VIVA: Pathology - Cardiovascular system Flashcards
What are the risk factors for abdominal aortic aneurysm?
Age >60
Male
Smoking
HTN*
Atherosclerosis*
Diabetes mellitus
Family history
Connective tissue disease (e.g. Marfan’s, Ehlers-Danlos)
Vasculitis
Trauma
Congenital
Infection
Inflammation
*needed to pass + two others
Describe the pathogenesis of an aneurysm
- Aneurysms can occur when the structure or function of the connective tissue within the vascular wall is compromised
- Atherosclerotic plaque in intima compresses media, with degeneration and weakness of the wall and cystic medial degeneration
- Local inflammation (proteolytic enzymes with collagen degradation, role of matrix metalloproteinases)
- Loss of vascular smooth muscle cells
- Inappropriate synthesis of non-elastic ECM
What is the definition of cardiomyopathy?
Heterogenous group of diseases of the myocardium that is associated with mechanical and/or electrical dysfunction* that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilation*
Primary cardiomyopathies can be congenital or acquired
Secondary cardiomyopathies have myocardial involvement as a component of a systemic or multisystem disorder
*needed to pass
What are the types of cardiomyopathy? Give a cause of each
Hypertrophic *: 75% genetic cause, autosomal dominant HCM
Dilated *: alcohol, myocarditis, idiopathic, peripartum, genetic
Restrictive *: infiltrative (amyloidosis, sarcoidosis), non-infiltrative (idiopathic, scleroderma)
*needed to pass + one example of each
What type of cardiomyopathy is alcoholic cardiomyopathy?
Dilated
What are the clinical consequences of an aneurysm?
- Painful/painless mass
- Rupture* (risk increases with diameter >5cm, modest increase >4cm; retroperitoneal or intraperitoneal with rapid fatal haemorrhage)
- Obstruction: branch obstruction (e.g. mesenteric, vertebral, renal)
- Embolism: plaque or thrombus
- Impingement/compression of adjacent structures (e.g. ureter)
- Infection (mycotic aneurysm)
*needed to pass + 2 others
Describe the pathogenesis of an aortic dissection
- HTN*: aorta of hypertensive patients have medial hypertrophy of vaso vasorum and degenerative changes in the media
- Connective tissue disease (inherited or acquired)
- Both of the above cause weakness in the media*
- An aortic dissection starts with an intimal tear* and the blood dissects into the media along laminar planes either distally or proximally leading to the formation of a medial haematoma which may then rupture outwards
- Can subsequently develop cystic medial degeneration
*needed to pass
How are aortic dissections classified?
By site of involvement (either classification to pass):
1. Stanford:
- Type A: proximal to L subclavian
- Type B: distal to L subclavian
2. Debakey:
- Type I: ascending and descending aorta
- Type II: ascending only
- Type III: descending only
What are the potential consequences of aortic dissection?
3 to pass:
- Rupture back into intima or through adventitia
- Rupture out or into pericardial, pleural or peritoneal cavities
- Cardiac tamponade, aortic insufficiency, MI, distal ischaemia, spinal cord ischaemia
- Death
What are the risk factors for aortic dissection?
- Male
- Age 40-60
- HTN*
- Connective tissue disorders (e.g. Marfans, Ehlers-Danlos)
- Complication of arterial cannulation (iatrogenic)
- Trauma
- Pregnancy
*needed to pass + 1 other
What are the pathological consequences of aortic stenosis?
- Concentric LV hypertrophy*
- LV outflow obstruction
- Myocardial ischaemia (coronary artery disease need not be present)
- Syncope
- Aortic dissection
- Heart failure (diastolic or systolic)
- Endocarditis (uncommon)
*needed to pass + 3 others
What are the most common causes of aortic stenosis?
2 to pass:
- Calcific/degenerative
- Bicuspid valve
- Rheumatic heart disease
What clinical signs may differentiate calcific aortic stenosis from rheumatic aortic stenosis?
- Rheumatic disease involves more than one valve (i.e. aortic and mitral)
- Absence of features of MS/MR
- Absence of features of AR
What are the predisposing factors for calcific aortic stenosis?
- Age*: normal valve 70-90yrs, bicuspid 50-70yrs
- Bicuspid valve or other congenital abnormality
- Wear and tear, chronic injury
- Hyperlipidaemia
- HTN
- Inflammation
- Other factors associated with atherosclerosis
*needed to pass + 1 other
What are the potential complications of a congenital bicuspid aortic valve?
- Calcification*
- Stenosis*
- Regurgitation
- Infective endocarditis
- Aortic dilation
- Dissection
*needed to pass + 2 others
What are the systemic and local factors that lead to atherosclerosis?
- HTN*
- Hyperlipidaemia*
- Toxins from cigarette smoke*
- Homocysteine
- Infectious agents
- Inflammatory cytokines (e.g. TNF) can also stimulate pro-atherogenic patterns of endothelial cell gene expression
Two most important causes of endothelial dysfunction are haemodynamic disturbances and hyperlipidaemia*
Local flow disturbances (e.g. turbulence at branch points)* leads to increased susceptibility of certain portions of a vessel wall to plaque formation
*needed to pass
Which arteries are most often affected by atherosclerosis?
3/5 to pass:
- Lower abdominal aorta
- Coronary arteries
- Popliteal arteries
- Internal carotid arteries
- Vessels of the circle of Willis
How does an atherosclerotic plaque suddenly cause symptoms?
2/5 to pass:
1. Rupture, ulceration or erosion:
- Of the intimal surface of atheromatous plaques exposes the blood to highly thrombogenic substances and induces thrombosis
- Such thrombosis can partially or completely occlude the lumen and lead to downstream ischaemia
2. Haemorrhage into a plaque:
- Rupture of the overlying fibrous cap, or of the thin-walled vessels in the area of neovascularisation, can cause intra-plaque haemorrhage
3. Atheroembolism:
- Plaque rupture can discharge atherosclerotic debris into the bloodstream, producing microemboli
4. Aneurysm formation:
- Atherosclerosis-induced pressure or ischaemic atrophy of the underlying media, with loss of elastic tissue, causes weakness resulting in aneurysmal dilation and potential vessel rupture
5. Occlusion:
- Small vessels can occlude, compromising distal perfusion
Describe the differences between stable and vulnerable atherosclerotic plaque
- Stable:
- Dense collagenous and thickened fibrous caps * with minimal inflammation * and small underlying atheromatous * core - Vulnerable:
- Thin fibrous cap *, large lipid core * and increased inflammation *
- Prone to rupture
*2/3 for each
