Medical autopsy - cardiovascular

Question 1

what causes myocardial ischaemia?

Answer 1

coronary atherosclerosis (90%)

coronary emboli

obstruction small myocardial vessels

decreased blood pressure (shock)

vasospasm

Question 2

how can myocardial ischaemia present? (4)

Answer 2

MI

angina

chronic IHD with heart failure

sudden cardiac death

Question 3

types of angina

Answer 3

stable (perfusion/demand imbalance, relieved by rest)

prinzmetal (artery spasm)

unstable (disruption or change in plaque)

Question 4

(usual) steps of MI

Answer 4

1. sudden change in plaque
2. activated platelets and mediators
3. coagulation cascade leading to thrombus
4. vessel occlusion and myocyte necrosis (irreversible damage after 20-30min)

Question 5

progress of myocardial necrosis

Answer 5

1. subendocardial (=NSTEMI)
2. extends to epicardium
3. full thickness necrosis (=STEMI)

Question 6

distribution of coronary arteries

Answer 6

LAD: apex, ant LV, ant 2/3 of septum

LCx: lateral LV

RCA: RV, post LV, post 1/3 of septum

Question 7

MI at 0-4 hrs

Answer 7

gross: none
histo: wavy myocytes

Question 8

MI at 4-24 hrs

Answer 8

gross: dark mottling
histo: necrosis, oedema, haemorrhage, contraction bands, eosinophilic

Question 9

MI at 1-3 days

Answer 9

gross: yellow centre
histo: neutrophils, loss of nuclei

Question 10

MI at 3-7 days

Answer 10

gross: yellow centre, hyperaemic rim
histo: phagocytosis by macrophages

Question 11

MI at 7+ days

Answer 11

gross: yellow tan (turning to grey white scar by 2 months)
histo: granulation tissue (turning to collagen scar by 2 months)

Question 12

reperfusion histo

Answer 12

haemorrhage (due to bleeding by injured blood vessels)

contraction bands (due to calcium through membranes of dead cells)

Question 13

possible consequences of MI (6)

Answer 13

contractile dysfunction

arrythmia

rupture (usu with haemopericardium and tamponade)

pericarditis (Dressler syndrome)

thrombus/aneurysm

chronic IHD

Question 14

what causes chronic IHD and what does it look like?

Answer 14

usually after MI due to hypertrophied unaffected myocardium

large heavy hearts, with CAD and healed infarcts

Question 15

causes of sudden cardiac death

Answer 15

fatal arrythmia (acute MI is most common trigger)

congenital/structural

valve disease

myocarditis

hereditary arrythmia

dilated or hypertrophic cardiomyopathy

drugs/metabloic/meds

Question 16

definition of hypertension

Answer 16

diastolic >90, systolic >140

Question 17

causes of hypertension

Answer 17

essential (>90%)

renal eg RAS

endocrine (eg phaeo)

CV (eg increased cardiac output)

neuro (eg psychogenic)

Question 18

consequences of hypertension

Answer 18

atherosclerosis

cardiac hypertrophy/heart failure

multi-infarct dementia

aortic dissection

CVA

renal failure

Question 19

formula for blood pressure

Answer 19

BP = cardiac output x vascular resistance

CO: blood volume, sodium etc

VR: constriction vs dilatation

Question 20

vascular changes in hypertension

Answer 20

1. hyaline arteriosclerosis: diffuse impairment of renal blood supply with glomerular scarring (=nephrosclerosis)
2. hyperplastic arteriosclerosis (onion skinning): due to malignant hypertension

Question 21

heart changes in hypertension

Answer 21

pressure overload with ventricular hypertrophy

L side: >2cm thick, >500g (micro: thick myocytes and interstitial fibrosis)

R side (cor pulmonale): acute dilatation and chronic thickening

Question 22

brain changes in hypertension

Answer 22

lacunar infarcts (sclerosis of small vessels)

slit haemorrhages (rupture of small vessels)

hypertensive encephalopathy: raised ICP (acute), multiinfarct dementia (chronic)

massive bleed (assoc with sclerosis)

Question 23

what is valve stenosis and what causes it?

Answer 23

= failure to open completely, leading to pressure overload

caused by:

rheumatic heart disease (AV or MV)

calcific aortic stenosis

calcification of congenitally deformed valve (AV)

Question 24

features of rheumatic heart disease

Answer 24

(immune disease after Strep throat)

macro: thick leaflets, fusion of commisures, thick and fused tendinous cords
micro: Aschoff bodies (inflammatory cell collections)

Question 25

what is valve insufficency and what causes it?

Answer 25

failure to close completely, leading to volume overload lots of causes: esp aortic dilatation in htn and aging and mitral valve prolapse in myxomatous degeneration also: Marfans, rh arthritis, infective endocarditis

Question 26

heart valve vegetations

Answer 26

rheumatic heart disease --.-.-.-.-.-- infective endocarditis ---\<0\>--- non-bacterial thrombotic endocarditis --o--o--o-- Libman-Sachs endocarditis (SLE) --0-o-.-0-o--

Question 27

potential problems with artificial valves (4)

Answer 27

thrombus infection dysfunction anticoag-related bleeding

Question 28

causes of myocarditis

Answer 28

viral infection (most common): cocksackie, CMV, HIV other infection: trypanosoma (Chagas disease), toxo, Lyme, diphtheria non-infectious: hypersensitivity (esp drugs) SLE, rh fever and other immune sarcoidosis transplant rejection

Question 29

pathological features of myocarditis

Answer 29

gross: normal or dilated, mottled micro: usu lymphocytic inflammation heals by progressive fibrosis eosinophils in hypersensitivity types giant cell variant (unknown cause)

Question 30

causes of aortic aneurysm (6)

Answer 30

connective tissue disease (Marfans, Ehlers-Danlos etc) collagen degradation in atherosclerosis cystic medial degeneration (due to htn) trauma vasculitis infection

Question 31

consequences of aortic aneurysm (3)

Answer 31

rupture obstruction/embolism compression of adjacent structure (eg ureter)

Question 32

what is aortic dissection and what causes it?

Answer 32

=blood-filled channel in media (may or may not be assoc with aneurysm) usually hypertensive (esp men in 40s-60s) also: CTD, iatrogenic, pregnancy

Question 33

types of aortic dissection

Answer 33

type A: starts at proximal aortic (DeBakey **II** to arch vessels, DeBakey **I** past arch vessels) type B: starts distal to arch vessels

Question 34

how does aortic dissection cause death?

Answer 34

1. rupture or 2. retrograde involvement of aortic valve (tamponande, infarct, valve insufficiency ect)

Question 35

What is HCM?

Answer 35

hypertrophic cardiomyopathy: structural disorder caused by point mutations in sarcomere proteins causes hypertrophy and myocyte disarray AD: 50% chance of inheritance