Validation of an adaptive transfer function method to estimate the aortic pressure waveform

Aortic pulse wavereflects cardiovascular status, but, unlike the peripheral pulse wave, is difficult to be measured reliably using noninvasive techniques. Thus, the estimation of aortic pulse wavefrom peripheral ones is of great significance. This study proposed an adaptive transfer function (ATF) method to estimate the aortic pulse wavefrom the brachial pulse wave. Aortic and brachial pulse waveswere derived from 26 patients who underwent cardiac catheterization. Generalized transfer functions (GTF) were derived based on the autoregressive exogenous model. Then, the GTF was adapted by its peak resonance frequency. And the optional peak resonance frequency for an individual was determined by regression formulas using brachial systolic blood pressure. The method was validated using the leave-one-out cross validation method. Compared with previous studies, the ATF method showed better performance in estimating the aortic pulse waveand predicting the feature parameters. The prediction error of the aortic systolic blood pressure and pulse pressurewere 0.2 ± 3.1 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.