Abstract
Abstract Background Pulsatile flow has been proved to protect vital organ function and microcirculation during extracorporeal membrane oxygenation (ECMO). Studies revealed that pulsatile shear stress plays a vital role in the microcirculatory function and integrity. The objective of this study was to investigate how pulsatility affects wall shear stress and microcirculation during ECMO. Methods Using the i-Cor system, we compared the effects of pulstile or non-pulsatile flows in a canine ECMO model, with hemodynamic parameters and peak wall shear stress (PWSS) calculated. Serum concentrations of syndecan-1 and heparan sulfate were measured at different time points during ECMO. Pulstile shear stress experiments were also validated in endothelial cells exposed to different magnitude of pulsatility, with cell viability, the expressions of syndecan-1 and endothelial-to-mesenchymal tranformation (EndMT) markers analyzed. Results The pulsatile flow generated more surplus hemodynamic energy and preserved higher PWSS during ECMO. Serum concentrations of syndecan-1 and heparan sulfate were both negatively correlated with PWSS, and significantly lower levels were observed in the pulsatile group. In addition, non-pulsatility triggered EndMT, with EndMT related genes up-regulated, and endothelial cells exposed to low pulsatility had the lowest possibility of EndMT. Conclusion The maintenance of the PWSS by pulsatility during ECMO contributes to the beneficial effects on glycocalyx integrity and microcirculatory function. Moreover, pulsatility prevents EndMT in endothelial cells, and low pulsatility exhibits the best protective effects. The augmentation of pulsatility may be a future direction to improve the clinical outcome in ECMO.
Highlights
Extracorporeal membrane oxygenation (ECMO), a life-saving approach, is essentially important for the treatment of patients with severe cardiorespiratory failure, including those extremely critical COVID-19 patients[1], overall survival rate for extracorporeal life support (ECLS) is increasing sluggishly over the past ten years[2]
Serum concentrations of syndecan-1 and heparan sulfate were both negatively correlated with peak wall shear stress (PWSS), and significantly lower levels were observed in the pulsatile group
The maintenance of the PWSS by pulsatility during extracorporeal membrane oxygenation (ECMO) contributes to the beneficial effects on glycocalyx integrity and microcirculatory function
Summary
Extracorporeal membrane oxygenation (ECMO), a life-saving approach, is essentially important for the treatment of patients with severe cardiorespiratory failure, including those extremely critical COVID-19 patients[1], overall survival rate for extracorporeal life support (ECLS) is increasing sluggishly over the past ten years[2]. It is generally acknowledged that microcirculatory malperfusion affects the endothelial integrity, which leads to hypoxia, edema, acidosis, and inflammatory responses. The standard circuit consists of a membrane oxygenator and centrifugal pump, of which the priming volume is smaller, with lower incidence of blood component damage[5]. The novel i-Cor system (Xenios AG, Heilbronn, Germany) consists of a diagonal blood pump that can provide pulsatile flow triggered by electrocardiogram and has been applied in Europe for several years[9, 10]. Pulsatile flow has been proved to protect vital organ function and microcirculation during extracorporeal membrane oxygenation (ECMO). Studies revealed that pulsatile shear stress plays a vital role in the microcirculatory function and integrity.
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