The UK Cardiac and Vascular Surgery Interventional Anaemia Response (CAVIAR) Study: protocol for an observational cohort study to determine the impact and effect of preoperative anaemia management in cardiac and vascular surgical patients

Marisa Chau, Toby Richards, Caroline Evans, Anna Butcher, Timothy Collier, Andrew Klein, Marisa Chau, Toby Richards, Caroline Evans, Anna Butcher, Timothy Collier, Andrew Klein

Abstract

Introduction: Preoperative anaemia is linked to poor postsurgical outcome, longer hospital stays, greater risk of complications and mortality. Currently in the UK, some sites have developed anaemia clinics or pathways that use intravenous iron to correct iron deficiency anaemia prior to surgery as their standard of care. Although intravenous iron has been observed to be effective in a variety of patient settings, there is insufficient evidence in its use in cardiac and vascular patients. The aim of this study is to observe the impact and effect of anaemia and its management in patients undergoing cardiac and vascular surgery. In addition, the UK Cardiac and Vascular Surgery Interventional Anaemia Response (CAVIAR) Study is also a feasibility study with the aim to establish anaemia management pathways in the preoperative setting to inform the design of future randomised controlled trials.

Methods and analysis: The UK CAVIAR Study is a multicentre, stepped, observational study, in patients awaiting major cardiac or vascular surgery. We will be examining different haematological variables (especially hepcidin), functional capacity and patient outcome. Patients will be compared based on their anaemia status, whether they received intravenous iron in accordance to their hospital's preoperative pathway, and their disease group. The primary outcomes are the change in haemoglobin levels from baseline (before treatment) to before surgery; and the number of successful patients recruited and consented (feasibility). The secondary outcomes will include changes in biomarkers of iron deficiency, length of stay, quality of life and postoperative recovery.

Ethics and dissemination: The study protocol was approved by the London-Westminster Research Ethics Committee (15/LO/1569, 27 November 2015). NHS approval was also obtained with each hospital trust. The findings of the study will be published in peer-reviewed journals.

Trial registration number: Clinical Trials registry (NCT02637102) and the ISRCTN registry (ISRCTN55032357).

Keywords: Anaemia; Patient blood management; cardiovascular surgery; iron deficiency; preoperative anaemia management.

Conflict of interest statement

Competing interestsMC’s salary is supported by Pharmacosmos A/S. TR reports grants from NIHR HTA (UK); grants from NHMRC (Australia); grants from NIAA / BJA / ACTA / VASGBI (UK); grants, personal fees and non-financial support from Pharmacosmos; grants, personal fees and non-financial support from Vifor Pharma; grants, personal fees and non-financial support from Acelity; grants, personal fees and non-financial support from Stroke Association; grants from Mason Medical Research Foundation; grants from UCH League of Friends; grants and non-financial support from Libresse/ Bodyform; outside the submitted work. TR is a regular speaker at national and international conferences on anaemia, blood transfusion, wound healing and vascular diseases for which he has received expenses for travel, accommodation and sundries. TR is the Director of The IronClinic Ltd, Director of Veincare London Ltd, and is also the Vascular lead for 18-week wait Ltd. CE is a Consultant for Pharmacosmos. AK has received research funding and honoraria from Pharmacosmos, Vifor Pharma, CSL Behring and Brightwake Ltd. AK is the Editor-in-Chief of Anaesthesia. There is no external or industry involvement in CAVIAR.

© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Figures

Figure 1
Figure 1
Patient categorisation. 6MWT, 6 mins walk test; CPET, cardiopulmonary exercise test; IV, intravenous; tHbmass, total haemoglobin mass.
Figure 2
Figure 2
Flow chart of the UK CAVIAR Study. * Collected from patient’s medical records. # Only relevant for the substudy arm. CAVIAR, Cardiac and Vascular Surgery Interventional Anaemia Response; 6MWT, 6 min walking test; CPET, cardiopulmonary exercise test; DAOH, days alive and out of hospital; HRQoL, health-related quality of life; ICU, intensive care unit; IV, intravenous; tHbmass, total haemoglobin mass.

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