4 SURGERY II 3B - Congenital Cardiac Diseases

Group 15 | Gi, Shei, Chup, Ella, Celene Edited by: MJ NG Page 1 of 12

Dr. VILLANUEVA Nov. 10, 2014

Surgery II 4.3b

CONGENITAL CARDIAC DISEASES

OUTLINE I. Classification of Congenital Heart

Disease Accdg to Type of Shunting II. Classification Based on Treatment

Option III. Patent Ductus Arteriosus

a. Embryology and Anatomy b. Fetal Circulation c. Definition d. Postnatal Closure e. Mechanism of Closure f. Determinants of Magnitude of

Shunting g. Physical Examination h. Natural Course i. Management

IV. Atrial Septal Defect a. Types of ASD b. Diagnosis c. Spontaneous Closure d. Management

V. Ventral Septal Defect a. Pathology b. Causes c. Classification Based on

Location d. Physiology e. Classification Based on

Defect Size f. Classical Manifestation g. Diagnosis h. Natural History i. Management

VI. Tetralogy of Fallot a. Manifestation b. Diagnosis c. Management

VII. Transposition of Great Arteries a. Pathophysiology b. Diagnosis c. Management

References

1. PowerPoint 2. Recording 3. Schwartz’s Principles of Surgery

TRADITIONAL CLASSIFICATION OF CONGENITAL HEART DISEASES

(ACCORDING TO TYPE OF SHUNTING)

LEFT-TO-RIGHT (ACYANOTIC)

RIGHT-TO-LEFT (CYANOTIC)

Patent Ductus Arteriosus (PDA)

Atrial Septal Defect (ASD)

Ventricular Septal Defect (VSD) Endocardial Cushion Defect (ECD)

Partial Anomalous Pulmonary Venous Return (PAPVR)

Tetralogy of Fallot (TOF)

Transposition of the Great Arteries (TGA)

Hypoplastic Left Heart Syndrome (HLHS)

NEWER CLASSIFICATION

(BASED ON BEST TREATMENT OPTION)

REPAIR ONLY

PDA

ASD

Aortic stenosis Aortic coarctation

Truncus arteriosus

TAPVR

Cor triatriatum

PALLIATION ONLY

Tricuspid atresia

Hypoplastic Left Heart Syndrome (HLHS)

REPAIR OR PALLIATION

VSD

TOF TGA

Taussig-Bing Syndrome (TBS) w/ or w/o pulmonary stenosis (PS)

Atrioventricular canal defects

Interrupted aortic arch Ebsteins Anomaly

DORV (Double Outlet Right Ventricle)

DORV with NON-committed VSD

DORV with Subaortic/doubly committed VSD w/o PS DORV with Subaortic or doubly committed

PATENT DUCTUS ARTERIOSUS (PDA)

Figure 1. Patent Ductus Arteriosus

EMBRYOLOGY AND ANATOMY

Ductus arteriosus develops from distal portion of the left 6th aortic arch

A right PDA joins the right pulmonary artery and the right aortic arch just distal to the right subclavian artery

A bilateral ductus may be present

Locally produced and circulating prostaglandins E2 and prostaglandin I2 induce active relaxation of the ductal musculature, maintaining maximal patency during the fetal period

**SEE APPENDIX C FOR PRENATAL VS POSTNATAL CIRCULATION

DUCTUS ARTERIOSUS IN THE FETAL CIRCULATION

At 6 weeks AOG, the DA is developed sufficiently to carry most of the right ventricular output.

The placenta receives the largest amount of combined (i.e., right and left) ventricular output (55%) and has the lowest vascular resistance in the fetus

SVC: drains the upper part of the body o the brain (15% of combined ventricular output) o goes to the right ventricle (RV) PA DA descending

aorta

IVC: drains the lower part of the body and the placenta o 70% of combined ventricular output o Oxygen saturation in the IVC (70%) > in the SVC (40%) o 1/3 blood is directed by the crista dividens to the left atrium (LA)

through the foramen ovale o 2/3 enters the RV and pulmonary artery (PA)

DEFINITION OF PDA

Postnatal communication between the main pulmonary trunk and descending thoracic aorta

Due to persistent patency of the fetal ductus arteriosus

Ductus arteriosus o Normally connects the main pulmonary trunk or the proximal

left pulmonary trunk with the descending thoracic aorta approximately 5 to 10 mm distal to the origin of the left subclavian artery

o PDA shape conical; large aortic end tapering to smaller PA end

o PDA length variable; few mm to cm.

