Valvular heart disease Surgery - therapy Flashcards
* What are the causes of cardiac ischaemia?
- Atherosclerosis
- Embolism – blood clot forms on aortic valve
- Coronary thrombosis
- Aortic dissection – tear on inside of the aorta – blood dissects into the inside of the aorta – creates an extra space between aortic layers – this wall expands at the expanse of the true lumen
- Arteritides – inflammation of the arteries
- Congenital
* What are the manifestations of ischaemic heart disease?
- Angina
- MI
- Arrythmias
- Chronic heart failure
- Sudden death
* What are the Dangerous patterns of Coronary Artery Disease?
- Left main stem stenosis
- 3 vessel coronary artery disease – where the narrowing is near the origin of the coronary artery there is a risk of sudden death
*Which patients are suitable for CABG?
- Adequate lung function
- Adequate mental function
- Adequate hepatic function
- Ascending aorta OK
- Distal coronary targets OK
- LV EF > 20%
What is the surgical treatment for treatment of ischaemic heart disease?
CABG,
. Coronary artery disease (CAD) is the narrowing of the coronary arteries – the blood vessels that supply oxygen and nutrients to the heart muscle
What are the possible conduits for CABG?
- Reversed saphenous vein
- Internal mammary arteries _ left one – branch of the subclavian artery – normally supplies blood to the breasts
- Radial arteries – radial is the easier artery to get out of the arm than the ulnar
What are long term outcomes for CABG?
- 50% have no further cardiac problems 10 years later
- Of the 50% who do have a problem, the majority are minor and easily controlled with medication
- 5% of patients may require repeat CABG
- Risk of death for a second CABG is much higher – 10%
Where does the cardioplumonary bypass machine pass blood to and from?
- Blood drained from the RA and returned to the ascending aorta
What is the function of the CPB machine?
- Heart and lung function taken over by CPB machine
What is the main problem of CPB machines?
Coagulopathy
When is air embolism more common?
- Air embolism is more common in open cardiac surgical procedures such as valve replacement than in closed cardiac operations such as CABG
What are the sternotomy related problems associated with surgery?
- Wire infection
- Painful wires
- Sternal dehiscence – wires are cut through the sternum – can be as a result of osteoporosis
- Sternal malunion
What are the Post-op problems in cardiac surgery?
Cardiac Tamponade
Death
Stroke
What is cardiac tamponade?
Compression of the heart by an accumulation of fluid in the pericardial sac - prevention of filling properly in the atria
What are the features of cardiac tamponade?
Primary features – Raised CVP, raised heart rate, low BP
Secondary features – Oliguria, increased oxygen requirements, metabolic acidosis
What is the treatment for cardiac tamponade?
Chest - reopening
What are the common valve surgeries in adults?
Mainly aortic and mitral valve surgery
What are the common valve surgeries in children?
- All four heart valves operated with roughly equal frequency
What are the commonest valve problems requiring cardiac surgery in aberdeen?
- Senile Tricuspid aortic stenosis
- Bicuspid aortic stenosis
- Degenerative MR
What is the presentation of aortic stenosis?
Presents as heart failure, angina, syncopal episodes or as an asymptomatic incidental finding
- The murmur is usually easily heard
ECG/ECHO findings for aortic stenosis?
Left ventricular hypertrophy
What is the likely AV gradient for aortic stenosis?
Above 50mmHg
When is atrial valve replacement recommended?
Severe aortic stenosis
What is the typical presentation for aortic regurgitation?
Heart failure, angina, or as an asymptomatic incidental finding
- The murmur is usually difficult to hear
- The louder the murmur the more severe the AR
When is aortic valve replacement necessary for aortic regurgitation?
- Recommended for severe AR especially with LV dilatation
- In severe AR the entire LV is filled with contrast after one diastolic interval during aortography
Describe the murmur of mitral stenosis?
- Murmur is usually difficult to hear
- If easily heard then the stenosis is severe
- May have to exercise the patient to hear the murmur
- Presystolic accentuation may be present
When is surgery recommended for mitral stenosis?
If MVA (mitral valve area) on ECHO is < 1.5cm2
Describe the murmur of mitral regurgitation
- Murmur is usually easy to hear
- If murmur is loud, MR is usually severe
What is severe mitral regurgitation associated with?
LV and LA dilatation, onset of AF and pulmonary hypertenison
When is mitral valve replacement necessary for mitral regurgitation?
When there is severe MR present
- Severe MR on ECHO characterised by systolic blood flow reversal in the pulmonary veins
What are the common causes of valvular heart disease in the adult?
- Degenerative – aotric or mitral valve – calcium forming in the valve – 10% of people over the age of 70. Degenerative mitral valve disease refers to mitral regurgitation
- Congenital – bicuspid aortic stenosis – middle age – aortic stenosis
- Infective – Endocarditis (sub – acute bacterial endocarditis streptococcus vividens from dental practice)(acute endocarditis – staph aureus – usually from drug abusers
- Inflammatory
What is the typical pathology of rheumatic fever?
Pancarditis
Related to streptococcal infections
Skin and joint manifestations are usual – migratory erythema – blotchy red skin, sore joints
treated with aspirin and bed rest.
What are the different types of vavles?
Biological valve and mechanical valve
Describe the biological valve
- No warfarin required but the valve wears out after 15 years
Describe the mechanical valve
- Last 40/50 years– Warfarin required for life. Valve lasts for > 40 years - Counselling for warfarin – can do high risk activity – head injuries are now likely to be fatal
What is a common treatment of mitral regurgitation?
Mitral valve repair,
- possible in many cases of degenerative MR. When complete valve competence is restored, repair is better than replacement for the mitral valve.
What gives rise to sub-acute and acute endocarditis?
- Strep viridans the commonest organism – gives rise to subacute bacterial endocarditis
- Staph aureus the second commonest organism – gives rise to acute bacterial endocarditis
What is the likelihood of cure with antibiotics alone of NVE and PVE?
- NVE (native valve endocarditis)- 90% chance of cure with antibiotics alone
- PVE (prosthetic valve endocarditis)– 50% chance of cure with antibiotics alone
- Chances of cure much higher with strep viridans endocarditis than with staph aureus
What are the indications for surgery in endocarditis?
- Severe valvular regurgitation – once the valve has been destroyed
- Large vegetations – vegetation can break off and cause stroke
- Persistent pyrexia – inability to control the infection
- Progressive renal failure – glomeruli inflammation – permanent renal damage
Antibiotics are given IV for 6 weeks post-operatively – kept in hospital for this
