Mutsumi Sorimachi

Blood flow velocity waveforms in the middle cerebral artery at rest and during exercise

Blood flow velocities in the middle cerebral artery (MCA) were measured under steady-state and incremental cycle exercises using a transcranial Doppler ultrasound velocimeter. The peak systolic velocity was found to rise markedly under exercise, while the end diastolic velocity tended to remain at the resting value. The relationship between peak systolic velocity and systolic blood pressure, and that between peak systolic velocity and heart rate were found to show a statistically significant correlation. The mean MCA blood velocity also showed a significant correlation with the mean arterial pressure and heart rate. The fluctuations of velocity and the resistance index were calculated in order to evaluate the hemodynamic load on the vessel wall; these also increased markedly under exercise. Such hemodynamic changes in activity might be important in understanding the genesis of vascular diseases, as well as the physiology of cerebral circulation.

Comparison of Diagnostic Accuracy between Pulse Volume Recording Parameters and Exercise-Ankle-Brachial Pressure Index in Patients with Ankle-Brachial Pressure Index above 0.91

Objective: The objective of this study was to clarify whether or not pulse volume recoding (PVR) parameters have screening capability equivalent to ankle-brachial pressure index after walking (Ex-ABI) for patients with 0.91 or higher ABI. Patients and Methods: The subjects were 87 patients (147 limbs) with symptoms of lower extremities with 0.91 or higher ABI. In all patients, upstroke time (UT), percentage of mean artery pressure (%MAP) of PVR and Ex-ABI were measured, and computed tomographic angiography (CTA) was concomitantly performed. Results: Area under the curve (AUC) of receiver operating characteristics (ROC) curves of Ex-ABI, %MAP, and UT were 0.90, 0.70, and 0.81, respectively. A significant difference was noted in AUC between Ex-ABI and %MAP (p <0.001). When the cut-off values were set at %MAP ≥45% and UT ≥180 msec, the accuracies of %MAP and UT were markedly lower than that of Ex-ABI. When the cut-off values were corrected to the values determined from the ROC curves (%MAP ≥41, UT ≥164 msec), the diagnostic accuracy of UT increased markedly. Conclusion: In patients with 0.91 or higher ABI, screening capability of PVR parameters was markedly lower than that of Ex-ABI, but UT has screening capability close to that of Ex-ABI when the cut-off value is corrected downward.