EPIDEMIOLOGY OF PDA IN PRETERM INFANTS

Incidence of PDA in preterm infants: 8 in1,000 live births o 45% PDA prevalence in infants <1,750 g birth weight o 80% PDA prevalence in infants <1,200 g birth weight


SURGERY II 4.3B

EPIDEMIOLOGY OF PDA IN FULL TERM INFANTS

Incidence of PDA in full-term infants: 1 in 2000 live births o 5% to 10% of all congenital heart lesions

2:1 female-to-male preponderance Exposure to rubella during the first trimester of pregnancy

o 60% association in the cardiovascular system Often associated w/ peripheral pulmonary stenosis & renal

artery stenosis

May be genetic Leading cause of death in infants with large PDA: Congestive heart

failure (CHF) with respiratory infection as secondary cause

POSTNATAL CLOSURE OF THE DUCTUS ARTERIOSUS FUNCTIONAL CLOSURE (10-15 HRS AFTER BIRTH)

Contraction and cellular migration of the medial smooth muscle in the wall of the ductus arteriosus o Shortening, increased wall thickness, protrusion into the lumen

of the thickened intima (intimal cushions or mounds)

ANATOMIC CLOSURE (BY 2 TO 3 WEEKS OF AGE)

Infolding of the endothelium, disruption and fragmentation of the internal elastic lamina, proliferation of the subintimal layers, hemorrhage and necrosis in the subintimal region

Permanent changes in the endothelium and subintimal layers of the ductus o Fibrosis results in permanent sealing of the lumen to produce

the ligamentum arteriosum

MECHANISM OF CLOSURE OF DUCTUS ARTERIOSUS AFTER BIRTH A. Increase in pO2 with ventilation after birth

Fetal life pO2: 18- 28mmHg postnatal increase in systemic pO2 (50 mm Hg after lung

expansion) is the strongest stimulus for constriction B. Decrease in prostaglandins with increase in pulmonary blood flow

PGE2 is the more potent relaxer of the Ductus Arteriosus PGE2 and PGI2 are formed intramurally in the Ductus Arteriosus

and exert their action locally on muscle cells

Due to low fetal pulmonary blood flow in utero, there is decreased catabolism of PG in the lungs

At birth, there is marked increase in the pulmonary blood flow allowing effective removal of the PG (decrease in PGE2 levels)

Note: The patency or closure of the DA represents a balance between the constricting effects of oxygen, relaxing effects of prostaglandins, and certain vasoconstrictive substances.

THREE DETERMINANTS OF THE MAGNITUDE OF PDA SHUNTING 1. Diameter and length of ductus arteriosus

After birth: degree of left-right shunts is regulated by size of the duct

2. Relationship of the systemic (SVR) and pulmonary vascular resistances (PVR)

16-18 weeks postnatally: PVR falls, shunt increases, flow determined by relative resistance of pulmonary and systemic circulations

With decrease in PVR, SVR becomes greater than PVR; leads to left right shunt

Unrestricted ductal shunt leads to: o Left ventricular volume overload o Increased la and pa pressures o Right ventricular strain due to augmented afterload

3. Pressure difference between the aorta and pulmonary artery

SMALL PDA MODERATE LARGE

FLOW RESISTANCE High Medium Low LEFT RIGHT SHUNT Small Medium Large

PULMONARY BLOOD FLOW

No increase Moderate High

LEFT VENTRICLE HYPERTROPHY

None Tolerable Possible

CLINICAL MANIFESTATIONS

SMALL PDA

Few patients are symptomatic

Attention is often brought to this condition only by the murmur

Detected at a routine physical examination

MODERATE PDA

Symptomatology related to left ventricular failure o Poor feeding, irritability, and tachypnea o Poor weight gain

The symptoms increase until about the second to third month of age

LARGE PDA

Symptoms indicative of severe left ventricular failure with pulmonary edema may occur early in infancy o Irritable, feed poorly, fail to gain weight, sweat

excessively o Increased respiratory effort and respiratory rates o Recurrent upper respiratory infections and

pneumonia

PHYSICAL EXAMINATION

**SEE APPENDIX A Murmur

o Grade 1-4/6 continuous (“machinery”) murmur is best audible at the left infraclavicular area or upper left sternal border

o The heart murmur may be crescendo systolic at the upper left sternal border in small infants or infants with pulmonary hypertension

o An apical diastolic rumble may be heard when the PDA shunt is large

Hyperdynamic circulation with widened pulse pressure Hyperactive precordium

NO cyanosis in uncomplicated PDA

Figure 2. Pattern of Murmur in PDA

LABORATORY RESULTS

Chest radiograph o Increased pulmonary vascularity o Cardiomegaly

ECG o LV strain, LA enlargement, possible RV hypertrophy

Echocardiogram o Demonstration of duct patency and shunt size


SURGERY II 4.3B

NATURAL COURSE

Spontaneous closure in premature infants. In term infants spontaneous closure rarely occurs

CHF and/or recurrent pneumonia develop in large PDA

PVOD

Sub-acute bacterial endocarditic

Aneurysm – rare

MANAGEMENT MEDICAL

For preterm infants: Indomethacin or Ibuprofen (Contraindications: renal insufficiency, necrotizing enterocolitis)

For term infants: those unresponsive to Indomethacin must undergo mechanical closure

No exercise restriction is needed in the absence of pulmonary hypertension

Prophylaxis for subacute bacterial endocarditis is indicated when indications arise

Treatment of symptomatic patients with CHF o Diuretics – to decrease blood volume going to pulmo circulation o Digoxin – to increase heart contractility o After-loader reducing agents – to prevent blood shunt from

aorta; lower systemic resistance so blood goes preferentially to systemic circulation)

CATHETER CLOSURE (STUDY) COIL CLOSURE PROCEDURE

Treatment of choice for all children more than a few months of age with ducts <3 mm in diameter

Performed using conscious sedation allowing the children to return to full activity by the next day

A catheter is advanced from femoral artery or vein across the PDA

An occluding coil is placed in the PDA with a single coil loop on the pulmonary artery side and the remaining three to four loops in the ductal ampulla

>97% successful with zero mortality and no significant morbidity

Percutaneous technique

AMPLATZER DUCT OCCLUDER

For larger PDAs 12 mm in diameter

Procedure is similar in duration, risk, and recovery time to the coil closure procedure

The devices are implanted antegrade from the femoral vein using long sheaths sized 6 to 8 French.

