Wall Shear Stress in the Feeding Native Conduit Arteries of Superficial Arteriovenous Malformations of the Lower Face is a Reliable Marker of Disease Progression.

PURPOSE: To assess the prognostic value of the wall shear stress (WSS) measured in the feeding native arteries upstream from facial superficial arteriovenous malformations (sAVMs). Reliable prognostic criteria are needed to distinguish progressive from stable sAVMs and thus support the indication for an aggressive or a conservative management to avoid severe facial disfigurement. MATERIALS AND METHODS: We prospectively included 25 patients with untreated facial sAVMs, 15 patients with surgically resected sAVMs and 15 controls. All had undergone Doppler ultrasound examination (DUS) with measurements of inner diameters, blood flow velocities, computation of blood flow and WSS of the feeding arteries. Based on the absence or presence of progression in clinical and imaging examinations 6 months after, we discriminated untreated patients as stable or progressive. RESULTS: WSS in the ipsilateral external carotid artery was higher in progressive compared to stable sAVMs (15.8 ±â€Š3.3dynes/cm² vs. 9.6 ±â€Š2.0dynes/cm², mean±SD, p < 0.0001) with a cut-off of 11.5dynes/cm² (sensitivity: 92 %, specificity: 92 %, AUC: 0.955, [95 %CI: 0.789-0.998], p = 0.0001). WSS in the ipsilateral facial artery was also higher in progressive compared to stable sAVMs (50.7 ±â€Š14.5dynes/cm² vs. 25.2 ±â€Š7.1dynes/cm², p < 0.0001) with a cut-off of 34.0dynes/cm² (sensitivity: 100 %, specificity: 92 %, AUC: 0.974, [95 %CI: 0.819-1.000], p = 0.0001). The hemodynamic data of operated patients were not different from those of the control group. CONCLUSION: WSS measured in the feeding arteries of an sAVM may be a simple reliable criterion to distinguish stable from progressive sAVMs. This value should be considered to guide the therapeutic strategy as well as the long-term follow-up of patients with facial sAVMs.

The [14C-N-methyl]-erythromycin breath test dosimetry complies with the French regulations for radiation safety.

The [14C-N-methyl]-erythromycin breath test (14C-ERMBT) is one of the most valuable probes for liver cytochrome P450-3A4 activity in humans. In order to extend the use of this test in France, we herein provide safety data regarding either patient dosimetry or worker exposure to [14C-N-methyl]-erythromycin. In order to determine the maximum radiation exposure for patient and nuclear medicine technician following one intravenous 14C-ERMBT [111 kiloBequerel (kBq)], we have used the dosimetric data gathered in animal studies and extrapolated to humans using a weight-based method, approximate data provided by the French Society of Radioprotection and erythromycin pharmacokinetics in humans, considering always the worst conditions for the patient and worker exposure determination. The radioactivity administered to a patient after one 14C-ERMBT was equal to 108.8 kBq (i.e. 98% of the total radioactivity in the 14C-erythromycin vial) leading to a patient effective dose of 20 microsievert (microSv) and a maximum effective dose after 14CO2 inhalation by the exposed worker of 16 microSv compared with a mean individual annual effective dose from natural and artificial radioactivity exposure of 3500 microSv in France. The 14C-ERMBT is safe and complies with the European regulations regarding the administration of 14C-labelled compounds in humans. It can therefore be used in clinical research in France without any particular safety requirement.

Variations of intrathoracic amount of blood as a reason of ECG voltage changes.

BACKGROUND: It is known that electroconduction of intrathoracic organs and tissues significantly influences the ECG voltage. It changes during therapy or exercise test due to redistribution and/or volume variations of blood and body fluids and their electroconductivity variations. This fact must be taken into consideration during interpretation of corresponding ECG. But there are no quantitative estimations of this influence on human ECG. The goals of this study were to estimate the influence of variations of thoracic electroconduction, and heart volume on QRS voltage in humans, due to gravity change. METHODS: ECGs of 26 healthy volunteers were analyzed in upright and supine position. Experimental conditions-acute change of gravity--are created in a special aircraft flying on Kepler's parabola trajectory. Each parabola includes phases of normo-, hypergravity (blood shifts in caudal direction), and microgravity (blood redistributes in cranial direction). Amplitude of QRS in Frank leads in all phases has been analyzed. 2-D echo studies for six subjects were used for estimation of heart volume change. RESULTS: In an upright position during hypergravity the amplitude of R wave in Z increases in 95% of cases (mean 0.19 mV). During microgravity amplitude of R wave in Z decreases in 95% (mean 0.24 mV). In supine position changes of QRS voltage are not significantly. CONCLUSION: Blood redistribution during gravity change leads to changes of QRS voltage, which is more expressed and steady on R in Z lead: an average near 0.2 mV. It is due to the balance between two factors: (a). changes of degree of short circuiting by variations in the amount of blood in thorax (b). changes of distance between heart and electrodes as a result of change in the position, form, and volume of the heart.