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Bypass considerations based on diagnosis 137

Case notes:

______________________________________________

Surgeon preferences:

______________________________________________

Figure 6.44 TOF repair with VSD patch and transannular outflow

patch. From Mullins and Mayer [1]. Reproduced with permission of

John Wiley & Sons.

138 Chapter 6

Total anomalous pulmonary venous

return and partial anomalous

pulmonary venous return

Same as total/partial anomalous pulmonary venous con-

nection (TAPVC/PAPVC)

Basics:

TAPVR can be classified by where the pulmonary venous

confluence is located. It may be supracardiac (commonly to a

confluence behind the heart, then to a vertical vein and then

the innominate vein and RA), cardiac (commonly to the

coronary sinus), or subdiaphragmatic (draining to the IVC

or portal vein) or mixed between these classifications. When

the pulmonary veins empty into the right heart, a septal

defect must be present to allow for right to left shunting and

left-sided blood flow. To note, if the pulmonary veins are

obstructed enough, a true crisis exists, and the patient will

require immediate surgery since medical management is

ineffective. Surgical correction for TAPVR is aimed at cre-

ating a pathway for the pulmonary veins to the left atrium.

Hypothermic circulatory arrest is commonly used.

Partial APVR (PAPVR) may also present where some of

the pulmonary veins return normally and some do not (as

with sinus venosus ASDs with right-sided pulmonary

veins returning to the RA).

Bypass notes:

• Cardioplegia is required.

• Bicaval venous cannulation may be used in older children

and adults. In this population, circulatory arrest is less

likely, and a target temperature of 24–28

°C is common.

• Single venous cannulation is more likely in neonates and

infants. However, bicaval cannulation may be used in this

population since it allows for intracardiac surgery for

associate defects during the cooling phase. A single venous

cannula can then be used during rewarm if desired. The

target temp is 18

°C if the surgeon wants circulatory arrest

to be a readily available option. Otherwise, 20–28 °C is

used.

• An ice wrap applied to the head to prevent warming is

common for procedures 25 °C and below.

• The venous line is usually clamped during circulatory

arrest when a single venous cannula is used. This allows

the surgeon to remove the cannula to facilitate visualiza-

tion at the field.

• If bicaval cannulation is used and caval tapes are applied,

the venous line may be left unclamped during circulatory

arrest.

• A left ventricular vent is not normally used with

singlevenous cannulation but is common with bicaval

cannulation.

• A drop sucker in the left atrium may be used with bica-

val cannulation.

• The LA may be undersized if flow through it has been

limited due to the anatomy. These patients will likely be

more difficult to precisely wean off bypass. These patients

may see large variations in filling pressures with minimal

change in volume status during weaning. The perfu-

sionist must be exceptionally careful not to overfill these

patients during separation from bypass.

• Scimitar syndrome is a form of PAPVR and is named for

the X-ray appearance of the enlarged curved sword

(scimitar) shaped pulmonary venous drainage from the

right lung to the IVC. The right lung is commonly hypo-

plastic and its blood supply is via MAPCAs.

Figure 6.45 Supracardiac total anomalous pulmonary venous return to

the left vertical vein. From Mullins and Mayer [1]. Reproduced with

permission of John Wiley & Sons.

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Bypass considerations based on diagnosis 139

Figure 6.46 Cardiac total anomalous pulmonary venous return to the

coronary sinus. From Mullins and Mayer [1]. Reproduced with

permission of John Wiley & Sons.

Figure 6.47 Infracardiac total anomalous pulmonary venous return to

the ductus venosus. From Mullins and Mayer [1]. Reproduced with

permission of John Wiley & Sons.

Figure 6.48 Partial anomalous pulmonary venous return with right

pulmonary veins returning to the junction of the superior vena cava

andright atrium. From Mullins and Mayer [1]. Reproduced with

permission of John Wiley & Sons.

Figure 6.49 Partial anomalous pulmonary venous return with RUPVs

returning to the superior vena cava and the right lower pulmonary

veinreturning to the right atrium. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

Case notes:

______________________________________________

Surgeon preferences:

______________________________________________

140 Chapter 6

d-Transposition of the great arteries

Basics:

Transposition of the great arteries is just that; the aorta and

pulmonary artery are transposed to the other’s ventricle. The

atria and ventricles are morphologically normal and located

appropriately. The right ventricular outflow is to the aorta,

while left ventricular outflow is to the pulmonary artery.

