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Aortic pressure wave reconstruction during exercise is improved by adaptive filtering: a pilot study.

Stok WJ, Westerhof BE, Guelen I, Karemaker JM - Med Biol Eng Comput (2011)

Bottom Line: The optimal resonance frequency was predicted from regression formulas using variables derived from the individual's peripheral pressure pulse, including a pulse contour estimation of cardiac output (pcCO).Using a genTF and without calibration, the error in estimated aortic pulse pressure was -7.5 ± 6.4 mmHg, which was reduced to 0.2 ± 5.7 mmHg with the indTFs using pcCO for prediction.Calibration resulted in less scatter at the cost of a small bias (2.7 mmHg).

View Article: PubMed Central - PubMed

Affiliation: Heart Failure Research Centre, Academic Medical Center, University of Amsterdam, Room M01-215, Meibergdreef 9, NL-1105 AZ, Amsterdam, The Netherlands. w.stok@amc.uva.nl

ABSTRACT
Reconstruction of central aortic pressure from a peripheral measurement by a generalized transfer function (genTF) works well at rest and mild exercise at lower heart rates, but becomes less accurate during heavy exercise. Particularly, systolic and pulse pressure estimations deteriorate, thereby underestimating central pressure. We tested individualization of the TF (indTF) by adapting its resonance frequency at the various levels of exercise. In seven males (age 44-57) with coronary artery disease, central and peripheral pressures were measured simultaneously. The optimal resonance frequency was predicted from regression formulas using variables derived from the individual's peripheral pressure pulse, including a pulse contour estimation of cardiac output (pcCO). In addition, reconstructed pressures were calibrated to central mean and diastolic pressure at each exercise level. Using a genTF and without calibration, the error in estimated aortic pulse pressure was -7.5 ± 6.4 mmHg, which was reduced to 0.2 ± 5.7 mmHg with the indTFs using pcCO for prediction. Calibration resulted in less scatter at the cost of a small bias (2.7 mmHg). In exercise, the indTFs predict systolic and pulse pressure better than the genTF. This pilot study shows that it is possible to individualize the peripheral to aortic pressure transfer function, thereby improving accuracy in central blood pressure assessment during exercise.

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Related in: MedlinePlus

Relation between resonance frequencies (Fpeak) during rest and exercise and pulse contour cardiac output (pcCO) calculated from the finger pressure wave
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Fig2: Relation between resonance frequencies (Fpeak) during rest and exercise and pulse contour cardiac output (pcCO) calculated from the finger pressure wave

Mentions: Regression analysis showed that pulse contour-derived CO [10, 23] (pcCO) as single parameter had the highest correlation with Fpeak (Fig. 2). The regression formula used to predict the Fpeak in the TF from pcCO was:1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{Fpeak}} = 0.32*{\text{pcCO}} + 2.68. $$\end{document}Fig. 2


Aortic pressure wave reconstruction during exercise is improved by adaptive filtering: a pilot study.

Stok WJ, Westerhof BE, Guelen I, Karemaker JM - Med Biol Eng Comput (2011)

Relation between resonance frequencies (Fpeak) during rest and exercise and pulse contour cardiac output (pcCO) calculated from the finger pressure wave
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3139898&req=5

Fig2: Relation between resonance frequencies (Fpeak) during rest and exercise and pulse contour cardiac output (pcCO) calculated from the finger pressure wave
Mentions: Regression analysis showed that pulse contour-derived CO [10, 23] (pcCO) as single parameter had the highest correlation with Fpeak (Fig. 2). The regression formula used to predict the Fpeak in the TF from pcCO was:1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{Fpeak}} = 0.32*{\text{pcCO}} + 2.68. $$\end{document}Fig. 2

Bottom Line: The optimal resonance frequency was predicted from regression formulas using variables derived from the individual's peripheral pressure pulse, including a pulse contour estimation of cardiac output (pcCO).Using a genTF and without calibration, the error in estimated aortic pulse pressure was -7.5 ± 6.4 mmHg, which was reduced to 0.2 ± 5.7 mmHg with the indTFs using pcCO for prediction.Calibration resulted in less scatter at the cost of a small bias (2.7 mmHg).

View Article: PubMed Central - PubMed

Affiliation: Heart Failure Research Centre, Academic Medical Center, University of Amsterdam, Room M01-215, Meibergdreef 9, NL-1105 AZ, Amsterdam, The Netherlands. w.stok@amc.uva.nl

ABSTRACT
Reconstruction of central aortic pressure from a peripheral measurement by a generalized transfer function (genTF) works well at rest and mild exercise at lower heart rates, but becomes less accurate during heavy exercise. Particularly, systolic and pulse pressure estimations deteriorate, thereby underestimating central pressure. We tested individualization of the TF (indTF) by adapting its resonance frequency at the various levels of exercise. In seven males (age 44-57) with coronary artery disease, central and peripheral pressures were measured simultaneously. The optimal resonance frequency was predicted from regression formulas using variables derived from the individual's peripheral pressure pulse, including a pulse contour estimation of cardiac output (pcCO). In addition, reconstructed pressures were calibrated to central mean and diastolic pressure at each exercise level. Using a genTF and without calibration, the error in estimated aortic pulse pressure was -7.5 ± 6.4 mmHg, which was reduced to 0.2 ± 5.7 mmHg with the indTFs using pcCO for prediction. Calibration resulted in less scatter at the cost of a small bias (2.7 mmHg). In exercise, the indTFs predict systolic and pulse pressure better than the genTF. This pilot study shows that it is possible to individualize the peripheral to aortic pressure transfer function, thereby improving accuracy in central blood pressure assessment during exercise.

Show MeSH
Related in: MedlinePlus