Outline of Lecture
INFARCTION
An infarct is an area of ischemic necrosis caused by occlusion of either arterial supply or the venous drainage.
IHD – 40% deaths in USA
Pulmonary infarction
Bowel infarction
Gangrene – serious problem in diabetics
Thrombotic or emolic occlusion
Rare causes include vasospasm, haemorrhage into athermatous plague
Extrinsic vessel compression by tumour
Torsion of vessel (testicular torsion)
MORPHOLOGY
RED INFARCT
Occur with venous occlusion
Affected tissue is congested due to sluggish venous flow.
WHITE INFARCT
Occur with arterial occlusion in solid organ in heart, spleen and kidney
COAGULATION MECHANISM
NEW CONCEPTS OF THE BLOOD COAGULATION REACTIONS
FORMATION OF THE FIBRIN CLOT
FIBRINOLYSIS
Plasminogen
Single chain glycoprotein found in plasma in concentration 20-40 mg/dl
During clotting process it form complex with fibrin
Plasminogen Activators
Factor XIIa, Kallibrein and HMWK
T-PA- secreted by endothelial cells
U.KA- produced by kidneys
Streptokinase – used therapeutically
DEGRADATION OF FIBRINOGEN AND NON CROSSLINKED FIBRIN
DEGRADATION OF CROSS-LINKED FIBRIN
Acute MI: Initial ECG
Non-diagnostic ECG’s
Normal
Subtle ST-T changes
Isolated T-wave changes
Negative U-waves
Normalization of previous abnormal ST-segment and T-waves
Conduction defects
“Silent” areas: right, posterior
Acute MI: Serum Markers
Biochemical Markers II
