High levels of D-dimers are associated with which conditions?

High levels of D-dimers are indicative of increased fibrinolytic activity and are commonly associated with conditions that involve thrombosis and fibrin breakdown. D-dimers are degradation products of fibrin and are commonly used in clinical practice as a biomarker for thrombosis. When there is the formation of a thrombus, such as in deep vein thrombosis (DVT) or pulmonary embolism (PE), fibrin is generated, and subsequently, D-dimers are released as the thrombus is degraded.

In the case of DVT, blood clots form in the deep veins, typically of the legs, and cause an increase in D-dimer levels due to the breakdown of fibrin in the clot. Similarly, pulmonary embolism occurs when a clot from the venous system dislodges and travels to the pulmonary arteries, leading to vessel obstruction. The formation and breakdown of fibrin due to the embolic event also result in elevated D-dimer levels.

Therefore, both conditions—DVT and PE—are associated with high D-dimer levels due to their mechanistic relationship with clot formation and subsequent fibrinolysis. Additionally, disseminated intravascular coagulation (DIC) also leads to elevated D-dimer levels; however,