n 1 © Europa Edition 2011. All rights reserved. EXPERT REVIEW EuroIntervention 2011;7-online publish-ahead-of-print September 2011 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 *Corresponding author: Glenfield Hospital, Groby Road, Leicester, LE3 9QP, United Kingdom. E-mail: annette.maz@hotmail.co.uk. Discontinuation of metformin in the setting of coronary angiography: clinical uncertainty amongst physicians reflecting a poor evidence base Annette Maznyczka 1 *, BSc, MBChB; Aung Myat 2 , BSc, MBBS, MRCP; Anthony Gershlick 1 , BSc, MBBS, FRCP 1. Department of Cardiology, Glenfield Hospital, Leicester, United Kingdom; 2. The Rayne Institute, St Thomas’ Hospital, King’s College London, London, United Kingdom Abstract Aims: Metformin is widely prescribed for the treatment of type 2 diabetes mellitus and is associated with a reduction in diabetes-induced cardiovascular morbidity and mortality. Concerns about metformin-associ- ated lactic acidosis (M-ALA) in patients undergoing contrast-based angiographic procedures have led to the development and publication of a number of guidelines to improve the management of this patient cohort. Methods and results: This review focuses on the evidence behind these guidelines and, in particular, that concerning metformin discontinuation in diabetic patients undergoing coronary angiography and percutane- ous intervention. This review addresses and compares guideline-directed management of such patients and includes the results of a UK physician survey to highlight variations in clinical practice. Conclusions: We conclude that evidence for M-ALA in diabetics on metformin undergoing coronary inter- vention is lacking and existing guidance on the management of such patients is inconsistent. More robust evidence is needed in the form of a large, adequately-sized randomised trial or extensive registry so that we can optimally manage those patients requiring contrast-based coronary interventions who are also taking metformin. KEYWORDS • metformin • lactic acidosis • coronary angiography • guidelines