Science AMA Series: I’m Dr. Lisa Moores, a pulmonologist, a member of the American College of Chest Physicians and an expert on the subject of thrombosis! Let’s talk blood clots! AMA!


My name is Dr. Lisa K. Moores, and I am board certified in critical care medicine, pulmonary disease and internal medicine and have worked on guidelines to help improve venous thromboembolism (VTE) patient care. I’m also the President-Elect of the CHEST Foundation, the philanthropic foundation of the American College of Chest Physicians, an organization representing 19,000+ clinicians practicing pulmonary, critical care and sleep medicine. I co-authored the American College of Chest Physician’s guidelines Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report in February 2016 and have been on the frontlines of VTE research for over a decade. AMA!

March is Blood Clot Awareness Month, and it is important to shed light on a leading cause of death and disability worldwide. A VTE, is a blood clot that forms in a vein deep inside the body that blocks important blood flow. VTE includes both deep vein thrombosis (DVT) and pulmonary embolism (PE), conditions that affect an estimated 350,000 to 600,000 Americans each year.

You might’ve heard the now debunked term ‘economy class syndrome’, a phenomenon that linked the formation of blood clots in veins with sitting in economy class for a long airplane flight and wondered, “Does this really exist?” No need to buy first-class’s a myth! Because of the many misconceptions on VTE, I have worked alongside the American College of Chest Physicians to release evidence-based guidelines, Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report, that provides 53 updated recommendations for appropriate treatment of patients with VTE.

VTE typically forms in the legs of individuals and can be caused by everyday things as simple as sitting for a long period of time. Other risk factors for a VTE include: estrogen use (including birth control), obesity, recent injury or surgery, cancer, blood-clotting disorders and smoking. Because it can affect almost anyone it is important to me to provide information for proper treatment and care.

Please feel free to ask about anything related to VTE, DVT, PE or pulmonary medicine. I will return at 2:30 p.m. EST to answer your questions. Ask me anything!

Conflict of Interest Disclosure: My thoughts and opinions are my own. They are not official opinions of the Uniformed Services University, the United States Army or the Department of Defense.

Has what you've learned in your research changed any of your own activities and/or daily habits?


Interestingly, and perhaps fortunately, I don't have a lot of risk factors for venous clots. That said, I am cognizant of keeping myself active. If I have to have a minor procedure, I make sure I get up and walk around as soon afterwards as I can. If I take a long-haul flight or road trip, I try to get an aisle seat, I pump my ankles frequently (and if it's a long overseas flight I use compression socks). In addition, I do not smoke (although as a pulmonologist there are many good reasons not to smoke!). Finally, I take every decision regarding home therapy seriously, weighing the benefits of taking them (such as birth control or perimenopausal symptoms) and the increased risk of blood clots.

Thanks for doing this. What are the signs and symptoms we should watch out for? Is there anything we should do/not do during a long-haul flight?


Signs of blood clots can be tough. They are a bit easier in the leg and usually involve unilateral leg pain, redness, and swelling. The pain can often worsen with flexing your ankle and foot. For clots in the lung (pulmonary embolism), they can be more subtle. You might notice mild shortness of breath, chest pain (particularly with a deep breath)...or it might be more severe with intense chest pain, coughing up blood...or even passing out. The general advice is that unless you are at high risk for a clot (which would be patients who have had one before, patients with active cancer, patients who have had a recent big surgery or traumatic event, significant obese patients), then you do not need to do much on a long-haul flight other than avoid being completely sedentary. Get up a walk around the aisle a few times. Flex your ankles and calves frequently while awake. And you can also use compression socks, which also help with fluid build up!

ICU RN here. I had a physician once tell me that he had a preference for warfarin vs. Some of the newer therapies post VTE/DVT/PE if the patient was obese.

He also mentioned a concern some have over using the usual warfarin therapeutic level for elderly women due to possible increased risk for hemorrhagic stroke.

Have you any preferences based on weight, age, or gender specifically with regard to drug therapies post VTE/DVT/PE?

