Remote ischaemic conditioning for prevention of acute kidney injury after valvular heart surgery: a randomised controlled trial

Abstract

Background: Repeated remote ischaemic conditioning (RIC) during weaning from cardiopulmonary bypass and in the early postoperative period may confer protection against acute kidney injury (AKI). We evaluated the effect of repeated RIC on the incidence of AKI in patients undergoing valvular heart surgery. Methods: Patients were randomised into either the RIC (n¼120) or control (n¼124) group. A pneumatic tourniquet was placed on each patient's thigh. Upon removal of the aortic cross-clamp, three cycles of inflation for 5 min at 250 mm Hg (with 5 min intervals) were applied in the RIC group. Additionally, three cycles of RIC were repeated at postoperative 12 and 24 h. AKI was diagnosed based on the Kidney Disease: Improving Global Outcomes guideline. The incidences of renal replacement therapy, permanent stroke, sternal wound infection, newly developed atrial fibrillation, mechanical ventilation >24 h, and reoperation for bleeding during hospitalisation were recorded. Results: The incidences of AKI were not significantly different between the control (19.4%) and RIC (15.8%) groups (a difference of 3.5 percentage points; 95% confidence interval: e6.8%e13.9%; P¼0.470). Perioperative serum creatinine concentrations were similar in the control and RIC groups (P¼0.494). Fluid balance, urine output, blood loss, transfusion, and vasopressor/inotropic requirements were not significantly different between the groups (all P>0.05). The occurrences of a composite of morbidity and mortality endpoints were not significantly different between the control (46.0%) and RIC (39.2%) groups (a difference of 6.8 percentage points; 95% confidence interval: e6.4%e20.0%; P¼0.283). Conclusions: The results of our study do not support repeated RIC to decrease the incidence of AKI after valvular heart surgery. Clinical trial registration: NCT02720549.

Effect of Remote Ischemic Conditioning on Bleeding Complications in Surgery: A Systematic Review and Meta-Analysis

“…A subgroup of 1,951 patients from 18 trials underwent cardiac surgery. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] The remaining 1,853 patients were included in 14 trials in various surgical settings: organ transplant donors or recipients (five trials), [45][46][47][48][49] tumor resection (five trials), 13,[50][51][52][53] abdominal aortic aneurysm repair (two trials), 54,55 and orthopaedic surgery (two trials) 56,57 (►Table 1). Preconditioning was the preferred study intervention used in 26 trials, 13,[28][29][30][31]33,34,[36][37][38][39][40][41][42][43][44][45][46]…”

“…Despite mean differences on trial level showing reduced intraoperative bleeding in RIC patients in seven out of nine trials, standard deviations were large compared with mean values, and the neutral study by He et al with symmetric data and low standard deviations carried a 95.8% weight in the applied randomeffects meta-analysis. 53 A possible explanation for RIC primarily affecting postoperative bleeding outcomes is that five out of 32 trials utilized per-or postconditioning, 32,35,[47][48][49] which were administered late in the surgical procedure. In these scenarios, RIC could not affect intraoperative bleeding outcomes, which would be influenced by other factors occurring before RIC was administered.…”

“…Regarding other types of bias, three trials were challenged by unbalanced randomization in preoperative or operative characteristics. 30,32,46 The main source of bias on review level is publication bias as indicated by funnel plot asymmetry for the primary outcome (►Fig. 10).…”

“…Re-operation for bleeding (11 trials; 624 RIC patients, 627 control patients) 27,28,30,32,[34][35][36]39,[42][43][44] was not significantly reduced by RIC, with relative risk 0.57 [0.29; 1.10] (P ¼ 0.09). There was no statistical heterogeneity (I 2 ¼ 0%) (►Fig.…”

Acute kidey injury risks during cardiac operations are too numerous to count? Could a single actionable variable be the answer?

“…Mannitol not considered an evidence-based intervention to limit AKI 10 Corticosteroid treatment in neonates undergoing cardiac surgery did not reduce AKI 11 N-acetylcysteine not helpful to reduce AKI (meta-analysis) 12 Allogeneic mesenchymal stem cells 13 Things with uncertain or conflicting evidence but being studied Dexmedetomidine and acetaminophen [14][15][16] Slidenafil for AKI (randomized controlled trial) 17 Intra-aortic balloon 18 Vascular endothelial integrity 19 Remote ischemic preconditioning 20,21 Dexmedetomidine and acetaminophen [14][15][16] Things that may worsen AKI risk during cardiac procedures Perioperative statin therapy (but not preoperative only therapy) increases AKI risk 22 Fibrinogen prophylaxis during heart transplant 23 Advanced age 80 y 24 Severe bleeding 25 https://doi.org/10.1016/j.jtcvs.2019.06.012…”