Remote Ischemic Preconditioning Stimulus Does Not Reduce Microvascular Resistance or Improve Myocardial Blood Flow in Patients Undergoing Elective Percutaneous Coronary Intervention

Introduction: Remote ischemic preconditioning (RIPC) may limit myocardial infarction by improving microvascular function and maintaining myocardial blood flow. We hypothesized that a RIPC stimulus would reduce coronary microvascular resistance and improve coronary blood flow during elective percutaneous coronary intervention (PCI). Method: We prospectively recruited 54 patients with multi-vessel disease (MVD = 32) or single vessel disease awaiting elective PCI. Patients with MVD had non-target vessel (NTV) index of microcirculatory resistance (IMR) determined, before and after target vessel (TV) PCI (cardiac RIPC). The effect of arm RIPC on serial microvascular resistance (R-p) was assessed in patients with single vessel disease. Results: TV balloon occlusion did not alter the NTV IMR: 16.5 (12.4) baseline vs. 17.6 (11.6) post cardiac RIPC, P = 0.65 or hyperaemic transit time. Arm RIPC did not alter R-p in patients with single vessel disease: Rp, mmHg.cm(-1).s(-1): 3.5 (1.9) baseline vs. 4.1 (3.0) post arm RIPC, P = 0.19 and coronary flow velocity remained constant. Conclusion: RIPC Stimuli during elective PCI do not affect coronary microvascular resistance or coronary flow in humans.