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  • Title: Drug-induced changes of the flow pulse contour recorded by directional CW-Doppler devices: a possible estimation of changes in vascular characteristic impedance and peripheral resistance.
    Author: Labs KH, Labs R.
    Journal: Methods Find Exp Clin Pharmacol; 1985 Nov; 7(11):603-8. PubMed ID: 2935691.
    Abstract:
    Ultrasound Doppler sonography using directional continuous wave Doppler devices is an inexpensive, simple tool used worldwide for the diagnosis and hemodynamic assessment of patients with peripheral vascular disease (PVD). In addition to pressure evaluation, the interpretation of Doppler velocity pulses has become routine within the last years. However, spontaneous variations in characteristic impedance of muscular arteries or in peripheral resistance will lead to respective variations of arterial reflection coefficients, with consequent changes of the arterial flow pulse reflection pattern and flow pulse contour. The authors studied peripheral Doppler wave forms in 20 volunteers after buccal administration of 1.6 mg of glyceryl trinitrate (GTN) and i.a. (femoral) injection of 30 mg tolazoline hydrochloride. Velocity pulse changes due to artificially introduced variation in peripheral resistance (reactive hyperemia, total arterial blockade) were compared to those induced by above maneuvers. An isolated decrease in characteristic impedance of muscular arteries without alteration of the peripheral resistance is characterized by an increase in the amplitudes of foreward as well as the reverse flow phase of the Doppler signal, with predominant increase of the early diastolic reverse flow phase and subsequent decrease in mean velocity. In contrast, isolated changes in peripheral resistance are reflected mainly by subsequent variations of the reverse flow phase amplitude of the Doppler signals.
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