Hemophilia & Anticoagulants in Cardiovascular Disease

BY DR. DAVID CLARK

Medical science is now learning more about an increasingly common type of patient, the older
hemophiliac. Until the development of clotting factor concentrates in the 1960s, most hemophilia patients did not live to old age. Then the AIDS crisis in the 1980s wiped out a large portion of the hemophilia community. It is only now in the early 21st century that we are encountering numbers of hemophilia patients needing treatment for the diseases of old age, including cardiovascular disease.

As people age, their cardiovascular risk factors such as hypertension (high blood pressure), obesity and diabetes generally increase. In fact, hemophilia patients are known to be at higher risk for hypertension. Smoking is another important risk factor, as it is for the general population. However, a hemophilia patient’s risk of death from myocardial infarction (heart attack) and stroke is lower for unknown reasons. Their risk of atherosclerosis (hardening of the arteries, which can lead to a heart attack) is the same, but does not lead to death as often. This has raised the question whether there is a protective effect of having hemophilia, especially for severe patients. However, raising factor levels with prophylaxis may eliminate that
effect.

Two additional cardiovascular issues being seen more frequently as hemophilia patients age are atrial fibrillation and acute coronary syndrome/angina. All of these are normally managed using long-term anticoagulants and antiplatelet medications, but are these appropriate for patients with hemophilia?

Hemophilia patients are typically warned to avoid medications like aspirin (an antiplatelet agent) because they could exacerbate their bleeding problems. Warfarin (Coumadin, an anticoagulant), which is often used as an anticoagulant for stroke prevention and treatment of atrial fibrillation and mechanical heart valves, is associated with an increased risk of intracranial hemorrhage, also an issue for hemophilia patients.

Because of the small number of patients, there is a real lack of data on treating hemophilia
patients with cardiovascular diseases. The first approach is to reduce risk factors, wherever possible.

Then, there are a number of reports in the medical literature of patients being treated successfully with anticoagulants and antiplatelet agents. Treating hemophilia patients is a complex matter. Each patient must be considered individually and monitored carefully, preferably with close cooperation between a cardiologist who has a thorough understanding of the cardiovascular properties of the drugs and a hematologist who has a good understanding of the clotting system.

Severe (FIX < 1%) and moderate (FIX 1-5%) hemophilia patients being treated with anticoagulants or antiplatelet agents are often placed on prophylaxis with trough levels in the 20-30% range. Mild patients (FIX 5-50%) can sometimes be treated while not on prophylaxis, but they should be monitored closely for any increased bleeding tendencies. Extended half-life factor products now make it easier to maintain higher trough levels, but the cost of treatment may be an issue. There is also a concern that increasing factor levels in elderly patients could trigger inhibitor development. Antiplatelet agents may be preferred in some cases because they are less dependent on maintaining higher trough levels.

Anticoagulants and antiplatelet agents that can be easily reversed are preferred, so that if bleeding occurs, it can be treated more quickly. Anticoagulants/antiplatelet agents should be used for the minimum time necessary, although with conditions like atrial fibrillation, therapy must be long term.

This is a new era in hemophilia treatment. There are no standard guidelines for treating many of the diseases of old age in patients with hemophilia. Physicians are generally proceeding carefully and are having success with many older patients. As they gain experience, treatment regimens should become better defined and more commonplace.

(From the Spring 2018 issue of Factor Nine News)