Abstract 11562: Remote Ischemic Conditioning Attenuates the Effect of System Delay in STEMI Patients Treated With Primary Percutaneous Coronary Intervention

Purpose: Remote ischemic conditioning (RIC) increases myocardial salvage, whereas extended system delay reduces myocardial salvage and increases infarct size in patients with ST-elevation myocardial infarction (STEMI). We investigated the influence of RIC on the effect of system delay in STEMI patients undergoing primary percutaneous coronary intervention (pPCI). Methods: In a prospective, single-blinded randomized controlled trial (n=251), we studied STEMI patients randomized to treatment with either pPCI alone or pPCI+RIC. RIC was performed during transport to hospital as 4 cycles of 5 min upper arm ischemia followed by 5 min of reperfusion. Area-at-risk, myocardial salvage index and final infarct size were assessed by single photon emission computerized tomography (SPECT). System delay was defined as time from emergency medical service call to pPCI-wire. Data were obtained from emergency medical service registries and files. Results: Data for final infarct size and system delay were available for 202 patients, and data for myocardial salvage index and system delay were available for 129 patients. Patients were equally distributed among treatment with pPCI alone or pPCI+RIC. Area-at-risk and system delay did not differ between patients treated with pPCI alone or pPCI+RIC (p=0.974 and p=0.909, respectively). While system delay in patients treated with pPCI alone was associated with significantly reduced myocardial salvage index (p=0.008) and increased final infarct size (p=0.043), these associations were attenuated in patients treated with pPCI+RIC (p=0.737 and p=0.628, respectively) with significantly different slopes (p=0.022) as shown for myocardial salvage index (figure). Conclusion: RIC attenuates the effect of extended system delay on myocardial salvage index and final infarct size in STEMI patients treated with pPCI, suggesting that the cardioprotective effect of RIC increases with extended duration of ischemia.