What is Deep Vein Thrombosis?
Deep Vein Thrombosis (DVT) is a disease caused by the appearance of blood clots in deep veins, generally in an individual's leg. It is estimated 900, 000 Americans suffer from DVT annually (Beckman et. al, 2010).
DVT arises following abnormalities in fibrinolysis, the process of clot removal. Healthy clot formation, and coagulation, prevent excessive bleeding (Hemorrhage). However, clots require elimination to resume normal bodily functions. A balance exists between coagulation and fibrinolysis, and if this balance is disturbed in favor of coagulation (lack of fibrinolysis shown in Figure 1), thrombosis ensues (Blann, 2009). Symptoms include swelling and pain similar to cramping starting in the calf. However, some cases of DVT do not have noticeable symptoms.
Figure 1 (Society of Interventional Radiology, 2003) Importance DVT itself is not fatal; however, the condition could trigger more serious issues. DVT seeds pulmonary embolism (PE), a fatal disease where a clot becomes lodged in the arteries of the lungs (Goldhaber & Morrison, 2002). PE has been linked to the death of 60,000 - 100, 000 Americans each year, with 10-30% of them dying within the first month of diagnosis (Beckman et al., 2010). Furthermore, a study conducted in the UK in 1989 indicated 28% of DVT patients fell victim to severe post-thrombotic syndrome, developing congestive lung disease, myocardial infarction, cancer, or stroke (Blann 2009).
Treatment
The basis of DVT treatment lies in targeting clotting proteins. Patients have a choice between two classes of treatment drugs; ones that are orally ingested, Vitamin K Antagonists (VKAs), mainly Warfarin, and Novel Anticoagulants (NOACs), and ones which are parenteral, Heparins and Hirudins (British Medical Association & Royal Pharmaceutical Society, 2009). A small number of non-drug treatments are also available in case an individual cannot tolerate drugs. The most common non-drug treatment is the inferior vena cava filter.
Orally Administered Drugs
Orally-ingested treatments consist of a wide range of drugs, each subgroup using different approaches to prevent inappropriate thrombosis. The first category of drugs VKAs, revolves around inhibiting the production of Vitamin-K-dependent thrombin and clotting factors in the liver (Lip & Hull, 2016).
The drug Warfarin is the most common of this group. Despite a slow onset, it effectively decreases clotting rates and in the long run, prevents the appearance of DVT. Warfarin possesses a narrow therapeutic index; thus, consumption of this drug demands close monitoring. A person's prothrombin time is tested and compared to the internationalized normal ratio (INR) (Blann, 2009). Although, this treatment is in the process of being replaced by the next generation of oral drugs, NOACs.
NOACs, Novel Oral Anticoagulants, are the future of DVT treatment. These drugs directly affect molecules of the coagulation pathway. They exist in two furt...
