Quantification of the Calibration Error in the Transfer Function-Derived Central Aortic Blood Pressures

Shih, Yuan Ta; Cheng, Hao Min; Sung, Shih Hsien; Hu, Wei

doi:10.1038/ajh.2011.146

Cited by 69 publications

(58 citation statements)

References 25 publications

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“…Similarly to aSBP, the between-method-difference of 4.6 mm Hg in aPP assessment is similar in extent with the relevant difference in bPP. These differences are in line with the results of experiments comparing different BP measuring techniques with invasive recordings, which showed that noninvasive application of generalized transfer function produces estimates of aSBP and aPP with errors similar to those inserted by oscillometric estimation of invasive bSBP and bPP [28]. It should be noted, however, that this significant difference in aPP measurements between the two devices, may suggest that they are not interchangeable in assessing this parameter, which was previously shown to be an important risk factor in ESRD patients [13].…”

Section: Discussionsupporting

confidence: 75%

Evaluation of a Novel Brachial Cuff-Based Oscillometric Method for Estimating Central Systolic Pressure in Hemodialysis Patients

et al. 2014

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Background/Aims: Elevated wave reflections and arterial stiffness, as well as ambulatory blood pressure (BP) are independent predictors of cardiovascular risk in end-stage-renal-disease. This study is the first to evaluate in hemodialysis patients the validity of a new ambulatory oscillometric device (Mobil-O-Graph, IEM, Germany), which estimates aortic BP, augmentation index (AIx) and pulse wave velocity (PWV). Methods: Aortic SBP (aSBP), heart rate-adjusted AIx (AIx(75)) and PWV measured with Mobil-O-Graph were compared with the values from the most widely used tonometric device (Sphygmocor, ArtCor, Australia) in 73 hemodialysispatients. Measurements were made in a randomized order after 10 min of rest in the supine position at least 30 min before a dialysis session. Brachial BP (mercury sphygmomanometer) was used for the calibration of Sphygmocor's waveform. Results: Sphygmocor-derivedaSBP and AIx(75) did not differ from the relevant Mobil-O-Graph measurements (aSBP: 136.3 ± 19.6 vs. 133.5 ± 19.3 mm Hg, p = 0.068; AIx(75): 28.4 ± 9.3 vs. 30.0 ± 11.8%, p = 0.229). The small difference in aSBP is perhaps explained by a relevant difference in brachial SBP used for calibration (146.9 ± 20.4 vs. 145.2 ± 19.9 mm Hg, p = 0.341). Sphygmocor PWV was higher than Mobil-O-Graph PWV (10.3 ± 3.4 vs. 9.5 ± 2.1 m/s, p < 0.01). All 3 parameters estimated by Mobil-O-Graph showed highly significant (p < 0.001) correlations with the relevant measurements of Sphygmocor (aSBP, r = 0.770; AIx(75), r = 0.400; PWV, r = 0.739). The Bland-Altman Plots for aSBP and AIx(75) showed acceptable agreement between the two devices and no evidence of systemic bias for PWV. Conclusion: As in other populations, acceptable agreement between Mobil-O-Graph and Sphygmocor was evident for aSBP and AIx(75) in hemodialysis patients; PWV was slightly underestimated by Mobil-O-Graph.

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Section: Discussionsupporting

confidence: 75%

Evaluation of a Novel Brachial Cuff-Based Oscillometric Method for Estimating Central Systolic Pressure in Hemodialysis Patients

et al. 2014

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“…Furthermore, modelderived central systolic pressures result to be generally lower than the SphygmoCor estimations, while diastolic values are higher. Notice that if the SphygmoCor estimations were adjusted to include the bias arising from its non-invasive calibration [6,7], the errors of the mathematical model would become very small: the mean difference would be equal to 0.4 mmHg for the systolic blood pressure and 4.4 mmHg for the diastolic ones. However, such a bias correction has to be considered as a speculation, as we have no data confirming that errors affecting our central pressure estimations obtained with the SphygmoCor exhibit the same mean value (i.e., the bias) measured in the large scale tests [6,7].…”

Section: Discussionmentioning

confidence: 99%

P5.4 Central Pressure Appraisal: Clinical Validation of a Subject-Specific Mathematical Model

