The effect of enhanced external counterpulsation on C-reactive protein and flow-mediated dilation in porcine model of hypercholesterolaemia

Background: Lipid disorder causes vascular endothelial cell damage and contributes to the early development of dyslipidaemia-induced atherosclerosis. In vivo and in vitro, it has been found that increasing shear stress can improve endothelial function. Clinically, enhanced external counterpulsation (EECP) plays important roles in the treatment of coronary artery disease by promoting arterial shear stress. The present study aims to evaluate the effect of EECP on vascular endothelial function in porcine hypercholesterolaemic model. Methods: Twenty-six hypercholesterolaemic pigs were equally divided into EECP group (HC-EECP group) and control group (HC group). Shear stress of a right forearm superficial artery was measured during EECP in comparison with the basal physiological status in the HC-EECP group. Endothelial-dependent flow-mediated vasodilation (FMD) was applied to assess endothelial function. Serum high-sensitivity C-reactive protein (hs-CRP) levels were measured at indicated time points. Results: Endothelial shear stress was increased significantly during EECP treatment (P<0.001). Compared to HC group, hs-CRP decreased significantly by EECP at 18- and 36-h, respectively (P<0.05). FMD was improved significantly by EECP compared to that of HC group at 18 h (11.09 +/- 5.63%) and at 36 h (11.42 +/- 2.75%) post-EECP, P<0.05. Meanwhile, in animals of HC group, FMD was decreased from baseline 7.76 +/- 3.70% to 6.75 +/- 3.57% at 18 h and 5.07 +/- 1.97% at 36 h, P<0.05. Conclusion: Long-term EECP can improve endothelial function partially by an increased endothelial shear stress in hypercholesterolaemic porcine model. This implies that long-term EECP can be used as a complementary therapeutic strategy to prevent atherosclerosis in hypercholesterolaemic patients.