Nsc1103D Clinical Sciences | Blood Assessment Answers

Draw a Concept Map on topic Blood clotting cascade affected by Warfarin.

Introduction

The clotting process consists of a system that enables the formation of blood clots following a tissue injury (Gee, 2018). During the process, various clotting factors are involved in a coagulation cascade. The clotting factors that control both intrinsic and extrinsic pathways include factors I, II, III, IV, V, VII, VIII, IX, X, XII and the tissue factors C and S. Furthermore, there are other crucial factors that enhance coagulation which includes vitamin K and calcium ions. (Gee, 2018). Some of the coagulation factors are activated by Vitamin K.Warfarin is a vitamin K antagonist thus it inhibits the clotting process (Tshikudi, Tripathi, Hajjarian, Van Cott & Nadkarni, 2017).Introduction of Warfarin into the body will in turn lead to a homeostatic  imbalance as it will inhibit the normal coagulation cascade.

How the coagulation cascade is affected by warfarin

Blood clotting cofactors play a major role in a coagulation cascade. Most of the blood clotting factors exists in inactive forms thus require activation in order to work. Deficiency, failure or inhibition of one or more cofactors will result in the failure of blood clotting factors activation leading to an imbalance.(Palta, Saroa & Palta, 2014). Vitamin K is used in the activation of factors X, IX, VII and II. The decrease in vitamin K will lead to inhibition of the clotting process, and its increase will enhance the coagulation cascade.  

The vitamin K epoxide reductase (VKOR) is a liver microsomal enzyme that acts as a catalyst in the conversion of specific vitamin K dependent glutamyl precursors to gamma-carboxyl glutamyl residue in a plasma form of these proteins. The final product formed after the whole carboxylation process is 2,3 epoxide of vitamin K Quinone which is the active form of vitamin K (Tshikudi, Tripathi, Hajjarian, Van Cott & Nadkarni, 2017).  Warfarin inhibits the clotting process by blocking the VKOR enzyme. The inhibition of VKOR leads to a reduction of vitamin K peroxides. Warfarin can also oxidize vitamin K into its inactive coenzyme commonly referred to as hydroquinone (Tshikudi, Tripathi, Hajjarian, Van Cott & Nadkarni, 2017). Since vitamin K is required in the carboxylation process of glutamyl carboxylase, the reduction and oxidation characteristics of Warfarin affect the whole coagulation process (Goodman, Brunton, Chabner & Knollmann, 2012).

Below is the concept map that demonstrates how warfarin affects the coagulation cascade.

Summary Concept map

• A summary concept map normally presents and shows a relationship between various facts, items, and values in the form of a diagram to illustrate a given concept of knowledge.
• A concept map is designed to illustrate an overall picture of a process by demonstrating how a number of interacting subsystems work to bring an overall outcome.
• The diagram below demonstrates how warfarin affects the coagulation process by inhibiting vitamin K dependent clotting factors.

Concept Map and the disease

• For instance, the above concept map can be used to explain a disease process of a patient recently admitted in an emergency unit with multiple injuries and suspected to be forming clots in blood capillaries.
• The body usually responds and initiates the clotting process after a tissues injury.
• During the clotting process, both the intrinsic and extrinsic pathways are involved where all the clotting factors are used.
• The vitamin K peroxides are used in the activation of clotting factors X, IX, VII and II, and proteins S and C which in turn lead to a non-interrupted coagulation process.
• Introduction of a warfarin dose to the patient will lead to inactivation of vitamin K peroxides to their coenzymes or oxidize them to hydroquinones thus the coagulation cascade is affected.
• This, in turn, will lead to continuous bleeding and smooth blood flow in the capillaries hence no clots will be formed

References

Gee, E. (2018). Principles and nursing management of anticoagulation. Nursing

Standard, 32(23), 50-63.

Goodman, L., Brunton, L., Chabner, B., & Knollmann, B. (2012). Goodman & Gilman's

The pharmacological basis of therapeutics. New York: McGraw-Hill.

Malátková, P., Sokolová, S., Chocholoušová Havlíková, L., & Wsól, V. (2016). Carbonyl

reduction of warfarin: Identification and characterization of human warfarin reductases. Biochemical Pharmacology, 109, 83-90.

Palta, S., Saroa, R., & Palta, A. (2014). Overview of the coagulation system. Indian Journal Of

Anaesthesia, 58(5), 515.

Tshikudi, D., Tripathi, M., Hajjarian, Z., Van Cott, E., & Nadkarni, S. (2017). Optical sensing of

anticoagulation status: Towards point-of-care coagulation testing. PLOS ONE, 12(8),