Reperfused MI...Characteristic Microscopic Pathology Findings Flashcards
What findings immediately follow reperfusion?
Beginning of Acute phase
contraction band necrosis and hemorrhage
coagulation necrosis (especially in center of big infarct) followed by neutrophilic infiltration
What findings immediately follow reperfusion?
Beginning of Acute phase
contraction band necrosis and hemorrhage
coagulation necrosis (especially in center of big infarct) followed by neutrophilic infiltration
When is coagulative necrosis first visible?
2 hours following reperfusion
no-reflow phenomenon
reversal of coronary obstruction by angioplasty or other means fails to restore blood flow into myocardium injured
What can no-reflow phenomenon be attributed to?
capillary endothelial swelling
capillary plugging by neutrophils
microthrombosis
microembolism
what can the hemorrhage caused by reperfusion be attributed to?
microvascular injury
What happens if microvascular flow is restored?
edema and neutrophilic infiltration throughout reperfused infarct
while myocytolysis occurs in viable myocytes around infarct
infiltration by macrophages
happens sooner and heavier than in unreperfused infarct…sometimes arrive by day 2
Fibroblasts
also may arrive sooner, as early as day 3
Early Subacute phase
Days 4-10
lymphocytes, sometimes eosinophils and plasma cells are present
formation of granulation tissue and then collagen
Reperfused infarct looks older than unreperfused infarct
Late Subacute phase
Days 11-end
with reperfusion, healing of large infarct can be…
accelerated from 12 to 7 wks
with reperfusion, healing of small infarct can be..
done within 2 wks
Reperfusion acclelerates…
healing by about 40% on average
Patches of preserved myocardium usually interspersed with…
scar
More of scar is commonly ____ rather than ___
interstitial rather than confluent
Reperfusion injury
damage of tissue when blood supply is restored after a period of ischemia
can happen in any organ
Examples of reperfusion injury
hemorrhage
no-reflow phenomenon
MOA of reperfusion injury
cell membranes (already abnormally permeable b/c of ischemia) may allow excess calcium into cells w/ reperfusion
O2 brought in by restored flow can give rise to injurious oxygen-derived free radicals and ROS
restored flow can bring overzealous inflammatory cells
interspersing of preserved mocardium with scar may…
make re-entrant ventricular cardiac arrhythmias more common b/c creates more irregular and circuitous routs for cardiac rhythm conduction
When is coagulative necrosis first visible?
2 hours following reperfusion
no-reflow phenomenon
reversal of coronary obstruction by angioplasty or other means fails to restore blood flow into myocardium injured
What can no-reflow phenomenon be attributed to?
capillary endothelial swelling
capillary plugging by neutrophils
microthrombosis
microembolism
what can the hemorrhage caused by reperfusion be attributed to?
microvascular injury
