9. ASD/VSD- Exam 3 Flashcards
normals BP: <40 weeks gestation
48-63 / 25-35
normals BP: <36 hours old full term
62 / 39
normals BP: >36 hours old full term
68 / 43
normals BP: 1 year
98-104 / 55-60
normals BP: 2 year
101-107 / 59-64
normals BP: 5 year
107-114 / 69-72
Normal BF per 0-3 kg
200 ml/kg
Normal BF per 3-10 kg
150 ml/kg
Normal BF per 10-15 kg
125 ml/kg
Normal BF per 15-30 kg
100 ml/kg
Normal BF per >30 kg
75 ml/kg
Normal BF per >55 kg
65 ml/kg
Most common ASDs occur where?
septum primum within the fossa ovalis (secundum ASD)
Less common ASDs occur where?
Defect can involve the septum secundum near SVC (sinus venosus defects)
what will an ASD cause
Will cause pressure mediated shunting L->R *compliant right heart R->L
What are Cyanotic shunts?
right to left shunt
What are Acyanotic shunts?
left to right shunt
What shunt is of the most concern you?
Cyanotic shunts R->L
How may shunts be quantitated?
PULMONARY BLOOD FLOW (Qp) SYSTEMIC BLOOD FLOW (Qs) –Qp/Qs –1:1 is a normal ration
what is the general rule for shunts that do NOT require treatment
The general rule is shunts that DO NOT cause an INCREASE in right heart size (Qp:Qs < 1.5) do NOT require treatment
pulmonary over circulation=
left to right shunt that causes an increase in right heart size
with a left to right shunt- what will the Qp/Qs ratio look like
over 1
Qp/Qs less than 1.5=
small shunt
Qp/Qs over 2=
large shunt
Qp/Qs= [formula]
(SatAO − SatMV) / (SatLA − SatPA) -SatAO is the aortic blood oxygen saturation -SatMV is the mixed venous blood oxygen saturation, -SatLA is the left atrial blood oxygen saturation -SatPA is the pulmonary artery blood oxygen saturation.
what are the 4 types of ASDs and which is most common
Ostium Secundum (the most common) Patent Foramen Ovale Ostium Primum Sinus Venosus
Ostium Secundum anatomy=
formed by failed growth of the septum secundum or rapid reabsorption of the septum primum
Ostium Secundum occurs where on the atrial septum
Middle of atrial spetum Only ASD suitable for percutaneous closure
Ostium Secundum causes what kind of mixing and sats
even distribution of mixing higher sats in RV starts out as a L->R shunt
Patent Foramen Ovale anatomy=
-small channel that has little hemodynamic consequence -it is a remnant of the fetal foramen ovale. -In some cases the PFO can be larger and require treatment -Normally closes due to pressure changes very early in life -“flap valve”
describe how Patent Foramen Ovale are supposed to close
–The initial inflation of the lungs causes changes: –Decreases PVR= in increased BF from PA. –That increased amount of BF from the RA to the RV and into the PA’s and less BF through the foramen ovale to the LA. –Q= P/R such that decreased R = increased flow –In addition, more blood returns from the lungs which increases the pressure in the LA. –The increased LA pressure and decreased RA pressure (due to PVR) forces blood against the septum primum causing the foramen ovale to close. –This action functionally completes the separation of the heart into two pumps
Ostium Primum anatomy=
located low in the septum and can be considered a type of AV septal defect –Could have RA saturations lower than RV without a VSD
Sinus Venosis anatomy=
located high in the septum where the vena cava intersects with the right atrium, frequently associated with partial anomalous venous return (PAPVR) –May be inferior and/or superior
Embryonic/fetal circulation is _____ to the neonatal circulation
different
________ forms separate chambers
Embryonic septation –Several septal defects of heart septation may only become apparent on this transition
what atrial septal defect occurs in all of us
the foramen ovale (between the 2 atria) which in general closes in the neonate over time.
Cardiac Septation [atrial and ventricular] occurs on what day? last how long?
Occurs at Day 27 Lasts 10 days -The formation of the cardiac septa occur simultaneously -During this time, no major changes in external appearance
Atrial Septation=
At day 27-28, the paired atria fuse together to form a common atrium. -Atrial septation occurs simultaneously and in cooperation with ventricular septation -Atrial septation also lasts approximately 10 days
in normal patients left heart pressure is ____ than right heart pressure. Why?
higher -This is because the 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
In the case of a large ASD (>9mm), which may result in a __________________ shunt
clinically remarkable left-to-right
with an ASD, Blood will shunt from the LA to the RA. what will this cause
This extra blood from the left atrium may cause a volume overload of both the RA and the RV (RA dilatation-> RA fibrosis) .
if an ASD that causes vol overload to the right heart goes untreated, what happens
If untreated, this condition can result in enlargement of the right side of the heart and ultimately right heart failure
describe the full effects of an ASD (the pathway)
ASD present -> Increased right sided volume -> Right atrial and ventricular dilatation -> Tricuspid annular dilatation (TR) -> Pulmonary congestion -> Pulmonary hypertension/Over circulation/Hypertrophy
With ASDs, Any process that increases the pressure in the LV can cause worsening of the ____ shunt. It also works on the ____ heart. Included are?
