1945Remote ischemic conditioning by single cuff inflation improves aortic elastic properties and endothelial glycocalyx thickness in acute myocardial infarction patients

Abstract

Background: Remote ischemic conditioning has been shown to reduce myocardial damage in patients with acute myocardial infarction (AMI) However, the effects of remote ischemic conditioning on arterial wall properties and endothelial integrity are not fully defined. Methods: We examined 150 patients with STEMI and 30 healthy controls. Patients were randomised in 2 remote ischemic conditioning protocols after a baseline assessment of vascular function (T0), a) one with two ischemic conditioning stimuli by brachial cuff inflation of both arms at 200mmHg for 5 min, separated by 15min, and each cuff deflation followed by vascular assessment (T1,T2), and a final vascular assessment (T3), 25 min after 2nd cuff deflation (double cuff inflation‐n=75) or b) a second with omission of the second cuff inflation (single cuff inflation‐n=75). In both protocols we measured the carotid‐femoral pulse wave velocity (PWV), augmentation index (AI), and central systolic blood pressure (cSBP) by Complior, perfusion boundary region (PBR‐ micrometers) of the sublingual arterial microvessels as a marker of endothelial glycoclyx thickness, and plasma malondialdehyde levels (MDA) as an oxidative stress marker. Results: Regarding the double cuff inflation protocol, aortic elasticity was impaired by the first ischemic event but improved after the second ischemia (PWV T0:11.46m/s, T1:11.57m/s, T2:11.47m/s, T3:11.52m/s p<0.05). The second protocol resulted in a more uniform aortic elasticity improvement (PWV T0: 12.09m/s, T1:11.74m/s, T2:11.59m/s, T3:11.81m/s). Patients with baseline PWV>11 m/s a) benefited from an earlier and greater improvement of aortic elasticity compared to patients with lower baseline PWV (mean difference in PWV improvement 3.5 m/s at T1, p=0.002) in both protocols after the first cuff inflation, b) the omission of the second ischemic cuff inflation resulted in an greater improvement of aortic elasticity at the final vascular assessment (PWV 11.3 single cuff vs 13.8 m/s double cuff inflation at T3, p<0.05). Similarly, a significantly greater glycocalyx integrity restoration was measured in patients with baseline PBR>2.1 (mean difference in PBR5‐ 25 improvement 0.5 micrometers at T1, p<0.001). Conversely, in healthy controls, AI, cSBP and PBR remained unchanged throughout the study (p>0.05). MDA was significantly reduced at T3 compared to baseline in STEMI (2.1±0.15 at T3 vs 2.59±0.15 at T0, p<0.001) while it remained unchanged in healthy controls. Conclusion: Remote ischemic conditioning confers acute short‐term improvement of vascular function, especially in patients with more impaired arterial elasticity and glycocalyx integrity, likely through oxidative stress reduction.