Tosello¹,

Guala²,

Leone³

et al. 2015

ARTRES

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“…The major source of error of such disappointing results may primarily arise from inaccurate cuff BP values used for calibration, as discussed in our previous study. 27 Further studies should be performed to investigate and quantify the effects of calibration errors on different methods for estimating SBP-C and central aortic pulse pressure.…”

Section: Discussionmentioning

confidence: 99%

“…Similar to other noninvasive methods, the major source of errors arises from the decreased accuracy of sphygmomanometer-measured brachial BP. 27 The improvement in the measurement accuracy of brachial BP by automatic BP monitors would be beneficial for risk assessment not only in current management of hypertension, but also in the clinical application of central BP concepts in the near future.In a previous study that tested the validity of 2 noninvasive SBP-C measurement devices, 28 large systematic bias and …”

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confidence: 99%

Application of the N-Point Moving Average Method for Brachial Pressure Waveform–Derived Estimation of Central Aortic Systolic Pressure

Shih

Cheng²,

Sung³

et al. 2014

Hypertension

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A lthough noninvasive blood pressure (BP) measured in the brachial artery (cuff BP) represents the basis for the present management of hypertension, 1-3 it has long been recognized that waveform morphology [4][5][6][7][8][9][10] differ considerably between the central aorta and peripheral arterial system. These discernible differences vary among individuals because of variable timing and amplitude of arterial wave reflections.11 More importantly, central systolic and pulse pressure (CBP) may predict cardiovascular outcomes more accurately than cuff BP. 12,13 The clinical application of CBP has been made possible by the advances in computational science and biomedical engineering. Noninvasive CBP is obtained using either tonometry-based 5,14,15 or, more conveniently, cuff-based techniques. [16][17][18] Recently, the capability of the N-point moving average (NPMA) method to estimate central aortic systolic BP (SBP-C) was demonstrated. 19 Using a common denominator related to the sampling frequency, the NPMA is a mathematical low-pass filter that is frequently used in the engineering field for removing random noise from a time series. The high-frequency components, resulting primarily from arterial wave reflections, 20 cause substantial transformations from central to peripheral aortic pressure waveforms and can be eliminated by the application of the NPMA. 19 Applied on radial artery pressure waveforms obtained using arterial tonometry, the NPMA method with a common denominator of 4 (one quarter of the acquisition sampling frequency) has been shown to define SBP-C accurately. 19 However, tonometry-based methods for estimating SBP-C are limited by the requirements of a sophisticated tonometric device and a certain level of operator skill. A cuff-based technique using the NPMA method would likely be more welcomed in clinical practice given the confirmation of its accuracy in measurement. In other words, this See Editorial Commentary, pp 665-667Abstract-The N-point moving average (NPMA) is a mathematical low-pass filter that can smooth peaked noninvasively acquired radial pressure waveforms to estimate central aortic systolic pressure using a common denominator of N/4 (where N=the acquisition sampling frequency). The present study investigated whether the NPMA method can be applied to brachial pressure waveforms. In the derivation group, simultaneously recorded invasive high-fidelity brachial and central aortic pressure waveforms from 40 subjects were analyzed to identify the best common denominator. In the validation group, the NPMA method with the obtained common denominator was applied on noninvasive brachial pressure waveforms of 100 subjects. Validity was tested by comparing the noninvasive with the simultaneously recorded invasive central aortic systolic pressure. Noninvasive brachial pressure waveforms were calibrated to the cuff systolic and diastolic blood pressures. In the derivation study, an optimal denominator of N/6 was identified for NPMA to derive central aortic systolic pressure. The mean difference ...

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Quantification of the Calibration Error in the Transfer Function-Derived Central Aortic Blood Pressures

Cited by 69 publications

References 25 publications

Evaluation of a Novel Brachial Cuff-Based Oscillometric Method for Estimating Central Systolic Pressure in Hemodialysis Patients

Evaluation of a Novel Brachial Cuff-Based Oscillometric Method for Estimating Central Systolic Pressure in Hemodialysis Patients

P5.4 Central Pressure Appraisal: Clinical Validation of a Subject-Specific Mathematical Model

Application of the N-Point Moving Average Method for Brachial Pressure Waveform–Derived Estimation of Central Aortic Systolic Pressure

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