> 98% closure rate at 6 months with minimal complications and no mortality

Figure 3. Non-surgical closure of PDA using Amplatzer occluder

PDAs larger than 12 mm o Use of septal closure devices

AGA septal occluder, VSD device, NMT CardioSEAL device o Covered stents in select cases

SURGICAL CLOSURE

Indication o Anatomic existence of PDA regardless of size because of the

increased mortality and risk of endocarditis

Contraindication o Presence of Pulmonary Veno-Occlusive Disease (PVOD)

Timing o Between 6 months and 2 years of age or when the diagnosis is

made in an older child. o In infants with congestive heart failure, pulmonary

hypertension or recurrent pneumonia, surgery is performed on an urgent basis.

The surgical approach is the most common method used for closure of PDA in newborns. o Left posterolateral thoracotomy via the 3rd or 4th ICS (4th or 5th

ICS in Schwartz)

LIGATION

Lesser probability to kill patient and thus, it is a much common procedure today; safer

[2]

The ductus is ligated with multiple large silk ligatures so that it is obliterated in its entire course.

In neonates, PDA is singly ligated with surgical clip or permanent suture

In smaller children, this usually amounts to two or three large silk ligatures.

Care must be taken during the procedure to avoid the recurrent laryngeal nerve, which usually courses around the PDA. In extreme cases of PDA, the use of cardiopulmonary bypass (CPB) may be needed to decompress the large ductus during ligation. [3]

TRANSECTION

Usually done in patients with a large PDA, especially older children Adequate mobilization can afford the opportunity to clamp both the

pulmonary arterial and aortic ends. This is followed by the ductal division and oversewing of the two stumps.

Advisable for short, broad ductus (width = length)

VIDEO-ASSISTED THORACOSCOPIC (VATS) CLIPPING

Seldom used because you can accidentally rupture PDA before you can open the patient, he can already die. [2]

This offers few advantages over the standard open surgical approach.


SURGERY II 4.3B

ATRIAL SEPTAL DEFECT

Figure 4. Atrial Septal Defect.

Pathway of blood: From IVC to RA and goes through the interarterial septum, crosses to LA LV then blood is ejected → this is normal in

perinatal circulation, but abnormal postnatally.

Defined as an opening in the interatrial septum that enables the mixing of blood from the systemic venous and pulmonary venous circulation

F > M (2:1)

Occurs as isolated anomaly in 5-10% of all CHDs

30-50% of CHDs have ASD as part of cardiac defect

TYPES OF ASD

Figure 5. Left to right: Ostium Primum, Ostium Secundum, Sinus Venosus

OSTIUM SECUNDUM

Most prevalent (80% of ASD)

Only type that may spontaneously close Results from failure of closure in neonate

OSTIUM PRIMUM

Near the area of the valve May lead to mitral regurgitation Heart failure

SINUS VENOSUS

Nearest to the roof of the heart

Partial anomalous pulmonary venous return Ostium Primum and Sinus Venosus are both failure in the growth of

septum

DIAGNOSIS Associated with right ventricular hypertrophy from the very start; in

contrast to most L-R shunts where LVH is present

Usually asymptomatic (patients with complaints are usually in their 2ndto 3rd decade of life already)

The amount of blood shunted across the defect is low because the atria are both low-pressure chambers.

Auscultation: Murmur is due to flow across Pulmonic valve (soft systolic murmur, loud P2) o Prominence of the first heart sound with fixed splitting of the

second heart sound (results from the relatively fixed left-to-right shunt throughout all phases of the cardiac cycle; the increased blood flow across the pulmonic valve going to the pulmonary arterial circulation causes a delay in the P2 component of the second heart sound)

LAB FINDINGS

Chest Radiograph: right atrial enlargement, right ventricular enlargement, prominent pulmonary artery, increased pulmonary vascular markings

ECG: right axis deviation, mild right ventricular hypertrophy, right bundle-branch block

2D Echo o 'Dropout' mid atrial septum – indicative of an ostium secundum

type of ASD o Drop out is lower – ostium primum o Drop out is higher – sinus venosus

**Drop-out is the defect[2]

Scimitar sign: true anomalous venous return of the right pulmonary veins into the inferior vena cava (rather than directly to the left atrium)

SPONTANEOUS CLOSURE RATE

100% spontaneous closure if <3mm at 1½ y/o

80% spontaneous closure if 3-8mm at 1 ½ y/o

>8mm rarely close spontaneously 87% overall spontaneous closure

MANAGEMENT

NONSURGICAL OR PERCUTANEOUS CLOSURE Usually used for ostium secundum

Use of septal occlude or pericardium

SURGICAL CLOSURE

Surgery indication: o Qp/Qs > 1.5:1

- Qp – pulmonary flow; Qs – systemic flow

Contraindication: pulmonary vascular resistance ( 10 U/m2 )