This relationship is classified as discordant. The Van Praagh

segmental classification set is {S,D,D}. The term “d-TGA”

originates from the last letter in the segmental classification

which indicates the ventriculoarterial relationship.

TGA is always associated with at least one septal defect

(ASD/PFO/VSD) and at times more (ASD/PFO and VSD).

A PDA may be present as well. In fact, adequate shunting at

the septal level (or PDA) is required to support life. Patients

are generally classified as TGA/IVS (TGA with intact ven-

tricular septum) or TGA/VSD (TGA with VSD). Patients

with inadequate ductal and/or septal shunting frequently

receive prostaglandins and a balloon atrial septostomy early

in the postnatal period to ensure that the two parallel circu-

lations created by d-TGA mix well enough to support life.

Collateral blood flow to the lungs may be present with

d-TGA and can affect the bypass cannulation strategy.

In the normal heart, the left coronary arises from the

left/anterior sinus of Valsalva and the right coronary artery

arises from the right/anterior sinus of Valsalva. In d-TGA,

the relationship between the great vessels is altered.

Coronary arteries in d-TGA are frequently termed “normal

for d-TGA.” Normal for d-TGA is for the left coronary

artery to come off of the left/anterior sinus of Valsalva

(which is the same as a normal heart) and for the right

coronary artery to come off the right/posterior sinus of

Valsalva (in the normal heart the RCA comes off the right/

anterior sinus of Valsalva). There are numerous other

branching patterns that can be seen as well as single coro-

nary artery.

Surgical correction is normally an arterial switch opera-

tion (ASO). The aorta and pulmonary artery are tran-

sected and moved to their respective ventricle. The

coronary arteries are removed in buttons from the right-

sided aortic root, mobilized, and then transferred to the

left-sided pulmonary root (which becomes the neoaortic

root). Significant stenosis of either outflow tract may pre-

clude the switch operation and require an alternate sur-

gical approach with a Nikaidoh or Rastelli type repair.

Bypass notes:

• Maximum anticipated flow for equipment selection:

3.5

L/min/m

2

.

• Cardioplegia is required.

• Left ventricular vent is common.

• Target temperature is 24–28 °C with bicaval cannula-

tion. Here, the septal defects are repaired on bypass.

This is more common in patients with a VSD.

• Target temperature 18 °C with single venous cannula-

tion. Here, the septal defects are repaired under

circulatory arrest. Deep hypothermia may be especially

helpful with multidose cardioplegia protocols as tem-

perature alone can have an arresting effect and direct

redosing of cardioplegia in neonates is difficult.

• IVS patients are more likely to have single venous can-

nulation. Here, the ASD can be closed with the venous

cannula directed down the IVC. The target temperature

in this case would be 24–28

°C. Alternately, the ASD can

be closed under circulatory arrest with a target temper-

ature of 18 °C.

• Single venous cannulation may be preferred if significant

collateral flow is expected. Bicaval cannulation may

result in difficult intracardiac visualization with collat-

erals causing significant left heart return during ASD

and/or VSD closure.

• An ice wrap applied to the head to prevent warming is

common for procedures 25 °C and below.

• Minimum dilutional hematocrit is 25–30%.

• pH-stat blood gas management is preferred.

• The coronary transfer is critical with arterial switch

operations. Early signs of coronary issues during

rewarming are usually addressed surgically. The perfu-

sionist should have additional cardioplegia ready in case

an additional period of myocardial arrest is required.

• It is important to know the surgeon’s preference for

maximum aortic pressure whenever the aorta has

been opened surgically, especially when allowing for

ejection.

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Bypass considerations based on diagnosis 141

Figure 6.50 d-TGA with IVS (before atrial septostomy). From Mullins

and Mayer [1]. Reproduced with permission of John Wiley & Sons.

Figure 6.51 d-TGA with VSD. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

Figure 6.52 Arterial switch operation for d-TGA/IVS (coronaries are

moved from the right-sided aortic root to the left-sided pulmonic/

neo-aortic root). From Mullins and Mayer [1]. Reproduced with

permission of John Wiley & Sons.

