Method for noninvasive measurement of central aortic systolic pressure.

A method for noninvasive generation of central aortic systolic pressure curves is presented. The method is based on plotting the occlusive pressure values applied at the brachial artery level against the time intervals needed for the aortic pressure wave to equalize and break through the occlusive pressure at the brachial artery level. These time intervals were obtained by measuring the time from the beginning of depolarization (the QRS complex) to the detection of the pressure wave at the temporarily occluded brachial artery. The validity of the method was documented by 3 different approaches. The pressure values measured by a device developed by us were superimposed on the simultaneously measured central intra-aortic pressure waves and all values were within one standard deviation from the central aortic recordings in 8 of the 10 patients studied. At the same time, the noninvasively recorded pressure waves were completely different from the peripheral artery pressure recorded simultaneously at the femoral artery site. The DP/DT values derived from the central aortic recordings and the noninvasive device correlated (r = 0.83). These results indicate that the noninvasive device measures the central aortic pressure or a close approximation of it. By combining noninvasive pressure measurements with volume measurements obtained by radionuclide angiography, noninvasive pressure-volume curves were generated in 10 subjects. Possible clinical application of the systolic noninvasive pressure-volume curves is suggested.