Aortic pulse wave reflects cardiovascular status, but unlike the peripheral pulse wave, is difficult to be measured reliably using non-invasive techniques. Therefore, the estimation of aortic pulse wave from peripheral ones is of great significance. Traditional methods using generalized transfer functions suffer inter-subject and intra-subject variability of the cardiovascular system. This study proposed an adaptive transfer function method to estimate the aortic pulse wave from the brachial pulse wave.
Aortic and brachial pulse waves were derived from 26 patients who underwent cardiac catheterization. The generalized transfer function was adapted by its peak resonance frequency, which was determined individually by regression formulas using brachial systolic blood pressure. The proposed method was validated using the Leave-One-Out cross validation method.
Compared with previous studies, the adaptive transfer function method showed better performance in estimating the aortic pulse wave and extracting the feature parameters. The error of the aortic systolic blood pressure and pulse pressure were 0.2 ± 3.1 mmHg and -0.9 ± 3.1 mmHg, respectively. The percentage errors of augmentation index, percentage notch amplitude and ejection duration were -2.1 ± 32.7%, 12.4 ± 9.2%, and -2.4 ± 3.3%, respectively.