Authors: Becky Maxwell, Andy Neill / Code: CAP20, CAP7, HAP19, HAP6, HAP8, HMP2 / Published: 20/07/2016
This is the first in a series of monthly Guidelines podcasts. This month @AndyNeill joins @maxirebecca to discuss the recent CHEST Guideline for Antithrombotic Therapy in VTE .
This has been covered previously by other sites including EM:RAP and there are numerous blog posts discussing the background evidence for treating Pulmonary Embolisms on Emergency Medicine Ireland so its probably worth having a look at what else is out there. In UK we follow the NICE Guidelines 2012 which we refer to during the podcast and compare and contrast recommendations with those of CHEST.
A summary of discussion points:
- Choice of anticoagulant: CHEST recommends Direct Oral Anticoagulants (DOACS). NICE currently recommend Warfarin but most centres in UK are already moving towards DOACS. Advantages of DOACS include increasing compliance and convenience for patients and clinicians.
- Choice of Anticoagulant in patients with active cancer: CHEST and NICE recommend LMWH.
- Duration of treatment: 3 months if provoked DVT/PE. If unprovoked consider a longer period of treatment (6 months). CHEST also recommends Aspirin for those who have completed their period of treatment this is not mentioned in the NICE guidance. The New England Journal of Medicine published two studies in 2012 looking at the benefit of Aspirin in preventing recurrence of VTE ASPIRE trial and WARFASA study
- Below knee DVT: CHEST recommends not routinely treating below the knee DVTs, if its a lower risk patient with no risk factors they recommend repeat scanning as an option rather than treatment with oral anticoagulants. NICE guidelines have no specific recommendation on below knee DVTs.
- Intervention Radiology: Catheter Directed Thrombolysis for DVTs -Typically done for iliofemeoral clots. CHEST recommends against this. NICE guideline suggest to consider this in ilofemoral DVT with vascular compromise.
- IVC filters CHEST advise against use of IVC filters. NICE suggest try a few options first Increase INR to 3-4 (remember current NICE recommendations are to use Warfarin!) or consider a trial of LMWH before going down the road of IVC filters
- Compression Stockings: previously there has been a recommendation to put compression stockings on patients with DVTs to prevent post-thrombotic syndromes. Khan et al published RCT in Lancet 2013, which suggested no real benefit. CHEST and NICE no longer recommend this.
- Sub segmental PE to treat or not to treat?: This is the recommendation most likely to result in debate from the CHEST Guidelines. CHEST state In patients with subsegmental PE (no involvement of more proximal pulmonary arteries) and no proximal DVT in the legs who have a low risk for recurrent VTE we suggest clinical surveillance over anticoagulation This is the first time that this has been suggested. This already has provoked a lot of debate check out EM:RAP for a debate discussing this by Jeff Kline and Tom DeLoghery. The more CTs we do the more of subsegmental PEs we diagnose, some studies have suggested that there is a large proportion of false positives. Hutchinson et al did a large study in Ireland 2015 suggesting that “PEs diagnosed by pulmonary CTA are frequently over diagnosed.”
- Outpatient Management CHEST guidelines recommend treating low risk PEs as an outpatient. This is already happening in lots of centres in the UK.
- Thrombolytics for PE CHEST recommend we lyse massive PEs, which is pretty straightforward. Submassive PEs are more difficult and CHEST recommend against this. Evidence isnt really there for this, The PEITHO trial a few years ago demonstrated no mortality benefit. NICE guidelines recommend against it even with RV dilation. N.B. There no mention of half dose lytics in any guideline as suggested by the MOPPET trial
- Thrombectomy for PEs CHEST suggest peripheral lytics over thrombectomy
- Recurrence of VTE: If already on DOAC CHEST recommend switching to LMWH. NICE recommend this as well.
Thats a brief summary of the elements of the CHEST Guidelines on VTE pertinent to the Emergency Department. We are not suggesting you immediately go out and change practice based on our discussion in the podcast but hope this gives you some food for thought and discussion. We’d love to hear your thoughts on these Guidelines so please get in touch!
Image credit: Wellcome images on Flickr