Cardioprotection of Repeated Remote Ischemic Conditioning in Patients With ST-Segment Elevation Myocardial Infarction

BACKGROUND: Repeated remote ischemic conditioning (RIC) after myocardial infarction (MI) has been shown to improve left ventricular (LV) remodeling in the experimental studies, but its cardioprotective effect in patients with ST-segment elevation myocardial infarction (STEMI) is still unknown. OBJECTIVE: To investigate whether repeated RIC started early after primary percutaneous coronary intervention (PCI) can improve LV function in patients with STEMI. METHODS: Patients with STEMI treated by primary PCI were included and randomized to the repeated RIC group (n = 30) or the control group (n = 30). RIC was started within 24 h after PCI and repeated daily for 1 week, using an Auto RIC device. 3D speckle-tracking echocardiography (STE) was used to assessed LV function. The primary study endpoint was the change in LV global longitudinal strain (GLS) from baseline to 1 month after PCI. RESULTS: The repeated RIC group and the control group were well-matched at baseline including mean GLS (−9.8 ± 2.6% vs. −10.1 ± 2.5%, P = 0.62). Despite there was no significant difference in mean GLS at 1 month between the two groups (−11.9 ± 2.1% vs. −10.9 ± 2.7%, P = 0.13), the mean change in GLS from baseline to 1 month was significantly higher in the treatment group than in the control group (−2.1 ± 2.5% vs. −0.8 ± 2.3%, P = 0.04). There were no significant differences in the changes in global circumferential strain (GCS), global area strain (GAS), global radial strain (GRS), LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV) between the two groups. Peak creatine kinase isoenzyme-MB, peak high-sensitivity troponin T, and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) levels at 24 h after PCI did not differ significantly between the two groups, but NT-proBNP levels at 1 week were significantly lower in the treatment group than in the control group [357.5 (184.8–762.8) vs. 465.0 (305.8–1525.8) pg/ml, P = 0.04]. CONCLUSION: Daily repeated RIC started within 24 h after PCI can improve GLS and reduce plasma NT proBNP levels in patients with STEMI.