Tag Archives: anticoagulation

Superficial Venous Thrombosis: watch and wait or anticoagulate?

Check out our ICEM poster on this.

So, I see this old chestnut is under discussion again. A couple of us from the EmergINg team brought a poster to ICEM on this very topic. Sure you’ll all degree it’s another thorny VTE question well worthy of discussion.

In keeping with Rick and Simons previous posts, this is a decision very much about risk. I have a young fit man with a clinical thrombophlebitis to the Long Saphenous Vein (LSV). It’s a bit sore, but he is well and has no overt risk factors for VTE. Do I bash out some NSAIDS and tell him that we’ve been ignoring these for ages, it will probably go away? Or do I try and maximise information through USS then go through the risks and benefits of differing treatment strategies?

The initial step to scan is an important one in my opinion. A lot of these will be associated with distally propagating calf DVT. Once you are in the axial deep calf veins then there is an increasing risk that at least warrants serial USS. These calf DVTs can be silent if the Superficial Venous Thrombosis (SVT)  is distractingly sore. Secondly, a scan can delineate the extension of the SVT and help you assess risk further. Is it >5cm for example, in which case the new American guidelines would recommend 45 days prophylactic dose Fonda/LMWH . Is it tiny and chronic? Does it go all the way up to the Sapheno Femoral Junction (SFJ), in which case a vascular surgeon may be interested in acutely tying off the vessel. The scan really helps and reassures the patient that you are taking their symptoms seriously.

Next comes the discussion regarding risk. Both of conservative and aggressive management. In the CALISTO study  1500 patients were treated conservatively for SVT and had a composite endpoint event rate of 5.9%. The Number Needed to Treat (NNT) with Fondaparinux would therefore be 20. Pretty good. But what actually made up the composite outcome?

Only 5 patients out of 1500 in the conservative group developed a PE (0.2%). Only 18 patients developed a DVT (1.2%). The majority of outcome events were made up of propagation within the superficial veins or recurrence. So you may not be doing quite as much good as you think you are with treatment. Also, any anticoagulant treatment of course carries a risk of bleeding. 1% in the Fonda group for any bleeding in this trial, which is likely to be more aggressively monitored than in the real world on more compliant patients (volunteering for research) and therefore reduced as a consequence. There has also been criticism of the study due to the lack of prescribed NSAIDS/monitoring. Many VTE clinicians wanted to see Fonda/LMWH vs naproxen, not Fonda vs placebo.

The Cochrane review on the topic has been updated to reflect the CALISTO trial results and provides a nice overview of the evidence . But we are left in the realms of uncertainty still. And we haven’t even started talking about cost effectiveness yet… though there is a nice article on this in the jounral CHEST here

“If we don’t treat your disease, the risk of serious clot related illness if probably about 1-2%. It will probably be sore for a while also. If we treat it the risks and symptoms are reduced, but about 1% patients may bleed or have a reaction to the drug. Also, you have to stick yourself daily with a needle for 45 days.”

What do you think? What would you want for your relative? What would you want for yourself? Low levels of risk but with emotive consequences like this are clinical situations where we as EPs need to stop and think carefully. We are often in a rush and used to making quick critical decisions. But in a situation like this one we need to understand the evidence and relay that in understandable terms to the person in front of us.

We are good at this overall. It is a particular skill set of Emergency Medicine. We just need to recognise when to use it and to force ourselves to take the time to do so.

Very interested to know what the world is doing about these where you are. Let us know and shout out if you feel strongly one way or the other.

Dan H.

Should POPs be mixed with Heparin?

We published an interesting BET in the EMJ earlier (open access version here) this year about the use of low molecular weight heparin for patients placed in below knee POPs in the ED. This is particularly pertinent to me as I have been unlucky enough to deal with several really nasty cases in the last few years.

Standby phone goes…….Young cardiac arrest on the way in…….as the doors to resus open you see the POP on the leg….and you know this is going to end badly.

Some of the conversations with the spouses and children of patients who have died young are memorable for all the wrong reasons.

So, there is no great surprise that the cause of death is inevitably massive PE, and this is where it gets interesting as we assume that this is a preventable death. If only they had been given prophylaxis then surely this would not have happened. Well, perhaps not as the event rate is low and heparin is not without it’s own complications, so what is the evidence?

Well, my colleagues Dan Horner and Cath Roberts found a pretty good systematic review on the subject that came to an interesting conclusion. The NNT for prevention of DVT is 14. Crikey, 14 people treated to prevent one DVT is a shocker to me as that reduction is a result of a big change on a very high event rate (>18% incidence of DVT in the placebo group)….but it’s one that I don’t see coming through the door of the ED. Considering the rate of POP applications in the fracture clinic next door if the rate was that high then why am I not swamped with fracture clinic patients with DVTs? A tricky question and I can only surmise, but arguably this is a different patient group to the spontaneous patients and as the BET states, the incidence of PE and fatality as a result of these rather common DVTs is low.

So, should we routinely treat? Do you routinely treat? Would this change your practice??

I must admit to having changed practice. I am much more likely to prescribe LMWH if there is even a sniff of a risk factor and no contra-indications and up until recently I’ve been using POPs much less frequently.

I’d also say that if I turn up in your ED with a broken leg that requires a POP I will be asking for the LMWH. I don’t think I want to risk a 1:5 – 1:6 chance of getting a DVT.

What about you? Would you, should you, could you, do you??

Simon Carley