Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a life support intervention for patients with refractory cardiogenic shock or severe cardiopulmonary failure. However, the choice of cannulation strategy remains contentious, partly due to insufficient understanding of hemodynamic characteristics associated with the site of arterial cannulation. In this study, a geometrical multiscale model was built to offer a mathematical tool for addressing the issue. The outflow cannula of ECMO was inserted into the ascending aorta in the case of central cannulation, whereas it was inserted into the right subclavian artery (RSA) or the left iliac artery (LIA) in the case of peripheral cannulation. Numerical simulations conducted on three patient-specific aortas demonstrated that the central cannulation outperformed the two types of peripheral cannulation in evenly delivering ECMO flow to branch arteries. Both the central and RSA cannulations could maintain an approximately normal hemodynamic state in the aortas, although the area of aortic walls exposed to abnormal wall shear stress (WSS) was considerably enlarged in comparison with the normal physiological condition. In contrast, the LIA cannulation not only led to insufficient delivery of ECMO flow to the right upper body (with ECMO flow fractions < 0.5), but also induced marked flow disturbance in the aorta, causing about 40% of the abdominal aortic wall and over 65% of the resting aortic wall to suffer from high time-averaged WSS (>5 Pa) and low time-averaged WSS (<0.4 Pa), respectively. The LIA cannulation also resulted in significantly prolonged blood residence time (>40 s) in the ascending aorta, which, along with abnormal WSS, may considerably increase the risk of thrombosis. In summary, our numerical study elucidated the impact of arterial cannulation site in VA-ECMO intervention on aortic hemodynamics and ECMO flow distribution. The findings provide compensatory biomechanical information for traditional clinical studies and may serve as a theoretical reference for guiding the evaluation and selection of cannulation strategies in clinical practice.

Early detection of vascular disease is fundamental to the prevention and treatment of systemic vascular lesions. The timely identification of vascular damage can be achieved by comprehensively assessing the structural anomaly and/or functional degeneration of the vasculature. The assessment may to some extent indicate the long-term detrimental effects of cardiovascular disease (CVD) risk factors on vascular health. A key aspect in the evaluation of vascular function is the measurement of arterial stiffness. In 2012, the arterial velocity-pulse index (AVI) and arterial pressure-volume index (API) were introduced, which are noninvasively measured with a brachial cuff, and can reflect the status of arterial stiffness in both the aorta and the brachial artery. A large number of relevant studies have demonstrated the strong associations between AVI/API and various CVD risk factors, underlining the substantial relevance of the indices in CVD risk assessment. In this review, we provide a systematic review of the progresses made in brachial cuff-based measurements of arterial stiffness. In addition, we summarize the results of the recent studies focused on exploring the associations of AVI/API with relevant risk factors as well as their roles in CVD assessment.