title: A pilot study investigating the effects of remote ischemic preconditioning in high-risk cardiac surgery using a randomised controlled double-blind protocol.
abstract: The efficacy of remote ischemic preconditioning (RIPC) in high-risk cardiac surgery is uncertain. In this study, 96 adults undergoing high-risk cardiac surgery were randomised to RIPC (3 cycles of 5 min of upper-limb ischemia induced by inflating a blood pressure cuff to 200 mmHg with 5 min of reperfusion) or control. Main endpoints were plasma high-sensitivity troponin T (hsTNT) levels at 6 and 12 h, worst post-operative acute kidney injury (AKI) based on RIFLE criteria, and noradrenaline duration. hsTNT levels were log-normally distributed and higher with RIPC than control at 6-h post cross-clamp removal [810 ng/ml (IQR 527-1,724) vs. 634 ng/ml (429-1,012); ratio of means 1.41 (99.17% CI 0.92-2.17); P=0.04] and 12 h [742 ng/ml (IQR 427-1,700) vs. 514 ng/ml (IQR 356-833); ratio of means 1.56 (99.17% CI 0.97-2.53); P=0.01]. After adjustment for baseline confounders, the ratio of means of hsTNT at 6 h was 1.23 (99.17% CI 0.88-1.72; P=0.10) and at 12 h was 1.30 (99.17% CI 0.92-1.84; P=0.05). In the RIPC group, 35/48 (72.9%) had no AKI, 5/48 (10.4%) had AKI risk, and 8/48 (16.7%) had either renal injury or failure compared to the control group where 34/48 (70.8%) had no AKI, 7/48 (14.6%) had AKI risk, and 7/48 (14.6%) had renal injury or failure (Chi-squared 0.41; two degrees of freedom; P = 0.82). RIPC increased post-operative duration of noradrenaline support [21 h (IQR 7-45) vs. 9 h (IQR 3-19); ratio of means 1.70 (99.17% CI 0.86-3.34); P=0.04]. RIPC does not reduce hsTNT, AKI, or ICU-support requirements in high-risk cardiac surgery.
authors.affiliation: Wellington Hospital, Capital and Coast District Health Board, Wellington, New Zealand. paul.young@ccdhb.org.nz
authors.forename: Paul Jeffrey
authors.initials: PJ
authors.lastname: Young
authors.forename: Paul
authors.initials: P
authors.lastname: Dalley
authors.forename: Alexander
authors.initials: A
authors.lastname: Garden
authors.forename: Christopher
authors.initials: C
authors.lastname: Horrocks
authors.forename: Anne
authors.initials: A
authors.lastname: La Flamme
authors.forename: Barry
authors.initials: B
authors.lastname: Mahon
authors.forename: John
authors.initials: J
authors.lastname: Miller
authors.forename: Janine
authors.initials: J
authors.lastname: Pilcher
authors.forename: Mark
authors.initials: M
authors.lastname: Weatherall
authors.forename: Jenni
authors.initials: J
authors.lastname: Williams
authors.forename: William
authors.initials: W
authors.lastname: Young
authors.forename: Richard
authors.initials: R
authors.lastname: Beasley
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology / Q000517:prevention & control; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage; D000368:Aged; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D016009:Chi-Square Distribution; D001026:Coronary Artery Bypass / Q000009:adverse effects; D003422:Critical Care; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects; D006801:Humans; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D009520:New Zealand; D009638:Norepinephrine / Q000008:administration & dosage; D010865:Pilot Projects; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood; D034941:Upper Extremity / Q000098:blood supply*
chemical_list: D000316:Adrenergic alpha-Agonists; D015415:Biomarkers; D020107:Troponin T; D009638:Norepinephrine