Paul J. Breslau

Importance of noninvasive ultrasonic-Doppler testing in the evaluation of patients with asymptomatic carotid bruits

An ultrasonic Duplex scanner was used to estimate the site and degree of extracranial arterial disease in two groups of patients with asymptomatic bruits. In the first 100 patients only the extent of disease was assessed with 37% of the sides with bruits having high-grade stenoses (greater than 50% diameter reduction) and one-half having lesions which narrowed the internal carotid artery by less than 50%. Seven percent were found to be normal. The remaining 6% had occlusion of the internal carotid artery. In a second group of 81 patients, the effect of the reported findings of the Duplex scan on patient management was reviewed. Only 13 patients underwent angiography and 11 of these were in patients with high-grade stenoses. Five carotid endarterectomies were performed and in each case, the patient had bilateral high-grade lesions. The implications of this diagnostic approach are discussed as well as the need for prospective studies of patients who present with an asymptomatic bruit.

Effect of carbon dioxide on flow patterns in normal extracranial arteries

Abstract To evaluate the velocity pattern changes in the extracranial carotid arteries, five normal subjects were studied with a 5-MHz pulse Doppler device combined with spectral analysis prior to and during breathing 6.8% carbon dioxide. Changes in flow were quantified by features derived from the velocity waveform of the common, internal and external carotid arteries. An increase in velocities during diastole correlated well with the expected increase in total blood flow induced by breathing 6.8% carbon dioxide. Increases in spectral width reflected the development of flow disturbances not apparent under basal conditions. These studies suggest that marked increases in flow produced by intracranial vasodilatation can dramatically alter the velocity patterns normally observed.

Pitfall of Venous Occlusion Plethysmography

The supposition that the lower limb expands uniformly in circumference during venous occlusion has been investigated. The 3 compartments of the calf were found to expand to differing degrees depending on the volume of muscle within the compartment. The effect of this phenomenon on the measurement of venous outflow and capacitance using an overlapping strain gauge was assessed. When using an overlapping strain gauge, the anatomical site of overlap was found to alter the measured values of outflow and capacitance by as much as 50%. These errors do not arise with strain gauges designed to fit a small range of limb circumferences, so that no overlap occurs. The reproducibility of plethysmography may be enhanced by attention to the site and degree of overlap of gauges which are designed to fit all sizes of limb. Technicians performing venous occlusion plethysmography should be aware of these variations, so that the examination technique can be stan dardized.

66. Die problematische Auswertung der Ausdehnung der arteriellen Verschlußerkrankung durch ein hämodynamisches und arteriographisches Untersuchungsverfahren

SummaryIn order to study the role of accurate haemodynamic assessment of aortoiliac disease, intra-arterial pressure measurements of 100 aorto-iliac segments were compared with Doppler velocity waveform analysis and contrast arteriography. The agreement between pressure measurements and contrast arteriography provided a Kappa of 0.41, the agreement between pressure measurements and velocity waveform analysis provided a Kappa of 0.41. There is evidence from the present data that contrast arteriography and Doppler studies underestimate haemodynamic significant aorto-iliac disease. Since the correlation is so poor, it is essential to use intra-arterial pressure measurements in every patient who is being considered a candidate for surgery.ZusammenfassungUm die drei verschiedenen diagnostischen Methoden bewerten zu können zur Diagnostik der aorto-iliacalen Läsionen sind mit Hilfe von invasiver Druckmessung, Dopplerregistration und Kontrastarteriographie 100 aorto-iliacale Trajekte untersucht worden. Sowohl die Übereinstimmung zwischen invasiver Druckmessung und Arteriographie wie auch die zwischen invasiver Druckmessung und Dopplerregistration gab ein Kappa von 0,41. Es hat sich herausgestellt, daß Kontrastarteriographie und Dopplerregistration im Vergleich zu invasiver Druckmessung die aorto-iliacalen Läsionen unterbewerten.