DVT into PE

April 18, 2012 1:11 PM

DVT developing into PE: % chance? What would happen?

A "pretty extensive" DVT just below the knee;
two weeks post diagnosis;
treated at home since diagnosis, with coumadin (initially coumadin+lovenox);
patient's INR now in therapeutic range (between 2.0 and 3.0).

(Young, relatively healthy patient's first DVT -- still working to discover cause.)


What are its chances now of developing into a PE?

And what would happen if it did? Would the patient probably be incapacitated right away / unable to call 911?

If treated properly in a hospital, what would be the PE's likelihood of being fatal?

(We're trying to figure out how much of a risk it is for this person to be alone for extended periods and/or alone overnight while sleeping.)

posted by sparrows to health & fitness (10 answers total)

I can't comment on the likelihood of the event, but I do recommend that anybody facing a risk of a debilitating medical event consider investing in a lifeline system if at all possible. Most companies will do a month-to-month contract.
posted by Sidhedevil at 1:28 PM on April 18, 2012

I would strongly urge that this person contact their doctor or a nurse in the doctor's office for personalized advice. If he or she is unable to call, and the office won't give you (the friend or relative) his or her medical information, ask them "hypothetically" what should be done in this situation. At the next opportunity, the person should list you as an authorized recipient of their medical information so that their condition and its risks can be fully discussed. But try calling anyway.
posted by desjardins at 1:40 PM on April 18, 2012 [1 favorite]

Your risk of dying from a PE (or indeed, since a proportion of PEs are without symptoms, even noticing you've had one) has a lot to do with your general health, especially your cardiovascular health. Add to that uncertainty the fact that you don't have any idea what caused this DVT in the first place, I really wouldn't like to try and assess those odds for you. So basically what desjardins said: ask the people who are treating them.
posted by Coobeastie at 1:45 PM on April 18, 2012

IANADyet, so take the quality of this information as somewhere between a poorly-edited Wikipedia page and a Bazooka Joe wrapper. I recently had to do a pretty involved presentation on DVT (deep venous thrombosis) / VTE (venous thromboembolism) that included this overly-complicated concept map drawing out a lot of the risk factors and processes behind the DVT, as well as some of the signs and symptoms of VTE in the lower righthand corner. Unless you're super-interested in the clotting cascade, you can ignore the part in the middle. Basically, look for increased heart rate, increased respirations, heart murmur, and most importantly sudden-onset pleuritic chest pain (worse on inhalation, not related to muscle pain).

The patient and his/her care team will know the most about best practices for home care. As has been pretty well-established above, there are a lot of factors that determine the risk factors and survival statistics for DVT and VTE.
posted by The White Hat at 9:22 PM on April 18, 2012

I did find the statistic that [warning: page has graphic image of swollen foot] untreated PE is fatal 30% of the time and treated PE is fatal 2% of the time.
posted by sparrows at 9:51 PM on April 18, 2012

Whatever this person's primary care provider says is the most reasonable thing to do - that's who knows enough about this person's case to judge. IANA physician, this is not advice of any sort, least of all health advice.

Just looking for recent papers with the right sort of analyses:

In a multicenter international (Spain, France, Italy) registry of over 15,000 patients presenting to participating hospitals with acute DVT or PE, Laporte et al. found that the cumulative death rate from PE among those who presented with DVT without PE over the subsequent three months was 5.5 per thousand. For patients under 75 years, the fatal PE rate for that population was 2.3 per thousand over three months. Three-quarters of fatal PEs occurred in the twelve days after the initial event (but the first event includes both DVT and PE.)
Other risk factors for fatal PE included cancer, cardiac or respiratory disease and immobilisation longer than 4 days for neurological disease.
Laporte S, Mismetti P, Decousus H et al., 2008, CIRCULATION 117(13):1711-1716

