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Sticky Blood? Questions And Answers About Pulmonary Embolism, Deep Vein Thrombosis (DVT), Clotting, and Factor V Leiden

Welcome!  This page has a list of questions about various clotting problems that have shown up on some of my support groups.  More will be added as questions are posted. 

3D Animation Of Pulmonary Embolism

A brief introduction to Pulmonary Embolisms

Videos And Books About Clots

My husband/wife/friend/myself had a pulmonary embolism and we don't know why. Is this normal?

Pulmonary embolisms and deep vein thrombosis that can cause a pulmonary embolism are both caused by venous blood clots. Everyone is at risk for a blood clot; however, some people are more at risk than others.

There are a number of clotting disorders that can cause excess clotting. Doctors can run a battery of tests that can help to determine if the patient has a clotting disorder1. These disorders as a whole are known as thrombophilia. If a patient does not have one of these disorders there is no need for alarm. Other factors can also cause increased clotting. Also, there are possibly forms of thrombophilia that have yet to be identified. One of the more common thrombophilias was just discovered in 19942.

If there are no found genetic risks, there are a number of other factors that can increase the risk of clotting. Clotting is increased by being stationary for long periods of time, being dehydrated, flying (especially very long flights), long car rides, pregnancy, having surgery, taking estrogen replacements, birth control pills, obesity, and etc. To see a detailed list, please see the suggested sites.

Preventing Blood Clots

  • How the blood clots
    How the blood clots, and how to prevent abnormal clotting
  • Antiplatelets | Internet Stroke Center
    Platelets are blood cells that are help the blood clot (stick together) and prevent bleeding. When the body has a cut, scratch, bruise or bleed, platelets go into action and begin to work. They can be thought of as materials (like bricks or blocks) t
  • Anticoagulants | Internet Stroke Center
    Anticoagulants are a class of drugs commonly used to prevent the blood from forming dangerous clots that could result in a stroke. Often called "blood thinners," anticoagulants are often the first medication prescribed by doctors following a stroke.
  • Thrombolytics | Internet Stroke Center
    Thrombolytic therapy is the use of drugs to break-up the clot that is causing the disruption in blood flow to the brain. It is crucial, imperative, and very important that you immediately go to the hospital when you first notice the warning signs
  • Thrombolysis - Cardiovascular and Interventional Radiological Society of Europe
    Thrombolysis means dissolving blood clots. Once a clot starts to form in a blood vessel it may carry on getting bigger until the whole vessel is blocked. Although the blood clot can be removed by an operation, it is also possible to dissolve the clo
  • Enzymes in Thrombolytic Therapy
    As in the inflammation reaction, the clotting of blood is an example of a defense mechanism which can overreact and require therapeutic intervention. It is now known that in normal tissues, there is a constant dynamic equilibrium between blood coagul

Blood clot prevention and treatment

What kind of medications will treat blood clots?

There are 3 drugs classes that are commonly used to treat blood clots in the body: antiplatelet, anticoagulant, and thrombolytic drugs. Which one of these drugs is used will depend on where the clot is in the body, how severe the clot is, and if the patient is stable.

To understand which one of these drug classes will be chosen, there must be an understanding of the blood clotting system. There are two major systems that work together to make blood clot: the platelet system and the thrombin system. Platelets are one of the many types of blood cells. When there is an injury, platelets will clump together to form a barrier. The thrombin system is more akin to glue. When there is an injury it forms a stringy substance that captures red blood cells in a web. When an injury occurs the thrombin web, red blood cells, and platelets come together to form a plug at the site of the injury.

In arteries, the main clotting system is platelets. In veins, the main clotting system is thrombin. This difference is what guides treatment of pulmonary embolisms, deep vein thrombosis, and clotting conditions such as Factor V Leiden. All of these conditions take place in the veins and therefore need treatment for vein type clots. Vein type clots are created with the thrombin system.

Antiplatelet drugs include Plavix, Aspirin, Aggrenox, and Ticlid. These drugs are used for prevention of clots in arteries.

