Non-invasive 24 hour ambulatory monitoring of aortic wave reflection and arterial stiffness by a novel oscillometric device: the first feasibility and reproducibility study.

BACKGROUND: Surrogates of aortic wave reflection and arterial stiffness, such as augmentation index (AIx), augmentation pressure, pulse wave velocity (PWV) and pulse pressure amplification (PPampl) are independent predictors of cardiovascular risk. A novel ambulatory, brachial cuff-based oscillometric device has been recently developed and validated, yielding 24-h assessment of the aforementioned parameters (Mobilo-O-Graph). Aim of this study was to investigate the feasibility and reproducibility of wave reflection and arterial stiffness estimation by pulse wave analysis using this device. METHODS: Thirty treated or untreated hypertensives (mean age: 53.6 ± 11.6 years, 17 men) had test-retest 24-h monitoring one week apart using the test device. RESULTS: Mean numbers of valid aortic readings per subject, between test and retest, were comparable. Approximately 12 aortic readings per subject (17%) were not feasible or valid. No differences were observed for any 24-h parameter between the two assessments. Bland-Altman plots showed no systemic difference, while the limits of agreement for each parameter indicated high reproducibility (AIx: -7.2 to 8.2%, AP: -3.7 to 4.1mm Hg, PWV: -0.39 to 0.41 m/s, PPampl: -0.08 to 0.06). This was further verified by intraclass correlation coefficients which were >0.8 for each parameter. CONCLUSIONS: Non-invasive 24-h estimation of wave reflection and arterial stiffness indices, derived by the test device, appear to be highly reproducible. Future studies should investigate whether these measurements have additive prognostic value for cardiovascular risk stratification, beyond common brachial blood pressure measurements or single estimations of wave reflection and PWV at office settings.

Feasibility and reproducibility of noninvasive 24-h ambulatory aortic blood pressure monitoring with a brachial cuff-based oscillometric device.

BACKGROUND: Accumulating evidence suggests the potential superiority of office aortic blood pressure (BP) over brachial in the management of arterial hypertension. The noninvasive aortic 24-h ambulatory brachial BP monitoring (ABPM) is potentially the optimal method for assessing BP profile. The objective of the present study was to investigate the feasibility and reproducibility to perform noninvasively 24-h aortic ABPM with a novel validated brachial cuff-based automatic oscillometric device (Mobilo-O-Graph) which records brachial BP and waveforms and assesses aortic BP via mathematical transformation. METHODS: Thirty consecutive subjects (mean age: 53.6 ± 11.6 years, 17 men) had a test-retest ABPM with at least 1-week interval. No modification of vasoactive drug treatment during the interval was allowed while similar 24-h activity during both recording days was recommended. RESULTS: The average number of valid readings for brachial vs. aortic BP were 69.9 ± 10.4 vs. 58.0 ± 13.3 in the initial 24-h assessment (P < 0.001) and 68.3 ± 10.8 vs. 56.4 ± 13.6 in the repeat assessment (P < 0.001). No differences in average 24 h aortic BP values were observed between the two assessments (systolic blood pressure (SBP) 115.9 ± 7.7 vs. 115.1 ± 6.0 mm Hg, respectively, P = 0.48, and diastolic 79.7 ± 7.4 vs. 79.2 ± 8.7, P = 0.54). Reproducibility indices of aortic pressure including, intraclass coefficient of variation (SBP: 0.80 (95% confidence interval 0.58-0.90); diastolic: 0.92 (0.83-0.96)) and s.d. of differences (SBP/diastolic: 6.0/4.5 mm Hg) indicated acceptable reproducibility. The Bland-Altman plots indicated no evidence of systemic bias. CONCLUSIONS: In conclusion, these data suggest that noninvasive 24-h ABPM is feasible and provides reproducible values. Future studies should validate the prognostic ability of 24-h aortic hemodynamics.