Timing of surgery is delayed until 3-4 years old because of possible spontaneous closure

Complications: CVA, arrhythmia o Heart block: ostium primum – AV node o Sinus node dysfunction: sinus venosus – posterosuperior of SVC

PRIMARY CLOSURE

Usually done in pediatric patients

PATCH CLOSURE Using pericardium or Teflon

Usually done in adult patients; pericardium is usually used except for high pressure like LV, synthetic grafts are used instead[2]


SURGERY II 4.3B

VENTRICULAR SEPTAL DEFECT

Figure 6. Ventricular Septal Defect

Most common form of congenital heart disease

VSD in newborns: 5-50/1000 Most common lesion in many chromosomal syndromes

56: 44 (F/M)

Multifactorial etiology : hereditary and environmental

PATHOLOGY

Normal development of the heart: the interventricular foramen closes and becomes the membranous part of the interventricular septum

Failure of the interventricular foramen to close: Ventricular Septal Defect o Left-to-right ventricular shunt during systole

CAUSES [1]

Deficient development of the proximal conus swellings.

Failure of the muscular portion of the interventricular septum to fuse with the free edge of the conus septum. (Membranous VSD)

Failure of the endocardial cushions to fuse. Excessive diverticulation of the muscular septum- perforations in the

muscular interventricular septum. (Muscular VSD)

Depending on the cause of the VSD, that would be the type or classification of VSD, the structure that did not fuse.

Four components of the ventricular septum: o Inlet septum o Trabecular septum o Outlet or infundibular septum o Membranous septum

CLASSIFICATION BASED ON LOCATION

PERIMEMBRANOUS (INFRACRISTAL, MEMBRANOUS)

Most common type of defect

Involves the membranous septum and includes the misalignment defects seen in Tetralogy of Fallot

Usually extends into muscular, inlet or outlet areas

Minor anomalies of the tricuspid valve forming as extra septal leaflets or pouches can partially or completely occlude the defect -- called the aneurysms

Age of optimum surgery: 2 year old if symptomatic or 5 year old if asymptomatic

Highest chance of spontaneous closure

OUTFLOW

Outlet, supracristal, infundibular, doubly committed subarterial

5 to 7%

A defect within the conal septum Beneath the pulmonary valve

No chance of spontaneous closure

INLET

Atrioventricular canal defects 5 to 8%

Part or all of the septum of the AV canal is absent

Posterior and inferior to perimembranous defect, beneath the septal leaflet of tricuspid valve and inferior to the papillary muscles

MUSCULAR

5 to 20%

Can occur anywhere along the trabecular septum o Central: mid-muscular, may have multiple apparent channels on

right ventricle side; coalesce to a single defect on left ventricle side

o Apical: multiple apparent channels on RV, maybe single defect in LV side as with central defect

o Marginal: along septal margin o “Swiss cheese” septum: large number of muscular defects

PHYSIOLOGY[1] (not discussed)

A. DEFECT SIZE: primary anatomic variable determining physiologic state

Small or medium size: limits L→R shunt

Large: no resistance to flow across the defect B. PULMONARY VASCULAR RESISTANCE: determines magnitude of

shunting in infancy

The small, muscular pulmonary arteries in the fetus become thin-walled with increased luminal size following birth.

Normal rate of decline in PVR that accompanies the above changes: right ventricular pressure reaches the adult values within 7-10 days

CLASSIFICATION BASED on DEFECT SIZE[1]

Basis of classification by size is relative to the size of aortic valve

SMALL VSD OR ROGET’S DEFECT

MEDIUM-SIZED LARGE- SIZED

<1/3 of aortic root </= 1/2 of the aortic orifice

Size of the aortic orifice

Large systolic pressure difference between

the 2 ventricles (high resistance to flow)

>/=20 mmHg Systemic pressure in

both ventricles

No tendency for increase in pulmonary

vascular resistance

Unusual to have marked elevation

of PVR

Gradual decline in PVR 1st few months

of life LA and pulmonary HPN

Continuous L→R shunt

Moderate L→R shunt (volume

overload of LA & LV and LVH)

Large L→R shunts (volume overload of

LA & LV and LVH) CHF: 2-8 weeks old

CLINICAL MANIFESTATIONS

[1]

SMALL MEDIUM LARGE

Murmur: 1-6 weeks Course benign Risk:

endocarditis (rare before 2 y/o) Appears healthy

Symptoms: 2 weeks old (tachypnea, excessive

sweating, fatigue, during feeds) May be preceded by

respiratory infection

Poor weight gain Signs of

CHF

Normal precordial activity (+/-) thrill in the lower left sternal border associated with Grade 4-

6 holosystolic murmur Heart sound: usually

normal

Hyperdynamic precordium Extended L & R ventricular areas (+) thrill, holosystolic murmur S2 widely split P2

normal or slightly increased

Left anterior precordial bulge after 4-6 months


SURGERY II 4.3B

DIAGNOSIS[1]

