VENTRICULAR SEPTAL DEFECT Dolly mathew

Development of IVS Muscular septum – primordial IV septum Closure of interventricular foramen& membranous septum formation- Rt & Lt bulbar ridges endocardial cushions

Anatomy

A VSD is a defect in the ventricular septum The ventricular septum consists of an inferior muscular and superior membranous portion The membranous portion -most commonly affected in adults and older children most common congenital cardiac anomalies. 3-3.8 per 1000 live births 30-60% of all newborns with a CHD Prospective studies give a prevalence of 2-5 per 100 births of trabecular VSDs that closes shortly after birth in 80-90% of the cases

Location of VSDs outlet perimembranous Muscular Swiss cheese Inlet

Classification

soto et al Perimembranous(membranous/ infracristal )-70-80% Muscular- 5-20% Central- mid muscular Apical Marginal- along RV septal junction Swiss cheese septum – multiple defects Inlet/ AV canal type-5-8% Supracrital/ subaortic- 5-7%

Types of VSD (kirklin) 1 2 3 4

Hemodynamic classification Restrictive- resistance that limits the shunt at the site of vsd LVSP > RVSP pulm /aortic systolic pressure ratio < 0.3 Qp / Qs<1.4/1 Moderately restrictive - RVSP high, but less than LVSP - Qp/Qs 1.4/2.2 Non restrictive -Shunt not limited at the site of defect RVSP , LVSP, PA , Aortic systolic pressures equal Qp/Qs >2.2 Flow determined by PVR

<1/3rd size of aortic root shunt limited by size of the defect Small VSD in infancy <1/3rd size of aortic root shunt limited by size of the defect Shunt entirely during ventricular systole L R shunt <50% LV output Pulmonary:systemic flow ratio < 2:1

VSD size about half – equal to the size of the aortic orifice Medium sized VSD VSD size about half – equal to the size of the aortic orifice When PA & RVSP are > 50% of systemic arterial pressure mod-large L R shunt develops p218

Large VSD Size equal to the aortic root Equalization of pressures in RV& LV Increased LA pressure opening of foramen ovale

Pathophysiology

During systole, blood is shunted from LV to RV passes through the lungs and re enters the LV via the pulmonary veins and LA causes volume overload on the LV Shunt into the RV elevates RV pressure and volume, leading to pulmonary hypertension. More noticeable in patients with larger defects

pathophysiology Magnitude of shunt: size, PVR Small defect: large resistance occurs at the defect Larger defect: resistance offered by the defect minimum : Shunt depends largely on PVR Lower the PVR, greater the LR Shunt

Enlargement of LA, LV,PA Shunt mainly in systole, when the RV also contracts Shunted blood goes directly to PA

Natural history

Natural history Spontaneous closure :75-85 % all VSDs :35% perimemb ( 1st 6/12) More frequent in small defects Decrease in size with age Inlet & outlet defects donot become smaller /close spont Large & nonrestrictive defects : 10- 15% endocarditis – risk of endocarditis 4-10% for the first 30 years of life High velocity turbulent jet into RV

CHF Large VSDs Mod sized VSDs survive into adulthood Increased rt sided flow  pulmonary vascular disease  Eisenmenger’s physiology if left untreated

Risk factors for decreased survival Shortness of breath, fatigue, DOE,progressive AR Cardiomegaly PASP >60mm Hg/ >1/2 of systemic pressure Good prognosticators Lack of symptoms normal LV size & function small LR shunt normal pulmonary pressures / resistance Intact vasodilator response in pulmonary vasculature

genetic factors Affected father- 2% Affected mother – 6% 25 yr survival for all pts with a VSD 87% Mortality increases with the size of VSD

Mechanisms of closure Growth & hypertrophy of septum around the defect By development of subacute bacterial endocarditis adherence of STL tissue to the margins (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

History & clinical features

History Incidence unrelated to maternal age, sex, birth order 3.3% 1st degree relatives of index patients Among 1st degree relatives with CHD, 1/3rd have vsd 30-60% siblings of index patients have vsd Parents with spontaneously closed vsd can have offspring with vsd

Normal wt gain & development Small VSD - infancy Normal wt gain & development 2-8 wks – tachycardia & tachypnea especially with infection 2-4/6 systolic mr, medium frequency

Large VSD - infancy Infant well in the immediate postnatal period Systolic mr LLSB after 1-7 days develop respiratory distress , in 2-8 wks Cardiomegaly Systolic thrill , along LSB S1 normal/ soft: s2loud narrow split Systolic mr , 2-3/6 intensity at birth, louder & harsh as shunt increases S3 & MDM at apex If the infant survives - subsequent course with persistent dyspnea, sweating, poor feeding, failure to thrive, LRTI

Beyond infancy Arterial pulse- brisk ( vigorous ejection from a volume overloaded ventricle) N pulse in eisenmenger’s - systemic stroke volume maintained Cyanosis & clubbing : eisenmenger’s JVP – N in small defects elevated - Mod restr & nonrestrictive vsd with ccf Precordial bulge ( large shunt 5-6 months) Harrison’s sulcus

Cardiomegaly RV heave in pts with RV vol overload Features of PAH Grade 2-5/6 systolic regurgitant mrLLSB MDM preceeded by S3 Infundibular vsd: early diastolic decrescendo mr of AR

