Cardiovascular Pathology 3 Flashcards
what is the definition of congenital
present at birth, as congenital anomaly or defect
what is the definition of hereditary
transmitted from parent to offspring; inborn; inherited
what is the definition of familial
present in some families and not others or occurs in more family members than would be expected by chance
usually but not always hereditary
what is the definition of acquired
originating after birth
not caused by hereditary or developmental factors but by a reaction to environmental influences outside of the organism
what are the 3 structures of fetal circulation
- foramen ovale: opening between atria which allows fetal blood to flow from right to left
- ductus arteriosus: connects the pulmonary artery and the aorta –> not so important to perfuse lungs in-utero
- ductus venosus: connects portal and umbilical veins to vena cava
what occurs at birth to the fetal circulation
at birth when lungs are oxygenated blood supply demands change, pressure changes force the foramen ovale closed immediately
identify the components of fetal circulation and its function
what are the 4 main categoies of congenital defects
1. failure of closure of fetal structures
2. septal defects (ASD, VSD)
3. great vessel defects
4. endocardial cushion defects
what are defects of the failure of closure of fetal structures
foramen ovale
ductus arteriosus
ductus venosus (liver)
what are septal defects
ASD
VSD
what are great vessel defects
defects of outflow tracts –> aortic or pulmonary valves
- dysplasia: malformed or disorderly
- stenosis: decreased lumen size
- malposition/fusion of great vessels
what are endocardial cushion defects
dysplasia of mitral or tricuspid valves
what is shown here
patent foramen ovale
septum primum –> once pressure changes at birth pushes the primum down –> blood will flow from left to right
what is shown here
patent ductus arteriosus
joins the pulmonary arteries and the aorta
will be working much harder and will get hypertrophy of the right side
will end up with too much volume going to left side –> eccentric hypertrophy
what is shown here
patent ductus arteriosus
should become a fibrous structure –> ligamentum arteriosum
what are portocaval shunts
- congenital anomalies
- intra-hepatic
- extra-hepatic
what are portocaval shunt congenital anomalies
normal flow from portal vein is diverted to systemic circulation bypassing the liver
normal hepatic detoxification of portal flow incomplete
hepatic encephalopathy neurological signs (head pressing, teeth grinding, dullness, increased ammonia has effect on brain)
what are intra-hepatic portocaval shunts
persistent ductus venosus
what are extra-hepatic portocaval shunts
portocaval shunt
portoazygous shunt
little vessels around liver that will open up and let blood go around the liver and go the the vena cava directly
what is shown here
persistent ductus venosus
pale and small liver
probe going through the portal vein and goes straight into the vena cava and not through the liver at all
blood not detoxified at all
what is atrial septal defect and what is the pathology
opening between atria
will get mixing of blood which heads into the lungs
in neonate –> increased blood flow LEFT to RIGHT atrium
volume overload –> increased central venous pressure (Right atrial pressure) –> right ventricle dilates a
if significant pulmonary hypertension develops –> flow reversed, cyanosis develops
what is shown here
atrial septal defect
what is shown here
atrial distention
edematous lungs –> pulmonary congestion, dark and red
depends on the extent of septal defect –> some animals will only have mild signs as they grow but with increased activity there will be increased clinical signs
what is shown here
bovine ventricular septal defect
right below aortic outflow
what is the significance of VSD dependent on
- size of defect
- pulmonic vascular resistance relative to systemic resistance
- left to right shunt
what is left ventricular output maintained by in VSD
- increased end diastolic volume
- increased contractility (Frank-Starling mechanism)
which ventricles hypertrophy in VSD
both
but left more obviously eccentric
what eventually occurs in VSD
pulmonary hypertension (reversal of shunt, cyanosis, death)
Eisenmenger complex
what is VSD shunt reversal
what are endocardial cushion defects
valvular defects: increased pressure pushing blood –> failure of forward flow
