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Transcript

 

Lee Tetreault:

Hello and welcome to frequently asked questions from the session The Clot Thickens: Cases in Anticoagulation Workup and Management of DVT. We are joined today by Dr. George Marzouka. Doctor, before we begin, can you provide a few key pointers for our audience from today's session? 

George Marzouka: 

Sure, one of the things that I wanted to bring home was the concept that except in cancer or pregnancy all DOACs are recommended over warfarin, and patients with cancer or pregnancy the preferred anticoagulant is low molecular weight heparin. In patients with an unprovoked DVT, aspirin is typically recommended after completing the first course of anticoagulation therapy. However, one of the key points that I try to make, if somebody is at high bleeding risk, you're going to stop anticoagulation after three months, but if they're low to moderate risk, you might wanna consider indefinite therapy with anticoagulants. But if you are gonna stop the anticoagulation, then adding aspirin is a great choice.

Lee Tetreault:

Great, let's get into some of these frequently asked questions. So, the thinking is, shouldn't you just put an IVC filter in anyone who has a DVT to prevent massive PEs.

George Marzouka: 

No, these devices are not benign and can cause harm. In patients who are able to tolerate anticoagulation, the recommendation is for them to be on anticoagulation, there is no added benefit to implanting an IVC filter.

Lee Tetreault:

And how long should you treat patients after a provoked DVT, for example, after knee surgery? 

George Marzouka: 

The first time it happens, no more than... No more and no less than three months. If it happens again then it might be time to consider a longer course of therapy, including possibly lifelong therapy.

Lee Tetreault:

Should you prescribe compression stockings to your patients with DVTs? 

George Marzouka: 

No, there's no benefit.

Lee Tetreault:

How good, really, is a D-dimer?  

George Marzouka: 

It's great at ruling out a DVT, but not specific enough to rule it in if it comes back positive. So when a DVT is the worst possible ideology on your list, then a D-dimer might be a quick way to get it off your list if it's negative.

Lee Tetreault:

So something that's a popular statement would be that you can use DOACs in patients with renal failure, is that true? 

George Marzouka: 

Yes and no. So there was a lot of concern when these drugs first came out, about the increased risk of bleeding in patients with renal impairment. Pharmacokinetic studies and, in particular, just one with only eight patients, showed that the drug levels were often higher in patients with impaired renal function, but the bleeding risk wasn't higher. The issue remains up for debate, though. Again, that study was a very small study with only a few patients. Recent abstracts have been published in JACS, suggesting a mortality benefit, with no increased risk of bleeding, across all levels of renal impairment even end-stage renal disease on hemodialysis with DOACs over warfarin. However, at this point, I would proceed with caution. Edoxaban, apixaban, rivaroxaban do have reduced dosing in patients with a creatinine clearance between 15 and 29, however, in patients with less than a creatinine clearance of 15 I would consider using warfarin, only.

Lee Tetreault:

And lastly, doctor, another popular train of thought is that DOACs should not be used in morbidly obese patients, is that true? 

George Marzouka: 

There are some concerns about decreased efficacy in morbidly obese patients. We're not really sure. There's some small studies that are showing that it's probably okay to treat these patients with DOACs. And then there's some reasoning that because most patients on warfarin... Not most, but a large percentage of patients on warfarin are not always in their therapeutic range, and maybe the... In the best patient you might be in the therapeutic range about 60% of the time, that it may be better, even if they're obese, to be on a DOAC, which will offer them some coverage all the time, than to be sub-therapeutic part of the time on warfarin. However, we don't have a clear answer about this yet, and it's still controversial, but there are studies under way to try to figure this out.

Lee Tetreault:

Great, doctor. Thank you so much for your time today.

George Marzouka: 

Thank you.