Edit: Whoops


Pharmacodynamics definitely play a role in anticoagulant selection. Obesity can affect the volume of distribution and availability of some of these drugs.....and it's difficult to monitor. Therefore the manufacturers often place warnings or adjustments based on body weight. Other physiologic (age) and medical conditions, as well as kidney and liver function, can affect the metabolism of these drugs and can affect the selection of agent and the dosing. Other factors that can play into selection include availability, price (insurance coverage) and patient preference.

What's a recent breakthrough in the treatment or diagnosis of VTE, DVT, PE or pulmonary medicine that you're excited about? Alternatively, what next breakthrough would you be excited to see?


I'm really excited about the fact that we are moving towards a more individualized approach to treatment, rather than treating every patient with a leg clot or lung clot the same based on the diagnosis. For example, looking at things that we know are associated with an increased risk in the future to help us decide whether a patient needs to stay on blood thinners or can take a "trial of life" off of them

For people who've suffered a blood clot, what do you think are the most important things to do (or to be aware of) to prevent future incidents?

I suffered a pulmonary embolism 2 years ago, when I was 22. I had no family history of blood clots. After I recovered, my doctor gave me the option to continue with warfarin treatment long term. I decided not to continue taking warfarin, but to live a much healthier, more active lifestyle and to stop smoking entirely. So far, I think I made the right choice.

What are your thoughts on long term warfarin treatment for people like myself, who've had an isolated incident?


This is a very interesting area for those of us in this area. The optimal duration of blood thinners is not entirely clear.....and appears to be different for different patients. Particularly in patients who develop a clot without an obvious reason. We know that you are at increased risk of a recurrence over those who have a reason for the clot (such as surgery). However, even with that increased risk, it does not mean you will definitely have another we are currently trying to find ways to identify patients at the greatest risk for recurrence. This group may want to stay on blood thinners. But those at low risk, may not want to!

I recently went from a job that requires a lot of movement and physical work to sitting in front of a computer for 8 hours. I always came home sore before, but now my legs are experiencing a new kind of soreness that I attribute to sitting too much.

I'm 30 years old and though I've never exercised much, I've always been healthy. No blood clots in my family history either. Am I at a higher risk for a blood clot now? Any diet/exercise tips to help with this?


Please see my responses to the above, which would be similar to your question.

Do you anticipate the recommendations for dvt treatment changing for patients with cancer from LMWH to any of the NOACs? Are there studies being done to research the efficacy of NOACs in cancer patients? Thank you for your time


The update of our guidelines that were published in 2016 did recommend the NOACs over VKA and LMWH in non-cancer patients. The only reason that we did not yet make the same recommendation in cancer patients is that these patients were excluded or low in numbers in many of the trials of these agents. There wasn't a really good reason for this from an efficacy or safety standpoint....the issue related more to a concern about interactions between the agents and chemotherapy. There are ongoing trials in this population and I would anticipate being to update the recommendations once these are completed!

What is your threshold for either thrombolysis or thrombectomy in patients that develop hemodynamic instability? I feel in current practice we just 'give up' on a lot of these massive PE cases, whereas we are much more aggressive in other thromboembolic diseases like stroke and MI.

Also, what do you feel the role of ECMO in adults will play in the treatment of massive PE?


One of my good friends and colleagues, a true expert in VTE, Dr. Tim Morris is going to chime in on this one!

Thank you for doing this AMA! I have several questions:

1) What exactly causes the elevated clot risk following an initial, provoked or unprovoked DVT/PE in a patient with no history of coagulation abnormality?

2) How quickly does a d-dimer return to normal following initiation of anticoagulation?

3) Is there a utility to performing a TTE in a patient with low risk PE?

4) Is there a way to reduce the risk of chronic thromboembolism?

5) How long does it take for a DVT to stabilize and reduce the risk of breakage/migration?

Thanks again!


hynogoggles...sorry for the late reply here, but you ask some great questions 1. We are actually not sure what causes the hypercoaguability in some patients (hence the term idiopathic or unprovoked). The three main causes of increased clotting are stasis (hence all the talk about long-haul flights and car rides), hypercoaguability (which can be genetic or acquired, like protein C deficiency or Factor V Leiden mutation) and trauma to the vascular system (like fractures, or surgery). We suspect that some of the idiopathic cases might be due to a disorder we have not yet identified. Sometimes an undiagnosed cancer can do this....but it's not common. We still have much to learn!

