Mini-Sternotomy Versus Conventional Sternotomy for Aortic Valve Replacement: Results from the MAVRIC Randomised Controlled Trial

Background: While Aortic Valve Replacement (AVR) outcomes have improved, morbidity remains significant. Need for transfusion is a key indicator of quality; transfusions are linked to prolonged hospital stay and increased mortality. Over one third of patients undergoing AVR via conventional median sternotomy require post-operative red-cell transfusion. Methods: MAVRIC was a single centre, single blind, randomised controlled trial, comparing AVR via manubrium-limited mini-sternotomy (intervention) and conventional median sternotomy (usual care) to assess the impact on post-operative red-cell transfusion. Patients were stratified by baseline logistic EuroSCORE and haemoglobin and followed for 12 weeks. The primary outcome was proportion of patients receiving red-cell transfusion within 7 days of index surgery. Findings: 271 patients were randomised using a central computer system with concealed allocation; 270 received surgery and contributed to the intention to treat analysis. No difference between intervention and usual care in red-cell transfusion within 7 days was found; 23/135 patients in each arm received a transfusion, odds ratio 1·0 (95% CI: 0·5, 2·0) and risk difference 0·0 (95% CI: -0·1, 0·1). Intervention reduced chest drain losses (mean 181·6ml (SD 138·7) vs usual care mean 306·9ml (SD 348·6)); this did not reduce red-cell transfusions. Mean valve size and postoperative valve function were comparable between intervention and usual care; 23mm vs 24mm, and 6/134 moderate or severe aortic regurgitation vs 3/130, respectively. Mini-sternotomy resulted in longer bypass times (82·7 minutes (SD 23·5) vs 59·6 minutes (SD 15·1)) and cross clamp times (64·1 minutes (SD 17·1) vs 46·3 minutes (SD 10·7)). Conventional sternotomy was more cost-effective with only a 5·8% probability of ministernotomy being cost-effective at a willingness to pay of £20,000/QALY. Interpretation: AVR via manubrium-limited mini-sternotomy did not reduce red blood cell transfusion within 7 days following index surgery when compared to conventional sternotomy. Clinical Trial Number: International Standard Randomised Controlled Trial Number (ISRCTN) ISRCTN29567910. Registered on 3 February 2014. Funding Statement: The trial was funded by the NIHR Research for Patient Benefit Programme (grant number PB-PG-1112-29035). GJM is supported by the British Heart Foundation (CH/12/1/29419) and the NIHR Leicester Biomedical Research Centre. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: This protocol and all trial-related documents were originally approved by the National Research Ethics Service Committee, North East - Newcastle & North Tyneside 1 in March 2014 (IRAS Project 137295; REC Reference 14/NE/0005). Since initial approval, three amendments have been made and approved; thus, this is version 5 of the protocol. Written informed consent will be obtained from all participants. The trial will be run according to the principles of ICH-GCP and in accordance with relevant UK legislation and the protocol.