Common carotid artery wall properties in Takayasu's arteritis.

The vessel wall properties of the common carotid artery have been noninvasively and quantitatively assessed with an ultrasonic instrument. Stiffness parameter beta, which represents the mechanical properties of the vessel, was calculated from the relationship between blood pressure and the diameter of the artery. There are no reports that quantitatively assess wall properties in Takayasu's arteritis. The authors compared, in vivo, the vessel wall properties of the common carotid artery in 14 patients with Takayasu's arteritis versus those in 60 normal subjects (controls). They measured changes in the inner diameter of the artery between systole and diastole with an ultrasonic, phase-locked, echo-tracking system. Beta was significantly higher in Takayasu's arteritis than in normal subjects (better than a 99% confidence interval). The findings for each decade were as follows: 3rd decade (20s): 35.7 +/- 28.9 vs 5.01-6.46, P=0.0001; 4th decade (30s): 19.5 +/- 9.71 vs 6.09-7.80, P=0.02; 5th decade (40s): 26.2 +/- 11.3 vs 7.26-9.28, P = 0.0001; 6th decade (50s): 19.1 +/- 4.27 vs 8.66-11.25, P = 0.0001. Takayasu's arteritis significantly impaired the mechanical performance of the common carotid artery. Thus, beta shows promise as a useful diagnostic indicator of Takayasu's arteritis.

Correlation of ultrasound-measured common carotid artery stiffness with pathological findings.

To quantitatively and noninvasively evaluate common carotid atherosclerosis in a series of patients, we measured the stiffness parameter beta, which represents the mechanical properties of the vessel. beta was calculated from the relationship between blood pressure and the diameter of the artery as measured by an ultrasonic, phase-locked, echotracking system. Increases in the severity grade of atherosclerosis as subsequently determined at autopsy were correlated with increased beta values in 60 common carotid arteries (r = .68). Patients with beta values greater than 13 had a pathological diagnosis of atherosclerosis in the common carotid artery. The sensitivity of this discrimination ratio was 80%, and the specificity was 80% as well. Thus, beta shows promise as a useful diagnostic indicator for detecting asymptomatic common carotid atherosclerosis.

A study on cerebral nicotine receptor distribution, blood flow, oxygen consumption, and other metabolic activities--a study on the effects of smoking on carotid and cerebral artery blood flow.

We investigated middle cerebral artery flow velocity (MCA-FV) by a noninvasive method to determine whether or not smoking causes an increase in cerebral blood flow (CBF). Furthermore we determined sequentially the changes in CBF caused by smoking in order to evaluate changes in responses at different times in daily activities and the effect from meals. The subjects were 25 healthy individuals ranging in age from 20 to 36 yr. MCA-FV was measured by a transcranial Doppler system. They smoked a filtered cigarette for 5 min at 1 P.M., 3 P.M., 6 P.M., 8 P.M., 10 P.M., 8 A.M., and 11 A.M. Results (1) Smoking caused increases in both common carotid artery flow volume and MCA-FV, and the percentage increase of these parameters showed a good correlation (r = 0.809). (2) MCA-FV increased significantly during the first (by 6.6%) and second halves (by 5.4%) of the smoking period. (3) The change in MCA-FV after meals was slight. (4) Smoking tended to increase MCA-FV during each smoking session but the changes were not significant. The pulsatility index reduced significantly during almost every smoking session. These results lead to the conclusion that smoking reduces vascular resistance in cerebral arteries and increases CBF.