  1. The d-dimer typically returns to normal within three fact, if it stays high beyond that it suggests that we have not "turned off" the process that started things and the patient might be at risk for a recurrence.

  2. No real utility in performing a TTE in low risk PE. Normal findings do not lower the prognosis further....and abnormal findings are not specific/strong enough to change initial management to more aggressive therapy.

  3. We are not entirely sure why some patients develop chronic thromboembolism while others do not. We know some risk factors (such as presentation with massive PE), but they are not really modifiable. I am hoping my friend and colleague Dr. Tim Morris will chime in he is an expert in this area!

  4. I'm not sure I've actually looked at this before....but generally speaking....5-7 days will stabilize acute clot....but it takes months for natural breakdown and resolution.

Do you think chronic fatigue syndrome is mostly due to blood flow restriction?


Sorry.....definitely not an expert in CFS and have seen no evidence of it's relationship to VTE

Hi Dr Moores! I have Primary Antiphospholipid Antibody Syndrome which caused me to have six miscarriages before I was diagnosed. I was my doctor's first patient with APS and since then, she has seen an additional fifteen women with APS and pregnancy loss. It makes me wonder if APS is something that has been around and undiagnosed for years but I was under the impression that it was environmental. I also have a very long history of heart disease in my family that goes back decades. What are the chances that APS has been undiagnosed in my family and genetically passed down, what are the risks to my daughters and what further problems could I potentially develop with Primary APS? Thanks!


APS is often genetically passed, so there is a chance that it exists in prior generations in your family. Those of us who work in the world of venous clots are very familiar with it....and it is the one genetic predisposition that I look for in patients because it is so severe and difficult to manage. Unfortunately I am not sure it is as well known to providers in other specialty areas.....we need to get the word out better!

Hello Dr. Moores - Thank you for your gift and doing this AMA.

I am very curious if there is any link between dehydration and blood clots?


Not that we have been able to confirm. It makes sense to think about it, however, and I do try to stay hydrated on long-haul flights (voodoo I guess)

If I'm going to be in the back of a cramped car cross country for 16 hours straight should I take an aspirin beforehand to cut down risk of dvt?


Similar to the advice we give for long-haul flights, we don't recommend taking any medications (aspirin or stronger blood thinners) to prevent clots from forming. This is because, although the risk for clots is greater when you are cramped in a vehicle, the overall rate of events is still very low. In addition, the studies done looking at using blood thinners have not shown conclusive evidence that this practice reduces symptomatic clots (although they might slightly reduce the incidence of asymptomatic events). However, it is always good practice to keep pumping your veins when you sit for long periods (whether in a car, on a plane, or at the office). Pump your ankles, message/stretch your calves, take frequent bathroom breaks....

As an RN here in the US, most of our patients wear sequential compression devices to help "prevent DVTs." I find the use of these devices excessive. I realize that we walk around a lot more at home than in the hospital but I mean Lovenox or regular heparin AND SCDs? Interested in your thoughts and thanks for the AMA.


This is another controversial area. SCDs are not as good as normal activity...or blood thinners. But sometimes we have no choice. The patient either can't be ambulatory, or can't receive blood thinners due to an increased bleeding risk. In these cases, SCDs are certainly better than nothing. On the other hand, whether they add additional protection to blood thinners is not known in most patient groups. They combination did seem to be more effective in patients undergo cardiac bypass surgery. The real key is that if you are going to use them, you need to put them on correctly and use them. All too often we walk by the patient bed or room and the SCDs are inflating on the floor!

Hi Dr. Moores

I was wondering if all people are on a "clutting continuum", in the sense that some people clutting easily and others not, with the main population between these poles? If it is this way, what determines where one is located on the continuum? Genetics/environment/behavior?


What is clutting?

What's the best thing to do if you have a parent who's passed away from a pulmonary embolism? Is it genetic or are there signs to look out for?


There are some known genetic predispositions to venous clots....disorders that change your physiology in a way the favors clotting more vigorously than normal. Unfortunately, the presence of these does not necessarily predict who will have a clot in the future....or even patients who have had a clot that will have another one. So, I would just watch for the signs (as I noted earlier in the post) and call your doctor if you notice them. I might also recommend that you relay this family history any time you might be at an increased risk independent of the family history (you have a surgery planned, a pregnancy, you have lower extremity trauma, you develop a cancer). This might help your healthcare team decide how to aggressive to be with prevention!

