Evaluation of low-dose colchicine in patients with cardiopulmonary bypass: study protocol for a randomised controlled trial

Introduction: Inflammation and myocardial damage caused by cardiovascular surgery with cardiopulmonary bypass (CPB) have been shown to be the major contributors to postoperative morbidity and mortality. Colchicine can reduce myocardial ischaemia-reperfusion injury in patients with chronic coronary artery disease. However, there is a lack of evidence whether colchicine could reduce myocardial injury after cardiovascular surgery. In this study, we aim to evaluate the effect of low-dose colchicine on myocardial protection during perioperative period in patients who undergo cardiovascular surgery with CPB.

Methods and analysis: In this randomised controlled trial, a total of 132 patients will be recruited from the Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital. Patients will be randomised into the colchicine treatment group and control group with a ratio of 1:1. Patients in the colchicine treatment group will receive 0.5 mg of colchicine daily for 3 days before surgery and 0.5 mg of colchicine daily for 5 days after surgery. Patients in the control group will receive placebo instead of colchicine for the same schedule. Level of postoperative myocardial injury will be assessed as the primary outcome. The secondary outcomes are biomarker levels for myocardial injury (such as creatine kinase-MB, cardiac troponin I, myohaemoglobin, type B natriuretic peptide, D-dimer) and inflammatory response markers (white blood cell, procalcitonin, interleukin-6, C reactive protein) for 5 consecutive days after surgery and poor postoperative outcomes.

Ethics and dissemination: This study has been approved by Medical Ethics Committee of Affiliated Nanjing Drum Tower Hospital, Nanjing University Medical College (approval number: 2020-293-01). Study results will be disseminated through publication in an open access journal.

Trial registration number: ChiCTR2000040129.