Reconstruction of the aortic pressure waveform using a two-level adaptive transfer function strategy

Abstract

Existing studies cannot estimate the high-frequency components of the aortic pressure waveform (APW) practically and reliably. To solve this problem, a two-level adaptive transfer function (ATF) strategy was proposed. Two ATFs were derived from raw and normalized brachial and aortic pressure waveforms. The APW was reconstructed with the amplitude and pulsatility information from the two ATFs. Experimental results showed that our method achieved lower errors for total waveform, diastolic blood pressure, the pressures at the start-systolic and dicrotic-notch points, and three high-frequency-dependent indices including the pressure at inflection point, augmentation index and the time interval from foot to inflection points (3.11 versus 4.24 mmHg, 1.74 versus 1.94 mmHg, 2.56 versus 2.75 mmHg, 6.94 versus 7.47 mmHg, 3.35 versus 3.80 mmHg, 9.56 versus 10.48 % and 24.64 versus 27.73 ms, respectively) compared with traditional generalized transfer function. The proposed method can accurately estimate both the shape and high-frequency components of APW.