LAUSR

Introduction Aprotinin is a serine protease inhibitor which is used in cardiac surgery as an anti-fibrinolytic agent to minimise patient bleeding. It was withdrawn from the European market in 2008 due to potential increased mortality when compared to tranexamic acid. Aprotinin was subsequently re-introduced in 2012 with narrow licencing indications, specifically isolated coronary artery bypass graft surgery in high risk patients. Minimisation of intra-operative blood loss plays an important role in patient outcomes, especially in decreasing the need for transfusion which carries its own mortality risks(3,. Tranexamic acid is utilised in the majority of cardiac surgery cases throughout Europe. We looked to quantify and determine indications for aprotinin usage in an Irish tertiary cardiac centre and compare findings to tranexamic acid. Methods Retrospective study of aprotinin usage in cardiac surgery in an Irish tertiary centre over a 3 year period to determine number of cases and indications. Data collection involved operative notes, patient records, pharmacy dispensing accounts. Aprotinin dosage intra-operatively was per the full or half Hammersmith protocol. A cohort which had undergone comparable cardiac surgery procedures with tranexamic acid as the anti-fibrinolytic agent were also studied. Results From 2018-2021, 21 cardiac surgeries were carried out using aprotinin as the sole anti-fibrinolytic agent to minimise patient bleeding in a high risk cohort. For the same time period, to provide scale, 737 cardiac surgeries were carried out using tranexamic acid. Each of the cases which utilised aprotinin represents an emergent, life-threatening operation. The emergency cases comprised: repair of Stanford type A aortic dissection (8, 38%); aortic valve replacement (7, 33.3%); mitral valve replacement (3, 14.3%); tricuspid valve replacement (1, 4.8%); mediastinal revision for cardiac tamponade (1, 4.8%). Valve replacements were complicated by: acute infective endocarditis, aortic root abscess, haematoma, failure of pre-existing prosthetic valves. 1 case utilised aprotinin as per the licenced indication: isolated CABG in patient with high bleeding risk. An ST-elevated myocardial infarction necessitated the emergency CABG procedure in this case. Discussion In summation, 95% of aprotinin usage for cardiac surgery in an Irish tertiary centre falls outside the remit of the licenced indication. Given similar findings in a number of European institutes(5), is it time to re-assess the existing guidelines on aprotinin use, with view to expansion of the licenced indications?