Congenital Heart Defects: ASD/VSD- Topic 9 Flashcards
1
Q
CPB Normorthermic Blood Flow
A
0-3 kg = 200 cc/kg/min 3-10 kg= 150 cc/kg/min 10-15 kg= 125 cc/kg/min 15-30 kg= 100 cc/kg/min >30 kg= 75 cc/kg/min >55 kg= 65 cc/kg/min
2
Q
CPB Normorthermic Blood Flow
A
0-3 kg = 200 cc/kg/min 3-10 kg= 150 cc/kg/min 10-15 kg= 125 cc/kg/min 15-30 kg= 100 cc/kg/min >30 kg= 75 cc/kg/min >55 kg= 65 cc/kg/min
3
Q
Atrial Septal Defects most commonly occur as defects in what?
A
Septum primum within the fossa ovalis (secundum ASD)
4
Q
Atrial Septal defects CAN involve the secundum near what?
A
SVC
sinus venosus defects are less common
5
Q
Atrial septal defects will do what to physiology?
A
Will cause pressure mediated shunting
L to R
R to L
6
Q
Which shunt is of most concern to you? L to R or R to L?
A
R to L; skips the lungs; cyanotic shunts
*BUT both are of concern; one can become the other because it is pressure mediated
7
Q
How is blood flow quantitated? (In shunts)
A
Pulmonary Blood Flow (Qp)
Systemic Blood Flow (Qs)
8
Q
What would expect the Qp/Qs ratio to be in a normal individual?
A
1 (1:1 ratio)
9
Q
When do shunts require treatment?
A
When they are symptomatic
10
Q
When do shunts require treatment?
A
When they are symptomatic
Pulmonary over circulation
Shunts causing increase in right heart size
11
Q
When do shunts require treatment?
A
When they are symptomatic
Pulmonary over circulation
Shunts causing increase in right heart size
Qp:Qs > 1.5
12
Q
When do shunts require treatment?
A
When they are symptomatic
Pulmonary over circulation
Shunts causing increase in right heart size
Qp:Qs > 1.5
13
Q
What is the most common type of atrial septal defect?
A
Ostium Secundum
14
Q
What are some common types of atrial septal defects?
A
Ostium Secundum
Patent Foramen Ovale
Ostium Primum
Sinus Venosus
15
Q
Ostium Secundum
A
Most common ASD type
Formed by failed growth of the septum secundum OR rapid reabsorption of the septum primum
Mid atrial
16
Q
What is the only type of ASD suitable for percutaneous closure?
A
Ostium Secundum ASD; defect in the middle of the atrial septum
17
Q
Patent foramen Ovale (PFO)
A
Small channel that has little hemodynamic consequence; it is a remnant of the fetal foramen ovale
*In some cases PFO can be larger and require treatment
18
Q
Patent foramen Ovale (PFO)
A
- Small channel that has little hemodynamic consequence; it is a remnant of the fetal foramen ovale
- Channel from birth; “Flap valve”
*In some cases PFO can be larger and require treatment
19
Q
Why would a PFO normally close?
A
Closes due to pressure changes very early in life
20
Q
Why would a PFO normally close?
A
Closes due to pressure changes very early in life
21
Q
Closure of Fetal Shunts
A
- The initial inflation of the lungs causes changes:
- Decreases PVR results in increased BF from PA
- Increased BF from RA to RV and into the PA’s and less BF through the foramen ovale to the left atrium
- More blood returns from lungs increases pressure inLA
- Increased LA pressure and decreased RA pressure (due to pulmonary resistance) forces blood against septum primum causing hte formane ovale to close
22
Q
What action functionally completes the separation of the heart into two pumps?
A
Closure of the PFO in a normal fetal heart after birth (changes in pulmonary pressures, resistance, BF)
23
Q
Ostium Primum ASD Location
A
Low in the septum and can be considered a type of AV septal defect (AVSD)
24
Q
Ostium Primum Sat Changes
A
Could have RA saturations lower than RV without a VSD
25
Ostium Secundum
Most common ASD type (90%)
Formed by failed growth of the septum secundum OR rapid reabsorption of the septum primum
Mid atrial
26
Ostium Primum Sat Changes
Could have RA saturations lower than RV without a VSD
27
Sinus Venosus ASD Location
high in the septum where the vena cava intersects with the right atrium; may be inferior or superior
28
What is sinus venosus ASD frequently associated with?
Partial anomalous venous return (PAPVR)
29
What is sinus venosus ASD frequently associated with?
Partial anomalous venous return (PAPVR)
30
What forms separate chambers of the heart?
