Efficacy and Safety of the Reduced Bivalirudin in Patients Undergoing Coronary Angiography or Percutaneous Coronary Intervention Stratified by Renal Function (REDUCE BOLUS): A Single-Blind, Stratified Randomized, Non-inferiority Trial

BACKGROUND: In clinical practice, some cases indicated that the loading dose of bivalirudin increased the bleeding risk, particularly in patients with renal insufficiency. Therefore, this study aimed to assess the efficacy and safety of the low-dose (80%) bolus injection of bivalirudin in patients undergoing cardiac catheterization stratified by renal function. METHODS: A total of 204 individuals in the REDUCE BOLUS trial were stratified 1:1 to the estimated glomerular filtration rate (eGFR) ≥ 60 ml/min cohort or eGFR < 60 ml/min cohort, then randomized 1:1 to the reduced bolus bivalirudin group (i.e., the experimental group) or normal bolus bivalirudin group (i.e., the control group), respectively. The primary end point was to compare the differences of the area under the curve of activated clotting time (ACT) between the two groups. The secondary end points were the postoperative net adverse clinical events (NACEs) before discharge, defined as the all-cause mortality, recurrent myocardial infarction, ischemia-driven target vessel revascularization, stroke, and bleeding events. RESULTS: Between January 3, 2020, and March 26, 2021, 204 patients undergoing coronary angiography were randomly assigned, including 102 (i.e., 51 in the control group and 51 in the experimental group) with normal eGFR and 102 (i.e., 51 control and 51 experimental) with abnormal eGFR. No difference was observed in the curve of ACT between the control group and the experimental group (0.55 ± 0.09 vs. 0.56 ± 0.08, P = 0.542 and 0.55 ± 0.06 vs. 0.57 ± 0.05, P = 0.075, respectively, for normal eGFR cohort and abnormal eGFR cohort). The one-sided 97.5% lower confidence bound for the difference in the area under the ACT curve was –0.017 and 0.0015 in eGFR ≥ 60 ml/min and eGFR<60 ml/min cohort, respectively, both above the preset non-inferiority criterion of -0.07, establishing the non-inferiority. There was no incidence of NACE and stent thrombosis before discharge in each group. CONCLUSION: In patients undergoing cardiac catheterization, the efficacy and safety of the reduced bolus of bivalirudin were non-inferior to the normal one, even in patients without chronic kidney disease. CLINICAL TRIAL REGISTRATION: [www.ClinicalTrials.gov], identifier [NCT03588611].