PATHOPHYSIOLOGY ,HEMODYNAMICS AND NATURAL HISTORY OF VSD

1. PATHOPHYSIOLOGY,
HEMODYNAMICS
AND NATURAL
HISTORY OF VSD

3. EMBYOLOGY OF IVS

5.  Parts of IVS :
- Membranous septum: Ventriculoatrial + Interventricular components
- Muscular septum: Inlet septum(lightly trabeculated)
Trabecular septum(heavily trabeculated)
Infundibular septum(non-trabeculated)

8.  VSD - m.c. congenital malformation of the heart(excluding BAV) – 20-30% of children in India with CHD
- Saxena, et al .: Indian Guidelines for Management of CHDs - Annals of Pediatric Cardiology / Volume 12 / Issue 3 / Sept-Dec 2019
 Classification of VSD :
- initiated by Soto et al in 1980
- further modified by Anderson, VanPraagh, Casteneda and others

9. Morphologic Classification of Ventricular Septal
Defect

10. PATHOPHYSIOLOGY
Left  Right shunt
Large pulmonary flow(↑Qp)
LA/LV Enlarged (Stage I)
↑Qp with PAH
Biventricular Enlargement (Stage II)
Severe PAH(Muscle hypertrophy + Intimal proliferation and fibrosis)
Shunt reversal (R L) LA/LV Normal size (Stage III)

11. Factors that influence the hemodynamics of VSD
 The size of the VSD
 Pressure gradient across RV/LV
 Pulmonary vascular resistance
 VSD may not be apparent at birth because of the nearly equal pressures in the right and left
ventricles and a lack of shunting.
 With increasing shunt corresponding to the increasing pressure difference between the ventricles,
these defects become clinically apparent.

13. RVSP PA PVR SHUNT HEMODYNAMICS
RESTRICTIVE VSD
< 1/3rd of Ao Orifice
NORMAL NORMAL NORMAL SMALL(1.5 : 1)
SYSTOLIC
NORMAL (LV PRESSURES are not
transmitted to RV)
MOD.RESTRICTIVE
VSD
1/3rd - 3/4th of Ao
Orifice
> NORMAL SUB-
SYSTEMIC
LOW
VARIABLE
MODERATE(1.5-2.2 : 1)
SYSTOLIC,DIASTOLIC
(LV VOO)
LV -↑VOO
RV -↑POO
NON-RESTRICTIVE
VSD - HIGH &
VARIABLE PVR
≥ 3/4th of Ao Orifice
RVSP ≈ LVSP
COMMON
CHAMBER
PA ≈ Ao HIGH
VARIABLE
PERSISTENTLY LARGE
(>2.2 : 1)
PVR dependent FLOW
LV -↑↑↑VOO
-SYSTOLIC DYSFUNCTION
RV -↑↑↑POO(SYSTEMIC AFTERLOAD)
PVR-HIGH
NON-RESTRICTIVE
VSD – HIGH &
PVR
RVSP > LVSP PA > Ao HIGH
FIXED
RIGHT LEFT EISENMENGERISATION of pulmonary
vasculature

14.  Restrictive VSD - Small (≤1.4 : 1) shunt due to significant pressure gradient between LV
and RV(pulmonary-to-aortic systolic pressure ratio < 0.3)
 Moderately restrictive VSD - moderate shunt (Qp/Qs of 1.4 to 2.2 : 1) with a
pulmonary-to-aortic systolic pressure ratio <0.66
 Large or nonrestrictive VSD - large shunt (Qp/Qs > 2.2) and a pulmonary-to-aortic
systolic pressure ratio >0.66.
 Eisenmenger VSD has a systolic pressure ratio of 1 and Qp/Qs less than 1 : 1 or a net
right-to-left shunt.

15. CLINICALLY
 RESTRICTIVE VSD :
- Asymtomatic and lives long
- Systolic murmur
- CXR and ECG may be completely normal
- IE is a usual risk d/t effect of shunt jet on STL
- More chances of Spontaneous closure

16.  MODERATELY RESTRICTIVE VSD :
- Symptomatic d/t ↑Qp – Easy fatiguability
Cough while feeding
Excessive Sweating
Restless on recumbent position and poor sleep
Gets better with Isotonic exercise d/t fall in SVR
- Delayed onset of murmur because delayed fall in PVR and can lead to CCF
- Thrill and Hyperactive precardium

17. - CXR shows Cardiomegaly, increased pulmonary vascularity with prominent PA segment is suggestive of
significant left-to-right flow.
- ECG shows LV VOO, LVH, LAE or BiVH
- Risk of IE and CCF because of LV VOO
- Rarely reaches adulthood, if not intervened