SMALL MEDIUM LARGE

ECG: Normal LVH/LAH Combined ventricular

hypertrophy

CXR: Normal LVE, LAE Increased

pulmonary vascular markings

Biventricular enlargement Increased pulmonary vascular

marking

Figure 7. Radiographic findings of

Medium VSD (LEFT) vs Large VSD (RIGHT)

NATURAL HISTORY

Spontaneous Closure – most small VSD’s, 20-30% close before 1 year old

Congestive heart failure – large VSD’s o Extra blood flows from the LV thru the RV to the lungs → LA →

LV → causes LA and LV overload → increase workload on the heart → increased HR and body’s demand for energy

o Extra blood flow in the lungs → rapid breathing, also increasing the body’s demand for energy

Growth failure – seen in infants o Baby is not able to eat enough to keep up with the body’s

increased energy demands

Bacterial endocarditis

Arrhythmia

Pulmonary HPN – sustained flow under higher pressure into the pulmonary arteries causes the arteries to become thickened and stiff. The amount of blood flow to the lungs decreases over time as the resistance to blood flow into the pulmonary arteries increases. However, this causes the right ventricle to work harder.

MANAGEMENT NONSURGICAL

Small: None except antibiotic prophylaxis

Moderate to large: o Furosemide (1-3 mg/k/day) o High caloric diet o Captopril (0.1 -0.3 mg/kg TID) o Digoxin if diuresis and afterload reduction not enough and

surgery not advisable

SURGICAL APPROACH Indications

Uncontrolled CHF, including growth failure, recurrent respiratory infection o “Control CHF through diuretics or Lanoxin; treat any infection; if

not controlled, then do surgery. If controlled, wait for patient to grow up a little before doing surgery.”

Large defects – prior to 2 y/o even without symptoms if with pulmonary artery hypertension

Older, asymptomatic children with normal pulmonary artery pressure if the pulmonary-systemic flow ratio (Qp/Qs) >2:1

Figure 8. VSD Repair (RA approach).

Defect(Orange-red)“Tatapalan lang ng patch (yellow) yung butas”

Requires the use of cardiopulmonary bypass with moderate hypothermia and cardioplegic arrest

How to expose the anomalies? o Right atrial approach is preferable for most defects (regardless

of the type of defect present, this is the approach used for the initial inspection of the cardiac anatomy)

o Left ventriculotomy is usually used for apical muscular defects

After careful inspection of the heart for any associated malformations, a patch repair is used to repair the septal defect, taking care not to avoid the conduction system.

If a definitive VSD closure cannot be accomplished such in “Swiss-cheese” VSD, temporary placement of pulmonary artery band can be used to control pulmonary flow. This allows time for spontaneous closure of many of the smaller defects, thus simplifying surgical repair.

TETRALOGY OF FALLOT

Figure 9. Tetralogy of Fallot: VSD, pulmonary stenosis,

overriding of the aorta and RV hypertrophy Arises as a result of the underdevelopment and anteroleftward

malalignment of the infundibular septum

10% of all congestive heart diseases

Most common cyanotic heart defect beyond infancy

Components o VSD – large perimembranous VSD adjacent to tricuspid valve o pulmonary stenosis - right ventricular outflow tract obstruction o overriding of the aorta o RV hypertrophy o If with Atrial Septal Defect PENTALOGY


SURGERY II 4.3B

MANIFESTATION

Cyanosis (significant when 6-12mos of life), tachypnea, clubbing Grade 3-5/6 systolic ejection murmur

Polycythemia develops secondary to cyanosis

Hypoxic spells in infants (“tet” spells), periods of extreme hypoxemia

Subacute bacterial endocarditis a common complication

DIAGNOSIS

ECG: right axis deviation, right ventricular hypertrophy, combined ventricular hypertrophy, right atrial hypertrophy

CXR: boot-shaped heart (couer en sabot)

Figure 10. Chest X-ray of TOF. “Boot-shaped heart is produced

because PA is blocked by pulmonary stenosis.”

MANAGEMENT NONSURGICAL

Propranolol

Treat Fe deficiency anemia

Dental hygiene & subacute bacterial endocarditis prophylaxis Balloon dilatation of RVOT & pulmonary valve

SURGICAL APPROACH

Optimal age of approach is not yet determined. Currently primary elective repair is preferred for infancy[3]

Surgical correction of TOF can either be: o a staged approach of antecedent palliation in infancy followed

by intracardiac repair o primary repair during first few months of life without palliative

surgery.

Primary goal: increase the flow of blood going to the pulmonary circulation. For total correction of TOF, the stenotic outflow tract is opened and the septal defect is repaired (i.e. patch closure). This is not possible at all times, which is why palliation may be initially required.

