Background Cardiovascular (CV) disease is a major cause of mortality and morbidity in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and arterial stiffness (AS) may be an early marker of this risk . Pulse Wave Velocity (PWV), a surrogate marker of AS, has been frequently used as an end point in the clinical trials. The Arteriograph provides an non-invasive means of measuring PWV and has been shown to be reliable . Little is known about its reliability in chronic inflammatory states.
Objectives To determine the reliability of measuring aortic stiffness using the Arteriograph in a routine rheumatology clinic setting.
Methods The reliability of aortic PWV measurement was evaluated in 24 participants who included healthy subjects and stable RA and SLE patients. PWV was recorded by 2 moderately trained observers in all participants on two occasions at least one week apart. During each study visit, both observers also repeated the PWV on one further occasion at least 15 minutes after the first observation. Reliability was assessed with Pearson correlation (r), intraclass correlation coefficient (ICC) and by limits of agreement (LoA) as per Bland-Altman recommendation
Results We studied 12 RA, 2 SLE and 10 healthy subjects (6 male, 18 female, one hypertensive, 2 smokers). The mean (SD) age in the RA/SLE group was 57.2 (17) years and healthy participant was 33 (18.9) years. The mean [SD] PWV was higher in the RA/SLE group (8.74 [1.84] m/s) than healthy participants (6.51 [1.21] m/s). We found very good intra-observer reliability (r- 0.91, ICC 0.95, LoA- 0.3 [1.6]) and inter-observer reliability (r -0.90, ICC- 0.94, LoA - 0.1 [1.7]) in the whole population. In a subgroup analysis we found moderately good reliability in RA/SLE group (r- 0.74, ICC- 0.85, LoA - 0.3 [2.80]) compared to healthy subjects (r - 0.93, ICC 0.95, LoA 0.11 [0.95]).
Conclusions Measurement of PWV by Arteriograph is reliable even when performed by moderately trained professionals. Compared to young healthy controls, PWV reliability performed less well in the RA/SLE group but was still within the acceptable limit. This could be due to higher PWV in RA/SLE group (proportional error - increase variability with higher PWV which has been seen in other studies ). Knowledge of this increased variability will help improve the estimation of statistical power required for future interventional studies.
Kahlenberg JM, Kaplan MJ. Mechanisms of premature atherosclerosis in rheumatoid arthritis and lupus. Annu Rev Med. 2013;64:249-63.
Roman MJ, Devereux RB, Schwartz JE, et al. Arterial stiffness in chronic inflammatory diseases. Hypertension. 2005;46(1):194-9.
Horvath IG, Nemeth A, Lenkey Z, et al. Invasive validation of a new oscillometric device (Arteriograph) for measuring augmentation index, central blood pressure and aortic pulse wave velocity. Journal of Hypertension. 2010;28(10):2068-75.
Naidu MUR, Reddy BM, Yashmaina S et al. Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: A pilot study. BioMedical Engineering OnLine. 2005;4: 49.
Disclosure of Interest None declared