title: Postoperative neurocognitive dysfunction in patients undergoing cardiac surgery after remote ischemic preconditioning: a double-blind randomized controlled pilot study.
abstract: BACKGROUND
  Remote ischemic preconditioning (RIPC) has been shown to enhance the tolerance of remote organs to cope with a subsequent ischemic event. We hypothesized that RIPC reduces postoperative neurocognitive dysfunction (POCD) in patients undergoing complex cardiac surgery.
  
  
  METHODS
  We conducted a prospective, randomized, double-blind, controlled trial including 180 adult patients undergoing elective cardiac surgery with cardiopulmonary bypass. Patients were randomized either to RIPC or to control group. Primary endpoint was postoperative neurocognitive dysfunction 5-7 days after surgery assessed by a comprehensive test battery. Cognitive change was assumed if the preoperative to postoperative difference in 2 or more tasks assessing different cognitive domains exceeded more than one SD (1 SD criterion) or if the combined Z score was 1.96 or greater (Z score criterion).
  
  
  RESULTS
  According to 1 SD criterion, 52% of control and 46% of RIPC patients had cognitive deterioration 5-7 days after surgery (p = 0.753). The summarized Z score showed a trend to more cognitive decline in the control group (2.16±5.30) compared to the RIPC group (1.14±4.02; p = 0.228). Three months after surgery, incidence and severity of neurocognitive dysfunction did not differ between control and RIPC. RIPC tended to decrease postoperative troponin T release at both 12 hours [0.60 (0.19-1.94) µg/L vs. 0.48 (0.07-1.84) µg/L] and 24 hours after surgery [0.36 (0.14-1.89) µg/L vs. 0.26 (0.07-0.90) µg/L].
  
  
  CONCLUSIONS
  We failed to demonstrate efficacy of a RIPC protocol with respect to incidence and severity of POCD and secondary outcome variables in patients undergoing a wide range of cardiac surgery. Therefore, definitive large-scale multicenter trials are needed.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00877305.
authors.affiliation: Clinic of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany. patrick.meybohm@kgu.de
authors.forename: Patrick
authors.initials: P
authors.lastname: Meybohm
authors.forename: Jochen
authors.initials: J
authors.lastname: Renner
authors.forename: Ole
authors.initials: O
authors.lastname: Broch
authors.forename: Dorothee
authors.initials: D
authors.lastname: Caliebe
authors.forename: Martin
authors.initials: M
authors.lastname: Albrecht
authors.forename: Jochen
authors.initials: J
authors.lastname: Cremer
authors.forename: Nils
authors.initials: N
authors.lastname: Haake
authors.forename: Jens
authors.initials: J
authors.lastname: Scholz
authors.forename: Kai
authors.initials: K
authors.lastname: Zacharowski
authors.forename: Berthold
authors.initials: B
authors.lastname: Bein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000209:etiology / Q000523:psychology* / Q000601:surgery; D001026:Coronary Artery Bypass / Q000523:psychology*; D004311:Double-Blind Method; D017558:Elective Surgical Procedures / Q000523:psychology*; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D010865:Pilot Projects; D011183:Postoperative Complications; D011446:Prospective Studies; D011581:Psychological Tests; D012720:Severity of Illness Index; D020107:Troponin T / Q000378:metabolism
chemical_list: D020107:Troponin T