Cardiothoracic Surgery Flashcards
what is coronary artery bypass graft (CABG)?
uses a graft blood vessel taken from elsewhere in the body to bypass a blockage in the coronary atery
where is the graft blood vessel usually taken from?
saphenous vein
scar in CABG
midline sternotomy scar
what does the right coronary artery supply (RCA)?
RA
RV
inferior aspect of LV
posterior septal area
what does the circumflex artery supply?
LA
posterior aspect of LV
what does LAD supply?
anterior aspect of the LV and anterior aspect of the septum
what does atherosclerosis cause?
stiffening of artery walls leading to hypertension and strain on the heart (increased resistance)
stenosis leading to reduced blood flow (angina)
plaque rupture, thrombus and ischaemia
what can ED be an indicator of?
arterial disease
what is cardiopulmonary bypass?
takes blood from the vena cava/ RA and pumps it through a machine that adds oxygen and removes CO2 fro the blood and pumps it back into the ascending aorta
what medication is given alongside cardiopulmonary bypass?
heparin
what is cardioplegia?
stopping the heart from beating
how to cause cardioplegia?
delivering a high K+ solution to the coronary circulation
three main options for graft vessels
saphenous vein (inner leg) internal thoracic artery radial artery
what is a pedicled graft?
artery is proximally attached to original site whilst changing where it supplies
what is a free graft?
separated from its original connections
why are vein grafts not as good as arteries?
become stenosed (intimal hyperplasia)
how long is recovery in grafts?
3 months uncomplicated
heart valve scar
midline sternotomy (mitral or aortic)
types of valve replacements
- bioprosthetic
2. metallic mechanical valve
lifespan of bioprosthetic
10 years
what is required in metallic mechanical valves?
lifelong anticoagulation
INR target in metallic mechanical valves
2.5-3.5
types of metallic mechanical valves
- Starr-Edwards
- Tilting disc
- St Jude valves/ bileaflet valves
why are star-edwards no longer used?
high risk of thrombus formation
which metallic mechanical valve type has the lowest risk of thrombus formation
st judes/ bileaflet valves
major complications of mechanical heart valves
thrombus
IE
haemolysis/ anaemia
when is a transcatheter aortic valve implantation TAVI used?
severe aortic stenosis
procedure in a TAVI
catheter inserted into the femoral artery under XR
balloon inflated to stretch valve and implant a bioprosthetic valve
two divisions of congenital heart disease
- cyanotic
2. acyanotic
what is cyanotic heart disease
bypasses pulmonary circulation (right to left shunt)
conditions that cause cyanotic heart disease
VSD
ASD
PDA
transposition of the great arteries
eisenmengers syndrome
blood flows across defect despite higher pressure in left size of the heart
types of ASD
- PFO (not strictly classified as ASD)
- ostium secondum
- ostium primum (tends to lead to AVSD)
why does blood move from left to right?
higher pressure in the left side of the heart
what does blood movement to the right side of the heart cause?
RVH
DVT + stroke
ASD or VSD clot
murmur in ASD
mid-systolic crescendo-decrescendo murmur at upper left sternal border with fixed split of S2 (pulmonary valve closing later due to blood flow increase)
management of ASD
watch and wait
percutaneous catheter closure
open heart surgery
anticoagulation
VSD condition associations
DOwn’s
Turner’s
can VSD develop after MI?
yes
murmur in VSD
pan-systolic at lower left sternal border (3rd-4th ICS)
systolic thrill
pan-systolic murmur
VSD
mitral regurg
tricupsid regurg
management of VSD
transvenous catheter closure
open heart surgery
risks IE
VVI pacing
used in atrial conditions as atria are not sending proper contractions to ventricles
fibrillation in the context of a normal HR
not particularly pathological
AAI pacing
used for SA node dysfunction
DDD mode pacing
both atria and ventricles