Improvement of symptoms Closing defect findings : soft s2 high frequency & shorter murmur Increasing PVR findings : increased RV pulsations s2 loud, narrow split Infundibular hypertrophy decreased LR shunt, findings : s2 decreases in intensity , crescendo-decrescendo systolic murmur in the ULSB, cyanosis (shunt reversal )

Eisenmenger’s apex by RV Palpable dilated hypertensive pulmonary trunk Loud pulmonary closure sound Very short or no systolic mr of vsd Short pulmonary ejection mr ULSB EDM of pulmonary regurgitation Loud harsh s1 coincident holosystolic mr of TR

ECG small defects unremarkable LA enlargement - Mod restrictive, large LR shunts left axis deviation Inlet vsd /AV septal defect 5% moderately restrictive vsds Ventricular septal aneurysms multiple vsds

LV enlargement in larger defects RVH - Mild or moderate elevation of RV pressure (rsR’ in V4R or V1) - Large VSD, equal ventricular pressures , elevated PVR RVH , RAD - Eisenmenger’s RBBB - Surgical repair

Chest x ray Small defects that were mod restrictive at birth – increased LV size, dilated pulmonary trunk & its branches Large shunts – hyperinflated lungs with flat hemi diaphragms LA enlargement best appreciated in the lateral position Increased PVR, decreases LR shunt, decreases heart size, enlargement of pulmonary trunk& its branches persists Nonrestrictive vsd with elevated but variable PVR- enlargement of all 4 chambers Eisenmenger’s syndrome- oligemic lung fields, RA,LA, LV normal, RV occupies the apex

Echocardiography

Common locations of vsd -2d echo

Echocardiography- doppler CFM-Direction, timing of flow IVG (mmHg) = 4v² PG = LVSP - RVSP LVSP - PG jet = RVsp ≈ Pasp RVSP = cuff systolic BP – 4v² PVR = TRV / TVI in RVOT x 10 + 0.16 High PA pressure, TRV/TVI rvot < 0.2 ; indicates low PVR, elevated pressure secondary to the flow

Cardiac catheterization Hemodynamic assessments cardiac index oximetry quantification of shunt To assess pulmonary vascular resistance Pts with increased PVR, with mod or large LR shunt If PVR is increased, response to 100% oxygen,NO tested

cineangiography Defect best imaged in LAO(70°)cranial (25°) Inlet defect - hepatoclavicular view ( 40°LAO,cranial angulation) Anterior muscular VSD- RAO view Aortography - r/o PDA ,coarctation

Other imaging modalities Cardiac CT- assess VSD anatomy in suboptimal echo imges No information about shunt fraction MRI delineate vsd location& shunt fraction in complex associated lesions

Management

Observation & follow up Small VSDs Medical management Medium sized vsd CCF- treat with diuretics & digitalis, ACEI failure ppted by LRTI- Treat both 2-3 months follow up RV & PA pressures assessed Failure to thrive Surgical Large vsd

drugs digoxin 10-20mcg/kg per day furosemide 1–3 mg/kg per day captopril 0.5–2 mg/kg per day enalapril 0.1mg/kg per day

Indications of surgical intervention Large VSD with pulmonary hypertension VSD with aortic regurgitation VSD with associated defects Failure of congestive cardiac failure to respond to medications

Timing of surgery in VSD <3months - if symptomatic 3-6 months - symptomatic, growth failure, increasing PAH >6 months – primarily based on PAH Wait till 1 yr , if no PAH

ACC/AHA guidelines 2008 for management of adults with CHD

Surgical VSD closure When pt has a history of IE Surgeons with training & expertise should perform VSD closure surgeries Closure of vsd indicated when Qp/Qs 2 or more & clinical e/o LV volume overload When pt has a history of IE

Surgical VSD closure B B IIa IIb III B Closure of vsd is reasonable when LR shunt is present at a Qp/Qs >1.5, with a PA pressure <2/3rd of systemic pressure & pulse volume recording < 2/3rd of SVR Closure of vsd is reasonable when LR shunt is present at a Qp/Qs >1.5, in the presence of LV systolic or diastolic failure Vsd closure not recommended in pts with severe irreversible PAH I IIa IIb III B I IIa IIb III

Interventional Catheterization for VSD Device closure of a muscular vsd may be considered,especially if its remote from tricuspid valve & aorta, if the vsd is associated with severe Lt sided chamber enlargement, or if PAH

VSD closure Direct closure of the defect Surgical mortality <1% Complications – RBBB- direct injury to rt bundle, disruption of purkinje fibers Residual shunt (<5% ) Injuries to tricuspid valve & aortic valve

PA banding PA banding- palliative procedure , when additional lesions make repair difficult Done in multiple VSDs 30-50% of original diameter is narrowed Systolic pressure of 25-30 mmHg beyond the constriction RV/PA pressure gradient > 45 associated with hypoxemia

Post op follow up Every 1-2 yrs VSD & mild PAH& repair after 3 yrs of age- watch for progressive pulmonary vascular disease long term follow up needed

Special situations

VSD with AR Peri membranous VSD with AR - 5-8% Subarterial VSDs – 30% Sagging or herniation of RCC or RCC+ NCC May cause RVOT obstruction Due to morphological abnormality of valve LV volume – regurgitant volume & shunt volume VSD murmur dates from infancy AR murmur appears (5-9 yrs)

LV  RA shunt Gerbode defect Shunt begins inutero Usually restrictive Rightward thoracic position of murmur X ray – RA enlargement disproportionate to the size of pulmonary trunk

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