Management of blood clots or thrombosis
Normally blood constantly flows smoothly through blood vessels. However, thrombosis, which is the formation of a clot inside a blood vessel, disturbs and obstructs efficient blood circulation. Thrombosis can have serious health consequences and even cause death.
Current antithrombotic therapies can be grouped into two classes: 1) Antiplatelet drugs that prevent platelet driven blood clots developing in arteries; and 2) Anticoagulant drugs that prevent blood coagulation driven clots developing in veins or those caused by heart arrhythmia, such as atrial fibrillation. In addition, there are fibrinolytic therapies which assist in dissolving clots after they form.
Under normal conditions, a vascular injury is healed via a series of specific activation, adhesion and aggregation of platelets, and subsequent coagulation activities. In some instances, these mechanisms can become exaggerated, leading to formation of a clot (thrombus).
A thrombus consists of platelets and fibrin. The optimum antithrombotic therapy should be directed towards both. None of the currently available antithrombotic drugs have both antiplatelet and anticoagulant effects. Neither do they specifically target the vascular injury area where the clot formation takes place, which are prone to inflammation that further enhances thrombus formation, and often vice versa.
This thromboinflammation is typically caused by atherosclerosis, where cholesterol, inflammatory cells and proteins accumulate at the vascular wall, enhancing the propensity to thrombosis. In addition, severe infections (e.g. COVID-19) or other inflammatory conditions (e.g. cancer or vasculitis) can trigger occlusive events at the affected vascular sites.