DISADVANTAGE: it has the resultant scar that would significantly impair right ventricula function that may lead to lethal arrhythmias [3]

MODIFIED BLALOCK-TAUSSIG SHUNT (BTS)

Antecedent palliation with the use of systemic-to-pulmonary shunts is preferred in unstable infants younger than 6 months of age o Those who have pulmonary atresia, significant branch

pulmonary artery hypoplasia or require an extracardiac conduit because of an anomalous left anterior descending coronary artery

3% mortality rate

Complications: right bundle-branch block, complete heart block, congestive heart failure, pulmonary regurgitatation

Fig11. TOF with Modified Blalock-Taussig Shunt

“Pag maliit ang pulmonary artery (due to stenosis), you cannot do an outright connection. So, we increase the blood flow to pulmonary arteries. We create a shunt – shunt systemic blood to PA, para dumami yung blood

na dadaan sa lungs. Thus, more oxygenated blood to go to LA and LV.”

TRANSATRIAL REPAIR [3]

Use of transannular patch

It involves the use of cardiopulmonary bypass

TRANSPOSITION OF GREAT ARTERIES

Figure 12. Transposition of the Great Arteries.

Aorta from the Right Ventricle, Pulmonary artery from the Left Ventricle

Connection of the atria to their appropriate ventricles with inappropriate ventriculoarterial connections

“Your pulmonary and systemic circulation, instead of series, naging parallel. So, umiikot-ikot lang yung blood. For the patient to survive, there should be a shunt. It can be in the form of an ASD, VSD, or PDA, as long as there is connection between left and right because of the parallel circulation.”

7-8 % of all CHD

Male predominance; M:F =2:1

75% with interventricular septum o ‘Simple’ TGA: with Patent Ductus Arteriosus o ‘Complex’ TGA:

20% with Ventricular Septal Defect 20% with Left Ventricular Outflow Tract Stenosis 7-10% with Aortic Arch Obstruction

PATHOPHYSIOLOGY

Transposition of Great Arteries (TGA) results in parallel pulmonary and systemic circulations o Oxygenated blood circulates thru the lungs & the left side of the

heart while deoxygenated blood circulates thru the systemic circulation and the right side of the heart.

o This is incompatible with life – needs an intracardiac shunt (e.g., ASD, VSD, PDA) to survive.


SURGERY II 4.3B

After birth, both ventricles are relatively noncompliant and thus, infants initially have higher pulmonary flow Left atrial enlargement

Left-to-right shunt via patent foramen ovale o Pulmonary blood flow > systemic blood flow o PULMONARY VASCULAR DISEASES Right Ventricular

Hypertrophy (because the right ventricle works against systemic vascular resistance)

DIAGNOSIS

ECG: RVH CXR: classic egg-shaped consideration

CARDIAC CATHERIZATION o Rarely used, usually in infants requiring surgery after the

neonatal period to assess the suitability of the LV to support the systemic circulation

MANAGEMENT ARTERIAL SWITCH OPERATION by JATENE

Figure 13. JATENE switch procedure.

A – coronary arteries are removed from the aorta B – coronary arteries are connected to pulmonary artery (PA) C – Aorta and pulmonary artery is transected above level of coronary ostia, then aorta is translocated posteriorly [LeCompte maneuver] D – Aorta is attached to the previous PA and becomes the neoaorta.

Good candidates for arterial switching procedures o LV pressure > 85% o LV post wall thickness > 4.5 mm o Coronary pattern amenable to transfer to neoaorta with

distention or kinking o LV inflow and outflow must be free of significant structural

abnormalities

2015B: The most important consideration is the timing of the surgical repair because it should be performed within 2 weeks after birth, before the left ventricle loses its ability to pump against systemic afterload.

SENNING OPERATION

Fig 14. Senning Operation.

ADDITIONAL NOTES(NOT DISCUSSED) COR TRIATRIATUM

Figure 15.CorTriatriatum.

(A) Common chamber draining to right atrium directly. (B) Common chamber draining into systemic venous circulation via an anomalous vein.

A rare CHD characterized by the presence of a diaphragm or membrane that partitions the left atrium into two chambers: o Superior chamber: receives drainage from the pulmonary veins o Inferior chamber: communicates with the mitral valve and the

left ventricle

PATHOPHYSIOLOGY AND DIAGNOSIS

Results in obstruction of the pulmonary venous return to the left atrium

If communication between superior and inferior chamber <3 mm, patients are symptomatic during first year of life

The afflicted infant will present with the stigmata of o Low cardiac output o Pulmonary venous hypertension o Congestive Heart Failure o Poor feeding

Physical examination may demonstrate o Loud pulmonary S2 sound o Right ventricular heave o Jugular venous distention o Hepatomegaly

Chest radiograph: cardiomegaly and pulmonary vascular prominence

ECG: right ventricular hypertrophy

2D echocardiography provides a definitive diagnosis

THERAPY

Cardiopulmonary bypass & cardioplegic arrest are used.

Just remove the membrane

TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION

Figure 16. Comparison between TAPVR and A Normal Heart.

Characterized by the abnormal drainage of the pulmonary veins into the right heart, whether through connections into the right atrium or into its tributaries

A B

C D


SURGERY II 4.3B

The only mechanism by which oxygenated blood can return to the left heart is through an ASD, which is almost uniformly present with TAPVC.

Unique to this lesion is the absence of a definitive form of palliation.

Thus, TAPVC with concomitant obstruction represents one of the only true surgical emergencies across the entire spectrum of congenital heart surgery.

