Comparative Validity And Reliability Of The Vicorder Device For Pulse Wave Analysis

Measurement of pulse pressure wave characteristics via pulse wave analysis (PWA) provides important hemodynamic information predictive of cardiovascular disease. Novel devices that use oscillometric cuffs to perform PWA (i.e., Vicorder) require less technician training and minimize patient burden but have not been thoroughly evaluated for validity or reliability. Purpose: To assess the comparative validity of PWA using the Vicorder vs. a criterion (SphygmoCor) and within-day reliability of the Vicorder. Methods: PWA was measured by the Vicorder (twice) and the SphygmoCor (once) in 15 adults (mean ± SD, age = 31.1 ± 12 y; BMI = 26.5 ± 6 kg/m2) during a single visit in randomized order. Each assessment included a 10-min of supine rest prior to two brachial cuff inflations to capture blood pressure (BP) and PWA. BP and PWA were repeated after a 2-min rest. If systolic or diastolic BP differed by >5 mmHg, a third measure was taken. A movement break was completed between assessments to reduce prolonged rest effects. Pearson's correlation coefficients (r) assessed validity between devices, categorized as weak (0-0.29), moderate (0.3-0.79), or strong (0.8-1). Intraclass correlation coefficients (ICC) assessed validity (between devices) and reliability (within Vicorder), categorized as poor (<0.5), moderate (0.5-0.75), or good (0.76-1.0). Summary of Results: Validity of PWA measures from Vicorder vs. the criterion indicated mostly strong (n = 6) or moderate (n = 4) correlations; however, ICCs between devices showed mostly poor agreement (n = 6) with fewer rated as moderate or better (n = 5). Vicorder reliability was more favorable, with all 11 measures rated as good with ICCs ≥0.81 (Table 1). Conclusions: Initial findings suggest that the Vicorder is reliable for PWA assessment; better r but poorer ICCs between devices suggest individuals may be similarly ranked by the Vicorder and SphygmoCor, but that PWA measures are not interchangeable. - Table 1. Comparative Validity of Vicorder vs. SphygmoCor and Reliability of Repeated Vicorder for Measuring PWA Comparative Validity between Vicorder and SphygmoCor Reliability within Vicorder PWA Measure Vicorder 1Mean (SD) SphygmoCorMean (SD) Vicorder 2Mean (SD) r 95% CI p-value ICC 95% CI p-value ICC 95% CI p-value HR 57.8 (7.1) 57.3 (8.1) 56.3 (8.7) 0.91 0.74-0.97 <0.001 0.93 0.80-0.97 <0.001 0.91 0.74-0.97 <0.001 Peripheral SBP 125.4 (10.9) 125.2 (9.9) 118.2 (10.0) 0.83 0.54-0.94 0.001 0.68 0.27-0.88 0.002 0.95 0.86-0.98 <0.001 Peripheral DBP 62.0 (8.7) 62.0 (7.8) 70.2 (8.6) 0.88 0.67-0.96 <0.001 0.53 0.05-0.81 0.017 0.92 0.77-0.97 <0.001 Peripheral PP 63.4 (5.9) 63.1 (5.4) 47.0 (4.8) 0.38 -0.17-0.75 0.163 -0.58 -0.85-(-0.11) 0.990 0.81 0.52-0.93 <0.001 Aortic SBP 117.1 (11.7) 116.6 (10.5) 103.7 (10.0) 0.87 0.66-0.96 <0.001 0.37 -0.16-0.73 0.082 0.97 0.91-0.99 <0.001 Aortic DBP 62.1 (8.7) 62.3 (7.8) 71.0 (62.3) 0.87 0.65-0.96 <0.001 0.48 -0.10-0.79 0.029 0.92 0.79-0.98 <0.001 Aortic PP 55.0 (5.4) 54.6 (4.9) 32.7 (4.5) 0.22 -0.33-0.66 0.441 0.37 -0.16-0.73 0.082 0.86 0.63-0.95 <0.001 MAP 84.6 (10.6) 84.3 (9.4) 82.5 (9.4) 0.89 0.69-0.96 <0.001 0.86 0.64-0.95 <0.001 0.94 0.84-0.98 <0.001 AP 6.8 (3.2) 6.7 (3.0) 2.6 (2.9) 0.69 0.27-0.89 0.005 0.20 -0.33-0.63 0.231 0.95 0.86-0.98 <0.001 Aix 12.4 (5.1) 12.1 (4.6) 7.9 (8.5) 0.38 -0.16-0.75 0.163 0.45 -0.10-0.77 0.040 0.94 0.82-0.98 <0.001 AIx@75 4.1 (7.7) 3.2 (7.5) -0.6 (10.5) 0.74 0.37-0.91 0.002 0.63 0.19-0.86 0.86 0.98 0.94-0.99 <0.001 Mean and standard deviation (SD) values were reported as bpm for HR, as a % for AIx and AIX@75, and as mmHg for all other measures. Bold p-values indicate statistical significance. Abbreviations: Systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), augmentation pressure (AP), augmentation index (AIx), augmentation index normalized to a HR at 75 bpm (AIx@75), Pearson’s correlation coefficient (r), intraclass correlation coefficients (ICC), and 95% confidence interval (95% CI)