Good morning Dr. Moores, current ER medic and soon-to-be 1st year medical student here.

I recently encountered a patient in the ED who was diagnosed with massive bilateral PEs. His CTA abd/chest showed a large clot in the pulmonary trunk with roughly 50% occlusion that extended bilaterally. We don't know the source of this clot, and I was hoping you might be able to shed some light on it. In my previous experiences with PEs they largely originated from extremity DVTs, and this seemed, to me at least, to be far too large to start there. Could you perhaps discuss possible causes for this? Additionally, how would this sort of clot be treated, given its proximity to the lungs?


We don't always find DVT when find PE; some probably came from the legs, but some form in-situ. The origin is less important than the physiology at presentation and other risk factors. The physiology will determine acute treatment (very stable patient might get routine anticoagulants on the floor (or even at home!), a somewhat sicker patient might be observed in an ICU....and those with hemodynamic instability might be treated with acute thrombolysis. There are risk scores (Pulmonary Embolism Severity Index (PESI), the simplified PESI, the BOVA, etc) that can help us with our initial assessment and exam. The risk factors help us determine the risk of recurrence....and thus how long we might treat with anticoagulants after this event.

Dr. Lisa, heart attacks run in my family and I am probably at higher than normal risk.

What are the most important things I can do to reduce my risk of a cardiac event or stroke?


First of all, I think only the kids in my neighborhood call me Dr. Lisa! For most patients, there is not a strong correlation between venous and arterial I would focus on reducing your cardiac risk factors (diet, exercise, blood pressure, cholesterol, smoking)

Good afternoon Dr. Moores. I've always wondered:

1) How quickly a pulmonary embolism or deep vein thrombosis is broken down following initiation of anticoagulants. Is there an improvement in function when this happens for P.E.s? Does this depend on size of infarction? Is there any way to usefully quantify the severity of a P.E.?

2) In the UK we use the wells P.E. score along with a d-dimer to exclude unlikely (but possible) P.E.s. It is always treated as a cutoff (ie: > 500 positive, below this negative/normal). Is there anything to be said about patients with just a slight elevation? It doesn't seem to be treated like a probability continuum in my limited experience.

Thanks for your time!


Initially the anticoagulants just prevent propagation of more clot....they really don't dissolve the clot that has formed (unless you use actual thrombolytic agents/fibrinolytics). What you are doing with the anticoagulants is preventing extension and formation of new clots, turning off the active "clotting physiology) and giving your body time to resolve the clots itself through breakdown. As long as your body is successful in this endeavor, you do see improvement in lung function.

We here in the US often also use the Wells PE Score and the D-Dimer to exclude PE. The sensitivity of most D-Dimer assays is so good that you can reliably exclude clot. However, the specificity is not as good. we know that aging, comorbid medical conditions, trauma, pregnancy, cancer, etc can lead to an elevated D-Dimer in the absence of clot. This is a another exciting area in that we are beginning to develop adjusted cutoff levels (more on the continuum you note) in special populations (one based on age is relatively far along in validation).

Hi Dr. Moores, thank you for doing this AMA.

I have protein C deficiency and got a DVT when I was 22(?) years old.

I used to be on Warfarin and I switched over to Rivaroxaban a few years ago. My quality of life definitely improved, without any side effects. The only thing that still nags at me is that, afaik, it's difficult to reverse the effects of the drug in a timely fashion. I had a serious concussion while I was stil on Warfarin but flushing my blood with frozen plasma quickly reversed the effects. My understanding is that it isn't possible with Rivarox, is this still the case?

Another question. It was explained to me that the "valves" in my leg don't completely close anymore, causing blood to stay in the leg and inducing a permanent swelling. Is there a way to fix them? I'm 29 years old now and I can see, year after year, that varicose veins are showing up more and more. I stay physically active and I wear the sock but I figure that once I hit 40 years old, it's not going to be any prettier.

It makes me wonder if by then I'll be able to swap it out with a cybernetic leg.


