When is a clot not from a hypercoagulable state?

A well-known complication of atrial fibrillation for patients to form clots.

EDITOR’S NOTE: Dr. Remer reported this story during a recent edition of Talk Ten Tuesdays.

A while ago, Allen Frady and Dr. Ronald Hirsch were having a lively discussion on LinkedIn regarding atrial fibrillation and the diagnosis of D68.69, Other thrombophilia which is the code used for “secondary hypercoagulable state.” I thought I was going to be able to weigh in quickly and decisively, but I exceeded my character limit, so I am bringing the discussion here.

Primary hypercoagulable states are easier to identify. They are hereditary abnormalities of coagulation where a physiologic anticoagulant pathway is not properly functional. Examples are antithrombin III deficiency, protein C and S deficiencies, and dysfibrinogenemias. The checks and balances of clotting don’t work, so the patient clots excessively.

There are conditions of acquired hypercoagulability which are referred to as secondary hypercoagulable states. Examples of this are pregnancy, hormonal therapy such as birth control pills, malignancy, and hyperlipidemia.

Allen questioned whether we are missing the diagnosis of secondary hypercoagulable state. He referred to a presentation by Dr. Vladimir-Ducarmel Joseph who referenced Virchow’s triad and posed atrial fibrillation as being a hypercoagulable state. Since AF affects approximately 1 percent of the population, Allen wondered whether we are missing a prime opportunity to capture D68.69, a comorbid condition or complication (CC).

Virchow’s triad is a pathophysiological concept to explain an increased likelihood of developing thrombi. The three components of the triad are stasis or abnormal blood flow, endothelial injury, and hypercoagulability caused by abnormal blood constituents. The more factors the patient has, the higher the risk of developing a clot.

The title of D68.69 is Other thrombophilia. Thrombophilia is defined in the Merriam-Webster medical dictionary as, “a hereditary or acquired disorder marked by an abnormal increase in the tendency of blood to clot and higher than normal risk of thrombosis.”

It is a well-known complication of atrial fibrillation for patients to form clots, usually in the atrial appendage, and for these clots to be propelled into the brain circulation causing stroke. The risk is about 5 percent, per year on average. The older the patient, the higher the risk. Patients are often placed on anticoagulation prophylactically. They have a higher than normal risk of thrombosis, but thrombi are not forming on the basis of an abnormal tendency for the blood to clot.

My opinion is just having a propensity for developing a clot, especially in a specific location, does not constitute a hypercoagulable state. Thrombogenic, yes, hypercoagulable, no. Having an injury or a previous DVT does predispose a patient to developing a clot. That is not a hypercoagulable state to me. I think the key question is, “Is the patient generally predisposed to a clot anywhere in their body because their coagulation system is not functioning properly?”

The higher than normal risk of thrombosis from other thrombophilia is due to an abnormal tendency of the blood to clot, not situational. Patients with atrial fibrillation don’t have blood with a higher tendency to clot; the provider does a risk-benefit analysis and renders their blood less likely to clot with extrinsic anticoagulation.

Should the provider be documenting all pregnant women, all patients on hormones, all patients with malignancies with D68.69? Not unless they are taking those secondary hypercoagulable states into account and assessing or treating it. The condition must meet the criteria of a secondary diagnosis.

As I think about everything nowadays, what about COVID-19? Experts are not sure of the mechanism, but the coronavirus does seem to make some patients hypercoagulable. They have a tendency to develop clots in various locations. This does legitimately meet secondary hypercoagulable status.

The key is how did the provider document it? Are they treating it with anticoagulation? I think this is query-worthy, because epidemiologically speaking, knowing the incidence of hypercoagulability in COVID-19 would be important.

My vote is atrial fibrillation is not a “secondary hypercoagulable state.” There is literature that refers to it this way but prepare yourself for a denial appeal unless there are extenuating circumstances.