title: Repeated Episodes of Remote Ischemic Preconditioning for the Prevention of Myocardial Injury in Vascular Surgery.
abstract: OBJECTIVE
  Remote ischemic preconditioning (RIPC) involves the phenomenon whereby transient episodes of limb ischemia induced by cuff inflation provide cardioprotection. The effectiveness of RIPC in vascular surgery is uncertain. This randomized, controlled trial was designed to investigate the potential of two episodes of RIPC to provide myocardial protection in patients undergoing vascular surgery.
  
  
  METHODS
  Patients undergoing an elective major vascular procedure (open abdominal aortic aneurysm (AAA) repair, endovascular aneurysm repair, and lower-limb bypass grafting) were randomized into RIPC group (n = 42) or control group (n = 43). Remote ischemic preconditioning consisted of three 5-minute cycles of upper limb cuff occlusion with 5-minutes of reperfusion between cycles, both 24 hours and immediately before surgery. Control patients received a similarly timed sham treatment. Cardiac high-sensitivity troponin T (hsTnT) concentration was measured in plasma at 6, 12, 24, and 48 hours post-surgery, and at 72, 96, and 120 hours in patients still in hospital. Perioperative clinical adverse events and readmissions within ∼12 months were recorded.
  
  
  RESULTS
  Myocardial injury was demonstrated perioperatively in 43% of RIPC patients and 49% of controls, as defined by a significant hsTnT elevation. These incidences were statistically equivalent (odds ratio 0.79, 95% confidence interval 0.33-1.85, P = .58). The 48-hour area under the curve for hsTnT change from baseline also revealed no difference (RIPC vs control median: 5.3 vs 7.5 ng/L.h, P = .22). Each group had one type I and one type II myocardial infarction and no difference in complications or readmissions.
  
  
  CONCLUSIONS
  This trial could not confirm that two episodes of RIPC reduce myocardial injury following vascular surgery. Along with other equivocal studies, it appears that RIPC does not induce a clear benefit in vascular surgery.
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Kate N
authors.initials: KN
authors.lastname: Thomas
authors.affiliation: School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: James D
authors.initials: JD
authors.lastname: Cotter
authors.affiliation: Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: Michael J A
authors.initials: MJ
authors.lastname: Williams
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand andre.vanrij@otago.ac.nz.
authors.forename: André M
authors.initials: AM
authors.lastname: van Rij
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000503:physiopathology / Q000601:surgery*; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D057510:Endovascular Procedures / Q000009:adverse effects; D005260:Female; D006801:Humans; D019194:Ischemic Preconditioning / Q000379:methods*; D007902:Length of Stay; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000097:blood / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D009520:New Zealand; D010359:Patient Readmission; D058729:Peripheral Arterial Disease / Q000503:physiopathology / Q000601:surgery*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012039:Regional Blood Flow; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood; D015854:Up-Regulation; D034941:Upper Extremity / Q000098:blood supply*; D058017:Vascular Grafting / Q000009:adverse effects
chemical_list: D015415:Biomarkers; D020107:Troponin T
keywords: ischemia; ischemic preconditioning; myocardial ischemic reperfusion injury; vascular surgical procedures