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)