Great question. The lack of quick reversal has made folks in medicine afraid of using them for this reason. The exciting news is that we now have reversal agents for these that are rapidly earning FDA approval. More importantly, these drugs have such a short period of effect in your body.....that often times the effect wears off before the bleeding becomes life-threatening.

As to your second question....treatment of venous insufficiency is advancing, so I am hoping that you have options beyond the cybernetic leg! Not sure there is much you can do about the insufficiency that has developed beyond what you are doing!

What are the best foods i can eat for heart and artery health and what should i avoid


Honestly guys....I am not a nutritionist...and I can barely keep up with all of the fad diets. Several friends that are cardiologists recommend a plant-based/vegan approach. I am a huge New England Patriots fan, so maybe if I followed their advice and signed up for Tom Brady's new Purple Carrot food delivery I could improve my heart health....but I think I would starve!

My older brother, 61 had a heart attack, 2 stents put in, but refuses to stop smoking--What are his risks of getting a blood clot?


As I mentioned earlier....outside of some rare medical conditions, there is not a strong association between venous and arterial (heart) clots. Smoking is, however, associated with an increased risk of blood clots.....and LUNG CANCER......not sure what else you can do to modify his behavior....but I would not quit trying!

As a female in my late 20's taking a combination birth control (desogen, which I believe is a 3rd generation BCP and slightly higher risk for DVT) should I be concerned about DVTs? What signs should I watch for? I often have muscle aches in my legs but they move around and don't have the typical signs of clots (warmth, swelling, pain to touch).

I have a paranoia of getting a blood clot but the birth control helps manage my PCOS so stopping it would cause other issues (not life threatening, simply cosmetic).


see my prior answers...but in general, unilateral swelling, redness or pain of one leg....acute shortness of breath, chest pain, coughing up blood....

Thank you for doing this AMA! Blood clots, DVT, and the like are an interest of mine (mostly out of fear) so I'm interested to see what comes out of this thread! Also, I hope you don't mind me asking a few questions in one comment and giving them a bit of a preface.

  1. What biological function causes estrogen use to lead to more clotting? Does this lead to more clotting issues in women in general, or is it specific to individuals who take estrogen?

  2. Two of the key prevention tips I see for DVTs are to stand up and exercise. Do exercises that have the body in a sitting-like position (IE using a recumbent bicycle) have a diminished effect on preventing clots because of the sitting position, or is the increased bloodflow from exercising enough?

  3. One of the things I've heard is that sitting is the worst position your body can be in for proper circulation (and thereby, clot prevention) and that you should either stand or lay down. While it makes some sense, it seems that bring sedentary in general poses the greatest risk more than the position. Is the position you're sedentary in related to anything, or is it just being sedentary that would lead to a possible clot?


  1. Although estrogen type and dosing will have varying effects, as a class of medications they alter the levels of natural clotting and fibrinolytic factors that leads to an imbalance, favoring clotting.
  2. You definitely want to stand and walk around if you can. When you sit, you "bend" or "pinch" the large veins that drain the legs. This can lead to stasis of blood, one of the key risk factors for venous clots in the leg. Exercising in that position, however, is still better than not moving at all, as it will increase blood flow and venous return.
  3. See above.....and I use a stand-up desk at work now!

I know that thrombosis can occur due to stents or valve replacements. Do people with these devices need to be more careful over VTE as well?


see my other replies...this is an arterial, rather than venous issue and is a bit different.

My wife was recently diagnosed with a DVT. She has been prescribed blood thinners, but apparently no effort is made to remove the clot itself. Is there a risk that the clot might move on its own? Is she, for instance, still at risk for pulmonary embolism?


As I noted in some other replies....the blood thinners are used primarily to prevent formation of more clot on the already formed clot....not really to dissolve the clot that is present. The body does that on it's own (in most patients). We have good clinical trials that show that, except in rare, severe cases, removing the clot primarily (either with thrombolytic drugs or mechanical devices) does not improve long-term outcomes for PE or DVT

I have a history of DVT and about a year ago had a DVT and PE. Went on Lovanox, then xarelto for six months. Blood work showed high homocysteine so now take B12 and folic acid. Getting more exercise by walking 3-4 miles a day. Feeling a lot better with no recurrence. What else can i do to stay healthy and avoid DVT in the future. Did the compression stockings and lost weight too. Thanks


Sounds like you've done all the right things. Just be cautious when other temporary risk factors pop up (like a surgery or long flight). You are one that will likely need more aggressive preventive therapy in those instances. Good luck!

