Q: What is "thrombophilia"?
A: Thrombophilia is a term used to describe a
group of conditions in which there is an increased tendency, often repeated and
often over an extended period of time, for excessive clotting. These include
con ditions due to:
1) family history of clotting or a diagnosis based on a demonstrated genetic
mutation such as factor V Leiden, protein C and S deficiencies, antithrombin
and prothrombin 20210A mutations.
2) an acquired condition such as lupus inhibitor or antiphos pholipid antibody,
which can occur in persons with systemic lupus erythromatosis. The development
of a blood clot is called thrombosis. The vascular system includes both the
venous system (the veins that deliver blood from the tissues to the heart) and
the arterial system (the system that delivers blood from the heart to the
tissues). Thrombotic episodes may occur in either system. The symptoms relate
to the part of the vascular system in which they occur, the extent of the clot
and whether the clot breaks off and travels to another part of the body (eg,
the lungs—pulmonary embolus, the brain—embolic stroke, etc). There are
different terms used to further define these thrombotic episodes such as deep
vein thrombosis (DVT) or peripheral vascular disease, when the clots are in the
arterial system (usually in the extremities). Although we are now able to
determine the underlying cause in some patients and families for this tendency
to an increased risk of excessive blood clotting, we are still not able to make
this determination in all cases. This means that there is still more to be
understood about why some persons and families have
Q: Is it a new disease?
A: Thrombophilia is not a new disease, but it has
become a more recognized and discussed topic due to an increased ability to
test for and identify some of the underlying contributing abnormalities.
Q: Who has thrombophilia?
A: Thrombophilia affects a large number of people
world. People who experience episodes of thrombosis, either as an isolated
event or as a repeated event, may be affected with a thrombophilic disorder.
There are people who have inherited an abnormality, such as factor V Leiden or
activated protein C resistance, who have an increased tendency for thrombosis,
but who may never personally experience a blood clot. They may, therefore, have
a known thrombophilic condition, but never experience a thrombosis.
Both children and adults may have thrombophilia, but it is more commonly
diagnosed during the tendency to show symptoms due to the contributing
adolescent and adult years due to normal changes in the hemostatic balance that
occurs with growth and aging. Both men and women may have thrombophilia. In
fact, women who have thrombophilia may have an increased effects of pregnancy
or use of hormonal agents.
Q: How many people in the United States have thrombophilia?
A: Thrombosis is a very common medical problem. It
is estimated that approximately two million people experience a DVT each year
in the United States. In addition, nearly half of patients with deep vein clots
experience long-term health consequences that adversely affect their quality of
life and require millions of dollars of treatment. Thrombosis may manifest
itself as the formation or presence of a blood clot in a blood vessel or one of
the cavities in the heart. In fact, emboli (clots or plugs brought by the blood
from another blood vessel and forced into a smaller vessel so as to obstruct
the circulation) from deep vein clots are a leading cause of death in
hospitalized patients. Annually, 200,000 to 300,000 patients develop this form
of clot for the first time during a hospitalization. Nearly 40% of these
patients suffer pulmonary emboli
(a clot that travels to the lung and obstructs a significant amount of blood
flow to the organ) that are fatal in 30% of the cases.
Recent research shows that these disorders contribute significantly to
morbidity and mortality in the United States. Each year, more than 600,000
Americans die from abnormal blood clots.
Factor V Leiden is the most common inherited abnormality causing an increased
tendency to thrombosis, and it affects approximately 5% to 7% of the Caucasian
population of European descent in the United States. Many of these people have
not yet experienced a clot.
Q: What are the differences between genetic and acquired
A: Genetic thrombophilia is an inherited
abnormality that leads to an increased risk of thrombosis throughout a person’s
life. The most common disorder that is an inherited thrombophilic disorder is
factor V Leiden, initially described by Dr. Dahlback in 1993. Acquired
thrombophilia refers to a group of disorders that an individual is not born
with, but may develop throughout his or her life due to another illness or
situation. An example of acquired thrombophilia is the development of a lupus
anticoagulant or antiphospholipid antibody syndrome.
