692 The effect of remote ischemic preconditioning in heart failure: A randomized controlled pilot study

Abstract

Remote ischemic preconditioning (RIPC) induced by transient limb ischemia confers myocardial and multi-organ protection in a variety of ischemic settings. RIPC may also improve skeletal muscle and exercise performance during activities limited by tissue hypoxia. To date, the effect of RIPC in patients with heart failure has not been explored, and may be associated with improved exercise capacity in this population. We performed a randomized double blind crossover trial of RIPC (4 cycles of 5-minutes upper limb ischemia/5 minutes reperfusion) compared to low-pressure sham control in ambulatory heart failure patients undergoing cardiopulmonary exercise testing. Patients with left ventricular systolic dysfunction and NYHA class II-IV heart failure were recruited from a single center, and randomly allocated to either RIPC or sham intervention immediately prior to undergoing symptom-limited stationary bicycle exercise with respiratory gas analysis. Patients then crossed over and completed the alternate intervention prior to repeat testing during a separate visit. The primary outcome measure was peak VO2 for RIPC versus sham; secondary outcomes included exercise duration, workload achieved and VE/VCO2 slope. Twenty patients completed the study protocol with paired testing a median of 18 days (IQ range 16-28 days) apart. Overall, RIPC prior to cardiopulmonary exercise testing was not associated with improvements in peak VO2 in this population (15.6 +/− 4.2 mL/kg/min vs 15.3 +/− 4.6 mL/kg/min; P = 0.33, for sham and RIPC, respectively). With respect to the secondary outcomes, there was no observed benefit of RIPC on exercise duration, workload achieved, anaerobic threshold, or VE/CO2 slope (Table). Post-hoc exploratory analysis did not identify any baseline clinical characteristics associated with an improved exercise performance following the RIPC intervention.Tabled 1 In this pilot study of RIPC in ambulatory heart failure patients with left ventricular systolic dysfunction, RIPC was not associated with improvements in objective measures of exercise capacity. Mechanistic studies and larger trials are needed to definitively rule out a benefit of RIPC in this population.