left-to-right right systemic hypertension, which increases the pressure that the LV has to generate in order to open the aortic valve
With ASDs, how does pulmonary over circulation occur
The RV will have to push out more blood than the left ventricle due to the L -> R shunt –Eventually pulmonary hypertension will develop
With ASDs, how does right ventricular failure (dilatation and decreased systolic function of the right ventricle) occur after pulmonary over circulation is present
–The pulmonary HTN will cause the RV to face increased afterload (PVR) in addition to the increased preload that the shunted blood from the LA to RA caused. –The RV will be forced to generate higher tension/pressures to try to overcome the pulmonary HTN
With ASDs, if the pulmoanry HTN and RV failure is left untreated what happens
the shunt will reverse!! –RA pressure > LA pressure –The pressure gradient reverses across the ASD –a right-to-left shunt (R->L) will now exist –This shunt reversal phenomena is known as Eisenmenger’s syndrome
ASD shunt reversal phenomena is known as?
Eisenmenger’s syndrome
What happens when Eisenmenger’s syndrome happens and the L->R shunts reverses to R->L?
oxygen-poor blood gets shunted to the left side of the heart. This will cause signs of cyanosis.
what are the surgical corrections for ASDs
- Percutaneous closure (Amplatzer) 2. Surgical Closure –Primary Closure=Closure by direct vision suture –Patch Closure=Uses pericardial tissue or Gore-Tex patch for closure
Percutaneous closure (Amplatzer) of the Ostium Secundum requires what to close the umbrella
ridged tissue
Surgical Correction of ASD’s incision sites (3)?
–Median sternotomy –Right thoracotomy (going between the ribs on the right side) –Sub-mammary (under the breast tissue on the right front of the chest)-very difficult
ASD cannulation sites: atrial+venous
Arterial: Aortic Venous: Bicaval (total CPB) –Single Atrial if the infant is small and DHCA is anticipated
ASD venting:
may use direct venting with a flexible since the heart is open
ASD cardioplegia:
Antegrade, usually a single dose will suffice 30ml/kg (maybe less- just enough to arrest the heart)
ASD case notes:
-Case is very, very quick, 5-10 min pump run -Will XC, Stay warm “drift down temp” -Can be challenging: (on CPB, XC, give CP, warm, correct Ca++,lytes, ABG’s, off CPB-MUF)
The ventricular septum consists of what portions
Inferior muscular portion Superior membranous portion
what are the 4 common regions for VSDs
Inlet Outlet (supracristal) Peri-membranous Septum Muscular Septum
what are the 3 common types of VSDs and the % occurrence for each
Membranous 75 % Muscular 20 % Supracristal (Outflow) 5 %
Muscular ventricular septal defect is found in what 4 locations
anterior mid-ventricular posterior apical
where are muscular VSDs found
lower part of the septum. They’re surrounded by muscle. (most close on their own during early childhood.)
where are membraneous VSDs found? what is special about them?
The membranous portion, which is close to the atrioventricular node. located near the heart valves –These VSDs can close at any time
what type of VSD is most common in adults and older children
Membraneous VSD
describe supracrystal VSDs
-Outflow tract VSD sub-valvular in nature -Can be considered synonymous with the infundibular (or conus) ventricular septum
where are supracrystal VSDs found? what is their occurrence
Outlet VSDs are found in the part of the ventricle where blood leaves the heart. T -These are the rarest type of VSD
The infundibular (or conus) septum separates what and accounts for what?
separates the tricuspid and pulmonary valves and accounts for the more superior placement of the pulmonary valve relative to the aortic valve
due to the location of the supracrystal VSD, what other bad things may happen
This portion of the septum also provides muscular rigid support for the aortic valve, especially the right coronary cusp—>which may cause a prolapse –cause poor right coronary flow and make it hard to deliver cpg
During systole, some of the blood from the LV leaks into the RV, passes through the lungs and reenters the LV via the pulmonary veins and LA. This may cause what 2 effects
- the circuitous refluxing of blood causes volume overload on the LV 2. because the LV normally has a much higher systolic pressure (~120 mm Hg) than the RV (~20 mm Hg), a L–>R shunt persists
with VSDs, the leakage of blood into the right ventricle causes what
elevates RV pressure and volume, causing pulmonary HTN
VSD effects are more noticeable in what patients? what are the symptoms?
This effect is more noticeable in patients with larger defects, who may present with breathlessness, poor feeding and failure to thrive in infancy
Patients with smaller defects may be?
asymptomatic
Ventricular Septation - review –The ventricular septum is formed by the outgrowth of the muscular ridge at the ________. –The ventricular septum grows in what direction?
interventricular foramen upward from the apex of the heart to the base of the heart
VSD cannulation: arterial + venous
Arterial: Aortic Venous: Bicaval (Total CPB) –Single Atrial if the infant is small and DHCA is anticipated
VSD venting:
may use direct venting with a flexible since the heart is open
VSD cardioplegia:
Antegrade, usually a single dose will suffice
VSD case notes:
–Case is quick depending on VSD location –Case may be 32°C, or DHCA if a small infant –Can be challenging, but usually you have more time with VSD –Ventricular function may be related to of the length of time the VSD has been present
why is Ventricular function may be related to of the length of time the VSD has been present
over time the ventricle may have compensated and hypertrophied
VSD surgical correction options:
- Percutaneous closure (Amplatzer) [can be tough] 2. Surgical Closure –Primary closure [less common b/c VSDs are muscular] –Patch Closure
