HEMODYNAMICS STRESS TEST USING FINGER-TO-TOE PULSE WAVE VELOCITY IN SUPINE AND SITTING POSITION IN END-STAGE KIDNEY DISEASE

Abstract

Objective: Aortic pulse wave velocity (PWV), a measure of arterial stiffness can either be measured by the ratio of distance to pulse transit time or, estimated based on the pulse wave profile (ePWV). Aortic PWV measurements are performed in the supine position as there is no added hydrostatic pressure along the arterial path, and the recording of the arterial pressure waveform of the femoral arterial is easier to perform. However, finger-to-toe PWV (ftPWV), a surrogate for aortic PWV, can easily be performed in other positions, such as the sitting position, giving the opportunity to examine arterial wall properties in a dynamic manner. The aim of the study was to observe the impact of the position (supine vs sitting) on the ePWV and on the measured ftPWV in patients with end-stage kidney disease. Design and method: In a cross-sectional study involving adult hemodialysis patients, we performed vascular assessments in the supine and the sitting position within the first 2 hours of their hemodialysis session. The ePWV was obtained using the Mobil-O-Graph and ftPWV was obtained using the pOpmètre®. Three measures were taken with each device. Generalized estimated equations were then used to calculate the average of ePWV and ftPWV with respect to each position. Results: In 46 patients (17 females), the average age was 71±12 years and the blood pressure was 136±24 /77±15 mmHg. The ePWV was 10.8 m/s (IC95% :10.1-11.4 m/s) in the supine position and 10.7 m/s (IC95%: 10.0-11.3 m/s) in the sitting position. However, the ftPWV was 12.1 m/s (IC95%: 9.6-14.7 m/s) in the supine position but it increased to 22.0 m/s (IC95%: 15.0-29.0 m/s) in the sitting position. This increase of 9.8 m/s was highly significant (P = 0.006) even though the brachial blood pressure and the heart rate had barely changed. Conclusions: This study shows that finger-to-toe PWV increases in the sitting position, offering us the opportunity to explore this postural changes in PWV as a possible vascular stress test.