Noninvasive measurement of femoral artery pressure for evaluating aortoiliac occlusive disease

Femoral systolic pressures measured by a compression technique (FSCP), were compared with proximal thigh systolic pressures (PTSP), for evaluation of aortoiliac occlusive disease. In phase I FSCP were measured by compressing the artery with a pressure cuff rolled into a cylinder and using disappearance of the profunda femoris Doppler signal (FSCP-D), or flattening of thigh plethysmographic waveforms (FSCP-P), as sensors. In normal extremities the compression techniques yielded false high values. The mean ratio of FSCP-D to brachial systolic pressure, FSCP-D/BSP, was 1.25 ± 0.06 and the mean FSCP-P/BSP was 1.37 ± 0.15, a value approximately equal to the mean PTSP/BSP, 1.38 ± 0.20. In patients with aortoiliac occlusive disease linear regression analysis revealed a good correlation between FSCP-D/BSP and direct intraoperative measurements of femoral/aortic systolic pressure, FSP/ASP, ( R = 0.79 and R 2 = 0.63), a fair correlation between FSCP-P/BSP and FSP/ASP ( R = 0.49, R 2 = 0.24) but a poor correlation between PTSP/BSP and FSP/ASP ( R = 0.35, R 2 = 0.12). In phase II studies a soft bladder was used for arterial compression. In normal extremities the mean FSCP-D/BSP was 1.07 ± 0.06, close to the predicted normal value of 1.00. In a second group of patients with occlusive disease a better correlation was observed between values of FSCP-D/BSP and FSP/ASP ( R = 0.91, R 2 = 0.82), than any of the correlations of noninvasive measurements with direct intraoperative values of FSP/ASP obtained in the first phase of the study.