Remote ischaemic conditioning before primary percutaneous coronary intervention seemed to improve long-term clinical outcomes in patients with ST-elevation myocardial infarction.

ObjectivesRemote ischaemic conditioning (RIC) promotes cardioprotection in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-elevation myocardial infarction (STEMI). The effect of RIC may be modified by cardiovascular risk factors and their medications. We examined whether cardiovascular risk factors, lipid and glucose levels, and medication use influenced the efficacy of RIC in patients with STEMI treated with pPCI.DesignPost hoc subgroup analysis of a single-centre randomised controlled trial.ParticipantsA total of 139 patients with STEMI, randomised during ambulance transport to hospital for pPCI with (n=71) or without (n=68) RIC, met the trial criteria and achieved data for a myocardial salvage index (MSI).InterventionsRIC was administered through intermittent arm ischaemia with four cycles of 5 min inflation and 5 min deflation of a blood pressure cuff.Primary outcome measuresMSI, estimated by single-photon emission CT. We evaluated the efficacy of RIC on the MSI in patient subgroups of cardiovascular risk factors, lipid and glucose levels, and medication use.ResultsWe found no significant difference in the efficacy of RIC in subgroups of cardiovascular risk factors, lipid and glucose levels, and medication use. However, point estimates indicated a reduced effect of RIC among smokers (median difference in MSI between RIC and control groups: −0.02 (95% CI −0.32 to 0.28) in smokers vs 0.25 (95% CI 0.08 to 0.42) in non-smokers, p value for interaction=0.13) and an increased effect of RIC in statin users (median difference in MSI between RIC and control groups: 0.34 (95% CI 0.03 to 0.65) in statin users vs 0.09 (95% CI −0.11 to 0.29) in non-statin users, p value for interaction=0.19).ConclusionsRIC as an adjunct to pPCI seems to improve MSI in our trial population of patients with STEMI regardless of most cardiovascular risk factors and their medications. Our post hoc finding on a limited sample size calls for further investigation in large-scale multicentre trials.Trial registration numberNCT00435266.

NCT00435266; post-results.

ObjectivesRemote ischaemic conditioning (RIC) confers cardioprotection in patients with ST segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI). We investigated whether preinfarction angina and coronary collateral blood flow (CCBF) to the infarct-related artery modify the efficacy of RIC.DesignPost hoc subgroup analysis of a randomised controlled trial.ParticipantsA total of 139 patients with STEMI randomised to treatment with pPCI or RIC+pPCI.InterventionsRIC was performed prior to pPCI as four cycles of 5 min upper arm ischaemia and reperfusion with a blood pressure cuff.Primary outcome measureMyocardial salvage index (MSI) assessed by single-photon emission computerised tomography. We evaluated the efficacy of RIC in subgroups of patients with or without preinfarction angina or CCBF.ResultsOf 139 patients included in the study, 109 had available data for preinfarction angina status and 54 had preinfarction angina. Among 83 patients with Thrombolysis In Myocardial Infarction flow 0/1 on arrival, 43 had CCBF. Overall, RIC+pPCI increased median MSI compared with pPCI alone (0.75 vs 0.56, p=0.045). Mean MSI did not differ between patients with and without preinfarction angina in either the pPCI alone (0.58 and 0.57; 95% CI −0.17 to 0.19, p=0.94) or the RIC+pPCI group (0.66 and 0.69; 95% CI −0.18 to 0.10, p=0.58). Mean MSI did not differ between patients with and without CCBF in the pPCI alone group (0.51 and 0.55; 95% CI −0.20 to 0.13, p=0.64), but was increased in patients with CCBF versus without CCBF in the RIC+pPCI group (0.75 vs 0.58; 95% CI 0.03 to 0.31, p=0.02; effect modification from CCBF on the effect of RIC on MSI, p=0.06).ConclusionsPreinfarction angina did not modify the efficacy of RIC in patients with STEMI undergoing pPCI. CCBF to the infarct-related artery seems to be of importance for the cardioprotective efficacy of RIC.Trial registration numberNCT00435266, Post-results.