Comment on Guidelines on oral anticoagulation with warfarin – 4th edition. Response to Gosai & Muthusamy

I thank Drs Gosai and Muthusamy for pointing out our omission in the fourth edition of the British Committee for Standards in Haematology warfarin guidelines (Keeling et al, 2011). We had originally intended a short paragraph on the use of warfarin to treat mural thrombus. In the third edition of the guideline (Baglin & Rose, 1998) it was stated that patients with mural thrombus after myocardial infarction are at greatest risk of embolization in the first 3 months, especially in the presence of a left ventricular aneurysm. Following initial heparin therapy, warfarin was recommended for 3 months to achieve an International Normalized Ratio of 2·5 (grade B, level III). This recommendation was not changed when the third edition was updated (Baglin et al, 2006). I agree there are no new data (the most recent reference cited by Drs Gosai and Muthusamy is from 1992) and that further study is necessary. Until then our recommendation remains unchanged and we would GRADE as 2C, a weak recommendation based on low quality evidence.