25. Valvular and Ischaemic Heart Disease: Surgeon's Approach Flashcards
What are the main causes for cardiac ischaemia? (6)
- atherosclerosis
- embolism
- coronary thrombosis
- aortic dissection (torn layers which make up aortic elastic wall)
- arteritis
- congenital (e.g. coronary arteries arising from pulmonary trunk rather than aorta)
Which arteries are mainly responsible for ischaemic heart disease?
coronary arteries
What is La Place law?
The larger the vessel radius, the larger the wall vessel tension required to withstand a given internal fluid pressure
What are the manifestations which lead to ischeamic heart conditions in diagnosis? (5)
- angina
- MI
- arrythmias
- chronic heart failure
- sudden death
What are the 2 main dangerous patterns for coronary artery disease?
- left main stem stenosis
2. 3 vessel coronary artery disease (disease can be nearer aorta and nearer capillary branches at the same time)
What are 2 main indications for operating on the heart by CABG? (coronary artery bypass graft)
- Symptomatic (any coronary artery disease pattern)
2. Prognostic (left main stem stenosis or 3 vessel disease); can save lives by improving outcome
What is the selection criteria of patients for CABG surgery? (6)
- adequate lung function
- adequate mental function
- adequate hepatic function
- ascending aorta stable
- distal coronary targets stable
- l. ventricle ejection fraction >20%
What are the main conduits (grafts) for CABG made of?
- reversed saphenous vein (from leg)
- internal mammary arteries
- radial arteries
(most common is saphenous vein but others are used if more grafts needed)
Define anastomosis.
- connection made surgically between two adjacent blood vessels, parts of intestine or any other body channels
Describe what CABG is.
- appropriate vessels are harvested from legs, arms or groin area
- the portion of the blocked coronary artery is bypassed using a portion of healthy vessels from elsewhere in the body
- surgeon attaches one end of the healthy vessel above the blockage and one end below the blockage
- blood bypasses the blocked part by going through the new graft to reach the heart muscle
What are common sternotomy (vertical incision into the sternum) related problems? (4)
- wire infection (most serious)
- painful wires
- sternal dehiscence (splitting of wires due to weakness and heart exposed)
- sternal malunion (not healed properly)
Why is infection below the sternum the most dangerous?
-infection can get into the heart and will cause anastamoses to break down and cause bleeding
What condition can also cause sternal dehiscence?
Osteoporosis; due to thinning of the bone
What are main post-op problems in cardiac surgery? (3)
- cardiac temponade
- death
- stroke
What is cardiac temponade?
- Pressure on the heart that occurs when fluid or blood builds up between the heart muscle and the outer covering sac of the heart
- Needle used to remove fluid or surgical pericardiectoy performed which removes part of the pericardium (covering of the heart)
- increased collection of blood in pericardial sac which increases pressure on heart
What are the primary features of a cardiac temponade following a cardiac surgery? (3)
- raised CVP (central venous pressure)
- raised heart rate
- low BP
What are the secondary features of a cardiac temponde following a cardiac surgery? (3)
- oliguria (small amounts of urine produced)
- increased oxygen requirements
- metabolic acidosis
What are 2 possible treatments for a cardiac temponade? (3)
- Fluid removed using a needle from tissue around the heart
- Surgical pericardiectomy/ pericardial window performed which removes part of pericardium
- oxygen given and drugs for control of BP
What are statistics for long term outcomes post CABG? (3)
- 50% have no further cardiac problems 10 years later
- of the 50% who do have a problem, majority and minor and easily controlled by medication
- 5% of patients may require a repeat CABG
What does adults cardiac surgery mainly include? (2)
- aortic valve surgery
- mitral valve surgery
What does paediatric cardiac surgery mainly include?
All 4 heart valves operated with roughly equal frequency
What are the main causes of valvular heart disease in the adult? (8)
- degenerative
- congenital (e.g. 2 bicuspid valves)
- infective
- inflammatory
- l. ventricle or r.ventricle dilatation
- trauma
- neoplastic
- paraneoplastic
What causes a lot of degenerative valvular heart disease?
Ca build up; can lead to regurgitation when chords are exposed to excessive pressure and chords snap
What are the most common organisms to cause infective valvular heart disease? (2)
- s. aureus
- s. viridans
(common in drug addicts and influenza patients)
What is the name of a valve which is the most affected by valvular heart disease?
tricuspid valve
What is rheumatic fever?
- a relapsing illness
- can develop from an untreated throat infection cause by group A streptococcus
- antibodies against bacteria attack the joints and heart which cause heart valves to swell which can lead to scarring of valve cusps/leadlets
- related to streptococcal infections
What is the hallmark pathology of rheumatic fever?
pancarditis; inflammation of the whole heart which can lead to unexplained heart failure symptoms (then think rheumatic fever)
What are the most prominent symptoms of rheumatic fever?
- joint pain
- skin manifestations
- shortness of breath and chest pain
What is a common disorder which occurs in 20-30% of rheumatic fever patients?
