Neuroprotective effect of remote ischemic preconditioning in patients undergoing cardiac surgery: A randomized controlled trial

Abstract

Background: The neuroprotective effect of remote ischemic preconditioning (RIPC) in patients undergoing elective cardiopulmonary bypass (CPB)-assisted coronary artery bypass graft (CABG) or valvular cardiac surgery remains unclear.

Methods: A randomized, double-blind, placebo-controlled superior clinical trial was conducted in patients undergoing elective on-pump coronary artery bypass surgery or valve surgery. Before anesthesia induction, patients were randomly assigned to RIPC (three 5-min cycles of inflation and deflation of blood pressure cuff on the upper limb) or the control group. The primary endpoint was the changes in S-100 calcium-binding protein β (S100-β) levels at 6 h postoperatively. Secondary endpoints included changes in Neuron-specific enolase (NSE), Mini-mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA) levels.

Results: A total of 120 patients [mean age, 48.7 years; 36 women (34.3%)] were randomized at three cardiac surgery centers in China. One hundred and five patients were included in the modified intent-to-treat analysis (52 in the RIPC group and 53 in the control group). The primary result demonstrated that at 6 h after surgery, S100-β levels were lower in the RIPC group than in the control group (50.75; 95% confidence interval, 67.08 to 64.40 pg/ml vs. 70.48; 95% CI, 56.84 to 84.10 pg/ml, P = 0.036). Compared to the control group, the concentrations of S100-β at 24 h and 72 h and the concentration of NSE at 6 h, 24 h, and 72 h postoperatively were significantly lower in the RIPC group. However, neither the MMSE nor the MoCA revealed significant between-group differences in postoperative cognitive performance at 7 days, 3 months, and 6 months after surgery.

Conclusion: In patients undergoing CPB-assisted cardiac surgery, RIPC attenuated brain damage as indicated with the decreased release of brain damage biomarker S100-β and NSE.

Clinical trial registration: [ClinicalTrials.gov], identifier [NCT01231789].

Keywords: cardiac surgery; neuroprotective effect; postoperative cognitive dysfunction; remote ischemic preconditioning; surrogate.

FIGURE 1

CONSORT flow diagram.

FIGURE 2

Estimated change trend in brain injury markers between RIPC group and control group across time points. S100-β (A); S-100 calcium-binding protein B. NSE (B); neuron specific enolase. Shaded areas indicate 95% confidence interval.

FIGURE 3

Estimated change trend in postoperative cognitive function between RIPC group and Control group across time points. Shaded areas indicate 95% confidence interval. MoCA (A); Montreal Cognitive Assessment. MMSE (B); Mini-mental State Examination.

FIGURE 4

Comparison of clinical indicators of postoperative recovery (length of intensive cardiac care unit stay, emergence time, extubation time and ventilation time) between the RIPC group and the control group.