Embryonic septation
31
What are key aspects in heart development?
1. Embryonic/fetal circulation is different to the neonatal circulation
2. Embryonic septation forms separate chambers
3. Several septal defects of heart septation may only become apparent on this transition
32
Which septal defect occurs in us all?
The foramen ovale (between the 2 atria) which in general closes in the neonate over time
33
At what day does cardiac septation occur?
Day 27
34
How long does cardiac septation last?
10 days
35
When do the formation of cardiac septa occur?
Simultaneously
36
During cardiac septation, how does the external appearance change?
No major changes in external appearance
37
Atrial Septation at what days?
27-28 (for 10 days)
38
What happens during atrial septation?
* The paired atria fuse together to form a common atrium
* Atrial septation occur simultaneously and in cooperation with ventricular septation
* Atrial septation also lasts 10 days
39
In normal individuals, are left or right sided pressures higher? Why?
Left heart pressures > Right heart pressures
Thick LV has to produce enough pressure to pump blood throughout the entire body, while the thin RV only has to produce enough pressure to pump blood to the lungs
40
In normal individuals, are left or right sided pressures higher? Why?
Left heart pressures > Right heart pressures
Thick LV has to produce enough pressure to pump blood throughout the entire body, while the thin RV only has to produce enough pressure to pump blood to the lungs
41
What size ASD would be considered "large"?
> 9mm
42
A large ASD may result in what kind of shunt?
Clinically remarkable left-to-right shunt; blood shunted LA to RA. This extra blood from LA may cause a volume overload of both the RA and the RV (RA dilatation leading the RA fibrosis)
43
What could happen if a large ASD went untreated?
Can result in enlargement of the right side of the heart and ultimately heart failure
44
What could happen if a large ASD went untreated?
Can result in enlargement of the right side of the heart and ultimately heart failure
45
How could an ASD result in pulmonary hyptertension?
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Increased right sided volume
Right atrial and ventricular dilatation
Tricuspid annular dilatation (TR)
Pulmonary congestion
Pulmonary hypertension
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46
How do Qp and Qs compare in pulmonary hypertension?
Qp > Qs
47
What could cause worsening of a left-to-right-shunt?
Any process that increases the pressure in the LV can cause worsening of the left-to-right shunt
48
What could cause worsening of a left-to-right-shunt?
Any process that increases the pressure in the LV can cause worsening of the left-to-right shunt; also works on the right heart
Systemic hypertension, increases pressure that the LV has to generate in order to open the aortic valve
49
What could cause worsening of a left-to-right-shunt?
Any process that increases the pressure in the LV can cause worsening of the left-to-right shunt; also works on the right heart
Systemic hypertension, increases pressure that the LV has to generate in order to open the aortic valve
50
If there is a L to R shunt, which ventricle has to push our more blood? What does this result in?
Right ventricle; constant overload of the right side of the heart will cause an overload of the entire pulmonary vasculature (pulmonary over-circulation)
51
If there is a L to R shunt, which ventricle has to push our more blood? What does this result in?
Right ventricle; constant overload of the right side of the heart will cause an overload of the entire pulmonary vasculature (pulmonary over-circulation)
52
Qp/Qs > 1.5/1.0
Problem!! Eventually pulmonary hyptertension will develop
53
What does pulmonary hyptension cause for the RV?
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Increased afterload (PVR)
In addition to increased preload that the shunted blood form the LA to RA caused
RV will be forced to generate higher tension/pressures to try to overcome the pulmonary HTN
Could lead to RV failure (dilatation and decreased systolic function of the RV)
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54
If Left to Right shunt is left uncorrected....
Pressure in right heart> pressure in left heart
RA pressure > LA pressure
Pressure gradient reverses across the ASD
Shunt reverses (R to L shunt)= Eisenmenger's syndrome
Oxygen-poor blood gets shunted to the left heart
Cyanosis
55
Eisenmenger's Syndrome
Reversal of a L to R shunt to become a R to L shunt
Oxygen-poor blood gets shunted to the left heart
Causes cyanosis
56
Eisenmenger's Syndrome
Reversal of a L to R shunt to become a R to L shunt
Oxygen-poor blood gets shunted to the left heart
Causes cyanosis
57
Surgical Correction of ASD's
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Percutanous Closure (Amplatzer)
Surgical Closure (Primary closure; patch closure)
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58
What is the only ASD that could undergo Amplatzer closure?