-insufficiency (regurgitation) –> mitral dysplasia, tricuspid dysplasia
what are great vessel defects
stenosis (outflow obstruction)
- aortic stenosis
- pulmonic stenosis
what is shown here
AV valve dysplasia
-distorted leaflets, short chordae
valve insufficient, R atrium enlarged R ventrcile hypertrophied
what are the forms of aortic stenosis
- subaortic fibrous ridge = most common
- subaortic stenosis = second most common inherited heart disease in dogs
mostly in large pure bred dogs
what is shown here
outflow tract obstruction
trying to push blood hard through aorta –> concentric hypertrophy
blood squirting through thiner lumen –> dilation through aorta
see jet lesions (damage to endocardium)
what is shown here
subaortic stenosis
jet lesion: can end up with fibrosis or mineralization (chronic indicator)
what is shown here
pulmonic stenosis
fibrosis
narrowing of lumen
the ventricle works harder –> thick right ventricle
the PA has a bulge and jet lesions
what are left to right shunts (4) and what do they cause
congenital abnormality
- patent ductus arteriosus
- atrial septal defects
- ventricular septal defects
- atrioventricular canal
extra blood flows through the lungs
what is tetralogy of Fallot
- over-riding (dextraposed) aorta (moved to right)
- ventricular septal defect (immediately under the aorta)
- pulmonary stenosis: obstruction of R outflow
- right ventricular hypertrophy: right ventricle works too hard
3 primary changes and 1 secondary change
what does tetralogy of Fallot
pulmonary stenosis determines severity
deoxygenated blood enters systemic circulation
cyanosis
too little blood flows to the lungs
what is shown
tetralogy of fallot
narrowing of pulmonary valve –> very hard to get blood to lungs
the right ventricle works hard and undergoes secondary hypertrophy
mixing of blood
what is shown here
tetralogy of fallot
thickened RV
stenosis of pulmonary valve determines severity of tetralogy of fallot
list the congenital CV defects (7)
- PDA: patent ductus arteriosus
- patent foramen ovale
- ASD: atrial septal defect
- VSD: ventricular septal defect
- AV canal: endocardial cushion defect
- PS: pulmonic stenosis:
- SAS: subaortic stenosis
what are common congenital defects in dogs
PDA, PS, SAS
what are common congenital defects in cats
mitral dysplasia, AV canal
what are common congenital defects in cattle
ASD, VSD, TGV
what are common congenital defects in pigs
SAS, AV canal
what are common congenital defects in horses
uncommon
what are congenital vascular anomalies
abnormal arterial or venous connections
- persistent right aortic arch
- portosystemic shunts: include persistent ductus venosus
what is persistent right aortic arch and what does it cause
normally everything should develop on left side of heart –> when ductus arteriosus closes it leaves a fibrous band between the aorta and the pulmonary artery –> doesn’t really matter because they are on the same side (left)
BUT if aorta develops from right aortic arch it will be across the midline –> fibrous band will collapse the soft structures between esophagus –> okay in neonates because milk based diet –> when on solid food, obstruction, regurgitation –> megaesophagus
what is shown here
calf with persistent right aortic arch
fibrous strip
normally on same side as pulmonary artery
what is shown here
persistent right aortic arch
vascular ring
what is shown here
dog vascular ring
which category of lesion does pulmonic stenosis fall into
congenital defects –> great vessel defect
tetralogy of fallot
what are the primary and secondary changes with pulmonic stenosis
tetralogy of fallot
- over-riding (dextraposed) aorta
- ventricular septal defect
- pulmonic stenosis (obstruction of R outflow)
- right ventricular hypertrophy
why does a persistent right aortic arch result in a regurgitating dog
explain using a diagram
list the congenital anomalies resulting in a left to right shift
abnormal arterial or venous connections
- persistent right aortic arch
- portosystemic shunts: include persistent ductus venosus
which congenital anomaly causes right to left shift?
list the 4 components of this anomaly and which component represents a secondary response
tetralogy of fallot
- over-riding (dextraposed) aorta
- ventricular septal defects
- pulmonic stenosis (obstruction of R outflow)
- right ventricular hypertrophy (secondary change)
