What is the expected outcome of thrombolytic drug therapy?
A. Increased vascular permeability
B. Vasoconstriction
C. Dissolved emboli
D. Prevention of hemorrhage
Correct Answer: C. Dissolved emboli.
Thrombolytic therapy is used to dissolve emboli and reestablish cerebral perfusion. Thrombolytic treatment is also known as fibrinolytic or thrombolysis, to dissolve dangerous intravascular clots to prevent ischemic damage by improving blood flow. Thrombosis is a significant physiological response that limits hemorrhage caused by large or tiny vascular injury.
Option A: Hemostasis and thrombosis are a result of an integrated and interactive response of the coagulation factors, blood vessels, and platelets. During thrombosis, circulating prothrombin is converted to its active form thrombin by activated platelets. Active thrombin then converts the fibrinogen into fibrin with eventual formation of a fibrin matrix. This process is counterbalanced by plasmin derived from plasminogen, which gathers in the fibrin matrix.
Option B: Tissue plasminogen activator (tPA) is a natural fibrinolytic found in endothelial cells. It shows fibrin specificity and affinity. The end goal of this therapy is to convert plasminogen into plasmin which is accomplished at the location of the thrombus and on the surface of fibrin by the binding of tPA to plasminogen. This binding helps the conversion.
Option D: Streptokinase is the first historical thrombolytic agent extracted from certain streptococcal strains. Researchers found another potential fibrinolytic agent in human urine named urokinase. In contrast to streptokinase, urokinase lacks antigenicity and directly converts plasminogen to plasmin. These two substances catalyze the formation of plasmin from plasminogen and are affected slightly by the local fibrin clot, thus have a higher systemic effect.
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