Anticoagulants affect the thrombin system. This class include Warfarin, Coumadin, low molecular weight heparins such as Lovenox, and heparin. These drugs are used to prevent venous clots such as a pulmonary embolism or deep vein thrombosis. They are also used for clotting conditions that affect the thrombin system such as Factor V Leiden.

Thrombolytics are also known as "clot busters". These drugs work quickly and aggressively to dissolve already formed clots. Thrombolytics are based on enzymes that the body uses naturally to break up clots. These drugs are administered in different ways depending on the specific drug but each one is given carefully at the site of the clot. Thrombolytics are very potent and carry a high risk of bleeding. For this reason they are only used in an inpatient procedure and are reserved for critical patients such as those who are having a stroke, are unconscious, need life support, or are unstable. When the risks of the condition outweigh the risks of the therapy these drugs can be a lifesaver. In patients with a stroke, if a thrombolytic is administered very early on, the patient may have little to no residual damage after the stroke.

Thrombolytics are never used as a preventative medication. Antiplatelets and anticoagulants are used for prevention. The class of preventative drugs will be chosen by a doctor based on the location of the potential lot and the clotting system that is involved.

For a discussion on how warfarin works, questions about warfarin, and information about nattokinase please see: 

Treatment of clots

Scroll to Continue
  • MedlinePlus Medical Encyclopedia: Pulmonary embolus
    A pulmonary embolus is a blockage of an artery in the lungs by fat, air, blood clot, or tumor cells.
  • Pulmonary Embolism
    A pulmonary embolism (PE) is a blood clot in the lung. It usually comes from smaller vessels in the leg, pelvis, arms, or heart. When a clot forms in the ...
  • Symptoms of Pulmonary Embolism
    Certain types of chest pain and unexplained shortness of breath are common symptoms of pulmonary embolism. This eMedTV article includes a detailed list of possible pulmonary embolism symptoms and signs, as well as symptoms of deep vein thrombosis.

What are the symptoms of a pulmonary embolism?

Pulmonary embolisms can be fatal.  If you are experiencing symptoms below with no known cause go to the emergency room!  There have been cases where people have had these symptoms for days or weeks and collapse and die.  If those people had gone to the ER they might have survived.  If caught early, pulmonary embolism can be treated.  If the clots become large enough or are in large numbers, the body will be depleted of oxygen.  Also, heart damage can occur from the more serious lung clots. 

  • Chest pain
  • Shortness of breath
  • Breathing heavily with little exertion
  • Anxiety or feelings of doom
  • Cough
  • Sweating
  • Passing out
  • Collapse
  • Rapid breathing
  • Rapid pulse
  • Lightheadedness 
  • Deep vein thrombosis (DVT) -
    Deep vein thrombosis — Comprehensive overview covers symptoms, treatment, prevention of this blood-clotting disorder.
  • Deep Vein Thrombosis
    A deep vein thrombosis is a blood clot that forms in a vein deep in the body. This portion of the eMedTV library provides an in-depth look at this condition, including information about its causes, symptoms, and treatment options.

What are the symptoms of Deep Vein Thrombosis (DVT)?

Deep vein thrombosis is a blood clot that can form in any vein in the body.  The most common site for a DVT is in the larger veins in the legs.  A DVT can be fatal.  These blood clots can break off and move into the lungs.  Clots in the lungs (pulmonary embolisms) can prevent the body from receiving oxygen and can make the heart work too hard.  They can be fatal.  Here are the symptoms of a DVT.  If you have any of these symptoms seek emergency care.

  • Swelling of the leg or other extremity
  • Pain or tenderness in the leg (the pain is usually in one leg and may only be present when standing or walking)
  • Pain, tenderness and redness on the leg or other area such as the arm or neck 
  • Feeling of increased warmth in the area of the leg (or other area) that is swollen or hurts
  • Red or discolored skin

Participate in the research:

Aren't I too young for blood clots?

