Doppler ultrasound in the measurement of pulse wave velocity: agreement with the Complior method

Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these methods. We studied 40 patients (29 male, aged 21 to 82 years) comparing the Complior method with Doppler. Agreement of both devices was high (R = 0.91, 0.84-0.95, 95% CI). The reproducibility analysis revealed no intra-nor interobserver differences. Based on these results, we conclude that Doppler ultrasound is a reliable and reproducible alternative to other established methods for the measurement of aortic PWV

Arterial stiffness & Sri Lankan chronic kidney disease of unknown origin

Chronic kidney disease (CKD) is common and independently associated with cardiovascular disease (CVD). Arterial stiffness contributes to CVD risk in CKD. In many developing countries a considerable proportion of CKD remains unexplained, termed CKDu. We assessed arterial stiffness in subjects with Sri Lankan CKDu, in matched controls without CKD and in those with defined CKD. Aortic blood pressure (BP), pulse wave velocity (PWV) and augmentation index (AIx) were assessed in 130 subjects (50 with CKDu, 45 with CKD and 35 without CKD) using the validated TensioMed™ Arteriograph monitor. Brachial and aortic BP was lower in controls than in CKDu and CKD subjects but no different between CKDu and CKD. Controls had a lower PWV compared to subjects with CKDu and CKD. Despite equivalent BP and renal dysfunction, CKDu subjects had a lower PWV than those with CKD (8.7 ± 1.5 vs. 9.9 ± 2.2 m/s, p < 0.01). Excluding diabetes accentuated the differences in PWV seen between groups (controls vs. CKDu vs. CKD: 6.7 ± 0.9 vs. 8.7 ± 1.5 vs. 10.4 ± 1.5 m/s, p < 0.001 for all). Sri Lankan CKDu is associated with less arterial stiffening than defined causes of CKD. Whether this translates to lower cardiovascular morbidity and mortality long term is unclear and should be the focus of future studies

The Vicorder device compared with SphygmoCor in the assessment of carotid-femoral pulse wave velocity in patients with peripheral arterial disease

To assess the reliability and reproducibility of the Vicorder's carotid-femoral pulse wave velocity (cfPWV) measurements in patients with peripheral arterial disease (PAD) and to compare between cfPWV measurements obtained using the Vicorder with those obtained using the SphygmoCor device as a reference. Some 30 patients with PAD (23 men, mean age 64.9±7.5) underwent cfPWV measurement twice by a single investigator during one visit using the Vicorder and the SphygmoCor according to the manufacturer's instructions. Intra-rater reproducibility for each device was assessed using intraclass correlation coefficients (ICC) and Bland-Altman method. The latter was also used to compare between the two devices. The mean difference (s.d.) between repeated measurements was 0.03±0.92 m s-1, P=0.85 and 0.01±0.54 m s-1, P=0.91 for the SphygmoCor and Vicorder, respectively. Measurements of cfPWV were highly reproducible using both devices (ICC=0.94 and 0.92, for the Vicorder and SphygmoCor, respectively). Limits of Agreement using the Bland-Altman method were -1.07 to 1.09 m s-1 and -1.79 to 1.85 m s-1 for the Vicorder and the SphygmoCor, respectively. Bland-Altman plots indicated that 90% of the cfPWV measurements using the Vicorder and 93% of the measurements using the SphygmoCor fell within two s.d.s of the mean difference. Transit time (TT) differed significantly between the two devices (mean difference 30±9.2 m s,

Measurement of pulse wave velocity in children and young adults: a comparative study using three different devices

To estimate the value of pulse wave velocity (PWV) in pediatric cardiovascular disease, prospective studies are needed. Various instruments based on different measurement principles are proposed for use in children, hence the need to test the comparability of these devices in this younger population. The objective of this study was to compare PWV measured by oscillometry (Vicorder (VIC)) with the gold standard of applanation tonometry (PulsePen (PP), Sphygmocor (SC)). PWV was measured in 98 children and young adults (age: 16.7(6.3-26.6) years (median(range)) with the above three devices at the same visit under standardized conditions. Mean PWV measured by VIC was significantly lower than that measured by SC and PP. There was no difference following path length correction of the VIC measurement (using the distance between the jugular notch and the center of the femoral cuff), (PP: 6.12(1.00), SC: 5.94(0.91), VIC: 6.14(0.75) m s(-1)). Velocities measured by the three devices showed highly significant correlations. Bland- Altman analysis revealed excellent concordance between all three devices, however, there was a small but significant proportional error in the VIC measurements showing a trend toward lower PWV measured by VIC at higher PWV values. Our study provides data on the three most frequently used instruments in pediatrics. Following path length correction of the VIC, all three devices provided comparable results. Thus, our work allows extrapolating data between previously established normal PWV values for children and forthcoming studies using these instruments to assess children at long-term risk of cardiovascular disease. The small proportional error of VIC needs additional technical development to improve the accuracy of the measurements.Hypertension Research advance online publication, 28 July 2011; doi:10.1038/hr.2011.103

Calibration mode influences central blood pressure differences between SphygmoCor and two newer devices, the Arteriograph and Omron HEM-9000

International audienceThe objective of this study was to compare central systolic blood pressure (cSBP) and augmentation index (AIx) from two recently introduced devices, Omron HEM-9000 (OM) and Arteriograph (AG), not using a transfer function with those of the widely used SphygmoCor (SC) calibrated on brachial blood pressure like OM. Random-order manufacturer-recommended measurements using SC and OM by radial tonometry and AG were taken on the left arm in 35 men (54±10 years) after 5 min supine rest. Results are means (95% confidence interval) of differences using paired t-tests. cSBP by OM was 4.1 (1.0-7.1) mm Hg higher than by AG. Both OM and AG estimated the mean cSBP to be significantly higher than did SC (114.8 mm Hg) by 12.5 (10.3-14.7) and 8.6 (4.9-12.3) mm Hg, respectively, although closely correlating with SC (r¼0.9). Calibrating SC with diastolic blood pressure (DBP) and more accurate mean arterial pressure (as DBP+0.4ÂPP) resulted in significantly higher cSBP statistically not different from AG's cSBP: 0.9 (À1.1 to +2.9)mm Hg, and closer to OM's: 5.1 (3.4-6.8)mm Hg. Radial AIx from SC and OM disagreed by 3 (0.7-5.4)%, and correlated (r¼0.8) with AG's brachial AIx. AG's aortic AIx was 7.9 (5.7-10.2)% higher than SC's, but closely correlated (r¼0.9). Clinically significant, higher cSBP measured by AG, OM and more accurately calibrated SC adds to previous data suggesting that SC measurements by classic calibration underestimate cSBP. Invasive studies involving all three devices would be more illuminating