Ostium Secundum
59
Surgical Closure of ASD: Incision
Median Sternotomy
Right thoracotomy
Sub-mammary (under breast tissue on right front of chest/very difficult)
60
Surgical Closure of ASD: Primary
Closure by direct vision suture
61
Surgical Closure of ASD: Patch
uses pericardial tissue or gore-tex patch for closure
62
SurgicalClosure of ASD: Cannulation
Arterial: Aortic
VEnous: Bicaval (Total CPB)
*Single atrial if infant and small and DHCA is anticipated
63
Surgical Closure of ASD: Venting
May use direct venting with a flexible since the heart is open
64
Surgical Closure of VSD: Cardioplegia
Antegrade; usually a single dose will suffice
65
Surgical Closure of VSD: Case Notes
Very, very quick (5-10 min pump run)
Will XC, Stay warm " drift down temp "
Can be challenging: (on CPB, XC, CPG, warm, correct Ca++, lytes, ABG's off CPB-MUF)
66
VSD
defect in the ventricular septum, the wall dividing the left and right ventricles of the heart
67
What does the ventricular septum consist of?
Inferior muscular portion
| Superior membranous portion
68
Common Regions of VSDs
Inlet
Outlet (supracristal)
Peri-membranous septum
Muscular septum
69
What is the #1 type of VSD we will see? (What percent)
Per-membranous septum (75%)
70
What percent of VSDs are muscular?
20%
71
What percent of VSDs are supracristal (outflow)?
5%
72
Muscular VSDs are found in what four locations?
Anterior
Mid-ventricular
Posterior
Apical
73
Muscular VSDs are found in what part of the septum?
lower part of the septum (they're surrounded by muscule)
74
The membranous portion of the ventricle is close to what?
AV node
75
Membranous VSDs are located near what?
Heart valves
76
What is the #1 type of VSD we will see? (What percent)
Peri-membranous septum (75%)
77
Membranous VSDs are located near what?
Heart valves; can close at any time
78
Supracristal VSD
outflow tract VSD sub-valvular in nature
79
Crista Supraventricularis can be considered synonymous with what?
Infundibular (or conus) ventricular septum
80
Outflow VSDs are found in what part of the ventricle?
Where blood leaves the heart; these are the rarest types of VSD
81
What are the rarest types of VSDs?
Outflow VSDs
82
What separates the tricuspid and pulmonary valves and accounts for the more superior placement of the pulmonary valves relative to the aortic valve?
Infundibular (or conus) septum
83
What separates the tricuspid and pulmonary valves and accounts for the more superior placement of the pulmonary valves relative to the aortic valve?
Infundibular (or conus) septum
84
Infundibular (or conus) septum provides muscular rigid support for what valve?
Aortic valve, especially the right coronary cusp (think prolapse)
85
VSD
defect in the ventricular septum, the wall dividing the left and right ventricles of the heart
86
Infundibular (or conus) septum provides muscular rigid support for what valve?
Aortic valve, especially the right coronary cusp (think prolapse)
87
VSD Blood Flow Pattern During Systole
some of the blood from the left ventricle leaks into the right ventricle, passes through the lungs and reenters the left ventricle via the pulmonary veins and left atrium
88
VSD Blood Flow Pattern During Systole
some of the blood from the left ventricle leaks into the right ventricle, passes through the lungs and reenters the left ventricle via the pulmonary veins and left atrium
Results: Overloads LV
Because the left ventricle normally has a must higher systolic pressure (120 mmHg) than the right ventricle (20 mmHG) a left to right shunt persists
Elevated RV pressure and volume --> pulmonary HTN
89
VSD Symptoms when there is a larger defect
Breathlessness, poor feeding, failure to thrive in infancy (patients with smaller defects may be asymptomatic)
90
Ventricular septum is formed by what?
Outgrowth of the muscular ridge at the interventricular foramen; ventricular septum grows upward from the apex of the heart to the base of the heart
91
VSD Cannulation
Arterial: Aortic
Venous: Bicaval (total Cpb)
Single atrial if the infant is small and DHCA is anticipated
92
VSD Repair: Venting
May use direct venting with a flexible since the heart is open
93
VSD Repair: Cardioplegia
Antegrade, usually with a single dose
94
VSD Repair: Case Notes
case is quick depending on VSD location
Case may be 32C or DHCA if small infant
Can be challenging, but usually you have more time with VSD
Ventricular function may be related to the length of time the VSD has been present
95
What could Ventricular function in a pt with a VSD be related to?
Length of time the VSD has been present
96
Surgical Correction of VSDs
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Percutaneous closure *can be tough with VSDs
Surgical closure (Primary, patch) *probably not primary
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