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Abstract
Objectives Remote 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.
Design Post hoc subgroup analysis of a randomised controlled trial.
Participants A total of 139 patients with STEMI randomised to treatment with pPCI or RIC+pPCI.
Interventions RIC was performed prior to pPCI as four cycles of 5 min upper arm ischaemia and reperfusion with a blood pressure cuff.
Primary outcome measure Myocardial 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.
Results Of 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).
Conclusions Preinfarction 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 number NCT00435266, Post-results.
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Footnotes
Collaborators CONDI Investigators: R Kharbanda, AK Kaltoft, CJ Terkelsen, NH Andersen, TM Hansen, S Trautner, JF Lassen, EH Christiansen, LR Krusell, SD Kristensen, L Thuesen, SS Nielsen, M Rehling, HT Sørensen, AN Redington and TT Nielsen.
Contributors KP, MRS and HEB did the data analysis and drafting of the manuscript. All authors participated in data acquisition and critical revision of the manuscript.
Funding This work was supported by Fondation Leducq (06CVD), the Danish Council for Independent Research (11-108354) and the Danish Council for Strategic Research (11-115818).
Competing interests MRS and HEB are shareholders in CellAegis Devices.
Ethics approval The Danish Committee on Health Research Ethics and The Danish Data Protection Agency.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Raw data and statistical coding are available from the corresponding author at kpryds@clin.au.dk.