Variability and reproducibility of carotid structural and functional parameters assessed with transcutaneous ultrasound e Results from the SAPALDIA Cohort Study Seraina Caviezel a, * , Julia Dratva b, c , Emmanuel Schaffner b, c , Alexandra Teynor d , Manfred W. Baumstark e , Christian Schindler b, c , Eric de Groot f, g , Luc Burdet h , Thomas Rothe i , Marco Pons j , Jean-Michel Gaspoz k , Thierry Rochat l , Nino Künzli b, c , Nicole Probst-Hensch b, c , Arno Schmidt-Trucksäss a a Institute of Exercise and Health Sciences, Div. Sports and Exercise Medicine, University of Basel, Birsstrasse 320B, 4052 Basel, Switzerland b Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland c University of Basel, Petersplatz 1, 4003 Basel, Switzerland d Augsburg University of Applied Sciences, An der Hochschule 1, 86161 Augsburg, Germany e Center for Internal Medicine, Department of Rehabilitation, Prevention, and Sports Medicine, Freiburg University Hospital, Hugstetterstrasse 55, 79106 Freiburg, Germany f Imagelabonline, Lutterveld 12, 4117GV Erichem, The Netherlands g Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9,1105 AZ Amsterdam, The Netherlands h Hôpital Intercantonal de la Broye, Avenue de la Colline 3, 1530 Payerne, Switzerland i Zürcher Höhenklinik Davos, Klinikstrasse 6, 7272 Davos Clavadel, Switzerland j Division of Pulmonary Medicine, Regional Hospital Lugano, Via Tesserete 46, 6900 Lugano, Switzerland k Department of Community Medicine and Primary Care, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4,1211 Geneva, Switzerland l Division of Pulmonary Medicine, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4,1211 Geneva, Switzerland article info Article history: Received 5 June 2013 Received in revised form 26 August 2013 Accepted 6 October 2013 Available online 18 October 2013 Keywords: Common carotid artery Ultrasound Arterial stiffness Intima media thickness Diameter Reproducibility abstract Objective: Carotid intima media thickness (CIMT) and local stiffness are vascular biomarkers of athero- sclerotic burden. We investigated the variability and reproducibility of clinically relevant structural (CIMT, lumen diameter) and functional parameters (strain, distensibility, compliance, b-stiffness index, Peterson’s elastic modulus and Young’s elastic modulus) measured in B-mode ultrasound sequences of the common carotid artery in the second follow up of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases In Adults (SAPALDIA3). Methods: Ultrasound sequential images were examined twice over a 1 cm segment across at least one heart cycle in 165 SAPALDIA3 participants. To assess variability and reproducibility of structural and functional parameters, individual coefficients of variation (CV), intraclass correlation (ICC), BlandeAlt- man plots and mixed effect regressions were used. Results: ICCs of repeated examinations ranged between 0.67 and 0.77 for blood pressure indices, between 0.87 and 0.97 for structural properties and between 0.75 and 0.79 for functional parameters. CV was lowest in structural parameters (1.6e4.6%), followed by blood pressure (5.1e7.9%) and functional indices (11.0e13.1%). Variations in all parameters were predominantly explained by subjects (>74% in functional, >82% in structural properties). BlandeAltman plots for functional indices showed mean and standard deviation of the respective mean value of 4.2(19.6)% for strain, 1.9(24.4)% for distensibility, 2.4(22.2)% for compliance, 3.0(24.4)% for b-stiffness index, 0.9(25.7)% for Peterson’s elastic modulus and 1.2(27.9)% for Young’s elastic modulus. Conclusion: The results show that SAPALDIA3 measurements of transcutaneous ultrasound examinations have an excellent reproducibility of structural parameters and a good reproducibility of functional indices. Ó 2013 Elsevier Ireland Ltd. All rights reserved. * Corresponding author. Tel.: þ41 61 377 87 44. E-mail address: seraina.caviezel@unibas.ch (S. Caviezel). Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis 0021-9150/$ e see front matter Ó 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.atherosclerosis.2013.10.010 Atherosclerosis 231 (2013) 448e455