Congenital Heart Disease - Students

8/13/2019 Congenital Heart Disease - Students

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Congenital Heart Disease

Cindy Chan, MD


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Tetralogy of Fallot

Coarctation of the aorta

Hypoplastic left heart syndrome

D-transposition of the great arteries

Total anomalous pulmonary venous connection

Atrial septal defect Ventricular septal defect


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In utero, placenta (with low resistance) providesoxygenation, and sends oxygenated blood (only 10% tolungs) to the body, bypassing lungs via patent foramenovale (PFO) and ductus arteriosis (DA)

At birth, lungs mechanically expand and baby takes firstbreath (vessels mechanically not compressed & O2 potentpulm vasodilator - so pulm vascular resistance decreases (ittakes 6-8 weeks for pulm resistence to go down to adultlevels))

When placenta taken out, systemic vascular resistenceincreases. (pulm and systemic resistance about same attime of birth). DA closes first 24-48 hrs, FO only reallyfunctionally closes (2-3 months to close, if at all)


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Cyanosis

in adults - blue lips & nailbeds

in babies - also blue around mouth & eyes

in dark skinned - check tongue & mucous

membranes


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No respiratory distress

pOa2 in utero is 25, but newborn pOa2 is 30

(adults are in the 80s)

there is enough oxygenation to meet tissue

demands


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Single S2

pulm valve abnormal (only hear aortic

closure)


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Hypoxemia

normal pH, pCO2 normal, pOa2 20-40s

(discomfort if down to teens)


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Pulmonarystenosis

Ventricular

septal defect

R ventricular

hypertrophy

Overridingaorta

Tetralogy of Fallot


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Physiology

Malaligned VSDblocked RV outflowtract and anteriorly displaced aortapulm

stenosishigh pressure in RV (where RVpressure = LV pressure) RVhypertrophy

Blood takes path of least resistance

Blue blood from RV to LV


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Tetralogy of Fallot


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Medical Management

PDA VERYimportant to move blood from L side (aorta)to the R side (pulmonary artery)

Prostaglandin E1 (PGE1) maintains or restores patency of

the ductus arteriosus Treatment of hypercyanotic spells focuses on decreasing

pulmonary vascular resistance (administration of oxygen,morphine) and increasing systemic vascular resistance (toincrease blood flow to lungs)

Decrease pulm resistance (O2, morphine)

Increase systemic resistance (knee-chest position, volumeexpansion, IV phenylephrine)


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Surgical Management - definitive

Closing the ventricular septal defect with a

patch (made of Daykron)

Enlarging the right ventricular outflow tract

incision across the pulmonary valve annulus

and placement of a patch of synthetic material

with resulting pulmonary regurgitation (butwell-tolerated if TV competent)


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Gray color - poor circulation to body

Tachypnea - increased blood volume in lungs

Differential pulses - disease like coartaction ofaorta

Single S2 - abnormal AV (sharp & distinct c/w

normal muffled S2 in newborns)

RV heave - extra RV work

ABG abnormalities - low pH, pO2 in 40s


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Coarctation of Aorta


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almost always located just beyond the

origin of the left subclavian artery and

across from the insertion of the ductusarteriosus

approximately 80% of patients with

coarctation have a bicuspid aortic valve


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Physiology

Coarctation of the aortaincreased LV

afterload of the left ventricleLV

hypertrophyCCF Proximal to coarctationincrease in BP

Distal to coarctationdecrease in BP

diminished and delayed femoral pulses


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Coarctation of the Aorta


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Post-stenotic

dilitation


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Medical Management

Also, inotropes for LV dysfunction and

diuretics for congestion


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Surgical Management


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Hypoplastic Left Heart Syndrome

aortic valve - hypoplastic, stenotic or atretic

mitral valve - hypoplastic, stenotic, or atretic

left ventricle - hypoplastic or absent

ascending aorta - typically hypoplastic


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Physiology

Nonfunctional LV pulm venous return

passes across ASD or PFO into RA

blood mixes with systemic venous returnRV pumps mixed blood to both lungs and

body (via PDA)

Flow across PDA dependent on pulmresistance vs. systemic resistance


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1. Hypoplastic ascending aorta and aortic arch.

2. Hypoplastic left ventricle.

3. Large patent ductus arteriosus supplying the only source of blood

flow to the body.4. Atrial septal defect allowing blood returning from lungs to reach

the single ventricle.


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Medical Management

PGE1

Increase pulmonary vascular resistance (viacarbon dioxide, inhaled nitrogen)

Decrease systemic vascular resitance (viaNitroprusside)

Avoid agents that decrease pulmonary vascularresistance (supplemental oxygen,

hyperventilation) Avoid agents that increase systemic vascular

resistance (pressors)


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Surgical Management

Fatal without surgical intervention

3 separate surgical procedures

Right ventricle and pulmonary artery are

utilized to pump to the systemic circulation


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Single S2 - position of great vessels (softer,

parallel/posterior pulm sound)

Hypoxemia - p02 in teens to 20s

D T iti f G t A t i


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D-Transposition of Great Arteries


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Physiology

2 parallel circulations

Blue blood (desaturated) from SVC/IVCto RAto RVto aortaeventually, SVC/IVC

Red blood (oxygenated) from lungsto pulmveinsto LAto LVto pulm artery

back to lungs

Mixing can occur through an atrial defect (ASD orPFO), a VSD or a PDA (best source is atrial defectbi-directional mixing)


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Transposition of Great Arteries


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Medical Management

The use of PGE1 is controversialshunting

in PDA unidirectional (aorta to pulm artery)

Also, extra blood flow going to the lungsresults in more blood flow returning to the left

atrium and distention of LA, which can close

foramen ovale


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Surgical Management


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Surgical Management


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Total Anomalous Pulmonary Venous Connection


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Total Anomalous Pulmonary Venous Connection

Supracardiac TAPVC


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Supracardiac TAPVC


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Physiology

obstruction to pulmonary venous flowbackpressure to pulmonary capillary bedpulmonary edema

no blood flow entering left atrium directly

all flow arrives in the left heart via right to leftshunting across the atrial communicationmarked hypoxemia


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Medical Management

Very little can be done medically

Positive pressure ventilation

Diuretics

PGE1 contraindicated

Widened PDA would increase pulmonary blood

flow and exacerbate the pulmonary venouscongestion


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Surgical Management

anastamose the common pulmonary vein tothe to the back of the left atrium with the

widest possible anastomosis to prevent anyongoing obstruction to pulmonary venousreturn

atrial communication and PDA then closed

veins with extremely high tendency to formscar tissue, with later complications

S i l M t


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Surgical Management


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ASD


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VSD


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PDA

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Congenital Heart Disease - Students

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