18.  LVH – Voltage criteria ( S in V1 + R in V5/V6 > 35mm or R in V5/V6 > 25mm)
 Left Axis Deviation
 LV strain pattern – ST depressions in V5/V6 with corresponding ST elevations in V1/V2/V3,
U waves in V1-V4

19.  Radiological features : Based on grades of PAH
Grade Mean PA
pressure
Systolic PA
pressure
Pacifico classification
(Ratio of PA systolic &
systemic systolic)
Radiological features
Mild 25-40 25-49 1/3-1/2 MPA dilatation
Moderate 41-55 50-69 1/2- 2/3 MPA dilatation
Rt Descending PA dilatation (>14-16 mm)
Mild peripheral pruning
Severe >55 >70 >2/3 Severe MPA dilatation ( +calcification)
Severe Hilar prominence
Severe pruning
RV enlargement ( Loss of retrosternal space)

20. MPA dilatation
Rt Descending PA dilatation
Mild peripheral pruning

21. Severe MPA dilatation ( +calcification)
Severe Hilar prominence
Severe pruning
RV enlargement ( Loss of retrosternal space)

22.  Non-Restrictive VSD :
- Present in infancy with CCF
- Symptomatology - Poor growth and development
Laboured breathing
Frequent URTI
Difficulty feeding and diaphoresis
Dyspnoea and irritability on lying down-improves with sitting

23. Suck-Rest-Suck cycles
Wakes up and
starts feeding
Feeds short of
satisfaction d/t
dyspnoea
Exhausted
Falls asleep
Hungry infant

24. EISENMENGER’S SYNDROME
 Regulation of shunt through a Non-restrictive VSD with amelioration of symptoms is almost always a
result of rise in PVR    Eisenmenger’s syndrome
 Victor Eisenmenger first identified and published in 1897”Congenital Defects of the Ventricular
Septum”
 Maude Abbott, a Canadian physician, named the condition as Eisenmenger’s complex(1936)
 Paul Wood, a British Cardiologist, defined this pulmonary HTN with reversed shunt as Eisenmenger’s
syndrome(1958)

25. It is a multisystem disorder involving :
 Red cell mass, Hemostasis
 Systemic vascular bed
 CNS
 Bilirubin kinetics
 Coronary circulation and Myocardium
 Uric acid Clearence
 Kidney
 Respiratory system
 Digits and long bones
 Gynecologic endocrinology

26. PATHOPHYSIOLOGY
Right  Left shunt
Cyanosis + ↓Tissue Oxygenation
Arterial Hypoxemia
Adaptive Erythrocytosis
↑ Hematocrit
↑ RBC turnover & Hemolysis
Indirect Bilirubinemia+Gall Stones
EXTRAMURAL CORONARY ECTASIA
Iron Deficiency(≤ 4 yrs)
CEREBRAL VENOUS THROMBOSIS
Paradoxical Emboli
STROKE
Thrombocytopenia(≥ 50yrs)
+
Abnormal vWF
Muco-cutaneous bleeding
Easy Bruising, Epistaxis,
Gingival bleeding, Menorrhagia,
PULM.HEMORRHAGE(MOST SERIOUS)
SUDDEN DEATH
↑ Shear stress in blood vessels
↑ NO,PGs
SYSTEMIC VASCULAR DILATION
SYNCOPE
Dilation of Hilar Arterioles +
Glomerular Capillaries
↑ PGDF,TGF β
PROTENURIA + GLOMERULOPATHY
Remodelling of
Coronary Microvasculature
↓ CORONARY VASCULAR
RESERVE
CLUBBING+HYPERTROPHIC
OSTEOARTHROPATHY
Hyperuricemia
Renal Calculi,Gouty Arthritis

28. GERBODE DEFECT ~0.08% of CHD
 LV–RA communications - congenital >> acquired-Post-MI, trauma, surgical, IE
 First mentioned in 1838 by Thurnam J. On aneurisms of the heart with cases(Autopsy report)
 First diagnosed by Kirby et al in a living patient directly on O.T table,18 Jan.1956 and closed it
successfully through right thoracotomy by inflow occlusion + Hypothermia
 In 1958, Gerbode et al successfully performed surgery on five patients with this anomaly and named
it Gerbode defect
 Caused by an anatomic deficiency of the membranous septum
The Gerbode Defect: Left Ventricular to Right Atrial Communication—Anatomic, Hemodynamic, and Echocardiographic Features - SILBIGER, ET AL - ECHOCARDIOGRAPHY: A Jrnl.
of CV Ultrasound & Allied Tech - 2009

29. Modified Riemenschneider and Moss Classification
1/3rd cases associated with other anomalies – most common being ASD(PFO/Secumdum ASD)

