A computational model of the cardiovascular system coupled with an upper-arm oscillometric cuff and its application to studying the suprasystolic cuff oscillation wave, concerning its value in assessing arterial stiffness

A variety of methods have been proposed to noninvasively assess arterial stiffness using single or multiple oscillometric cuffs. A common pitfall of most of such methods is that the individual-specific accuracy of assessment is not clearly known due to an insufficient understanding of the relationships between the characteristics of cuff oscillometry and cardiovascular properties. To provide a tool for quantitatively investigating such relationships, we developed a computational model of the cardiovascular system coupled with an oscillometric cuff wrapped around the left upper arm. The model was first examined by simulating the inflation-deflation process of the cuff. The simulated results reasonably reproduced the well-established characteristics of cuff oscillometry. The model was then applied to study the oscillation wave generated by a suprasystolic cuff that is currently under considerable debate regarding its validity for assessing aortic stiffness. The simulated results confirmed the experimental observations that the suprasystolic cuff oscillation wave resembles the blood pressure wave in the proximal brachial artery and is characterised by the presence of two systolic peaks. A systemic analysis on the simulation results for various cardiovascular/physiological conditions revealed that neither the time lag nor the height difference between the two peaks is a direct indicator of aortic stiffness. These findings provided useful evidence for explaining the conflicts among previous studies. Finally, it was stressed that although the emphasis of this study has been placed on a suprasystolic upper-arm cuff, the model could be employed to address more issues related to oscillometric cuffs.