ANATOMY AND EMBRYOLOGY

TAPVC arises when the pulmonary vein evagination from the posterior surface of the left atrium fails to fuse with the pulmonary venous plexus surrounding the lung buds.

Obstruction to pulmonary venous drainage is a powerful predictor of adverse natural outcome.


Because both pulmonary and systemic venous blood return to the right atrium in all forms of TAPVC, a right-to-left intracardiac shunt must be present for the afflicted infant to survive.

The child with TAPVC may present with severe cyanosis and respiratory distress necessitating urgent surgical intervention if a severe degree of pulmonary venous obstruction is present.

Two-dimensional echocardiography is very useful in establishing the diagnosis. It can usually identify the pulmonary venous connections.

Cardiac catheterization is not recommended in these patients because the osmotic load from the IV contrast can exacerbate the degree of pulmonary edema. When cardiac catheterization is performed, equalization of oxygen saturations in all four heart chambers is a hallmark finding in this disease because the mixed blood returned to the right atrium gets distributed throughout the heart.

THERAPY

Operative correction of TAPVC requires the following: o Anastomosis of the common pulmonary venous channel to the

left atrium (uses a baffle to direct the blood from the pulmonary veins into the left atrium)

o Obliteration of the anomalous venous connection o Closure of the ASD

The perioperative care of these infants is crucial because episodes of pulmonary hypertension can occur within the first 48 hours. o This contributes significantly to mortality following repair o Muscle relaxants and narcotics should be administered during

this period to maintain a constant state of anesthesia.

The most significant postoperative complication of TAPVC repair is Pulmonary Venous Obstruction.

AORTIC COARCTATION

Figure 17. Sites of Aortic Coarctation

ANATOMY

Defined as a luminal narrowing in the aorta that causes an obstruction to blood flow, usually located distal to the left subclavian artery.

Causes extensive collateral circulation

o Predominantly involves intercostals and mammary arteries o This translates into the well-known finding of the ff:

"Rib-notching" on chest radiograph Prominent pulsation underneath the ribs

Other associated anomalies may be seen with COA but the most common is that of a bicuspid aortic valve

PATHOPHYSIOLOGY

Symptoms develop with left ventricular outflow obstruction - This translates to backflow to the pulmonary circulation which causes pulmonary overcirculation

Later in the disease the patient develops biventricular failure.

Systemic hypertension also develops as a result of the ff: o Obstruction to ventricular ejection o Hypoperfusion which activates renin–angiotensin–aldosterone

system (RAAS) Early surgical correction may prevent the development of long-term

hypertension which causes the development of aneurysms, aortic dissection and myocardial infarction later in life.

DIAGNOSIS

COA is seen in two stages of life: o In the newborn period if other anomalies are present o Present in the late adolescent period with the onset of left

ventricular failure Physical examination presents with the ff:

o Hyperdynamic precordium with a harsh murmur localized to the left chest and back

o Femoral pulses dramatically decreased when compared to upper extremity pulses

o Cyanosis may be apparent until ductal closure

Echocardiography will demonstrate narrowed aortic segment

THERAPY

Management of COA in all age groups has traditionally been surgical.

The most common surgical techniques o Resection with end-to-end anastomosis o Extended end-to-end anastomosis

Allows treatment of transverse arch hypoplasia May promote arch growth Not feasible when segment is long or with previous surgery

The most common complications after COA repair at the repair site are late restenosis & aneurysm formation

Particularly common after patch aortoplasty when using Dacron material COA

TRUNCUS ARTERIOSUS

Figure 18. Truncus arteriosus

ANATOMY AND EMBRYOLOGY

A rare anomaly characterized by a single great artery that arises from the heart -It overrides the ventricular septum, and supplies all circulations (pulmonary, systemic, and coronary circulations).


SURGERY II 4.3B

The two major classification systems are those of o Collett and Edwards

This focuses on the origin of the pulmonary arteries from the common arterial trunk

Type I: truncus one pulmonary artery two lateral pulmonary arteries

Type II: truncus two posterior/posterolateral pulmonary arteries

Type III: truncus two lateral pulmonary arteries o Van Praagh

Based on the presence or absence of a VSD formation, the degree of formation of the aorticopulmonary septum, and the status of the aortic arch

Figure 19. Collete Edwards (Type I-III) and Van Praagh (A1-A4)

During normal embryonic life, truncusarteriosus normally begins to

separate and spiral into a distinguishable anterior pulmonary artery and posterior aorta.

Persistent truncus represents an arrest in embryologic development at this stage.

Neural crest plays a crucial role in the normal formation of the great vessels. o Neural crest also develops into pharyngeal pouches that give rise

to the thymus and parathyroid glands. o This explains the prevalent association of truncus arteriosus and

DiGeorge syndrome.

In majority of cases, the leaflets are thickened and deformed, which leads to valvular insufficiency. o usually three leaflets (60% of cases) o bicuspid (50% of cases) o quadricuspid valve (25% of cases)

PHYSIOLOGY AND DIAGNOSIS

Figure 20. Truncus Arteriosus. Note the Purple lines.

The truncusarteriosus fails to properly divide into the pulmonary trunk and aorta.

