Title: Manubrium-limited ministernotomy versus conventional sternotomy for aortic valve replacement: a randomised controlled trial (MAVRIC)
Funder: Department of Health (England)

Abstract: Background Conventional surgery for aortic valve replacement is one on the most common heart operations, and is usually performed using median sternotomy, in which the sternum is divided completely (from the collar bone to the bottom of the breast bone). The operation includes cardiopulmonary bypass established by siting cannulas in the right atrium and ascending aorta. Minimally invasive aortic valve replacement, using a new technique called manubrium-limited ministernotomy, divides only the top quarter of the sternum (the manubrium) leaving the rest of the sternum intact. The operation involves cardiopulmonary bypass established using femoral vein (in the groin) and ascending aorta cannulation. Over one third of patients undergoing conventional median sternotomy develop clinically significant bleeding and require a post-operative red blood cell (RBC) transfusion (1,2). Blood transfusion can have adverse clinical effects after cardiac surgery including post-operative lung injury, organ dysfunction, confusion, and immunosuppression (3); complications of transfusion have been directly linked to prolonged hospital stay and increased mortality after cardiac surgery (4). In a case series of 50 patients undergoing conventional aortic valve replacement at James Cook University Hospital (JCUH) in 2011/2012, 30% (n=15) required a red blood cell transfusion; in 60 patients undergoing manubrium-limited aortic valve replacement 13% (n=8) required a red blood cell transfusion. Case series data suggest a significant and clinically important difference in the need for RBC transfusion between patients undergoing the conventional and manubrium-limited surgical technique. Given the implications of transfusion for NHS resources and patient outcomes, and the potential benefits from this new technique, this indicates the need for a definitive trial. Aims MAVRIC is a randomised controlled trial, which will evaluate the effect of a manubrium-limited ministernotomy on RBC transfusion rates in patients requiring aortic valve replacement. The primary outcome of the trial is the proportion of patients who receive a RBC transfusion within 7 days of surgery. Patient-focused secondary outcomes will include: the number of patients who receive a RBC transfusion during the entire hospital stay, number of units transfused, haematological parameters, postoperative blood loss 12 hours after surgery, surgical conversion rates, re-operation rates, change in FEV1 and FVC compared to baseline, time to patients being ‘fit for discharge’, health care utilisation including length of hospital stay and follow up to 3 months following surgery, quality of life EuroQol (EQ-5D-3L, EQ-VAS) at baseline, 6 weeks and 3 months, operative success established by echocardiogram (echo) at 6 weeks following surgery, and adverse events. Cost and cost effectiveness analyses, evaluating the difference in blood transfusion rates will be modelled stochastically from within the trial using patient level data to inform policy and practice. Plan of Investigation Patients requiring isolated aortic valve replacement at The James Cook University Hospital, Middlesbrough will be recruited to the study. Eligible patients will be randomised (1:1 ratio) to undergo a conventional or manubrium-limited operation. Patients will be assessed for RBC transfusion requirements, surgical outcomes, and followed for 3 months to assess patient functioning, quality of life and economic outcomes. Benefits Reducing the need for RBC transfusion has clear and pressing implications for the direct patient experience, post-operative recovery, and subsequent morbidity in this population. In terms of cost alone, if the manubrium-limited approach reduced RBC transfusion by one unit and hospital stay by one day, this would likely result in a net cost reduction of approximately £1.4 million for the NHS each year. A robust trial of the manubrium-limited technique compared with conventional surgery is needed to ensure that appropriate surgical strategies deliver improved patient outcomes and efficient use of NHS resources.


Research activity codes: 6.4 SURGERY
Health categories: CARDIOVASCULAR