Figure 6.53 Rastelli repair for d-TGA/VSD/PS (VSD is patched to the

aorta and a conduit is placed from the RV to the PA). From Mullins and

Mayer [1]. Reproduced with permission of John Wiley & Sons.

Case notes:

______________________________________________

Surgeon preferences:

______________________________________________

142 Chapter 6

Tricuspid atresia

Basics:

Tricuspid atresia in the neonate is normally seen with inade-

quate right ventricular size (due to the lack of blood flow

through the RV in utero), an ASD, VSD, and a PDA. The

pulmonary valve in tricuspid atresia can be atretic, dysplastic,

or unrestrictive. Surgical repair is dedicated to ensuring a

stable source of pulmonary blood flow, which may require a

BTS, PAB, or no intervention at all if the pulmonary and

systemic circulations are balanced with septal defects and

sufficient antegrade flow through the PA. If the right heart is

unable to provide pulmonary blood flow, the patient is usu-

ally led down the pathway of staged procedures toward a

Fontan circulation. A Damus–Kaye–Stansel procedure may

be performed when tricuspid atresia is associated with TGA

and a restrictive VSD.

Bypass notes:

• Maximum anticipated flow for equipment selection:

3.5

L/min/m

2

.

• Cardioplegia is not normally needed for BTS or BDG

procedure. It is normally required for intracardiac

work.

• Single venous cannulation is used for BTS procedure.

• Bicaval cannulation is used for BDG and Fontan

procedures.

• Left ventricular vent is not normally needed.

• Target temperature is 28–34

°C.

• Minimum dilutional hematocrit is 30–40% for single

ventricle palliation.

• pH-stat blood gas management for cases is performed at

30 °C or below.

Figure 6.54 Tricuspid atresia with BVF type ventricular septal defect

and unrestrictive pulmonary artery. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

Case notes:

______________________________________________

Surgeon preferences:

______________________________________________

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Bypass considerations based on diagnosis 143

Tricuspid regurgitation/insufficiency

Basics:

Tricuspid regurgitation/insufficiency (TR/TI) is com-

monly due to right ventricular dilation that can be

caused by numerous conditions. Significant TR can lead

to right heart failure. TR is commonly associated with

Ebstein’s Anomaly and as a late finding after repair of

complete atrioventricular canal defect. Repair of the

valve may include placing an annuloplasty ring which

helps control the annulus size and provide for improved

leaflet coaptation.

Bypass notes:

• Maximum anticipated flow for equipment selection:

3.0 L/min/m

2

.

• Cardioplegia is required.

• Bicaval cannulation is required.

• Left ventricular vent is common.

• Target temperature is 28–32 °C.

• Minimum dilutional hematocrit is 25–30%.

• pH-stat blood gas management for cases is performed at

30 °C or below. Alpha-stat blood gas management is per-

formed for adults and patients with suspected vascular

disease.

• Valve irrigation solution is ideally scavenged with cell

saver or wall suction.

• Valve testing solution may be scavenged with pump

suckers or cell saver suction

• Excessive valve testing solution returned to the pump

will require sodium bicarbonate for buffering. The

patient’s sodium may rise if bicarbonate administration

is regular.

• Consideration should be given to informing the surgeon

of the sodium load when the patient’s sodium level rises

above 150 mmol/L.

• Aggressive conventional ultrafiltration may be helpful

in maintaining the hematocrit.

• DUF or ZBUF may be helpful in adjusting the sodium

level when relatively large volumes of test solution are

returned to the pump.

See section “Reoperations” in Chapter5.

Case notes:

______________________________________________

Surgeon preferences:

______________________________________________

Figure 6.55 Tricuspid regurgitation. Adapted from Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

144 Chapter 6

Truncus arteriosus

Basics:

Truncus arteriosus (TA) can be described as a single great

artery arising from the ventricular outflow tracts in the

presence of a large VSD. From this common trunk emerges

the aorta and pulmonary arteries. TA can be classified by

how the pulmonary arteries arise from the aorta:

• TA type I has a main pulmonary artery coming off of the

aorta.

• TA type II has right and left pulmonary arteries arising

separately from the posterior aorta but close together.

• TA type III has right and left pulmonary arteries arising

separately from the aorta from different sides and per-

haps different levels.

