Medical autopsy - cardiovascular Flashcards
what causes myocardial ischaemia?
coronary atherosclerosis (90%)
coronary emboli
obstruction small myocardial vessels
decreased blood pressure (shock)
vasospasm
how can myocardial ischaemia present? (4)
MI
angina
chronic IHD with heart failure
sudden cardiac death
types of angina
stable (perfusion/demand imbalance, relieved by rest)
prinzmetal (artery spasm)
unstable (disruption or change in plaque)
(usual) steps of MI
- sudden change in plaque
- activated platelets and mediators
- coagulation cascade leading to thrombus
- vessel occlusion and myocyte necrosis (irreversible damage after 20-30min)
progress of myocardial necrosis
- subendocardial (=NSTEMI)
- extends to epicardium
- full thickness necrosis (=STEMI)
distribution of coronary arteries
LAD: apex, ant LV, ant 2/3 of septum
LCx: lateral LV
RCA: RV, post LV, post 1/3 of septum
MI at 0-4 hrs
gross: none
histo: wavy myocytes
MI at 4-24 hrs
gross: dark mottling
histo: necrosis, oedema, haemorrhage, contraction bands, eosinophilic
MI at 1-3 days
gross: yellow centre
histo: neutrophils, loss of nuclei
MI at 3-7 days
gross: yellow centre, hyperaemic rim
histo: phagocytosis by macrophages
MI at 7+ days
gross: yellow tan (turning to grey white scar by 2 months)
histo: granulation tissue (turning to collagen scar by 2 months)
reperfusion histo
haemorrhage (due to bleeding by injured blood vessels)
contraction bands (due to calcium through membranes of dead cells)
possible consequences of MI (6)
contractile dysfunction
arrythmia
rupture (usu with haemopericardium and tamponade)
pericarditis (Dressler syndrome)
thrombus/aneurysm
chronic IHD
what causes chronic IHD and what does it look like?
usually after MI due to hypertrophied unaffected myocardium
large heavy hearts, with CAD and healed infarcts
causes of sudden cardiac death
fatal arrythmia (acute MI is most common trigger)
congenital/structural
valve disease
myocarditis
hereditary arrythmia
dilated or hypertrophic cardiomyopathy
drugs/metabloic/meds
definition of hypertension
diastolic >90, systolic >140
causes of hypertension
essential (>90%)
renal eg RAS
endocrine (eg phaeo)
CV (eg increased cardiac output)
neuro (eg psychogenic)
consequences of hypertension
atherosclerosis
cardiac hypertrophy/heart failure
multi-infarct dementia
aortic dissection
CVA
renal failure
formula for blood pressure
BP = cardiac output x vascular resistance
CO: blood volume, sodium etc
VR: constriction vs dilatation
vascular changes in hypertension
- hyaline arteriosclerosis: diffuse impairment of renal blood supply with glomerular scarring (=nephrosclerosis)
- hyperplastic arteriosclerosis (onion skinning): due to malignant hypertension
heart changes in hypertension
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
brain changes in hypertension
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)
what is valve stenosis and what causes it?
= 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)
features of rheumatic heart disease
(immune disease after Strep throat)
macro: thick leaflets, fusion of commisures, thick and fused tendinous cords
micro: Aschoff bodies (inflammatory cell collections)
what is valve insufficency and what causes it?
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
heart valve vegetations
rheumatic heart disease –.-.-.-.-.–
infective endocarditis —<0>—
non-bacterial thrombotic endocarditis –o–o–o–
Libman-Sachs endocarditis (SLE) –0-o-.-0-o–
potential problems with artificial valves (4)
thrombus
infection
dysfunction
anticoag-related bleeding
causes of myocarditis
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
pathological features of myocarditis
gross: normal or dilated, mottled
micro:
usu lymphocytic inflammation
heals by progressive fibrosis
eosinophils in hypersensitivity types
giant cell variant (unknown cause)
causes of aortic aneurysm (6)
connective tissue disease (Marfans, Ehlers-Danlos etc)
collagen degradation in atherosclerosis
cystic medial degeneration (due to htn)
trauma
vasculitis
infection
consequences of aortic aneurysm (3)
rupture
obstruction/embolism
compression of adjacent structure (eg ureter)
what is aortic dissection and what causes it?
=blood-filled channel in media (may or may not be assoc with aneurysm)
usually hypertensive (esp men in 40s-60s)
also: CTD, iatrogenic, pregnancy
types of aortic dissection
type A: starts at proximal aortic (DeBakey II to arch vessels, DeBakey I past arch vessels)
type B: starts distal to arch vessels
how does aortic dissection cause death?
- rupture
or 2. retrograde involvement of aortic valve (tamponande, infarct, valve insufficiency ect)
What is HCM?
hypertrophic cardiomyopathy:
structural disorder caused by point mutations in sarcomere proteins
causes hypertrophy and myocyte disarray
AD: 50% chance of inheritance