Thank you for doing this AMA. I have a power port for TPN and fluids. I've had this line for over a year with no clotting issues, but they're always on the back of my mind. I hep lock my line after every use and tend to be bleeder anyway. Are there any good studies out there on the incidence of PE and clots outside the line in persons with VADs?


Sorry you need the line. Not fun. Good news is that we cannot find evidence that we need to use anticoagulants to prevent clots around these lines. Doesn't mean they can't develop....and we treat them if we do....but we try to preserve the line.

RN here. We put SCD s on every pt who is have a procedure over one hour, regardless of risk factors or type of sedation. How necessary is this? How long does a patient have to lay b perfectly still before a blood clot forms?


probably overkill. SCDs are used in high risk patients/procedures who cannot take blood thinners. Low risk patients who can get up and walk around soon after their procedure should be fine without them. They probably won't be compliant with them anyway!

Hi Dr. Moores. My wife and her family have a history of a hypercoagulative disorder known as Factor IV Leiden, but the details don't seem to be common knowledge among physicians. Homozygosity is apparently more dangerous, while heterozygotes such as my wife are at increased risk after 'activation,' e.g. trauma. Are you familiar with this, and other hypercoagulative blood disorders, specifically with respect to pregnancy?


yes......a homozygous mutation is more of a risk than a heterozygous mutation (as the latter still have some functional gene)

What are your thoughts about MS patients getting stents placed in thier necks so close to thier brains?


Not an expert on this, so will keep my mouth shut!

What are your views on the "Health at Any Size" movement? Are Pulmonary issues connected with diet and obesity, or are there other factors that play a larger role?


You should always strive to be as healthy as you can be.....but obesity in itself, regardless of overall health level, will increase your risk of VTE and other pulmonary function limitations.

Please excuse my lack of medical terminology. My stepfather was going to go in for a procedure where they were using some sort of a umbrella/ tent filter device inside the vein or artery to capture any clots that happened to escape during the procedure. Will this be something that medicine may try to mechanically implement in the future for heart surgeries so people like Bill Paxton won't have a stroke afterwards?


This is a bit more complicated. Bill Paxton had a stroke which came from the arterial side. I am not an expert on placing "filters" in the carotid arteries to prevent this during cardiac surgery. However, we do have "filters" that can be placed in the large vein that comes from your legs through your abdomen to the heart. These have been used to treat patients with venous clots that cannot take blood thinners, but have also been used to prevent lung clots in patients that are at risk for developing leg clots...and have been used in some procedures for pulmonary clot removal. This is a controversial area and medical societies don't always agree on the indications.

Hello Dr. Moores, current IM resident and soon to be Pulm/CCM fellow this summer here.

What is you opinion of the relevance of subsegmental PE and the treatment (or perhaps lack of treatment) regimen?


Great of the ones we tried to tackle in our recent guideline update. With newer generation scanners we are clearly finding more small, incidental clots (or perhaps even false positive findings). Physiologically these may not be as important if there is no other evidence of clot and the patient has good heart and lung function. However, we have no good randomized trials to test this hypothesis. There is a large trial going on in Europe as we speak to address this question....more to follow!

why is interventional radiology stealing all the procedures?


From whom? Are you a vascular surgeon? ;-)

Hi there, hope you're having a great day :) How can you prevent/get rid of vericose veins?


varicose veins are actually a separate issue and are often not related to VTE. Hopefully we'll get a vascular surgeon on this forum who can answer your question!

I'm taking estrogen so I'm already at a higher risk of blood clots. What can I do to lower my risk in general, and what are the warning signs that a blood clot is forming? If one forms, can it be broken apart by exercise?


If you really need the estrogen, then you may need to accept the increased risk...but you may want to explore other options. Other than that, as I've mentioned this afternoon....the risks for VTE are synergistic. So, avoid all the ones you can (don't smoke, don't let yourself get sedentary). If you have to have a surgery that might increase your risk, let your healthcare team know about the estrogens so that they can assess how aggressive to be with preventive therapy.

