Comment on “Preoperative Statin Use and 90-day Mortality After Noncardiac Surgery”

Abstract

agents [16 (21.6%) vs 15 (20.8%), P ¼ 1.000] and beta-blocker [21 (28.4%) vs 20 (27.8%), P ¼ 1.000] were not significantly different as well. Similarly, in the subgroup analysis according to ABO compatibility, there were no significant differences in baseline patient comorbidity and medication status.Regarding the abolishing effect of RIPC, contrary to Kim et al, there are several studies showing beneficial effect of anesthetics in RIPC. 6,7 Furthermore, in our study, both the RIPC group and the control group were treated with the same anesthetic protocols throughout the operations. Therefore, Kim et al's mentions are unlikely to have significant confounding factors in the current study.Lastly, as clearly stated details in Discussion section, we would like to emphasize that multiple mechanisms have been proposed to explain the protective effects of RIPC, including humoral, neurogenic, and systemic pathways. 8 Therefore, it is reasonable to assume that more than 1 pathway may have been involved in the effect of preconditioned liver grafts obtained by RIPC that acted in a sequential or a parallel manner for additive effects. Importantly, the protective effect of preconditioning has a biphasic pattern-the acute protective effects wane after a few hours, and the delayed second window of protection occurs after 12 to 24 hours. 9 We presume that the delayed second window of protection, along with the possible combination of humoral and other pathways, would have affected the recipients through the preconditioned grafts. Therefore, Kim et al's notion of simple graft irrigation significantly hindering the protective effects of RIPC may be overlooking the complexity of the protective mechanism of RIPC. As for the referenced study by Kim et al, 5 it is not surprising that a clinically significant difference in graft function was not observed (only 2 cases/78 patients) in a study using recipient side of RIPC. Instead, given the importance of donor graft, our clinical trial has a value that firstly assessed impact of donor side RIPC on the postoperative liver function of recipients.