A thrombus is a pathologic mainfestation of normal hemostasis.
COmmon: 1:1000
1 million Americans year.
Affects all adult age groups
Third most common cardiovascular disease.
Potentially lethal. Most common preventable death in hospitals.
D-dimer
Three primary influences lead to thrombus formation - endothelial injury, alterations in blood flow, and hypercoagulability.
Endothelial injury is the dominant cause of thrombosis, being capable of acting alone. It is particularly important in the heart or arterial circulation, where high flow volumes prevent platelet adhesion and dilute clotting factors.
Endothelial injury occurs in the heart during myocardial infarction, over ulcerated plaques in atherosclerosis, or at sites of inflammation during vasculitis.
Loss of endothelium exposes ECM, leading to platelet adhesion, release of tissue factor, and local depletion of PGI2 and PAs.
The endothelium can also become dysfunctional, producing larger amounts of procoagulant factors such as platelet adhesion molecules, tissue factor, or PAI or smaller amounts of anticoagulant factors.
Endothelial injury can be initiated by homocystinuria, hypercholesterolemia, radiation, or cigarette smoke products.
Turbulence can lead to arterial and cardiac thrombosis by injuring the endothelium or by producing local countercurrents and areas of stasis.
Stasis is a major factor in venous thrombosis.
Flow alterations disrupt laminar flow, bringing platelets in contact with the vessel wall. They also prevent inflow of anticlotting factors and increase clotting factor concentration, and promote endothelial cell activation.
NEJM paper on cancer-induced thrombosis