30. Aneurysmal transformation – Wu et al
Morphogenetic process for Infra-valvular shunts

31. LV  RA
Large Systolic ∆ + Small Diastolic ∆
SHUNT depends on Size & PVR
Large Shunt
RA/RV Enlarged
↑ RV preload  LV
LA/LV Enlarged
Severe PAH may develop but uncommon
Biventricular overload
Acute/Chronic Heart Failure
RL shunt caused by
(1) Diastolic flow reversal across defect (RALV)
(2) continuous RALA shunt across PFO/OS-ASD

32.  Asymptomatic to severe heart failure
 Characteristic murmur : loud, harsh pansystolic, Grade III–VI, getting softer with inspiration, radiationing
posteriorly and often associated with a thrill along the left sternal border –
SEA GULL MURMUR
 Raised JVP, liver pulsation, and peripheral edema indicating RHF

34. NATURAL HISTORY
 Refers to the progression of a disease process in an individual over time, in the absence of treatment
 Spontaneous closure
 Premature death
 Pulmonary vascular disease
 Development of aortic incompetence
 Bacterial endocarditis
 Development of infundibular PS

35. Spon Closure Rate
 Rate of spontaneous closure depends on SIZE and LOCATION of VSD
 Muscular VSDs are more likely to close spontaneously, especially if they are not large
 Small VSDs have a >50% chance of spontaneous closure by 5 years
>80% chance by adolescence
Saxena, et al .: Indian Guidelines for Management of CHDs - Annals of Pediatric Cardiology / Volume 12 / Issue 3 / Sept-Dec 2019

36.  Perimembranous VSDs (accounted for most of the moderate to large VSDs)
39% required surgical closure
29% closed spontaneously by 6 years of age
 Muscular VSDs – 3% required surgical closure
69% closed spontaneously by 6 years of age
The natural history of ventricular septal defects - S W Turner, S Hunter, J P Wyllie

37.  Most of the VSDs(~75%) close spontaneously within the first two years of life
 Afterwards, the chance of spontaneous closure diminishes remarkably but extend till adolescence.
 Muscular and membranous VSDs with diameters < 6 mm have the best chance of spontaneous closure
Spontaneous closure of ventricular septal defects in the first year of life - Lin MH et al - J Formos Med Assoc. 2001

38. Age-wise Probability of Spontaneous closure of Small VSD :
 34% by 1 year
 67% by 5 years
 75% by 10.5 years

39. Mech of closure
 Adherence of tricuspid leaflet , or chordal tissue to the edges of VSD.
 Growth & hypertrophy of septum around the defect
 Negative pressure effect exerted by a high velocity stream flowing through the
defect
 Ventricular septal aneurysm
 Prolapse of aortic cusp
 Intrusion of a sinus of Valsalva aneurysm

40. VSD unlikely to close
 Sub-pulmonary
 Juxta-arterial
 Inlet
 Mal-aligned
 Gerbode defect
 Very large
Saxena, et al .: Indian Guidelines for Management of CHDs - Annals of Pediatric Cardiology / Volume 12 / Issue 3 / Sept-Dec 2019

41. Premature death
 About 10% of children with large VSDs die in 1st year, primarily due to congestive heart failure Saxena,

42. Pul vascular disease
In the historic series of Dr. Paul Wood, 52% of patients with large VSD developed irreversible pulmonary
vascular disease with the onset in infancy in four-fifths of them
 Common with Subpulmonary VSD
 Chances of development of PVD with age (PVR > 8 U.m2)
YR Probability
10 yr 10 %
20 yr 50 %
30 yr 80 %
40 yr 100 %

43. Updated clinical classification for PAH associated with
CHD, Nice, France, 2013.

44. Development of AR – seen in 6%
Mechanism :
 Lack of support to aortic annulus : Diastolic prolapse of unsupported cusp.
 Venturi effect : Cusp is sucked during systole
More with Subaortic/ Juxtaarterial VSD and Smaller VSD

45. Bacterial endocarditis : 2-3 decade, on right side
 Among congenital heart disease, VSD is the most frequent anomaly in right- sided IE
 One of the important indications for VSD closure
 The incidence of IE among ventricular septal defects (VSD) was 0.2%- 2%
 Baumgartner et al.Guidelines for the management of grown- up congenital heart disease (new version 2010). Eur Heart J. 2010.

46. Development of infundibular PS : 13 % pts
Gasul Syndrome :
 VSD with acquired PS, Gasul found that about 5- 10 % VSD patients develop PS in follow up(JAMA
1957, circulation 1963)
 Progressive right ventricular outflow tract obstruction (Gasul phenomenon) may develop in 13% and
aortic regurgitation (AR) in 6% of patients