The cardioprotective effects of adenosine-induced cardioplegic arrest versus saline in aortic valve replacement patients: A randomized controlled trial

Background and aims: Adenosine is a widely used potent cardioprotective drug, but the effect of an adenosine bolus in initial cardioplegia on cardioprotection in aortic valve replacement (AVR) patients has not been demonstrated. The aim of this double-blind randomized clinical trial was to compare intra-aortic adenosine bolus with saline on the postoperative myocardial function in patients undergoing AVR. Methods: Aortic valve stenosis patients scheduled for elective or urgent AVR surgery were randomized to receive either a 20 mg (4 mL) single dose of adenosine or a saline into the ascending aorta during the first cardioplegia infusion. The primary outcome was cardiac index (CI (L/min/m 2 ) at four timepoints (before incision, after weaning from cardiopulmonary bypass (CPB), at 7 p.m. on the operation day, and at 6 a.m. the next morning). Secondary outcomes included left ventricular stroke work index, right ventricular stroke work index, and myocardial biomarkers at the same timepoints. Results: Between November 2015 and March 2018, 45 patients were recruited, 23 in the adenosine group and 22 in the placebo group. The last follow-up date was 17 March 2018. There were no statistically significant differences in CI (mean differences with 95% confidence interval (95% CI): 0.09 L/min/m 2 at baseline (−0.20 to 0.38), −1.39 L/min/m 2 (−3.47 to 0.70) at post-CPB, −0.39 L/min/m 2 (−0.78 to 0.004) at 7 p.m., and −0.32 L/min/m 2 (−0.68 to 0.05) at 6 a.m., ( p = 0.066)), right ventricular stroke work index, ( p = 0.24), or cardiac biomarkers between the groups. Left ventricular stroke work index was lower in the adenosine group (−3.66 gm/m 2 (−11.13 to 3.81) at baseline, −17.42 gm/m 2 (−37.81 to 2.98) at post-CPB, −3.36 gm/m 2 (−11.10 to 4.38) at 7 p.m., and −3.77 gm/m 2 (−10.19 to 2.66) at 6 a.m. ( p = 0.021)). Conclusions: There were no differences between 20 mg adenosine bolus and saline in the first cardioplegia infusion in CI improvement in AVR surgery for aortic valve stenosis. EudraCT number: 2014-001382-26.