A recent metaanalysis found that patients with calf DVT without PE had a probability less than 1 in 1000 of developing PE within one year and 1.2% within three years (95% confidence interval 0.2-8.2%). Pretty broad confidence intervals because even in the pooled data there were only 171 calf DVTs without PE to look at. And that's developing any PE, not just a fatal PE, in the subsequent time period.
Baglin T, Douketis J, Tosetto A et al., 2010, Journal of thrombosis and haemostasis 8 (11):2436 -42
posted by gingerest at 9:56 PM on April 18, 2012 [2 favorites]

sparrows, I just wanted to point out that there is an error in your statistical reasoning so far. Remember that the treatment for DVT and PE is the same (anticoagulation). The only PEs that get additional treatment aside from what your patient is already getting are the rare people with massive PEs who are unstable or in cardiac arrest - they are treated with clot busting drugs (thrombolytics).

The statistics that you posted and that gingerest posted are regarding people who either presented initially with PEs alone or presented initially with DVT and PE together.

These statistics do not reflect the likelihood of developing a PE when you are appropriately treated on anticoagulation already. Even the second part of your statistic refers to people who are treated after being diagnosed with PE, not to people who were already treated before they developed PE. You cannot infer that mortality rates would be the same in these two different populations.

That all being said, it is possible, but very rare, for people to develop PE while they are appropriately anti coagulated (so much so that if the INR is therapeutic, and the patient comes in with chest pain or shortness of breath, we typically think they are still unlikely to have a PE unless the story raises a much higher level of suspicion). Such people who get clots despite blood thinners may require placement of an IVC filter to prevent PE. I cannot give you an exact statistic on how often this happens, though. I can tell you that massive PEs that would cause a cardiac arrest or incapacitate someone are quite rare. Anecdotally, in my 5 years practicing emergency medicine I've never seen a patient that I knew for sure to have been incapacitated by a massive PE (although I've seen a few cardiac arrests that could hypothetically have been caused by PE). I have never used thrombolytics.

Most people with PE either have zero symptoms - yes, you can have a PE and have no symptoms at all, I've seen a number of PEs identified on routine CT scans being done for other reasons - or they have the typical symptoms of chest pain or feeling somewhat short of breath. IANYD and this is not medical advice, I can't advise you anything about your situation specifically. I can tell you we generally do not advise people that if they have a DVT they need to be supervised by others.

Most people who have a diagnosis of DVT are on anticoagulation for 6 weeks to 6 months - are you really going to be able to keep this person under watch for all that time? Anyway, if you have any other questions, you can MeMail me.
posted by treehorn+bunny at 10:44 PM on April 18, 2012 [3 favorites]

oh, sorry, it's late at night and I'm running on little sleep. Didn't notice that gingerest's paper actually does include specifics about people with DVT who received appropriate treatment and mortality rates. That sounds like a good answer. :-) My concern about the confounding factors only applies to the original stats you posted.
posted by treehorn+bunny at 10:47 PM on April 18, 2012 [2 favorites]

This is anecdotal, but my family member (very healthy middle-aged guy) suffered from a PE, related to DVT below the knee. (The root cause of all of this was a sports injury.) I was not there, but the pain set in during the middle of the night so while it's possible he was already awake, I think he said the pain was severe enough to wake him. The (somewhat hospital-averse) patient wanted to see if it went away; his partner said, "It could be a PE. Put on your fucking pants, we're going to the hospital."

So in our experience: I think I was told that the pain was an 8 out of 10. Both the patient and his partner were immediately aware it was an emergency, and there was enough time to have a conversation to make a decision, and then drive 20 minutes or so to the ER. Had he been alone, I think he would have known to call 911 immediately and would have been able to speak to explain the problem.

I'm sorry you're going through this. It's very scary when you start reading about PEs. For whatever it's worth, several years later, it is something that has faded into the background for the most part and our patient is healthy and thriving.
posted by juliplease at 5:46 AM on April 19, 2012

Nothing but reassuring news from the Dr appt today. Many thanks for your help, everybody.
posted by sparrows at 2:45 PM on April 19, 2012