSDs continue to have tachypnea
and or/failure to thrive.
• These patients undergo surgical closure in infancy, preferably before
six months of age.

48. Eisenmenger syndrome
• The patient with Eisenmenger syndrome needs very
specialized care at centers, with trained personnel capable of
managing myriad medical problems.
• Arrhythmias, endocarditis, gallstones, gouty arthritis,
hemoptysis, pulmonary artery thrombosis, and symptomatic
hypertrophic osteoarthropathy are frequently seen.
• Pregnancy is poorly tolerated and many believe
contraindicated in this disorder.
• Echocardiography and magnetic resonance imaging are used
to evaluate right ventricular function.

49. SURGICAL MANAGEMENT
• Decisions regarding surgery, and the type of surgical
procedure, must be made on a case by case basis.
• Factors to consider include
– the severity of failure
– likelihood of progression of pulmonary vascular disease
– other complications
– likelihood of reduction in size or spontaneous closure of the defect
– the morbidity and mortality of the procedure in young infants in the
center where the surgery is to be performed

50. Indications
• Infants <6 months (<3 months for those with trisomy 21) who have
uncontrolled heart failure despite maximal medical and dietary
interventions or who have pulmonary hypertension.
• Children with a persistent significant shunt (Qp:Qs >2:1) with
elevated PA pressures should undergo surgical repair.
• Children with a persistent significant shunt and normal PA pressures
may be considered for surgical closure. However, the optimal
management remains controversial. A conservative nonsurgical
approach for these patients consists of annual follow-up for
assessment of change in clinical status and estimation of PA
pressure by echocardiogram and examination.
• Subpulmonic and membranous defects, regardless of size, with
aortic regurgitation should be surgically corrected before the aortic
valve is permanently damaged. The decision to close small defects
with aortic valve prolapse without aortic regurgitation is
controversial.

51. Intracardiac repair
• Direct patch closure of the defect under cardiopulmonary
bypass and/or deep hypothermia is the procedure of choice in most
children and at most centers.
• The approach (eg, transatrial, right ventriculotomy, apical
ventriculotomy) depends upon the type and location of the defect,
as well as the preference of the surgeon.
• Whenever possible, ventriculotomies should be avoided.
• Current surgical mortality is <3% for single VSDs and VSDs with
aortic valve insufficiency (AI), and about 5% for multiple VSD repair.

52. • Most perimembranous and inlet defects are repaired using a
transatrial surgical approach (the septal leaflet of the tricuspid
valve may need to be detached to repair some inlet defects).
• Defects in the outlet septum can be repaired through the
pulmonary valve.
• Multiple muscular defects, especially if near the apex, pose a
difficult operative problem.

53. Transcatheter closure
• The era of percutaneous VSD closure has evolved significantly
since Lock et al. initial description of the procedure.
• Percutaneous VSD closure is now an acceptable alternative to
surgical closure of VSDs with very high procedural success
rates.
• The overall rate of residual shunting is quite small and
decreases with time with the vast majority of residual shunts
being trivial or small and not hemodynamically significant.
• Continued improvements in both the devices available as well
as the technique of implantation are likely to result in
decreases in complication rates and further improvements in
procedural outcomes.

54. Conclusions
• It is one of the most common CHD.
• All cases of suspicion should be evaluated by cardiologist.
• Majority of VSD’s require only close follow up because of tendency
to close spontaneously.
• Echocardiography remains the central and most important tool for
evaluation.
• Large VSD’s should be effectively managed for heart failure and
early surgery to be considered.
• Newer techniques and hardware are allowing more and more
device closures with excellent success rates.