New monitoring software for larger clinical application of brachial artery flow-mediated vasodilatation measurements.
BACKGROUND
The reproducibility of brachial artery flow-mediated vasodilatation (FMD) is limited by the operator dependence of most measurement methods.


METHODS
A new automated computerized analysis of brachial artery ultrasound scan providing a continuous evolution of the diameter during acute hyperemia, reactive to short hyperemia of the forearm and hand, was tested in 10 normal volunteers and 26 asymptomatic patients with cardiovascular risk factors such as hypertension, hypercholesterolemia, heavy smoking, history of premature coronary heart disease and the metabolic syndrome. FMD was the percentage of the maximum hyperemic diastolic diameter from baseline. Within-reading variations in FMD and diameters were assessed by reading one scan from the same subject twice by two observers. The within-subject variability of FMD was assessed by analysing two repeated measurements in the same subject by the same operator 1 h, 1 week or 1 month apart.


RESULTS
Coefficients of variation (CV) of repeated FMD readings were 7.5% in normal volunteers and 6.9% in patients with risk factors. CV of repeated FMD measurements 1 h apart were 7.8% in normal volunteers and 16.5% in patients with risk factors. In normal volunteers, CV of repeated FMD measurements 1 week apart was 9.6%, and in patients with risk factors CV of repeated FMD measurement 1 month apart was 18.1%.


CONCLUSIONS
This method overcomes the variability of FMD measurement seen with conventional manual analysis in normal volunteers, and to a lesser extent in patients with major cardiovascular risk factors, thus supporting its clinical applicability to patients with disease conditions.
Craiem
Damian
D
Universidad Favaloro, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina.
Chironi
Gilles
G
Gariepy
Jerome
J
Miranda-Lacet
Jennifer
J
Levenson
Jaime
J
Simon
Alain
A
D000328:Adult; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000150:complications / Q000000981:diagnostic imaging; D006940:Hyperemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006973:Hypertension / Q000150:complications / Q000000981:diagnostic imaging; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000000981:diagnostic imaging; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012107:Research Design; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D012984:Software; D013997:Time Factors; D014463:Ultrasonography; D014664:Vasodilation