CV surgery and congenital heart defects Flashcards
1
Q
CV surgery questions
A
- Aneurysm= 2x normal size
- Reasons to operate on an Ao aneurysm (type B only): persistent pain, mal perfusion, aortic rupture
- Ao aneurysms: type A includes ascending, type B only descending
- Ao stenosis: long latency period (w/o Sx), but once Sx appear 50% will be dead in 2 yrs
2
Q
Classification of congenital heart defects (CHDs)
A
- Acyanotic (shunt) lesions: atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA)
- Obstructive lesions: pulmonic stenosis, aortic stenosis, coarctation of aorta
- Cyanotic lesions: transposition of great arteries, tetralogy of fallot
3
Q
Physiology of left to right shunts
A
- Pulmonar artery pressure should be about 1/5th of systemic pressure
- Right heart/pulmonary circulation is low resistance, high capacitance
- Left heart/systemic circulation is high resistance, limited capacitance
- Left-right communication (defect): redirection of oxygenated blood from high resistance (systemic) to low resistance (pulmonary) circulation
- Redirection is based on resistance, not pressure
4
Q
Atrial septal defect (ASD)
A
- Left-right atrial shunt
- Since the RV is more compliant than LV there is R heart volume overload
- There is RAE, prominent RV impulse, and possible dilated RV
- There is systolic ejection murmur (pulmonic- due to increased volume thru pulmonic valve) and split S2
- Late risks: paradoxic embolism, arrhythmias
- Rx: device closure
5
Q
Ventricular septal defect (VSD) 1
A
- Can be pressure restrictive (pressure difference btwn ventricles is maintained- small hole) or pressure non-restrictive (pressure difference equalizes btwn ventricles as more blood enters RV- large hole)
- Pressure restrictive VSD: LVP»RVP and there is harsh systolic ejection murmur
6
Q
Ventricular septal defect (VSD) 2
A
- Pressure non-restrictive VSD: LVP=RVP, but PVR (pulmonary vascular resistance) is less than SVR, so there is L->R shunt
- Results in CHF, systolic murmur (blood going thru VSD from LV->RV since SVR>PVR) and diastolic murmur (increased flow from LA->LV)
- Can lead to pulmonary HTN and then the shunt reverses (since PVR>SVR)
- In a R-L shunt there is cyanosis (not all blood reaches lungs), and a loud P2
7
Q
Clinical course of VSDs
A
- Unrestrictive VSDs will often need surgery in infancy to prevent CHF
- Late risks: endocarditis, Ao valve prolapse
- Rx: surgical closure
8
Q
Patent ductus arteriosus (PDA)
A
- Prevalent in premature infants
- Closes due to increase in pO2 and decrease in prostaglandins (PGE1)
- Causes a shunt of oxygenated blood from Ao to pulm arteries (PVR<SVR)
- This leads to continuous murmur (both diastolic and systolic) b/c there is constantly blood moving from Ao to PA
- Risks: newborns at risk for CHF, respiratory failure and children at risk for endocarditis
- Rx: coil occlusion
9
Q
Obstructive congenital heart defects
A
- Pulmonic stenosis, Ao stenosis, coarctation
- Ventricle must generate increased pressure, leading to compensatory hypertrophy, hyperplasia, post-steonitic arterial dilation
- Newborns are in high-output state (increased HR) and increased pressure requirement results in early circulatory failure
10
Q
Pulmonary stenosis
A
- Obstruction to RV systolic ejection: RVH and PA dilation
- May be mild (ASx), moderate (exercise limitation), or severe
- Severe (RVP>LVP) may be comorbid with ASD (R->L atrial shunt) resulting in cyanosis
- PE: harsh systolic murmur @ upper sternal borders radiating to lungs, ejection click, possible hepatomegaly
- Can see PA enlargement and post stenotic dilation on CXR
- RVH (possible RAE) on ECG
- Rx: ballot catheter dilation
11
Q
Aortic stenosis
A
- Dysplasia of Ao leaflets leads to limited valve motion
- Obstruction to LV systole: LVH and mitral insufficiency (secondary MR)
- Also mild (ASx), moderate (exercise limitation), and severe (LV failure)
- PE: harsh systolic murmur, ejection click, suprasternal thrill
- Rx: balloon catheter and surgery
12
Q
Hypoplastic left heart syndrome (HLHS)
A
- Underdeveloped LV size, hyper plastic septum and LV wall
- Must keep PDA open
- Rx: Norwood procedure where they fuse Ao to RV and Rv does all the work
13
Q
Coarctation of the Ao
A
- Narrowing of Ao causing a large gradient btwn Asc and Desc Ao
- High BP in UEs but low or normal in LEs
- May lead to increased renin-angiotensin activation (due to decreased renal perfusion), rib-notching (for collateral circulation)
- Neonatal coarctation: hypoplastic aortic isthmus
- Discrete coarctation: discrete narrowing of Ao
- Clinical course: may get CHF in newborn, and if there is PDA the lower extremities will get cyanosis due to PDA deoxygenated blood
- If severe coarctation want to keep PDA open (give PGE1) to promote blood flow to LEs
- Rx: surgical intervention
14
Q
Tetralogy of Fallot 1
A
- 4 things: VSD, pulm stenosis, RVH, overriding Ao (over the RV)
- There is mal-alignment of infundibular septum: unequal distribution of LV/RV outflow tracks
- This along w/ VSD and pulm stenosis lead deoxygenated blood to be shunted R->L to Ao leading to cyanosis
- Severity depends on pulm stenosis, b/c that dictates PVR and thus the amount of shunting
15
Q
Tetralogy of Fallot 2
A
- Pts will have harsh systolic murmur (PS), decreased pulmonary arteries in CXR, along w/ boot-shaped heart on CXR, clubbing from chronic cyanosis
- Pts often squat when feeling out of breath to increase venous return and TPR
- Rx is surgical repair