Sydenham’s chorea/ St Vitus’ Dance can occur:
characterised by uncoordinated jerking movements affecting the face, hands and feet
What is rheumatic fever treated with?
Aspirin and bed rest (or long term course of antibiotics to prevent fever coming back)
What does chronic rheumatic heart disease often lead to? (2)
- progressive mitral valve problem diagnosis
2. aortic valve problem diagnosis
What is the most common heart problem worldwide and major cause of death in pregnancy?
chronic rheumatic heart disease
What is the organism which gives rise to subacute bacterial endocaditis?
strep viridans
What is the organism which gives rise to acute bacterial endocarditis?
staph aureus
What are 2 types of endocarditis?
- native valve endocarditis
2. prosthetic valve endocarditis
Which type of endocarditis (affecting which valve) has better chance of being cured with antibiotics alone?
- native valve endocarditis has 90% chance of cure with antibiotics alone
- prosthetic valve endocarditis has 50% chance of cure with antibiotics alone
Which organism has better chances of being cured?
strep viridans has higher chances of being cured rather than staph aureus
Why does prosthetic valve endocarditis have a worse prognosis?
- since infection is in the artificial valve, it doesn’t have its own blood supply like a natural valve
- antibiotics cannot diffuse effectively through a metal which means outcome isn’t as efficient
What are indications for surgery in endocarditis? (4)
- severe valvular regurgitation
- large vegetations
- pesistent pyrexia
- progressive renal failure, e.g. glomerulitis
What is given to surgical endocarditis patients post-operatively and for how long ?
antibiotics given through IV for 6 weeks
What does aortic stenosis typically present as? (4)
- heart failure
- angina
- syncopal episodes
- asymptomatic incidental finding
Is aortic stenosis murmur easily heard?
Yes, easy to detect (loss of aortic S2 differentiates it form aortic sclerosis)
What is aortic sclerosis?
- calcification and thickening of the 3-cusp/leaflet aortic valve in the absence of obstruction of ventricular flow
- increasingly common with increasing age
What can aortic stenosis eventually lead to?
L. ventricular hypertrophy:
as left ventricle has to pump harder to pump blood into the aorta through the narrowed valve
What is the AV gradient in l. ventricular hypertrophy?
AV gradient >50mmHg
What investigations are done to detect l. ventricular hypertrophy in aortic stenosis patients? (2)
- ECG
2. ECHO
What treatment is recommended for severe aortic stenosis patients?
aortic valve replacement
What does aortic regurgitation often present as? (3)
- heart failure
- angina
- asymptomatic incidental finding
Is the aortic regurgitation murmur easily found?
No; it’s difficult to hear
What is the link between murmur noise and severity?
The louder the murmur, the more severe the aortic regurgitation
What is the best treatment for severe aortic regurgitation?
aortic valve replacement; especially with l. ventricle dilatation (especially with l.ventricle dilatation)
Is mitral stenosis murmur easily heard?
No, it’s usually difficult to hear (if easily heard then stenosis is severe)
When is surgery recommended for mitral stenosis?
If mitral valve stenosis on echo is <1.5cm^2
Is mitral regurgitation murmur easily heard?
Yes, it’s easy to hear (if murmur is loud, then mitral regurgitation is severe); presystolic accentuation may be present
What is severe mitral regurgitation associated with? (3)
- left ventricular and left atrial dilation (hypertrophy)
- onset of atrial fibrillation
- pulmonary hypertension
What is severe mitral regurgitation on ECHO characterised by?
characterised by systolic blood flow reversal in the pulmonary veins
How does cardiopulmonary bypass work?
- blood is drained from the r.atrium and returned to the ascending aorta
- heart and lung function is taken over by CPB machine
- induced hypothermia
- systemic anticoagulation necessary
What is the blood flow like during CPB (cardiopulmonary bypass)?
it’s non-pulsatile
What is the max. time limit for the cardiopulmonary bypass?
12 hours (max. cardiac ischaemic time is 6 hours)
What healthcare professional operates the CPB (bypass) machine?
perfusionist
What is the most common problem during a cardiopulmonary bypass?
coagulopathy (body’s ability to coagulate is impaired)
In what surgical procedures are air embolisms more common?
More common in OPEN cardiac surgical procedures e.g. valve replacements (than closed cardiac operations such as CABG)
What are the different valve approaches? (3)
- biological valve
- mechanical valve (most patients)
- mitral valve REPAIR
What is the main pro and con of biological valve?
Pro= no warfarin required Con= valve wears out after 15 years
What is the main pro and con for a mechanical valve?
Pro= valve lasts for >40 years Con= Warfarin required for life
When is mitral valve repair possible?
Possible in many cases of degenerative mitral regurgitation; when complete valve competence is restored, repair is better than replacement for the mitral valve
What are characteristics of an aortic stenosis? (SAD)
- syncope
- angina
- dyspnoea
= SAD
What are causes of aortic regurgitation? ( CREAM)
- congenital
- rheumatic disease/ damage
- endocarditis
- aortic dissection
- Marfan’s
= CREAM
