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

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.

To investigate whether repeated RIC started early after primary percutaneous coronary intervention (PCI) can improve LV function in patients with STEMI.

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.

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].

Daily repeated RIC started within 24 h after PCI can improve GLS and reduce plasma NT proBNP levels in patients with STEMI.