In my experience, no. Typically society and doctors feel that clots are a disease in the older population. In a very informal survey of some of the support groups that I frequent I found the following numbers:

  • Ages 19 or younger 7%
  • Ages 20-24 10%
  • Ages 25-29 18%
  • Ages 30-34 13%
  • Ages 35-39 18%
  • Ages 40-44 11%
  • Ages 45-49 7%
  • Ages 50 or older 15%

As you see, ages 25-29 and 35-39 had the highest percentage of first clots. This could be because the people at the support groups are those ages, or, it could be a common occurrence. I suspect that younger people do have a lot of lifestyle risk factors that help clots to form. Birth control, pregnancy, and extensive travel where one sits immobile for long periods are all very common for younger people.

Is there a connection between Factor V Leiden and appendicitis?

After searching the CINAHL, PubMed, and Medline medical journal databases I have found no articles citing a relationship between Factor V Leiden or thrombophilia and appendicitis. 

There are no studies linking Factor V Leiden and endometriosis.  This implies that there is no increase in endometriosis within the Factor V Leiden population.

Factor V Leiden can complicate the treatment of endometriosis.  Endometriosis is typically treated with birth control hormones1.  Hormones, in particular estrogen, increase the risk of blood clots by three to four times2.  Individuals with Factor V Leiden have a substantially higher risk of blood clots than a typical individual while on hormone therapies.  This may mean that people with endometriosis and FVL are much more likely to clot.  When a younger person clots doctors often want to know why.  This may mean more people with endometriosis are being tested for FVL due to the clotting.  I am guessing that many people with endometriosis may have discovered their FVL condition because of the hormone therapies used in treatment.  This would account for the relationship between Factor V Leiden and endometriosis. 

What kind of birth control can I use?

Individuals with a condition that increases the risk of clotting need to be cautious in their birth control choices. Hormones such as estrogen are known to increase the chances of clots. These clots can be serious and potentially fatal. Any type of thrombophilia increases the risk of clotting while on hormone based contraceptives. A history of deep vein thrombosis or pulmonary embolism also increases this risk.

Birth control with a high risk of clotting:

  • combination birth control pills with estrogen and progestin
  • newer generation oral contraceptives
  • older, estrogen only pills
  • birth control patch (Ortho Evra)
  • birth control ring (Nuvaring)
  • implants or injections containing estrogen

Birth control with a medium or unknown risk of clotting:

  • an IUD with progestin such as Mirena
  • progestin only mini pills
  • progestin injections (Depo Provera)

Birth control with no risk of clotting:

  • copper IUD
  • diaphragm
  • Lea's Shield
  • cervical cap
  • sponge
  • male condom
  • female condom
  • abstinence
  • fertility charting and tracking
  • spermicide

The progestin based contraceptives have warnings about using them with a history of clotting. At this time, the only research about progesterone has been in the area of hormone replacement therapy. This research shows an increase in clotting. The dosing of progestin for contraception is much lower. To stay on the cautious side, avoid all hormones. Just because there is no research on this relationship does not mean that progestin is safe.

Individuals on anticoagulation therapy may have additional options. While anticoagulated, the clotting risk is significantly lowered. Also, bleeding may be markedly increased during menstruation. Some physicians feel that oral contraception can be used safely while anticoagulated and that it will help with the excess bleeding. A doctor can help weigh the pros and cons of this option.

While on anticoagulation, some doctors may be nervous about the copper IUD as it increases bleeding. Typical menstrual bleeding before the IUD should be observed and considered before choosing a copper IUD.

With any of these choices, talk to a doctor. Talk to your entire team if you have more than one doctor managing your care. A hematologist, OBGYN, and family doctor will all have different views.

Women's issues and blood clotting

Alternatives to hormonal based contraception

Support groups

Evidence based medicine resources and articles

What experience do you have with clots?