Q: Who takes care of patients with thrombophilia?
A: Many healthcare professionals take care of
people with thrombophilia. For example, primary healthcare providers
(pediatricians, internal medicine physicians, family practitioners,
obstetricians and gynecologists, emergency physicians, etc) may all care for
patients with this disorder. Subspecialists, such as pulmonologists, vascular
surgeons, neurologists and hematologists, may also care for this patient
population. Other specialists, such as pathologists and radiologists, may
provide services to these patients including diagnostic and interventional
services. There is an increasing tendency to have these patients seen at some
point by a facility or physician that provides expertise in this area.
Q: How is thrombophilia related to hemophilia?
A: Thrombophilia is the reverse side of the
process of blood clotting compared to hemophilia. While people with hemophilia
have an increased tendency to bleed, people with thrombophilia have an
increased tendency to clot. Just as hemophilia is caused by an abnormality of a
blood-clotting factor, some forms of thrombophilia are also caused by an
abnormality or deficiency of a blood-clotting factor. In some cases these
clotting factors may have an abnormality that leads to an increase in their
function (such as factor V Leiden). Thrombophilia is also related to hemophilia
in that the providers that staff hemophilia treatment centers (HTCs) may be
well suited to provide specialized services to this population, as well. People
with hemophilia may also inherit a thrombophilic abnormality; in fact, it has
been shown that people with hemophilia who also inherit factor V Leiden, begin
bleeding at a later age and may bleed less frequently.
Q: What kinds of treatment do people with thrombophilia
A: People with thrombophilia may receive
medications that affect the coagulation system, just as people with hemophilia
do, but not always in the same manner. Some people with thrombophilia may
receive "replacement factor concentrate" to treat their thrombophilia either on
a long-term or an intermittent basis, depending on the underlying cause of
their thrombophilia. Some people with thrombophilia are treated with
medications that are classified as blood thinners, which decrease a person’s
ability to form a clot. Examples of these medications include aspirin, heparin,
low molecular weight heparin and coumadin. There are also some specific
medications (thrombolytic agents) that are given under certain circumstances to
dissolve clots. People with hemophilia who have central venous access devices
that have become clotted may receive small doses of these medications locally.
People with thrombosis may receive these agents in larger doses that are either
given at the site of thrombosis or systemically. People with thrombophilia may
receive medications only during a time of increased risk of thrombosis or for a
prolonged period of time (even for a lifetime), depending on their specific
diagnosis and clinical circumstances.
Q: Is there a patient organization that advocates for
improved treatment and more research?
A: Yes, there is a national organization called
the "American Thrombosis Association," which has been formed to advocate for
the population affected with these disorders in the United States. Go to www.airhealth.org on the Web— it is advocating for
changes in airline practices to prevent "economy class syndrome." Economy class
syndrome is more accurately described as DVT. It occurs when blood clots form
in leg veins during long periods of immobility. These can be fatal if they
enter the heart or lungs, and there have been several deaths reported among
airline passengers. Airlines reject any link between cramped air travel and
DVT, but have started giving passenger advice through inflight videos,
magazines and their Web sites.
Q: What is the CDC Pilot Program?
A: NHF is interested in thrombophilia because many
HTCs are providing care for these patients. The Centers for Disease Control and
Prevention (CDC) is also interested in thrombophilia, due to its impact on the
health of so many people in the United States. Similar to hemophilia care and
prevention services delivered through HTCs, CDC is developing a pilot program
to demonstrate the effectiveness of multi-disciplinary comprehensive care to
persons with clotting disorders who, in many cases, are currently receiving
fragmented care. The goal is to prevent disease and improve medical outcomes.
An expanded population served by HTCs may help in the long-term survival of
these specialized treatment facilities.
Q: How many HTCs are caring for thrombophilia patients?
A: Many HTC medical directors provide care to
people with clotting disorders. The demand for hematological expertise from HTC
providers is growing at a rapid rate.