Passive leg raising induced brachial artery dilation: Is an old technique a simpler method to measure endothelial function?

• Published in: Atherosclerosis 2010-09, Vol.212 (1), p.188-192
• Main Authors: Kamran, Haroon, Salciccioli, Louis, Namana, Vinod, Venkatesan, Bhuvaneshwari, Santana, Casey, Stewart, Mark, Lazar, Jason M
• Format: Article
• Language: English
• Subjects: Adult; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Blood Flow Velocity; Brachial Artery - diagnostic imaging; Brachial Artery - physiopathology; Cardiology. Vascular system; Cardiovascular; Cardiovascular Diseases - physiopathology; Cardiovascular system; Cross-Sectional Studies; Diagnostic Techniques, Cardiovascular; Endothelial function; Endothelium, Vascular - physiopathology; Female; Heart Rate; Humans; Hyperemia; Hyperemia - physiopathology; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Leg; Male; Medical sciences; Middle Aged; New York; Passive leg raising; Patient Positioning; Predictive Value of Tests; Regional Blood Flow; ROC Curve; Ultrasonography, Doppler; Vasodilation
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2010.05.019

Abstract Objectives Passive leg raising (PLR) is a diagnostic maneuver that has been shown to cause brachial artery dilation (BAD). The objectives of this study were to compare BAD induced by PLR with flow mediated dilation (FMD), and to investigate the mechanism of PLR-BAD. We studied a total of 75 subjects with and without cardiovascular risk factors/disease in order to provide a wide range of FMD responses. Methods Using ultrasound, PLR-BAD and FMD induced by release of arterial cuff occlusion were measured. Results BA diameter increased from 0.33 + 0.06 at baseline to 0.35 ± 0.06 cm ( p < .001) (4.8% increase) upon PLR and from 0.33 ± 0.06 to 0.37 ± 0.06 (11.8%) upon hyperemia. PLR induced BAD was significantly correlated with FMD ( r = .82, p < .001). On receiver operating characteristic analysis of the two techniques, the area under the curve was 0.86 (95% CI 0.79–0.94, p < .001). Heart rate variability measures remained unchanged upon PLR indicating minimal contributions from changes in autonomic activity. The combination of FMD and PLR did not result in greater BAD than did FMD alone consistent with a common underlying mechanism. Mean blood flow velocity increased prior to BAD suggesting that shear stress increases prior to BAD. Conclusions BAD occurs in response to PLR and is proportional to FMD, although the magnitude of PLR-BAD is less than half that of FMD. It appears to occur by the same endothelial dependent mechanism as FMD. PLR-BAD may be used as a surrogate measure of FMD to evaluate vascular function, and has the advantage of being simpler to perform.