Surgical correction is aimed at closing the VSD, ensuring

a competent truncal valve, providing pulmonary blood

flow with a right ventricle to pulmonary artery conduit

incorporating the PAs removed from the truncus and

patching the aorta where the PAs formerly arose.

Bypass notes:

• Maximum anticipated flow for equipment selection:

3.0

L/min/m

2

.

• Cardioplegia required.

• Truncal valve regurgitation may require direct coronary

delivery of cardioplegia. The perfusionist should pre-

pare 1.5–2 doses of cardioplegia.

• Truncal valve regurgitation may require cardioplegia

delivery early in the case. The perfusionist should

prepare the cardioplegia as soon as bypass parameters

are deemed acceptable.

• Bicaval cannulation is required.

• Left ventricular vent is common.

• Target temperature is 28–32 °C.

• Consideration should be given to going on bypass slowly

and cooling slowly to prevent LV distention secondary to

truncal valve regurgitation and\or ventricular fibrillation

due to a cool prime rapidly entering the heart.

• Minimum dilutional hematocrit is 25–30%.

• pH-stat blood gas management is preferred.

• The pulmonary arteries must be controlled before or soon

after commencing bypass since runoff to the pulmonary

circulation can compromise systemic perfusion (much

like a PDA or MAPCAs which need to be controlled).

• It is important to know the surgeon’s preference for

maximum aortic pressure whenever the aorta has been

opened surgically, especially when allowing for ejection.

Figure 6.56 Truncus arteriosus Type I. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

Figure 6.57 Truncus arteriosus Type II. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

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Bypass considerations based on diagnosis 145

Case notes:

______________________________________________

Surgeon preferences:

______________________________________________

Figure 6.58 Truncus arteriosus Type III. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

Figure 6.59 Truncus arteriosus Type 1 Repair. RV to PA conduit,

ascending aorta repair and VSD patch. From Mullins and Mayer [1].

Reproduced with permission of John Wiley & Sons.

146 Chapter 6

Ventricular septal defect

Basics:

A VSD is a communication between the right and left

ventricles. While conceptually these are simpler defects,

they can be varied in presentation. They may present as

a singular small hole centrally located in the septum

requiring only primary closure or present as multiple holes

in different parts of the septum, which may be difficult for

the surgeon to visualize and address. VSDs are commonly

classified by location in the ventricular septum:

• Membranous VSD—located in the membranous septum.

• Outlet, subarterial, subpulmonary, or conoventricular

VSD—located below the aortic and pulmonary valves,

high in the infundibular septum.

• Inlet VSD (canal type)—located near the “inlet” to both

ventricles, between the mitral and tricuspid valves, gen-

erally more posterior than membranous VSDs.

• Muscular VSD—located low in the septum approaching

the apex of the heart.

• The communication between ventricles which exists in

patients with a hypoplastic ventricle (as with DILV or

tricuspid atresia) is referred to as the BVF. The BVF is

the only inlet connection to the rudimentary ventricle.

This interventricular communication is often impor-

tant for the systemic ventricular outflow tract. It is

treated quite differently than other septal communica-

tions. This communication is usually not closed but

rather itisleft as is or enlarged to prevent outflow tract

obstruction.

• Surgical correction for true VSDs is aimed at closing the

hole(s) primarily (suture only) or with a patch. The

patch material is most commonly synthetic (Dacron or

Gore-Tex, etc.), but autologous pericardium may also be

used.

Bypass notes:

• Maximum anticipated flow for equipment selection:

3.0

L/min/m

2

.

• Cardioplegia required (induced ventricular fibrillation

may be used alone or in addition).

• Bicaval cannulation is required.

• Left ventricular vent is common.

• Target temperature is 28–34

°C.

• Minimum dilutional hematocrit is 25–30%.

• pH-stat blood gas management for cases is performed

at30 °C or below. Alpha-stat blood gas management is

performed for adults and patients with suspected

vascular disease.

Membranous septum

Ao

PT

Outlet

component

TV

Inlet

component

Apicaltrabecular

components

Figure 6.60 Location of ventricular septal defects. From Stark et al. [2].

Reproduced with permission of John Wiley & Sons.

Subarterial

outlet

defect

Perimembranous defect

Ao

PT

TV

Muscular defects

Figure 6.61 Location of ventricular septal defects. From Stark et al. [2].

Reproduced with permission of John Wiley & Sons.

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