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A case that changed my practice – a near miss with warfarin

The case

The man’s wife called up our surgery, worried about her husband – ‘he’s been so poorly, up all night for three days with pain in his leg’. It sounded like I ought to see him, so I arranged an appointment for the next day. He duly attended, limping into the room. He had developed sudden pain in his right lower leg confined to below the knee. The leg was shiny, swollen, red and pulseless, but the capillary return was brisk enough. It didn’t look like the classical acute ischaemic leg. The patient had been taking warfarin for atrial fibrillation for over a year. I wasn’t at all sure what was going on, but the suddenness suggested  a vascular cause so I referred him to the vascular team.

The outcome

Two weeks later, after the patient had been seen by the vascular team, I read the clinic letter with a feeling of guilt that I perhaps should have admitted him. His superficial femoral artery was blocked but percutaneous intervention wasn’t deemed necessary as the leg was viable. Phew. We knew that the patient liked the odd pint, but when I interrogated his INRs and put them into graphic form it  was clear just how little time he was spending in therapeutic range. You can see a copy of this graph in the online version of this article.

I wrote to the haematologist about switching to a novel anticoagulant and received a non-committal reply that  I could switch if I wanted to. The vascular surgeon was similarly on the fence. So  I switched anyway, and the patient is now on dabigatran. He understands the importance of taking it, but his anticoagulant control is no longer dependent on his diet and variable alcohol intake.

What I learned

I recalled seeing a graph of mortality against time in therapeutic range which showed how poorly controlled warfarin is worse than not being on warfarin at all – and this case certainly reinforced that. Go to the online version of this article to see this graph. Anticoagulation can seem a mundane area of practice, but this case brought home to me the clear and present danger of atrial fibrillation – one of our fastest growing long-term morbidities.

How this changed my practice

I now review patients’ level of control regularly and, instead of hoping that patients with poor control will improve, just throw in the towel and use a newer medication in those cases. We have wanted an alternative to warfarin for 50 years and now three have come along at once! So I’m not going to run the risk of  a patient having a stroke just because they cannot get good control on warfarin.


Dr Nigel Rowell is a GP specialist in heart failure and a hospital practitioner in cardiology at the James Cook University Hospital, Middlesbrough

Competing interests: Dr Rowell has received honoraria for giving lectures for Boehringer Ingelheim on stroke management and novel anticoagulants