The two main pathophysiologic consequences of truncusarteriosus are: o The mixing of systemic and pulmonary venous blood that leads

to arterial saturations near 85% o The presence of a nonrestrictive left-to-right shunt, which occurs

during both systole and diastole, the volume of which is determined by the resistances of the pulmonary and systemic circulations

The presence of these lesions often results in severe heart failure and cardiovascular instability early in life

Truncusarteriosus usually present in the neonatal period, with signs and symptoms of o CHF and mild to moderate cyanosis due to left-to-right shunting o A pansystolic murmur at the left sternal border

Chest radiography will be consistent with o Pulmonary overcirculation o Right aortic arch can be appreciated (~35%)

ECG: Non-specific; normal sinus rhythm with biventricular hypertrophy

Echocardiography with Doppler color flow or pulsed Doppler is diagnostic, provides information to determine o The type of truncus arteriosus o The origin of the coronary arteries, and their proximity to the

pulmonary trunk o The truncal valves, and the extent of truncal insufficiency

Cardiac catheterization can be helpful in cases where pulmonary hypertension is suspected.

The presence of truncus is an indication for surgery and repair should be undertaken in the neonatal period, or as soon as the diagnosis is established.

Eisenmenger's physiology found in older children is the only absolute contraindication to correction surgery.

Repair is completed by o Separation of the pulmonary arteries from the aorta o Closure of the aortic defect (occasionally with a patch) to

minimize coronary flow complications

AORTOPULMONARY WINDOW

Figure 21. Aortopulmonary window

A rare congenital lesion characterized by incomplete development of the septum that normally divides the truncus into the aorta and the pulmonary artery


A large left-to-right shunt with increased pulmonary flow PLUS the early development of CHF o Like other lesions with left-to-right flow, the magnitude of the

shunt is determined by the size of the defect, as well as the Pulmonary Vascular Resistance

Infants with APW present with frequent respiratory tract infections, tachypnea with feeding, and failure to thrive

Cyanosis is usually absent because these infants deteriorate before the onset of significant pulmonary hypertension

THERAPY

All infants with APW require surgical correction once the diagnosis is made.

Repair is undertaken through a median sternotomy and the use of a cardiopulmonary bypass.



Surgery II 4.3b


APPENDIX A. PHYSICAL EXAMINATION FINDINGS OF PDA DEPENDING ON ITS DIAMETER AND LENGTH

PHYSICAL EXAMINATION

PERIPHERAL

PULSE

ARTERIAL PULSE

PRESSURE

PRECORDIAL ACTIVITY

HEART SOUND MURMUR OTHERS

SMALL PDA May be full Slightly

increased Normal

S1 and S2 Normal

In early infancy

May be a short period when no murmur is heard

Short systolic murmur may then be heard In late infancy to older children

Typical, continuous murmur heard best in the second lics

Often accentuated at recumbent position or during inspiration

MODERATE PDA

Increased HR

Bounding

Wide (Low

diastolic Pressure)

Hyperdynamic Thrusting

apical pulse

S1 and S2 difficult to hear due to loud murmur

S3 apex

Continuous murmur: o More intense, more extensive radiation, and

well heard posteriorly o Much harsher quality with low-frequency

components o Eddy sounds that vary from beat to beat

give the murmur a machinery quality

Systolic thrill may be palpable at the

ULSB

LARGE PDA Increased

HR Bounding

Wide

Markedly hyperdynamic

Thrusting left ventricular apical impulse

S1 and S2 accentuated

S3 Apex

No murmur is heard with severe failure With control of left ventricular failure:

moderately loud systolic murmur in the pulmonary area or occasionally in 3rd or 4th ics

The typical continuous murmur is less usual Prominent mid-diastolic mitral flow rumble is

commonly audible at the apex

If w/ pulmonary edema, rales on

all lung fields

APPENDIX B. DIAGNOSTIC TEST FINDINGS OF PDA

CXR ECG 2D Echo

SMALL PDA

Normal

Slight prominence of MPA Normal

Delineate the PDA size and flow patterns

MEDIUM PDA

Cardiomegally o LVH and LAE

prominent MPA

increased PVM

prominent ascending aorta with unfolding of arch

Left ventricular hypertrophy (LVH) in older infants and children

Left atrial enlargement (LAE) may be present

Demonstrate LAE, LVH and PDA

Flow and velocity patterns

LARGE PDA

Markedly enlarged MPA Accentuated pulmonary vascular

markings are markedly

Interstitial fluid

Enlarged left atrium or pulmonary arteries

Lobar collapse or emphysema owing to bronchial compression may occur

Prominent LVH, with deep Q and taller R waves

T waves diphasic or even inverted

RVH may be evident, w/ upright T waves in the right precordial leads and increased R-wave amplitude in the right precordial leads

LAE, widened P wave

LAE and ventricular diameters, hypertrophy if present, and the PDA itself

Doppler evaluation will demonstrate flow and velocity patterns and will allow for an estimate of pulmonary arterial pressure



Surgery II 4.3b


APPENDIX C. PRENATAL VS POSTNATAL CIRCULATION AS WELL AS THE ANATOMIC CHANGES

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4 SURGERY II 3B - Congenital Cardiac Diseases

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