July 18, 2008 I entered the hospital after having episodes of severe shortness of breath, high blood pressure, fast pulse, and being very sweaty. Looking back, the symptoms went back a number of months prior to my trip to the emergency room. I walked into the emergency room. It was a good day as I had been resting for a large portion. My pulse and breathing were up, but, not off the charts. I had good oxygen saturation (96%). Luckily, my family doctor who referred me encouraged the ER doc to do a contrast dye spiral CT. The results from that were astounding. They didn't even wait for a radiologist to look at them. I had multiple, large clots in both lungs. I was placed on heparin immediately and moved up to a ward that had a lot of observation. I wasn't allowed out of bed until they had done the ultrasound on my legs the next day. They found no clots. My heart had an echocardiogram. It was fine. I spent 11 days in the hospital trying to get therapeutic on warfarin. Day 11 they sent me home with Lovenox as I still had an INR under 2.0. I checked in with my primary care doctor on Monday and my INR finally was up. It took about 3 months to stabilize my INR. Through watching my vitamin K so that I have some every day I have become very stable. I am very, very grateful for warfarin. I have had very few side effects from the warfarin. I have had problems though with the residual problems from the pulmonary embolisms. I was off of work for 3 months and since going back have had a lot of sick time. Colds raise my pulse and cause me to cough... a lot. I am frequently tired. I have chest pain. It isn't bad, but it is creepy feeling my lungs and my heart. I also have developed reactive airway disease (a lot like asthma). I have made 2 trips to the ER since my original trip in. Once was nothing. The other time found the reactive airway disease. My pulse is still higher than typical and it goes up very very easily. I was taking classes as well as working full time prior to the embolisms. Now, I am just working. I hope to regain everything in time.

What were your symptoms?

  • Feeling like I had to yawn but was not getting a "full yawn" in when I did it
  • Having to breath deep breaths while talking
  • Extreme sweating
  • Anxiety
  • High blood pressure
  • Resting pulse over 100 (around 120 most days)
  • No tolerance to heat/couldn't cool down
  • Walking 100' made me feel like I had run a number of laps
  • Couldn't keep pace with people when walking with them
  • Fatigue 

I wear one of these at all times

What was your treatment?

While in the hospital I was placed on heparin. Once home I took Lovenox for 1 day. I was placed on warfarin while in the hospital. I am still on it. I was taken off of it a year after the hospitalization. My tests were clean and I have had no further clots.  I will do nothing unless I plan to get pregnant, have a long haul flight, are bedridden, or have surgery. When I take trips I need to drink lots of water or electrolytic fluid. I need to be up and walk every 1-2 hours while traveling (or any other time).  

Medications that I used:

  • Tessalon
  • Symbicort
  • Albuterol
  • Warfarin (INR 2.0-3.0, 10 mg every day except Tuesday, 12.5 mg on Tuesday, INR checks once a month or with medication changes)
  • Medical alert bracelet as well as an account with MedicAlert that list my warfarin, other medications, pulmonary embolism, Factor V Leiden, and emergency contact information.

What caused your pulmonary embolism?

There are no clear cut answers to this one. I had a number of factors that compounded. Hopefully the tests this summer find nothing other than what I have listed below. Because a number of triggers piled up, it is hoped that I will be able to come off of warfarin and never clot again.

  • It was summer and over 90 degrees many days, I likley was dehydrated
  • I was on combination oral contraceptives to treat high testosterone levels. Oral contraceptives are a blood clot trigger
  • In April I was on 4 plane trips and two 12 hour car rides within a 3 week period
  • There was a marked amount of stress in my life at this time
  • I was having a nasty sinus infection as well as really bad headache/migraine problems. Migraines can cause hypercoagulation
  • I have heterozygous Factor V Leiden. This contributed a clot risk that made me 10% more likely to clot than another person.


How do clots go away/dissolve?

One of the questions that people often have is "will my clots go away?"  The answer is yes.  Every person has tiny blood clots that form and are dissolved on a regular basis.  The problems crop up when the body is forming clots more quickly than they are being broken down.  This allows large clots to form that can prevent blood flow through a vein or break off and travel through the body.  The anticoagulants that are given after a pulmonary embolism or deep vein thrombosis work by preventing new clots from forming.  The body takes care of the clots that have already formed.  A number of enzymes are present in the body that break down clots.  These enzymes are the basis for the thrombolytic drugs also known as clot busters.  This process can take days to months depending on the severity and size of the clots.  The d-Dimer test that is often used in the diagnosis of clots works by measuring the amount of these enzymes in the body. 

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