Do you have any evidence or reason to believe that skinny jeans increase the risk of DVTs? If so, what types of warning signs should someone be watching for?


Why would you wear skinny jeans to begin that the uniform for eating Hawaiian Pizza?

My 82 year old friend had a mild heart attack last year and is on Plavix after having a stent placed. He has been waiting to have a knee replacement and he was unable to have it because he's on the blood thinner for a total of 12 months. He was told that after he's been on Plavix for a year he will be able to have this knee surgery. What are the chances of him throwing a clot?


This is a slightly different issue, as the clots surrounding withdrawal of plavix are arterial in nature. Stay tuned, as we are currently updating our guidelines on the use of anticoagulants in the periopertaive period, particularly in patients who have had stents placed and are on anti-platelet therapy.

I've heard that it is quite easy to get/develop a blood clot. how true is that? Is it quite easy to simply develop a clot and poof* you're done?


Lol. In the most severe/extreme cases, sudden pulmonary embolism can be fatal. But this is not the norm. In addition, there are known risk factors for developing clots that we have discussed with other questions today (obesity, smoking, cancer, surgery, genetics, etc). These risk factors are synergistic. If you have them all, you will clot more easily than others. If you have none of them, not so much!

Hi, I have lung issues in part I believe due to a methylation disorder. Can you explain methylations role on lung function especially related to blood clotting. It seems there is a connection from something I read in a fertility journal.

Thank you.


no clue...sorry! What methylation disorder?

I don't even really know what to ask here. My wife has a two foot long blood clot from her left ovary to just below her knee. I'm afraid she is going to die every day, even though she often seems to be doing okay, but she is wrapped in depression and she has become very different and distant.

She used to love hiking and dancing, and she is a well-known local preschool teacher, but her illness keeps her from doing many of the things she loves, and she has been able to spend less and less time with her kids. This could be disastrous for her, because she can't have children of her own due to severe endometriosis.

This is killing her and I don't know what to do.

We can't get insurance for a number of reasons I don't quite understand, although one is that this is considered a pre-existing condition, even though she developed it while her primary care physician overlooked it for at least six months. The medications cost a ridiculous amount, and without insurance we can barely get her taken care of.

Her medication is ridiculously expensive, even ordering it through a different country where they can manufacture it cheaper than here in the states. Ive been working hard to make ends meet. I had just started what was looking to be a very profitable multimedia company to help people get jobs in artistic fields, but this has taken most of my time and business is drying up.

I don't know what I'm asking, but is there anything I should know or anything we can do? I love her very much and I can't lose her.


So sorry. It sounds like her therapy is appropriate. Behavioral health counseling might be helfpul?

Dr. Moore,

One last question (promise). : )

I was under the assumption that excess testosterone (i.e. H.R.T. or anabolic steroids) contributed to DVT's, yet from the literature I have read; it appears that Estrogen is the main culprit.

Am I missing something?

Thanks again!


you are correct......estrogen is a much stronger risk factor. That said, all of the other effects of testosterone use are much scarier to me....and I'd certainly stay away from anabolic steroids!

Hi Dr. Moore, thanks for taking the time to do an AMA. Quick question:

I spend an unconscionable amount of time on the toilet at work each day to avoid my responsibilities. I usually only leave when I can no longer feel my feet, and frantically shifting my weight around no longer helps blood flow. Am I in danger of forming a blood clot over time due to my daily toilet seat dance? Thank you!


may be time to look for another job!

I have heterozygous Factor V Leiden. Most of my female relatives on my mother's side have Factor V and many have had blood clots. Should I have my sons tested for Factor V? My Ob-Gyn said it wasn't a concern for males but I still worry.


It can be a factor for males as well. That does not mean you should get them all we don't always know what to do with the results. Even if they are positive, it doesn't mean they will have a blood clot!

if my right leg gets numb easily do i have thrombosis. how much longer do i have to live


I doubt leg numbness means you have thrombosis, and how long you live may be more relevant to who you owe money to.



See my answers....I'm working through all the comments!

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